First network node, second network node, communications system and methods performed thereby for handling measurement of a delay

Abstract

A computer-implemented method, performed by a first network node (111) operating in a core network (101) of a communications system (100). The first network node (111) sends (404), to a second network node (112) operating in the core network (101), an indication. The indication indicates to measure a delay in a flow of data having a first QoS, between the second network node (112) and a communication device (130). The indication indicates to measure the delay by sending a first packet to the communication device (130), from a first IP address to be allocated by the second network node (112) and receiving, by the second network node (112) on the first IP address, a second packet in response to the first packet from the communication device (130). The first network node (111) receives (405) another indication from the second network node (112) indicating a response to the indication sent. Publ.

Description

[0001] FIRST NETWORK NODE, SECOND NETWORK NODE, COMMUNICATIONS SYSTEM AND

[0002] METHODS PERFORMED THEREBY FOR HANDLING MEASUREMENT OF A DELAY

[0003] TECHNICAL FIELD

[0004] The present disclosure relates generally to a first network node and methods performed thereby for handling measurement of a delay. The present disclosure also relates generally to a second network node, and methods performed thereby for handling the measurement of the delay. The present disclosure also relates generally to a communications system, and methods performed thereby for handling measurement of the delay. The present disclosure also relates generally to computer programs and a computer-readable storage mediums, having stored thereon the computer programs to carry out these methods.

[0005] BACKGROUND

[0006] Computer systems in a communications network or communications system may comprise one or more network nodes. A network node may comprise a processing circuitry which, together with computer program code may perform different functions and actions, a memory, a receiving port, and a sending port. A network node may be, for example, a server. Network nodes may perform their functions entirely on the cloud.

[0007] The communications system may cover a geographical area which may be divided into cell areas, each cell area being served by a type of network node, a network node in the Radio Access Network (RAN), radio network node or Transmission Point (TP), for example, an access node such as a Base Station (BS), e.g., a Radio Base Station (RBS), which sometimes may be referred to as e.g., gNB, evolved Node B (“eNB”), “eNodeB”, “NodeB”, “B node”, or Base Transceiver Station (BTS), depending on the technology and terminology used. The base stations may be of different classes such as e.g., Wide Area Base Stations, Medium Range Base Stations, Local Area Base Stations, and Home Base Stations, based on transmission power and thereby also cell size. A cell may be understood to be the geographical area where radio coverage may be provided by the base station at a base station site. One base station, situated on the base station site, may serve one or several cells. Further, each base station may support one or several communication technologies. The telecommunications network may also comprise network nodes which may serve receiving nodes, such as user equipments, with serving beams.

[0008] The standardization organization Third Generation Partnership Project (3GPP) is currently in the process of specifying a New Radio Interface called Next Generation Radio or New Radio (NR) or 5G-Universal Terrestrial Radio Access (UTRA), as well as a Fifth Generation (5G) Packet Core Network, which may be referred to as 5G Core Network (5GC), abbreviated as 5GC.

[0009] Figure 1 is a schematic diagram depicting a particular example of a 5G system architecture of a policy and charging control framework, as defined by 3GPP, which may be used as a reference for the present disclosure. An Application Function (AF) 1 may provide a service in the communications system and may interact with the 3GPP Core Network through a Network Exposure Function (NEF) 2. The AF 1 may allow external parties to use the Exposure Application Programming Interfaces (APIs) offered by the network operator. In case the AF 1 is trusted, e.g., internal to the network operator, the AF 1 may interact with the 3GPP Core Network directly, with no NEF 2 involved. The NEF 2 may support different functionality. Specifically, the NEF 2 may support different Exposure APIs. A Session Management Function (SMF) 3 may support different functionalities. The SMF 3 may be understood to be in charge of Session Management e.g., Protocol Data Unit (PDU) Session Establishment, modification and release, including setting up and maintaining the tunnel between User Plane function (UPF) 4 and Access Network (AN) node. The SMF 3 may receive Policy and Charging Control (PCC) rules from a Policy Control Function (PCF) 5 and may configure the UPF 4 accordingly using Packet Detection Rules (PDRs) and other rules associated with Quality of Service (QoS), forwarding or reporting instructions among others. Based on the PCC Rules, the SMF 3 may determine which QoS Flows may need to be established between the User Equipment (UE) and the UPF 5 and may instruct the UE, and the AN, via an Access and Mobility Function (AMF) 6, and the UPF 4 accordingly. The PCF 5 may support a unified policy framework to govern the network behavior. Specifically, the PCF 5 may manage the QoS framework by providing PCC rules to the SMF 3 with Flow filters and the associated QoS marking. The UPF 4 may support handling of user plane traffic based on the rules received from the SMF 3, e.g., packet inspection and different enforcement actions such as Sponsored Data or QoS handling. A Unified Data Repository (UDR) 7 may store data, grouped into distinct collections of subscription-related information: subscription data, policy data, structured data for exposure, and application data. A Charging Function (CHF) 8 may support charging related functionality, specifically online and offline charging. The PCF 5 may provide policy rules to a User Equipment (UE) through the AMF 6. The AMF 6 may support different functionality, e.g. Termination of Non-Access Stratum (NAS) signalling, NAS ciphering and integrity protection, registration management, connection management, mobility management, access authentication and authorization, and security context management. Particularly relevant for this disclosure, the AMF 6 may be used to convey information from / to the UE through NAS signaling, including the UE Policies provided by the PCF 5. A Network Data Analytics Function (NWDAF) 9 may be understood to represent an operator managed network analytics logical function. The NWDAF 9 may be part of the 5GC architecture and may use the mechanisms and interfaces specified for 5GC and Operations, Administration and Maintenance (OAM). Each of the UDR 7, the NEF 2, the NWDAF 9, the AF 1 , the PCF 5, the CHF 8, the AMF 6, the SMF 3 and the UPF 4 may have an interface through which they may be accessed, which as depicted in the Figure, may be, respectively: Nudr 10, Nnef 11 , Nnwdaf 12, Naf 13, Npcf 14, Nchf 15, Namf 16, Nsmf 17 and N4 18.

[0010] QoS Rules

[0011] Quality of Service (QoS) may be understood as an in indicator of a performance of a network as experienced by a device, such as a UE, of an end user. QoS may take several different aspects into consideration, such as packet loss, bit rate, burstiness, transmission delay, and jitter. QoS may be understood to be based on QoS Flows. Each QoS flow may be understood to have a unique identifier called QoS Flow Identifier (QFI).

[0012] The QoS Flow may be understood to be the finest granularity of QoS differentiation in a PDU Session. User Plane (UP) traffic with the same QFI may receive the same forwarding treatment. Rules in UE and AN may be understood to map QoS flows to Data Radio Bearers (DRBs). Every QoS flow may be understood to have a QoS profile that may include QoS parameters and QoS characteristics. QoS parameters may be understood as for example, 5G QoS Identifier (5QI), priority, bit rate, packet delay budget, packet error rate, maximum data burst volume, and averaging window. QoS characteristics may be understood as for example, packet loss, bit rate, burstiness, transmission delay, and jitter.

[0013] 5GC networks may use the QoS framework to associate data flows with their corresponding QoS flow by marking a packet with the selected QFI. The PCF may command the QoS framework by installing PCC rules on the SMF. The rules may contain Service Data Flow (SDF) filters and the corresponding QoS requirements. The SMF may decide then which QoS flow to use for that traffic, e.g., the applicable QFI marking. The SMF may then provide to the UPF and the UE the corresponding marking rules for the traffic and QoS properties for the QoS Flow.

[0014] Internet Control Message Protocol (ICMP)

[0015] The Internet Control Message Protocol (ICMP) may be understood as a network layer protocol used by network devices to diagnose network communication issues. It may be understood to be mainly used by network devices, such as routers, to send error messages and operational information indicating success or failure when communicating with another Internet Protocol (IP) address. In addition, ICMP may be used to determine whether or not data may be reaching its intended destination, and if reachable, it may also be possible to determine the delay, one way or round trip. ICMP may be understood to use the basic support of IP as if it were a higher level protocol, however, ICMP may be understood to be an integral part of IP, and may be understood to have to be implemented by every IP module. ICMP may be understood to be specified by the Internet Engineering Task Force (IETF)

[0016] [3][4],

[0017] Up until now, no method to characterize the QoS flow compliance to QoS characteristics has been widely deployed. Existing methods to characterize such compliance may be complex, with implications in devices and networks nodes. Moreover, existing methods to characterize the QoS flow compliance to QoS characteristics may not always be applicable and, under certain circumstances, provide erroneous values.

[0018] SUMMARY

[0019] According to the foregoing, it may be understood to be an object of embodiments herein to simplify and improve the reliability of methods to characterize the QoS flow compliance.

[0020] Particularly, it is an object of embodiments herein to improve the handling measurement of a delay in a communications system.

[0021] According to a first aspect of embodiments herein, the object is achieved by a computer- implemented method, performed by a first network node. The method is for handling measurement of a delay. The first network node operates in a core network of a communications system. The first network node sends, to a second network node operating in the core network of the communication system, an indication. The indication indicates to measure the delay in a flow of data having a first QoS, between the second network node and a communication device. The indication indicates to measure the delay by sending a first packet to the communication device, from a first IP address to be allocated by the second network node and receiving, by the second network node on the first IP address, a second packet in response to the first packet from the communication device. The communications device communicates via the communications system. The first network node also receives another indication from the second network node. The another indication indicates a response to the indication sent by the first network node.

[0022] According to a second aspect of embodiments herein, the object is achieved by a computer-implemented method, performed by the second network node. The method is for handling the measurement of the delay. The second network node operates in the core network of the communications system. The second network node receives, from the first network node operating in the core network of the communication system, the indication. The indication indicates to measure the delay in the flow of data having the first QoS, between the second network node and the communication device. The indication indicates to measure the delay by sending the first packet to the communication device, from the first IP address to be allocated by the second network node and receiving, by the second network node on the first IP address, the second packet in response to the first packet from the communication device. The communications device communicates via the communications system. The second network node sends the another indication to the first network node. The another indication indicates the response to the indication received from the first network node. The first network node is also configured to receive the another indication from the second network node. The another indication is configured to indicate the response to the indication configured to be sent by the first network node.

[0023] According to a third aspect of embodiments herein, the object is achieved by the first network node, for handling the measurement of the delay. The first network node is configured to operate in the core network of the communications system. The first network node is configured to send, to the second network node configured to operate in the core network of the communication system, the indication to measure the delay in the flow of data configured to have the first QoS between the second network node and the communication device. The indication is configured to indicate the second network node is to measure the delay by sending the first packet to the communication device, from the first IP address to be allocated by the second network node and receiving, by the second network node on the first IP address, the second packet in response to the first packet from the communication device. The communications device is configured to communicate via the communications system.

[0024] According to a fourth aspect of embodiments herein, the object is achieved by the second network node, for handling the measurement of the delay. The second network node is configured to operate in the core network of the communications system. The second network node is configured to receive, from the first network node configured to operate in the core network of the communication system, the indication. The indication is configured to indicate to measure the delay in the flow of data configured to have the first QoS between the second network node and the communication device. The indication is configured to indicate to measure the delay by sending the first packet to the communication device, from the first IP address to be allocated by the second network node and receiving, by the second network node on the first IP address, the second packet in response to the first packet from the communication device. The communications device is configured to communicate via the communications system. The second network node is also configured to send the another indication to the first network node. The another indication is configured to indicate the response to the indication configured to be received from the first network node.

[0025] According to a fifth aspect of embodiments herein, the object is achieved by the communications system, for handling the measurement of the delay. The communications system is configured to comprise one or more of: the first network node and the second network node.

[0026] According to a sixth aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processing circuitry of the first network node, cause the first network node to carry out the method performed by the first network node.

[0027] According to a seventh aspect of embodiments herein, the object is achieved by a computer-readable storage medium, having stored thereon the computer program, comprising instructions which, when executed on at least one processing circuitry of the first network node, cause the first network node to carry out the method performed by the first network node.

[0028] According to an eighth aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processing circuitry of the second network node, cause the second network node to carry out the method performed by the second network node.

[0029] According to a ninth aspect of embodiments herein, the object is achieved by a computer-readable storage medium, having stored thereon the computer program, comprising instructions which, when executed on at least one processing circuitry of the second network node, cause the second network node to carry out the method performed by the second network node.

[0030] By sending the indication to measure the delay by sending the first packet to the communication device, from the first IP address to be allocated by the second network node and receiving, by the second network node on the first IP address, the second packet in response to the first packet from the communication device, the first network node may enable the second network node to then measure the delay between the communications device and the second network node in an easy and reliable way wherein the delay may be measured with dedicated packets, that is, packets that may be sent and received as instructed by the first network node, and which thereby may not need to be dependent on other packets being sent or received in order to perform the measurement. This may enable to avoid a risk that there may be no suitable UL or DL packets being sent when the measurements may need to be performed. Furthermore, by instructing the second network node to allocate the IP address, the second network node may ensure that the second packet in response to the first packet is then received at the allocated first IP address. This may be understood to advantageously ensure that the second packet may be received successfully at the second network node, e.g., by the correct NF instance, by ensuring that the second packet may not be blocked, dropped or redirected to another network node due to traffic-routing or security policies. Internally the second network node may accept the response in the first IP allocated. This may further be based, for example, on an ICMP ping ID.

[0031] Furthermore, the first network node may be enabled to, in some examples, later receive a report of the allocated first IP address from the second network node, so that the first network node may subsequently be enabled to indicate to the communications device which QoS flow the second packet may need to be sent on by indicating the first IP address allocated by the second network node, e.g., by constructing a QoS Rule.

[0032] A further advantage may be understood to be that the advantages just described may be achieved while having less impacts than, e.g., the standardized QoS monitoring function on 3GPP. Embodiments herein may be understood to be able to be implemented “out of the box” with the communication device.

[0033] Furthermore, the advantages just described may be achieved with non-3GPP access.

[0034] By receiving the another indication from the second network node, the first network node may ensure that the indication may have been successfully received by the first network node and therefore that the second network node may be understood to have received the instructions provided by the first network node in the indication sent.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Examples of embodiments herein are described in more detail with reference to the accompanying drawings, according to the following description.

[0037] Figure 1 is a schematic diagram illustrating an example of a 5G Network Architecture, according to existing methods.

[0038] Figure 2 is a schematic diagram illustrating monitoring on two QoS Flows to determine Round- Trip Time (RTT) of asymmetric data flows, according to existing methods.

[0039] Figure 3a and Figure 3b show each a schematic diagram illustrating a non-limiting example of a communications system, according to embodiments herein.

[0040] Figure 4 is a flowchart depicting embodiments of a method in a first network node, according to embodiments herein.

[0041] Figure 5 is a flowchart depicting embodiments of a method in a second network node, according to embodiments herein.

[0042] Figure 6a and Figure 6b show each a schematic diagram depicting a non-limiting example of a method performed by a second network node, according to embodiments herein.

[0043] Figure 7a and Figure 7b are a signalling diagram depicting a non-limiting example of a method in a communications system, according to embodiments herein. The signalling diagram of Figure 7a is continued on Figure 7b.

[0044] Figure 8 is a schematic block diagram illustrating two non-limiting examples, a) and b), of a first network node, according to embodiments herein.

[0045] Figure 9 is a schematic block diagram illustrating two non-limiting examples, a) and b), of a second network node, according to embodiments herein. DETAILED DESCRIPTION

[0046] As part of the development of embodiments herein, one or more challenges with the existing technology will first be identified and discussed.

[0047] As stated earlier, up until now, no reliable method to characterize the QoS flow compliance to QoS characteristics has been implemented. Although a method has been standardized in 3GPP, known as Per QoS Flow Per UE QoS Monitoring in 3GPP, it has not been widely implemented and deployed as it is complex and it has significant impacts in several Network Functions (NFs). According to Per QoS Flow Per UE QoS Monitoring in 3GPP, the delay between a UE and RAN may be measured separately, and then the delay between UPF and RAN may be measured separately.

[0048] The measurements may be performed by attaching additional data to packets that may be being forwarded between the UPF and the UE. This may be understood to mean that there are no dedicated packets used to perform the measurements.

[0049] In the measurement between the UPF and RAN, a timestamp may be taken when a DL packet may be sent, and sent as metadata together with the packet. In a later UL packet, RAN may include the original timestamp, a timestamp of when the DL packet was received, and a timestamp of when the UL packet was sent. That may however only provide measurements between UPF and RAN. Therefore, in addition, the RAN may include the UL and DL delay to the UE. This may be understood to mean that the SMF may be required to instruct the RAN to perform the QoS measurements, which may be understood to mean that all the customer RAN nodes may need to support this. It may be understood to also mean that when the UE may move to the coverage of another RAN node, some work may be needed to inform the new RAN node that QoS measurements may need to be done, adding complexity to the procedure. In addition, since no dedicated packets are used, there is a risk that there is may be no suitable UL or DL packets being sent when the measurements may need to be performed.

[0050] State of the art methods try to characterize the QoS tunnels of the PDU Sessions by calculating the RTT of Transmission Control Protocol (TCP) flows based on the reception of an Acknowledgement (ACK) for the messages that may have been sent. However, this method only works for TCP flows, not for User Datagram Protocol (UDP) or Quick UDP Internet Connections (QUIC) flows, which represent the gross of the total traffic. The reason may be understood to be that acknowledgements may understood to not be visible, or available, in those transport protocols.

[0051] Other methods may be designed using ping, also known as ICMP ping, generation from the UPF to the UE. An ICMP ping may be understood as a request from one network node to another network node, requesting it to, e.g., immediately, send a response, to check if there may be network connectivity between the two network nodes. In addition, ICMP ping may be used to measure a delay when sending packets between the two network nodes. ICMP echo may be understood to deliver RTT measures. That is, measures that are not specific Uplink (UL) and Downlink (DL) measures. Consequently, values derived from existing methods based on ICMP ping cannot be trusted when the traffic is sent on the PDU session over two QoS flows, e.g., when traffic may have different QoS requirements for UL and DL, a.k.a. asymmetric data flows. In such cases, the UPF may decide the QoS Flow for the DL, and the UE for the UL. If it does not have explicit filters for the ping traffic, the Ping reply will be sent on the QoS Flow for the default rule. The default rule may be understood to be a rule that may be used to decide what QoS flow to use for packets when no other filters may match the packet. By default, packets may be understood to go on the QoS flow indicated by the default rule, unless some other rule may specify otherwise. Or, if the UPF marks the packet as reflective, the UE may send an ICMP ping reply in the same QoS Flow it came from. In both cases, the ICMP Ping and / or reply may not use the same QoS Flows than the data traffic for which the delay may be desired to be measured, and the RTT measured is therefore not correct.

[0052] As an alternative, two ICMP Ping may be sent, one on each of the two QoS Flows, and the received may try to estimate the RTT, for example, as an addition of1X RTT measured on each of the QoS Flows. However, this may be far from reality unless the QoS Flow properties for UL and DL are the same, or both QoS flows have the same QoS properties. Figure 2a is a schematic diagram illustrating monitoring on two QoS Flows to determine RTT of asymmetric data flows, according to existing methods. Depicted in Figure 2a is a first data flow 21 from a UPF 22 to a UE 23, and an a second data flow 24 from the UE 23 to the UPF 22. The first data flow 21 is in one QoS Flow 25, whereas the second data flow 24 is in another QoS Flow 26. The QoS Flow 25 carrying the first data flow 21 has a delay of A in the DL and a delay of B in the UL, with and RTT of A+B, and the another QoS Flow 26 carrying the second data flow 24 has a delay of X in the DL and a delay of Y in the UL, with an RTT of X+Y. Accordingly, the RTT for the data flow is the sum of A+Y.

[0053] Figure 2b depicts the same scenario as in Figure 2a, except that in Figure 2a, there are two symmetrical data flows: a third data flow 27 between the UPF 22 and the UE 23, and a fourth data flow 28 between the UE 23 and the UPF 22. The third data flow 27 is the one QoS Flow 25, whereas the fourth data flow 28 is in the another QoS Flow 26. The third data flow 27 has an RTT of A+B, and the fourth data flow 28 has an RTT of X+Y.

[0054] Similarly, the second flow 24 has a third delay X in the DL direction and a second delay Y in the UL direction, and therefore the RTT for the second flow 24 in the second flow 24 is the sum of X+Y. When two ICMP Ping may be sent, one on each of the two QoS Flows, the estimated RTT (sRTT) according to the alternative just described, may be calculated as the sum of all the delays, X+Y +A+B, divided by 2. However, the experienced RTT (xRTT) in reality may be understood to be A for the ping sent in the DL and b for the ping sent in the UL. When the DL delay and the UL delay is the same for both flows, that is when A=B and X=Y, the estimated RTT may be understood to be the same as the experienced RTT. Similarly, if the DL delay is the same for both flows, that is when A= X, and the UL delay is the same for both flows, that is when and B=Y, the estimated RTT may be understood to also be the same as the experienced RTT. However, in all other cases, the estimated RTT will be different than the experienced RTT.

[0055] Certain aspects of the present disclosure and their embodiments address one or more of the challenges identified with the existing methods and provide solutions to the challenges discussed.

[0056] Embodiments herein may be understood to address the problems identified with the existing methods and may be understood to relate to ICMP Ping for QoS packet delay measurement. More particularly, some embodiments herein may relate to a simple mechanism for Mobile Network Operators (MNOs) to be able to monitor the compliance to QoS requirements, such as the round trip packet delay for an SDF.

[0057] The methods described herein may be understood to be based on the ICMP protocol to measure the round trip packet delay between the UPF and the UE. According to some examples of embodiments herein, a UPF may send an ICMP echo request to a UE from a UPF reserved IP address. An ICMP echo request may be understood as a message sent from one network node to another network node, requesting the second network node to immediately send a response back, thereby verifying that there is network connectivity between the two network nodes, and making it possible to determine the round trip delay between the two network nodes. The ICMP echo may be marked with the QFI corresponding to the service data flow QoS Flow in the DL. The UPF may notify the used IP address to the SMF, and the SMF may then include the UPF reserved IP address as part of the UE QoS rules in the UE. The UE, at reception of the ICMP echo request, may generate an ICMP echo response and it may mark the UL packets based on the QoS rules provided by the SMF, which may include the filter for the UPF reserved IP address, ensuring that the UL packets receive the correct QFI marking in the UL, and the UL contribution to the RTT may then be measured on the right QoS Flow. That is, the service data flow QoS Flow in the UL.

[0058] Additionally, for scenarios where the UE may support IPv4, and the UE may be time synchronized with the UPF, e.g., in automation scenarios, embodiments herein may also provide an approach to measure one way delay measurement granularity by using the ICMP timestamp request and timestamp reply. According to ICMP protocol, a timestamp request may be sent to another host and a timestamp reply may be received. The purpose of the timestamp request and reply may be understood to be to measure the delay and / or round-trip time between entities, e.g., between the devices. The embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which examples are shown. In this section, embodiments herein are illustrated by exemplary embodiments. It should be noted that these embodiments are not mutually exclusive. Components from one embodiment or example may be tacitly assumed to be present in another embodiment or example and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. All possible combinations are not described to simplify the description.

[0059] Figure 3a and Figure 3b each depict a non-limiting example, respectively, of a communications system 100, in which embodiments herein may be implemented. In some example implementations, such as that depicted in the non-limiting example of Figure 3a, the communications system 100 may be a computer network. In other example implementations, such as that depicted in the non-limiting example of Figure 3b, the communications system 100 may be implemented in a telecommunications system, sometimes also referred to as a telecommunications network, cellular radio system, cellular network, or wireless communications system. In some examples, the telecommunications system may comprise network nodes which may serve receiving nodes, such as communication devices. The communications system 100 may for example be a network such as a 5G system, or a newer system supporting similar functionality, such as for example, a Sixth Generation (6G) system. In some examples, the communications system 100 may support, additionally, or in some examples, alternatively, a Long-Term Evolution (LTE) network and may support other technologies such as a for example, e.g., LTE Frequency Division Duplex (FDD), LTE Time Division Duplex (TDD), LTE Half-Duplex Frequency Division Duplex (HD-FDD), and LTE operating in an unlicensed band. The telecommunications system may also support other technologies, such as Wideband Code Division Multiple Access (WCDMA), Universal Mobile Telecommunications System Terrestrial Radio Access (UTRA) TDD, Global System for Mobile communications (GSM) network, GSM / Enhanced Data Rate for GSM Evolution (EDGE) Radio Access Network (GERAN) network, Ultra-Mobile Broadband (UMB), EDGE network, network comprising any combination of Radio Access Technologies (RATs) such as e.g. MultiStandard Radio (MSR) base stations, multi-RAT base stations etc., any 3rd Generation Partnership Project (3GPP) cellular network, Wireless Local Area Network / s (WLAN) or WiFi network / s, Worldwide Interoperability for Microwave Access (WiMax), IEEE 802.15.4-based low-power short-range networks such as IPv6 over Low-Power Wireless Personal Area Networks (6LowPAN), Zigbee, Z-Wave, Bluetooth Low Energy (BLE), or any cellular network or system. The telecommunications system may for example support a Low Power Wide Area Network (LPWAN). LPWAN technologies may comprise Long Range physical layer protocol (LoRa), Haystack, SigFox, LTE-M, and Narrow-Band loT (NB-loT).

[0060] The communications system 100 comprises a core network 101. The core network 101 comprises a plurality of network nodes, whereof a first network node 111, and a second network node 112 are depicted in Figure 3a and Figure 3b. It may be understood that the core network 101 may comprise and / or operate in communication with more network nodes than those represented on Figure 3a and Figure 3b. For example, in some examples, the core network node 101 may comprise a third network node, a fourth network node, etc., even if these network nodes are not depicted in Figure 3a or Figure 3b.

[0061] Any of the first network node 111 and the second network node 112 may be understood, respectively, as a first computer system and a second computer system. In some examples, any of the first network node 111 and the second network node 112 may be implemented as a standalone server in e.g., a host computer in the cloud 120, as depicted in the non-limiting example depicted Figure 3b for both of the first network node 111 and the second network node 112. Any of the first network node 111 and the second network node 112 may in some examples be a distributed node or distributed server, with some of their respective functions being implemented locally, e.g., by a client manager, and some of their functions implemented in the cloud 120, by e.g., a server manager. Yet in other examples, any of core network 101 may also be implemented as processing resources in a server farm.

[0062] The first network node 111 may be a node having a capability to manage sessions of data communication between a communications device operating via the communications system 100, such as the communications device 130 described below, and another network node having a capability to manage service of an application to a communications device such as the communications device 130, e.g., an AF / Application Server (AS). The first network node 111 may support different functionalities, such as receiving rules from a function controlling policy in the communications system 100, and configuring the second network node 112 accordingly. As depicted in Figure 3a and Figure 3b, in a particular non-limiting example wherein the communications system 100 may be a 5G network, the first network node 111 may be an SMF. In another non-limiting example wherein the communications system 100 may be a 4G network, the first network node 111 may be a Packet Data Network Gateway Control Plane (PGW-C), or a Traffic Detection Function Control Plane (TDF-C).

[0063] The second network node 112 be understood to be a node that may have a capability to support handling of user plane traffic, including packet inspection, packet routing and forwarding, traffic usage reporting, and Quality of Service (QoS) handling for user plane, e.g., LIL / DL rate enforcement, e.g., based on rules received from the first network node 111. As depicted in Figure 3a and Figure 3b, in a particular non-limiting example, wherein the communications system 100 may be a 5G network, the second network node 112 may be UPF. In another non-limiting example, wherein the communications system 100 may be a 4G network, the second network node 112 may be a Packet Data Network Gateway User Plane (PGW-U), or a Traffic Detection Function User Plane (TDF-U). A communications device 130 may communicate via the communications system 100. The communications device 130 may be also known as a e.g., user equipment (UE), wireless device, mobile terminal, wireless terminal and / or mobile station, mobile telephone, cellular telephone, laptop with wireless capability, Internet of Things (loT) device, or Customer Premises Equipment (CPE), just to mention some further examples. The communications device 130 in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or a vehicle-mounted mobile device, enabled to communicate voice and / or data, via a RAN, with another entity, such as a server, a laptop, a Personal Digital Assistant (PDA), or a tablet, a Machine-to-Machine (M2M) device, an loT device, e.g., a sensor or a camera, a device equipped with a wireless interface, such as a printer or a file storage device, modem, Laptop Embedded Equipped (LEE), Laptop Mounted Equipment (LME), USB dongles, CPE or any other radio network unit capable of communicating over a radio link in the communications system 100. The communications device 130 may be wireless, i.e., it may be enabled to communicate wirelessly via the communications system 100 and, in some particular examples, may be able to support transmission using beamforming. The communication may be performed e.g., between two devices, between a device and a radio network node, and / or between a device and a server. The communication may be performed e.g., via a RAN and the core networks 101 comprised within the communications system 100.

[0064] The communications system 100 may comprise one or more radio network nodes, whereof a radio network node 140 is depicted in Figure 3b. The radio network node 140 may typically be a base station or Transmission Point (TP), or any other network unit capable to serve the communications device 130, e.g., a wireless device, or a machine type node in the communications system 100. The radio network node 140 may be e.g., a 5G gNB, a 4G eNB, or a radio network node in an alternative 5G RAT, e.g., fixed or WiFi. The radio network node 140 may be e.g., a Wide Area Base Station, Medium Range Base Station, Local Area Base Station, and Home Base Station, based on transmission power and thereby also coverage size. The radio network node 140 may be a stationary relay node or a mobile relay node, and it may be embodied in the form of a satellite. The radio network node 140 may support one or several communication technologies, and its name may depend on the technology and terminology used. The radio network node 140 may be directly connected to one or more networks and / or one or more core networks, such as the core network 101.

[0065] The communications system 100 covers a geographical area which may be divided into cell areas, wherein each cell area may be served by a radio network node, although, one radio network node may serve one or several cells.

[0066] The first network node 111 may communicate with the second network node 112 over a first link 151 , e.g., a radio link or a wired link. The first network node 111 may communicate with the any of the communications device 130 over a second link 152, e.g., a radio link or a wired link. The second network node 112 may communicate with the communications device 130 over a third link 153, e.g., a radio link or a wired link. The first network node 111 may communicate with the radio network node 140 over a fourth link 154, e.g., a radio link or a wired link. The second network node 140 may communicate with the radio network node 140 over a fifth link 155, e.g., a radio link or a wired link. The radio network node 140 may communicate with the communications device 130 over a sixth link 156, e.g., a radio link.

[0067] Any of the first link 151 , the second link 152, the third link 153, the fourth link 154, the fifth link 155 and / or and the sixth link 156 may be a direct link or it may go via one or more computer systems or one or more core networks, such as the core network 101 in the communications system 100, or it may go via an optional intermediate network. The intermediate network may be one of, or a combination of more than one of, a public, private, or hosted network; the intermediate network, if any, may be a backbone network or the Internet, which is not shown in Figure 3a nor in Figure 3b.

[0068] Although terminology from Long Term Evolution (LTE) / 5G has been used in this disclosure to exemplify the embodiments herein, this should not be seen as limiting the scope of the embodiments herein to only the aforementioned system. Other wireless systems supporting similar or equivalent functionality may also benefit from exploiting the ideas covered within this disclosure. In future telecommunication networks, e.g., in the sixth generation (6G), the terms used herein may need to be reinterpreted in view of possible terminology changes in future technologies.

[0069] In general, the usage of “first”, “second”, “third”, “fourth”, “fifth” and / or “sixth” herein may be understood to be an arbitrary way to denote different elements or entities and may be understood to not confer a cumulative or chronological character to the nouns it modifies.

[0070] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0071] Embodiments of a computer-implemented method, performed by the first network node 111 , will now be described with reference to the flowchart depicted in Figure 4. The method may be understood to be for handling measurement of a delay. The first network node 111 operates in the core network 101 of the communications system 100. In some embodiments, the communications system 100 may be a 3GPP network. In some embodiments, the communications system 100 may be a 5G system. The core network 101 may be a 5G Core Network.

[0072] Several embodiments are comprised herein. In some embodiments, all the actions may be performed. In some embodiments, two or more actions may be performed. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. A non-limiting example of the method performed by the first network node 111 is depicted in Figure 4.

[0073] In Figure 4, optional actions are represented with dashed lines.

[0074] Action 401

[0075] In this Action 401 , the first network node 111 may receive a first indication from the second network node 112 operating in the core network 101 of the communication system 100.

[0076] The first indication may indicate a capability of the second network node 112 to measure a delay in a flow of data having a first QoS. The delay may be understood to be between the second network node 112 and the communication device 130. The capability may be to measure the delay by sending a first packet, and receiving on a first IP address, a second packet in response to the first packet.

[0077] In some embodiments, the first packet may be an ICMP ping. More particularly, in some embodiments, the first packet may be an ICMP Echo request and the second packet may be an ICMP Echo response. In other embodiments, the first packet may be an ICMP Timestamp request and the second packet may be an ICMP Timestamp response.

[0078] In embodiments herein, the term ICMP Ping may be understood to refer to ICMP Echo, e.g., which may be used when only RTT may be monitored, or ICMP Timestamp, which may be used when one-way delay may be monitored. Nevertheless, the ICMP Timestamp may also be used when RTT may be monitored.

[0079] In some embodiments, the first network node 111 may manage an SMF. The second network node 112 may manage a UPF. In some of such embodiments, the first network node 111 may receive the first indication in this Action 401 , e.g., via the first link 151, during a Packet Forwarding Control Protocol (PFCP) association procedure between the UPF and the SMF entities. During this procedure, the second network node 112 may share its capabilities so that the first network node 111 may then be enabled to consider them for a PDU Session UPF selection. In particular embodiments, the first indication may be an added new User Plane (UP) function feature to allow the first network node 111 , e.g., the SMF, to know that the second network node 112, or similar nodes, e.g., UPFs, may support this capability and thus may influence the second network node 112 selection performed by first network node 111 , e.g., UPF selection. For example, as shown in Table 1 , the first indication may be an added new feature to Table 8.2.25-1 : UP Function Features, of 3GPP TS 29.244, v18.5.0, which in this non-limiting example is called ICMP Ping for QoS packet delay Measurement (IPQDM). In Table 1 , M stands for Mandatory, O stands for Optional, CN-TL stands for Core Network Talker Listener function and QMDRM stands for QoS Monitoring of Data Rate Measurements.

[0080] Table 1.

[0081] Action 402

[0082] In some embodiments, in this Action 402, the first network node 111 may select the second network node 112 to measure the delay based on the indicated capacity in Action 401.

[0083] For example, the first network node 111 may decide to perform QoS Monitoring using ICMP based Monitoring and accordingly, it may select a network node capable of handling the user plane of the communications device 130, such as the first network node 111, e.g., a UPF, supporting the ICMP Ping for QoS packet delay Measurement feature.

[0084] This may happen, for example, after the communications device 130 may trigger a PDU session establishment, e.g., sending a PDU Session Establishment Request to a third node in the core network 101 , e.g., an AMF. During the PDU Session Establishment, the first network node 111 may select a fourth network node, e.g., a PCF, and establish a Session Management (SM) Policy Association with the selected third network node to receive SM policies for the user PDU session. Information provided by the PCF may include the PCC rules for the PDU session.

[0085] The PCF may indicate the QoS requirements for certain traffic, e.g., as part of an SM Policy Association Establishment and a QoS Monitoring request by sending the PCC rules. To illustrate the embodiments herein, in two particular non-limiting examples, Example A and Example B, the PCC rules may be as follows. According to Example A, UL and DL traffic may have the same QoS requirements and UL and DL traffic may be sent on the same QoS Flow. The PCC rule may indicate that the Destination IP address (DstIP) = IP2, the (5QI) = 2 and the QoS Monitoring policy may include RTT packet Delay, etc... According to Example B, the PCF may provide two unidirectional PCC rules if the QoS requirements may be different for each direction, that is, DL and UL data traffic may be going to be sent on different QoS Flows. PCC Rulel may apply to traffic to a first AS, AS1 , and may indicate that DstIP = IP2, 5QI = 3, and QoS Monitoring policy may include RTT packet Delay, etc.. PCC Rule2 may apply to traffic from AS1 and may indicate that the Source IP address (SrclP) = IP2, 5QI = 2, and QoS Monitoring policy may include RTT packet Delay, etc...

[0086] Based on the PCF QoS Monitoring request indicated in the PCC rules, the first network node 111 may then decide to perform QoS Monitoring using ICMP based Monitoring and it may, accordingly, select the second network node 112, e.g., a UPF, based on the first indication received in Action 401 , as being a second network node supporting the ICMP Ping for QoS packet delay Measurement feature, and therefore capable to perform the QoS Monitoring using the ICMP based Monitoring. The decision by the first network node 111 may be based on several factors, such as if the first indication from the second network node 112 indicates that the second network node 112 supports the feature, operator policies configured on the second network node 112 indicating that ICMP Ping may need to be used instead of other 3GPP methods, etc. This may be configured for example if the operator may know that their RAN may not support other approaches.

[0087] Action 403

[0088] In this Action 403, the first network node 111 may determine one or more flows to be measured by the second network node 112.

[0089] Determining may be understood as calculating, deriving or similar.

[0090] The determining in this Action 403 may be based on the QoS requirements that the PCF may have indicated. As part of the QoS requirements from the PCF, the first network node 111 may determine that additional QoS Flow(s) may be needed to satisfy the QoS requirements for this traffic, and based on this, initiate the setup of the QoS flows that may be required. In parallel, again, e.g., based on the QoS Monitoring Control requirements for the data flows, the first network node 111 may determine that QoS monitoring may be required for some QoS flows.

[0091] In this Action 403, the first network node 111 may also determine QoS Monitoring per QoS flow Control Information for the second network node 112, that the first network node 111 may then send in rules, which may be referred to herein as one or more first rules, e.g., Session Reporting Rules, to the second network node 112. QoS Monitoring Control per QoS flow Information may be understood as information, e.g., an indication or instruction, e.g., comprised in an IE, the information indicating which QoS flow to monitor, how to monitor the QoS flow, and how to report the results of the monitoring, e.g., how often, or at what thresholds to report, etc. It may also contain the indication that ICMP Ping may be required to be used. The QoS Monitoring per QoS flow Control Information may be part of the SRR rules.

[0092] For that, the first network node 111 may take into account the following. When the first network node 111 may decide to perform QoS Monitoring using ICMP based Monitoring, the second network node 112 may need to be instructed so that it may send the first packet, e.g., an ICMP Ping, on the QoS Flow selected for the DL traffic. For that, the rule may need to include the QFI of the QoS Flow carrying the DL. When two QoS Flows may need to be monitored, one for DL and the other for the UL traffic, such as in Example B, one rule may need to include the QFI of the QoS Flow carrying the DL traffic and another rule may need to include an IP allocation request plus allocated IP notification request.

[0093] Action 404

[0094] In order to measure the delay in the flows of data of Example A and Example B, so that the correct RTT values may be obtained, the first packet, e.g., an ICMP ping, may be understood to need to be transmitted on the same QoS Flows than the data traffic.

[0095] In this Action 404, the first network node 111 sends, to the second network node 112 operating in the core network 101 of the communication system 100, an indication. The indication indicates to measure the delay in the flow of data having the first QoS, between the second network node 112 and the communication device 130. The indication indicates to measure the delay by sending the first packet to the communication device 130, from the first IP address to be allocated by the second network node 112 and receiving, by the second network node 112 on the first IP address, the second packet in response to the first packet from the communication device 130. As stated earlier, the communications device 130 communicates via the communications system 100. That is, while the communications device 130 may not be necessarily comprised in the communications system 100, it may use the communications system 100 to perform communications with other entities.

[0096] The first network node 111 may be understood to send the indication to the second network node 112, as selected by the first network node 111 in Action 402.

[0097] The indication indicates to measure the delay in the flow of data as determined in Action 403.

[0098] The indication sent to the second network node 112 may be understood to be a second indication. The second indication may be understood to include instructions to the second network node 112. The instructions may be indicated in the one or more first rules.

[0099] The second indication may be understood to be based on the determined one or more flows to be measured, e.g., based on whether the one or more flows correspond to Example A or Example B, as described earlier, that is, whether there is a single flow, and whether it is in UL or DL, or whether there may be more than one flow, with or without the same QoS.

[0100] The QoS Monitoring per QoS flow Control Information that the first network node 111 may determine in Action 403 may indicate that the ICMP Ping may need to be used. The QoS Monitoring per QoS flow Control Information may be included in the one or more first rules sent to the second network node 112.

[0101] In some embodiments, the second network node 112 may have to measure the delay as one of the following options. According to one option, the second network node 112 may have to measure the delay as a first difference between a first timestamp of the sending of the first packet by the second network node 112, and a second timestamp of arrival of the second packet from the communication device 130 as received by the second network node 112. That is, the second network node 112 may have to measure the delay as a RTT.

[0102] According to another option, the second network node 112 may have to measure the delay as a second difference between the first timestamp and a third timestamp of arrival of the first packet at the communication device 130. That is, the second network node 112 may have to measure the delay specifically in the DL. In some examples, the second difference may be used for measuring combinations of RTT, DL, or UL.

[0103] According to yet another option, the second network node 112 may have to measure the delay as a third difference between a fourth timestamp of a sending of the second packet by the communication device 130, and the second timestamp. That is, the second network node 112 may have to measure the delay specifically, and / or only, in the UL. In some examples, the third difference may be used for measuring combinations of RTT, DL, or UL.

[0104] These options may be indicated in the one or more first rules.

[0105] Any of the RTT delay, the specific DL delay and the specific UL delay measurements may be performed with Timestamp request and responses. RTT delay may be performed with ICMP Echo request. In some embodiments, one of the following options may further apply. In one group of embodiments wherein the first packet may be an ICMP Echo request and the second packet may be an ICMP Echo response, the first timestamp may be of the sending of the ICMP Echo request by the second network node 112 and the second timestamp may be of the arrival of a first Echo response to the Echo request from the communication device 130 as received by the second network node 112. One advantage of this group of embodiments may be understood to be that they may enable the second network node 112 to measure the roundtrip packet delay between the communications device 130 and the second network node 112 in an easy and reliable way using ICMP Echo request and Echo reply messages.

[0106] In another group of embodiments wherein the first packet may be an ICMP Timestamp request and the second packet may be an ICMP Timestamp response, and one of the following may apply: the first timestamp may be of the sending of the Timestamp request by the second network node 112, the second timestamp may be of the arrival of the Timestamp response from the communication device 130 at the second node 112, the third timestamp may be of the arrival of the Timestamp request at the communication device 130, and the fourth timestamp may be of the sending of the Timestamp response from the communication device 130 to the second network node 112.

[0107] An advantage of the another group of embodiments wherein the first packet may be an ICMP Timestamp request and the second packet may be an ICMP Timestamp response, may be understood to be that they may enable the second network node 112 to measure one way packet delay granularity between the communications device 130 and the second network node 112 by using the ICMP timestamp and timestamp reply messages. In addition, another advantage of the another group of embodiments wherein the first packet may be an ICMP Timestamp request and the second packet may be an ICMP Timestamp response, may be understood to be that they may enable the second network node 112 to measure the round-trip packet delay between the communications device 130 and the second network node 112. This may be understood to be only possible when the communications device 130 and the core network 101 may be time synchronized and the session may support IPv4. For example, this may be used in a controlled environment e.g., for automation.

[0108] In other words, in the indication the first network node 111 may instruct the second network node 112 on how to measure the delay in a flow, and / or in the one more flows.

[0109] A single data flow may have an UL component and a separate DL component. Each component may be on separate QoS flows.

[0110] In some embodiments wherein the first QoS may be in the uplink and the flow of data may have the first QoS, or a second QoS, in the downlink, the measurement may have to be performed in the uplink and in the downlink. In some of such embodiments, the indication may indicate that the second network node 112 may have to: report back to the first network node 111 the allocated IP address and refrain from marking reflective in the first packet. Reflective may be understood to mean that the communications device 130 may dynamically derive QoS rules based on received DL packets such that the corresponding UL packets may be sent on the same QoS flow as the DL packets were received on. In the embodiments wherein the first QoS may be in the UL and the flow of data may have the first QoS in the DL, refraining from marking reflective in the first packet may be understood to have the advantage of not requiring the communications device 130 to support reflective QoS, and it may be understood to not require the first network node 111 to perform the signalling required to setup reflective QoS. In the embodiments wherein the first QoS may be in the UL and the flow of data may have the second QoS in the DL, refraining from marking reflective in the first packet may be understood to have the advantage of avoiding that the measured QoS may be different from the QoS that the data flow may be experiencing by avoiding that the second packet may be sent in the same QoS flow as the first packet when UL and DL may be in different QoS flows.

[0111] In an alternative group of embodiments, the indication may indicate the measurement may have to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet. Marking reflective in the first packet may be understood to have the advantage of not requiring that the allocated first IP address is reported to the first network node 111 , and the first network node 111 may not have perform a special action when determining what QoS Rules to send to the communications device 130.

[0112] In some embodiments, the indication, that is, the second indication, may be comprised in a PFCP Session Establishment or Modification request.

[0113] One possible implementation of the second indication may comprise enhancing the different information elements for QoS Monitoring in the Session Reporting Rules (SRRs). For example, enhancing the QoS Monitoring per QoS flow Control IE, which may be included in the Session Reporting Rule (SRR) Information Element (IE) Create / Update as described e.g., in 3GPP TS 29.244, v. 18.5.0, 7.5.2.9 / 7.5.4.20, which may be sent from SMF to UPF during PFCP Session Establishment and / or Modification procedures, according to 3GPP TS 29.244, v18.5.0, 6.3.2 / 6.3.3. The update may comprise being able to indicate the ICMP Ping based monitoring method for the measurements. This may be understood to be enough for e.g., Example A. For this, the update may comprise indicating whether round trip time and / or one way delay granularity may be being requested. It may be noted that depending on whether only RTT and / or one-way delay(s) may be requested, the second network node 112, e.g., the UPF, may be going to use ICMP Echo or ICMP Timestamp. For RTT, both Echo and Timestamp may be used, but Echo request may only be used for RTT, while Timestamp may also measure one-way delay. For IPv4, Timestamps may potentially always be used, while for IPv6 only Echo may be understood to be supported, therefore, only Echo may be used. However, Echo may be used for IPv4 as well. Optionally, the update may comprise providing ICMP Ping based Monitoring Control information specific to embodiments herein. In other words, the ICMP Ping based Monitoring Control IE may comprise information that may be specific to the ICMP based measurement, while the other lEs may comprise information that may be generic for all 5 forms of QoS monitoring per QoS flow per UE. The update providing ICMP Ping based Monitoring Control information specific to embodiments herein may be needed for e.g., Example B.

[0114] Table 2 below is a non-limiting example implementation of these enhancements. In Table 2, the new elements and / or values corresponding to embodiments herein with respect0 to Table 7.5.2.9-3: QoS Monitoring per QoS flow Control Information in 3GPP TS 29.244 v.

[0115] 18.5.0, are highlighted in bold.

[0116]

[0117]

[0118] Table 2.

[0119] In some examples, the indication, that is, the second indication, may comprise one or more session reporting rules.

[0120] 5 By in this Action 404 sending the indication to measure the delay by sending the first packet to the communication device 130, from the first IP address to be allocated by the second network node 112 and receiving, by the second network node 112 on the first IP address, the second packet in response to the first packet from the communication device 130, the first network node 111 may enable the second network node 112 to then measure0 the round-trip delay between the communications device 130 and the second network node 112 in an easy and reliable way wherein the delay may be measured with dedicated packets, that is, packets that may be sent and received as instructed by the first network node 111 , and which thereby may not need to be dependent on other packets being sent or received in order to perform the measurement. This may enable to avoid a risk that there5 may be no suitable UL or DL packets being sent when the measurements may need to be performed. Furthermore, by instructing the second network node 112 to allocate the IP address, the second network node may ensure that the second packet in response to the first packet is then received at the allocated first IP address. This may be understood to advantageously ensure that the second packet may be received successfully at the second0 network node 112, e.g., by the correct NF instance, by ensuring that the second packet may not be blocked, dropped or redirected to another network node due to traffic-routing or security policies. Internally the second network node 112 may accept the response in the first IP allocated. This may further be based, for example, on an ICMP ping ID.

[0121] Furthermore, the first network node 111 may be enabled to, in some examples, later5 receive a report of the allocated first IP address from the second network node 112, so that the first network node 111 may subsequently be enabled to indicate to the communications device 130 which QoS flow the second packet may need to be sent on by indicating the first IP address allocated by the second network node 112, e.g., by constructing a QoS Rule.

[0122] A further advantage of this Action 404 may be understood to be that the advantages just described may be achieved while having less impacts than the standardized QoS monitoring function on 3GPP. Embodiments herein may be understood to be able to be implemented “out of the box” with the communication device 130. In some instances, some configuration of the communication device 130 may be needed, e.g., if it may block ICMP echo packets, but there may be understood to be no impact on any standards related to the UEs. There may be understood to be no impact either on AMF or (R)AN.

[0123] Furthermore, the advantages just described may be achieved with non-3GPP access.

[0124] Action 405

[0125] In this Action 405, the first network node 111 receives another indication from the second network node 112. The another indication indicates a response to the indication sent by the first network node 111. The another indication may be understood as a third indication.

[0126] The first network node 111 may receive the another indication via the first link 151.

[0127] By receiving the another indication from the second network node 112, the first network node 111 may ensure that the second indication may have been successfully received by the first network node 111 and therefore that the second network node 112 may be understood to have received the instructions provided by the first network node 111 in the second indication.

[0128] The another indication may be comprised in a PFCP Session Establishment or Modification response.

[0129] In embodiments wherein the first QoS may be in the uplink and the flow of data may have the first QoS, or the second QoS, in the downlink, the measurement may have to be performed in the uplink and in the downlink, and the (second) indication may have indicated that the second network node 112 may have to: report back to the first network node 111 the allocated IP address and refrain from marking reflective in the first packet, the another indication may indicate the allocated IP address.

[0130] For Example B, the second network node 112 may have been requested to report the allocated IP address and the response may include the allocated IP address. In a nonlimiting example, the another indication may indicate the allocated IP address = 10.0.0.1 and the identifier of the request this information may refer to.

[0131] One possible implementation may be enhancing the PFCP Session Establishment / Modification response as described in 3GPP TS 29.244, v. 18.5.0, clause 7.5.317.5.5, for the case the request may have included ICMP Ping based Monitoring Control Information requesting to allocate and report allocated IP address, so that it may include a new Created SRR IE as shown in Table 3 and Table 4 below. Table 3 is a non-limiting example of enhancements on Table 7.5.3.1-1 : Information Elements in a PFCP Session Establishment Response from 3GPP TS 23.244, v. 18.5.0. Table 4 is a non-limiting example of a new IE that may be added in PFCP Session Establishment / Modification response.

[0132] In Table 3, Appl. stands for Application, ID stands for Identifier and F-SEID stands for Fully Qualified Session Endpoint Identifier.

[0133] Table 3.

[0134] 5 Table 4

[0135] Informing the first network node 111 about which IP address may have been allocated may be understood to not always be required. Informing the first network node 111 about which IP address may have been allocated may be based, rather than on how many QoS0 flows may be being measured, on the total number of QoS flows that may exist in a session. In a session with multiple QoS flows, even if only one is measured, the first network node 111 may need to be informed about the IP address allocated, or if reflection may be needed. This may be needed so that the first network node 111 may create the rules that may steer the UL traffic onto the correct QoS Flow. 5 If there is only one QoS flow then the SMF does not need to be informed. Another special case is also if there are multiple QoS flows and it is the default QoS flow that is to be measured, in which case there is most likely no need for an IP address (but to be sure it works as expected it is best to use one).

[0136] In alternative embodiments, wherein the (second) indication may indicate the 0 measurement may have to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet, the another indication may lack an indication of the allocated IP address. This may have the advantage of saving signalling resources, since indicating the allocated IP address in such embodiments in the another indication may not be necessary, as the reflective mark may indicate the second packet may need to be sent to the same IP address from which the first packet may have been received.

[0137] Action 406

[0138] In this Action 406, the first network node 111 may determine, based on the received another indication, one or more rules to be used by the communication device 130 to send the second packet in reply to the first packet. The one or more rules may indicate a flow to be used by the communication device 130 to send the reply to the allocated IP address. The one or more rules determined in this Action 406 may be referred to herein as one or more second rules, or simply, one or more rules, may be QoS Rules. The QoS Rules may be determined according to the QoS Monitoring needs. The one or more second rules may comprise a packet filter set, e.g., according to the received PCC rules from the fourth network node.

[0139] This Action 406 may be performed in some embodiments wherein the first QoS may be in the uplink and the flow of data may have the first QoS, or the second QoS, in the downlink, the measurement may have to be performed in the uplink and in the downlink, the indication may indicate that the second network node 112 may have to: report back to the first network node 111 the allocated IP address and refrain from marking reflective in the first packet, and the another indication may indicate the allocated IP address. Accordingly, when the another indication may include the requested allocated IP address, the first network node 111 may generate a Packet Filter Set for the QoS Rules according to the received PCC rules. If needed, the first network node 111 may also include a filter matching the allocated IP address. This may be needed, e.g., in example B and in Example A if reflection is not supported.

[0140] The first network node 111 may, in this Action 406, for example, construct a QoS Rule, as one of the one or more second rules, that may specify that all ICMP traffic to the first IP address allocated by the second network node 112 may have to be sent on the selected QoS Flow.

[0141] Determining may be understood as calculating, deriving, generating or similar. That the determining in this Action 406 may be based on the received another indication may be understood to mean that the determining may be triggered by the received another indication. Moreover, the determining may be based on the allocated IP address indicated in the another indication, e.g., the first network node 111 may, in some cases, generate, or derive, filters that may comprise the allocated IP address received in the another indication.

[0142] By determining the one or more second rules, the first network node 111 may advantageously ensure that the communications device 130 may then send the second packet in reply to the first packet on the same flow that the data may follow, and hence ensure that the measurement is performed by the first network node 111 on the correct flow.

[0143] Action 407

[0144] In this Action 407, the first network node 111 may send a further indication towards the communication device 130. The further indication may indicate the determined one or more rules. This may be understood to mean that in some embodiments, the one or more second rules may comprise the allocated IP address indicated by the second network node 112 in the another indication.

[0145] In some examples, the one or more second rules may be QoS rules. Hence, the further indication may, in those examples, indicate one or more QoS rules.

[0146] The further indication may be understood as a fourth indication.

[0147] The sending in this Action 407 may be performed, e.g., via the second link 152, or via the fourth link 154 and the sixth link 156.

[0148] As explained above, by sending the further indication towards the communications device 130, the first network node 111 may advantageously ensure that the communications device 130 may then send the second packet in reply to the first packet on the same flow that the data may follow, by e.g., instructing the communications device 130 to do so, and hence ensure that the measurement is performed by the first network node 111 on the correct flow.

[0149] In some embodiments, one or more of the following may apply: the indication may be comprised in a PFCP Session Establishment or Modification request, the another indication may be comprised in a PFCP Session Establishment or Modification response, the first network node 111 may manage an SMF, the second network node 112 may manage a UPF, the communications system 100 may be a Third Generation Partnership Project network, the communications system 100 may be a 5G System, and the core network 101 may be a 5G Core Network.

[0150] The first network node 111 may send the further indication towards the communications device 130 by sending a Namf_Communication_N1 N2_Message_Transfer message as in procedure in specifications to convey to the communications device 130, through the third network node, e.g., an AMF, the one or more second rules, e.g., the QoS Rule for UL traffic mapping to QoS Flow, the QoS Profile, for example A the Reflective QoS Attribute is set.

[0151] The communications device 130 may then acknowledge the reception towards the third network node.

[0152] Embodiments of a computer-implemented method performed by the second network node 112, will now be described with reference to the flowchart depicted in Figure 5. The method may be understood to be for handling the measurement of the delay. The second network node 112 operates in the core network 101 of the communications system 100.

[0153] The method may comprise the following actions. Several embodiments are comprised herein. In some embodiments, the method may comprise all the actions. In other embodiments, the method may comprise one or more actions. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. It should be noted that the examples herein are not mutually exclusive. Components from one example may be tacitly assumed to be present in another example and it will be obvious to a person skilled in the art how those components may be used in the other examples.

[0154] The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 and will thus not be repeated here to simplify the description. For example, the indication, that is, the second indication, may comprise one or more session reporting rules.

[0155] Action 501

[0156] In this Action 501, the second network node 112 may send the first indication to the first network node 111. The first indication may indicate the capability of the second network node 112 to measure the delay by sending the first packet and receiving on the first IP address, the second packet in response to the first packet.

[0157] In some embodiments, one or more of the following may apply: the indication may be comprised in a PFCP Session Establishment request, the another indication may be comprised in a PFCP Session Establishment or Modification response, the first network node 111 may manage the SMF, the second network node 112 may manage the UPF, the communications system 100 may be a 3GPP network, and the communications system 100 may be a 5G system.

[0158] Action 502

[0159] In this Action 502, the second network node 112 receives, from the first network node

[0160] 111 operating in the core network 101 of the communication system 100, the indication to measure the delay in the flow of data having the first QoS, between the second network node

[0161] 112 and the communication device 130. The indication indicates to measure the delay by sending the first packet to the communication device 130, from the first IP address to be allocated by the second network node 112 and receiving, by the second network node 112 on the first IP address, the second packet in response to the first packet from the communication device 130. The communications device 130 communicates via the communications system 100.

[0162] In some embodiments, the second network node 112 may have to measure the delay as one of: the first difference between the first timestamp of the sending of the first packet by the second node 112, and the second timestamp of arrival of the second packet from the communication device 130 as received by the second network node 112, the second difference between the first timestamp and the third timestamp of arrival of the first packet at the communication device 130, and the third difference between the fourth timestamp of the sending of the second packet by the communication device 130, and the second timestamp.

[0163] In some embodiments, one of the following options may apply. According to one option, the first packet may be the ICMP Echo request and the second packet may be the ICMP Echo response, and the first timestamp may be of the sending of the ICMP Echo request by the second network node 112 and the second timestamp may be of the arrival of a first Echo response to the Echo request from the communication device 130 as received by the second network node 112.

[0164] According to another option, the first packet may be the ICMP Timestamp request and the second packet may be the ICMP Timestamp response, and wherein one of: the first timestamp may be of the sending of the Timestamp request by the second network node 112, the second timestamp may be of the arrival of the Timestamp response from the communication device 130 at the second node 112, the third timestamp may be of the arrival of the Timestamp request at the communication device 130, and the fourth timestamp may be of the sending of the Timestamp response from the communication device 130 to the second network node 112.

[0165] In some embodiments, the indication may indicate that the second network node 112 may have to report back to the first network node 111 the allocated IP address and refrain from marking reflective in the first packet.

[0166] In alternative embodiments, the indication may indicate the measurement may have to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet.

[0167] Action 503

[0168] In this Action 503, the second network node 112 may allocate the IP address based on the received indication.

[0169] This Action 503 may be performed in embodiments wherein the first QoS may be in the uplink and the flow of data may have the first QoS, or the second QoS, in the downlink, the measurement may have to be performed in the uplink and in the downlink, the indication may indicate that the second network node 112 is to: report back to the first network node 111 the allocated IP address and refrain from marking reflective in the first packet. In such embodiments, the another indication sent in Action 504 may indicate the allocated IP address.

[0170] Action 504

[0171] In this Action 504, the second network node 112 sends the another indication to the first network node 111. The another indication indicates the response to the indication received from the first network node 111.

[0172] In some embodiments, the indication may indicate the measurement may have to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet. In such embodiments, the second network node 112 may refrain from indicating the allocated IP address in the another indication. n some embodiments, the method performed by the second network node 112 may comprise the following Action 505, Action 506, Action 507 and Action 508.

[0173] Action 505

[0174] At some point during the course of operations of the communication system 100, the communications device 130 may send data traffic. The data traffic of the communications device 130 sent to and / or from other destinations than AS1 may be sent in LIL / DL over the default bearer and / or QoS flow, as it may be understood to not have a dedicated QoS / PDR rule on the communications device 130 and the second network node 112. The default QoS flow may be understood to be the path for all the traffic that may be sent by the device 130 without a specific marking rule.

[0175] The UE data traffic exchanged with AS1 may be sent in UL and / or DL over dedicated QoS Flows. Dedicated QoS rules and PDR rules may have been installed on the communications device 130 and the second network node 112, e.g., according to Examples A and B, a depiction of which is shown in Figure 6.

[0176] The second network node 112 may detect the communications device 130 may be showing activity on the QoS Flow, and it may decide to start monitoring QoS.

[0177] In this Action 505, the second network node 112 may send the first packet from the allocated IP address to the communication device 130, based on the received indication, that is, the second indication.

[0178] The second network node 111 , in embodiments herein, may initiate measurement of the delay, e.g., by sending the first packet, upon detection of data traffic to or from the communications device 130, that is, e.g., only when detecting data traffic to or from the communications device 130.

[0179] In a non-limiting example, the second network node 112 may send the first packet as an ICMP ping from IP = 10.0.0.1 to the communications device 130 over the QoS flow with 5QI=2. Unless the second network node 112 may have been instructed otherwise in the indication, the ICMP ping packet may include the “reflective" indication. That is, DL and UL packets may go on the same QoS Flow, which may be understood be according to the needs of Example A.

[0180] In an example implementation, the first network node 111 may have included, in the second indication, an indication not to mark “reflective” ICMP Ping based Monitoring Control described in Action 404, Table 2, or this may be implicit to the fact that ICMP Ping based Monitoring Control may have also been received.

[0181] When in Action 403, the first network node 111 may not have requested one-way delays, the second network node 112 may send the first packet as an ICMP Echo, which may be understood to not require time synchronization between the communications device 130 and the second network node 112. When the first network node 111 may have requested one-way delay(s), the second network node 112 may send the first packet as an ICMP timestamp message instead of an ICMP echo message, and the communications device 130 may include the timestamps in the response.

[0182] Action 506

[0183] In this Action 506, the second network node 112 may receive, at the allocated IP address, the second packet from the communication device 130 in response to the first packet.

[0184] If reflective has been marked on the ping packet, the communications device 130 may send the second packet as an ICMP Ping response on the same QoS Flow, 5QI= 2 in example A. If the communications device 130 has been provisioned a QoS Rule for the IP = 10.0.0.1 as part of the filter information update via Action 407, the communications device 130 may be able to send the second packet as an ICMP ping response on the QoS Flow with 5QI= 3 following these rules in example B.

[0185] Action 507

[0186] In this Action 507, the second network node 112 may determine the delay based on at least one of the first difference, the second difference and the third difference. That is, the second network node 112 may determine the RTT and / or one-delays as requested.

[0187] If the method is performed for more than one flow, the second network node 112 may calculate the RTT and / or one-delays for each flow.

[0188] Action 508

[0189] In this Action 508, the second network node 112 may output an additional indication of the determined delay. The additional indication may be a fifth indication. As an example, in this Action 508, the second network node 112 may report the QoS monitoring result of the first QoS flow, the second QoS flow, or other QoS flows using the mechanisms available in the specifications.

[0190] In a first example, the additional indication may be output by sending it to the first network node 111 in a Session Report IE, e.g., in accordance with 3GPP TS 29.244, v. 18.5.0, Table 7.5.8.6-1 , which may be sent from the second network node 112 to the first network node 111 using PFCP Session Report procedures, e.g., in a PFCP Session Report.

[0191] In a second example, the additional indication may be output by sending it directly to a consumer of the measurement using UPF event Exposure of QoS Monitoring event, e.g., in accordance with 3GPP TS 29.564, v. 18.4.0 [2] , e.g., in a Nupf_EventExposure_Notify.

[0192] Figure 6a is a schematic diagram depicting how data traffic to and / or from AS1 may be transmitted in Example A, as described earlier, according to embodiments herein. Figure 6a particularly shows data binding to QoS Flows in Example A. The communications device 130 is a UE and the second network node 112 is a UPF. In Example A, data traffic 601 to and / or from AS1 may be transmitted between the communications device 130 and the second network node 112 on the same flow 602 having the same QFI, 5QI= 2. In Example A depicted in Figure 6a, the second network node 112, according to Action 505, sends the first packet as an ICMP ping, and marks reflective in the first packet, or the allocated IP may be sent to the first network node 111 and included in the QoS rules in case reflective QoS may not be supported. Consequently, the second network node 112 then receives, at the allocated IP address, according to Action 506, the second packet from the communication device 130 in response to the first packet. Advantageously, the communications device 130, in accordance with the one or more second rules indicated by the first network node 111 in the further indication, has been instructed to send the second packet to the allocated IP address using the flow 602, and not via the default QoS flow 603. The second packet may have the allocated first IP address as the Destination IP Address, and one of the one or more second rules, e.g., QoS Rules, may indicate that all packets to that IP address may need to be sent over the desired QoS flow.

[0193] Figure 6b is a schematic diagram depicting how data traffic to and / or from AS1 may be transmitted in Example B, as described earlier, according to embodiments herein. Figure 6b particularly shows data binding to QoS Flows in Example B. The communications device 130 is a UE and the second network node 112 is a UPF. In Example B, DL data traffic from AS1 604 may be transmitted towards the communications device 130 from the second network node 112 on the a first flow having a first QoS 605 with a QFI, 5QI= 2. UL data traffic to AS1 606 may be transmitted towards the second network node 112 from the communications device 130 on the a second flow having a second QoS 607 having a QFI, 5QI= 3. In Example B depicted in Figure 6b, the second network node 112, according to Action 505, sends the first packet as an ICMP ping on the first flow, and refrains from marking reflective in the first packet. Reflective may be understood to have as consequence that the second packet from the communication device 130 in response to the first packet may go on same QoS Flow than the first packet. Advantageously, the communications device 130, in accordance with the one or more second rules indicated by the first network node 111 in the further indication, has been instructed to send the second packet to the allocated IP address via the second flow 607, and not via the default QoS flow 603. The second packet may have the allocated IP address as the Destination IP Address, and one of the QoS Rules may indicate that all packets to that IP address may have to be sent over the desired QoS flow. The packet may also be steered to the right QoS flow due to reflection. Either reflection may be used, or the allocated IP address may be used, included in the one or more rules mentioned earlier.

[0194] Figure 7a is a sequence diagram depicting a non-limiting example of signalling between nodes in the communications system 100, according to embodiments herein. In Figure 7a, the communications device 130 is a UE, the first network node 111 is an SMF and the second network node 112 is a UPF. The core network 101 further comprises the third network node 701 as an AMF and the fourth network node 702 as a PCF. The communications system 100 further comprises a RAN comprising at least the radio network node 140. It may be understood that in the following example depicted in Figure 7a that any reference to the SMF may be understood to equally refer to the first network node 111, any reference to the UPF may be understood to equally refer to the second network node 112, any reference to the AMF may be understood to equally refer to the fourth node, any reference to the PCF may be understood to equally refer to the fifth node and any reference to the UE may be understood to equally refer to the communications device 130. Any of the features described in relation to Figure 4 and Figure 5 may be understood to equally apply to the pertinent actions depicted in Figure 7a. Along this procedure, the term ICMP Ping may be understood to refer to ICMP Echo, e.g., which may be used when only RTT may be monitored, or ICMP Timestamp, which may be used when one-way delay may be monitored. In Step 1), at the PFCP Association procedure between the UPF and the SMF entities, the second network node 112, according to Action 501 and Action 401 , may share its capabilities with the first network node 111, so that the first network node 111 may consider them for the PDU Session UPF selection. In Step 2), the UE may trigger a PDU session establishment sending a PDU Session Establishment Request to the AMF 701. It may be noted that the sequence diagram in Figure 7a does not include all the signaling messages involved in the PDU Session Establishment procedure. Only the relevant signaling messages for embodiments herein are described in subsequent steps. At Step 3, during PDU Session Establishment, the SMF, in accordance with may select a PCF and establish an SM Policy Association to receive SM policies for the user PDU session. Information provided by the PCF may include the PCC rules for the PDU session. In this example, the PCF may indicate the QoS requirements for certain traffic and QoS Monitoring request by indicating QoS monitoring need for certain QoS flows through PCC Rules. At Step 4, the SMF may decide to perform QoS Monitoring for the QoS flows indicated by the PCC rules using ICMP based Monitoring and, according to Action 402, it may select a UPF supporting the ICMP Ping for QoS packet delay Measurement feature. At Step 5, the SMF may bind PCCs to QoS Flows: the first network node 111 may, according to Action 403, determine which QoS Flow(s) may be needed to satisfy the QoS requirements for this traffic. The first network node 111 may also determine the QoS Monitoring per QoS Flow Control Information for the second network node 112, corresponding to the ICMP Ping that it may have to send to the second network node 112. At Step 6, the first network node 111 may, according to Action 404 and Action 502, send a PFCP Session Establishment or Modification Request including the instructions to the second network node 112. At Step 7, the second network node 112 may, according to Action 503, allocate an IP address for the monitoring of this QoS Flow using ICMP Ping. The allocated IP address may then be used as source IP address for the ICMP ping generation. In concrete for the solution flow diagram, it allocates the IP = 10.0.0.1 . The second network node 112 may allocate as many IPs as may be needed for ICMP, one for each QoS flow to monitor. At Step 8, the second network node 112 may, according to Action 504 and Action 405, send a response back to the first network node 111 by sending the created SSR over a PFCP Session Establishment or Modification Response.

[0195] Figure 7b is continuation of the sequence diagram depicted in Figure 7a. Hence, the entities depicted are the same as those depicted in Figure 7a. It may be understood that in the following example depicted in Figure 7b that any reference to the SMF may be understood to equally refer to the first network node 111, any reference to the UPF may be understood to equally refer to the second network node 112, any reference to the AMF may be understood to equally refer to the fourth node, any reference to the PCF may be understood to equally refer to the fifth node and any reference to the UE may be understood to equally refer to the communications device 130. Any of the features described in relation to Figure 4 and Figure 5 may be understood to equally apply to the pertinent actions depicted in Figure 7b. In Step 9), after the first network node 111 may have received the another indication from the second network node 112, the first network node 111 may, according to Action 406, determine the QoS Rules according to the QoS Monitoring needs. At Step 10, the first network node 111 may, according to Action 407, send the further indication in a Namf_Communication_N1N2 Message_Transfer_message, as in procedure in specifications, to convey to the communications device 130, through the third network node 701 , the QoS Rule for UL traffic mapping to QoS Flow, the QoS Profile, for example A, the Reflective QoS Attribute may be set. The third network node 701 may forward the further indication towards the RAN, e.g., the radio network node 140, in an N2 PDU Session Request, a Non Access Stratum (NAS) message. The RAN, e.g., the radio network node 140 may then forward the further indication towards the communications device 130 in an AN-specific resource set up, e.g., a PDU Session Establishment accept, and the communications device 130 may acknowledge the reception towards the third network node 701 , via the RAN, e.g., the radio network node 140. The RAN may then send an N2 PDU Session Response (Rsp) back to the third network node 701. As shown in Step 11 , at some point, the communications device 130 may be sending data traffic. The communications device 130 data traffic may be sent to / from other destinations than AS1 in UL / DL over the default bearer / QoS, as that traffic may be understood to not have a dedicated QoS / PDR rule on the communications device 130 and the second network node 112. The communications device 130 data traffic exchanged with AS1 may be sent in UL / DL over dedicated QoS Flows. Dedicated QoS rules and PDR rules may have been installed on the communications device 130 and the second network node 112, as depicted, for example on Examples A and B in Figure 6a and Figure 6b, respectively. At Step 12, the second network node 112 may detect the communications device 130 is showing activity on the QoS Flow, and it may decide to start monitoring QoS. The second network node 112 may then, according to Action 505, send the first packet as an ICMP ping from the allocated IP address IP = 10.0.0.1 to the communications device 130. The second network node 112 may then receive, according to Action 506, the second packet from the communications device 130 at the allocated IP address. At Step 13, the second network node 112 may, according to Action 507, determine the RTT and and / or one-way delays as requested, on each of the IP addresses it may have allocated, if multiple monitoring requests for the delay may have been received, e.g., if the delay may be measured in more than one flow. At Step 14, the second network node 112 may, according to Action 508, send the additional indication of the determined delay by reporting the QoS monitoring result of the QoS flows using the mechanisms available in the specifications, e.g., in a PFCP Session Report to the first network node 111 in the Session Report IE, in accordance with TS 29.244, v. 18.5.0, Table 7.5.8.6-1 , which may be sent from the second network node to the first network node 111 using PFCP Session Report procedures. The second network node 112 may additionally or alternatively send the additional indication directly to a consumer of the measurement using the second network node 112 event Exposure of QoS Monitoring event, in accordance with 3GPP TS 29.564, v. 18.4.0 [2]) As a summarized overview of the foregoing, embodiments herein may be understood to provide a mechanism which may be understood to allow an MNO to reliably measure the round trip packet delay and / or one way delay for a Service data Flow by using the well-known ICMP protocol, which may allow MNOs to support observability and congestion detection. Observability may be understood to refer to QoS round trip packet delay and / or one way delay monitoring for profile compliance. Congestion Detection may be understood to refer to a reliable round trip packet delay and / or one way delay measurement to characterize the channel congestion and be able to apply shaping functions, such as adaptive bitrate (ABR) shaping or Large Flow Shaping.

[0196] Some embodiments herein may comprise to update the 3GPP TS 29.244, v. 18.5.0 specification, only Stage 3 specification, to incorporate some of the embodiments herein.

[0197] For the approach to measure one way delay measurement granularity by using the ICMP timestamp and timestamp reply, embodiments herein may comprise to extend PFCP Association Setup and Update with new UP Function Feature, e.g., as indicated by the updated UP Function Feature IE, to indicate support for ICMP Ping for packet delay Measurement.

[0198] Some embodiments herein may comprise to extend Session Reporting Rules for QoS Monitoring in PFCP Session Establishment and Session Modification Request to indicate measurements using ICMP ping are requested and whether UPF needs to report back the ICMP allocated IP.

[0199] Some embodiments herein may comprise to extend Session Reporting reports and response to Session establishment / Modification messages to report the allocated IP addresses.

[0200] Some embodiments herein may comprise to extend PFCP Session Establishment and Session Modification Response with a new IE to inform of the IP allocated for the SRR.

[0201] Certain embodiments disclosed herein may provide one or more of the following technical advantage(s), which may be summarized as follows.

[0202] One advantage of embodiments herein may be understood to be that they may enable a network operator to measure the round-trip packet delay between a UE and a UPF in an easy and reliable way using ICMP echo and Echo reply messages.

[0203] Another advantage of embodiments herein may be understood to be that they may enable the network operator to measure one way packet delay granularity between the UE and the UPF by using the ICMP timestamp and timestamp reply messages. This may be understood to be only possible when the UE and the core network may be time synchronized and the session may support IPv4. For example, this may be used in a controlled environment e.g., for automation.

[0204] A further advantage of embodiments herein may be understood to be that they may have less impacts than the standardized QoS monitoring function on 3GPP. Embodiments herein may be understood to be able to be implemented “out of the box” with most UEs. For some UEs, some configuration may be needed, e.g., if they block ICMP echo packets, but there may be understood to be no impact on any standards related to the UEs. There may be understood to be no impact either on AMF or (R)AN.

[0205] Furthermore, embodiments herein may also work with non-3GPP access and to measure delay in a 4G network. In a 4G network, any reference herein to flow may be equally understood to equally apply to a bearer.

[0206] Figure 8 depicts an example of the arrangement that the first network node 111 may comprise to perform the method described in Figure 4, Figure 7a and / or Figure 7b. The first network node 111 may be understood to be for handling the measurement of the delay. The first network node 111 is configured to operate in the core network 101 of the communications system 100.

[0207] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 and will thus not be repeated here. For example, the indication, that is, the second indication, may be configured to comprise one or more session reporting rules.

[0208] In Figure 8, an optional component is indicated with dashed lines.

[0209] The first network node 111 is configured to send, to the second network node 112 configured to operate in the core network 101 of the communication system 100, the indication to measure the delay in the flow of data configured to have the first QoS between the second network node 112 and the communication device 130. The indication is configured to indicate the second network node 112 is to measure the delay by sending the first packet to the communication device 130, from the first IP address to be allocated by the second network node 112 and receiving, by the second network node 112 on the first IP address, the second packet in response to the first packet from the communication device 130. The communications device 130 is configured to communicate via the communications system 100.

[0210] The first network node 111 is also configured to receive the another indication from the second network node 112. The another indication is configured to indicate the response to the indication configured to be sent by the first network node 111.

[0211] In some embodiments, the second network node 112 may be configured to measure the delay as one of the following: the first difference between the first timestamp of the sending of the first packet by the second network node 112, and the second timestamp of arrival of the second packet from the communication device 130 as configured to be received by the second network node 112, the second difference between the first timestamp and the third timestamp of arrival of the first packet at the communication device 130, and the third difference between the fourth timestamp of the sending of the second packet by the communication device 130, and the second timestamp.

[0212] In some embodiments, one of the following may apply. In a group of embodiments, the first packet may be configured to be the ICMP Echo request and the second packet may be configured to be the ICMP Echo response, and the first timestamp may be configured to be of the sending of the ICMP Echo request by the second network node 112 and the second timestamp may be configured to be of the arrival of a first Echo response to the Echo request from the communication device 130 as configured to be received by the second network node 112. In another group of embodiments, the first packet may be configured to be the ICMP Timestamp request and the second packet may be configured to be the ICMP Timestamp response, and one of the following may apply: the first timestamp may be configured to be of the sending of the Timestamp request by the second network node 112, the second timestamp may be configured to be of the arrival of the Timestamp response from the communication device 130 at the second node 112, the third timestamp may be configured to be of the arrival of the Timestamp request at the communication device 130, and the fourth timestamp may be configured to be of the sending of the Timestamp response from the communication device 130 to the second network node 112.

[0213] In some embodiments wherein the first QoS may be configured to be in the uplink and the flow of data may be configured to have the first QoS, or the second QoS, in the downlink, the measurement may be configured to be performed in the uplink and in the downlink, the indication may be configured to indicate that the second network node 112 may have to: report back to the first network node 111 the IP address configured to be allocated and refrain from marking reflective in the first packet, and the another indication may be configured to indicate the IP address configured to be allocated, the first network node 111 may be configured with the following two configurations. In some embodiments, the first network node 111 may be configured to determine, based on the another indication configured to be received, the one or more rules to be used by the communication device 130 to send the second packet in reply to the first packet. The one or more rules may be configured to the a flow to be used by the communication device 130 to send the reply to the IP address configured to be allocated.

[0214] In some embodiments, the first network node 111 may be configured to send the further indication towards the communication device 130. The further indication may be configured to indicate the one or more rules configured to be determined.

[0215] In some embodiments, the indication may be configured to indicate the measurement may have to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet. The another indication may be configured to lack the indication of the IP address configured to be allocated.

[0216] In some embodiments, the first network node 111 may be configured with the three following configurations.

[0217] In some embodiments, the first network node 111 may be configured to receive the first indication from the second network node 112. The first indication may be configured to indicate the capability of the second network node 112 to measure the delay by sending the first packet, and receiving on the first IP address, the second packet in response to the first packet.

[0218] In some embodiments, the first network node 111 may be configured to select the second network node 112 to measure the delay based on the capacity configured to be indicated.

[0219] In some embodiments, the first network node 111 may be configured to determine the one or more flows to be measured by the second network node 112, the indication configured to be sent to the second network node 112 may be configured to be the second indication, and the second indication may be configured to be based on the one or more flows to be measured configured to be determined.

[0220] In some embodiments, one or more of the following may apply: the indication may be configured to be comprised in the PFCP Session Establishment or Modification request, the another indication may be configured to be comprised in the PFCP Session Establishment or Modification response, the first network node 111 may be configured to manage the SMF, the second network node 112 may be configured to manage the UPF, the communications system 100 may be configured to be the 3FPP network, the communications system 100 may be configured to be the 5G System, and the core network 101 may be configured to be the 5G Core Network.

[0221] The further indication may be configured to comprise the one or more QoS rules. The embodiments herein in the first network node 111 may be implemented through one or more processors, such as a processing circuitry 801 in the first network node 111 depicted in Figure 8, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first network node 111. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the first network node 111.

[0222] The first network node 111 may further comprise a memory 802 comprising one or more memory units. The memory 802 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the first network node 111.

[0223] In some embodiments, the first network node 111 may receive information from, e.g., the second network node 112, the communications device 130, the third network node 701 , the fourth network node 702, the radio network node 140, another network node or communications device, and / or another structure in the communications system 100, through a receiving port 803. In some embodiments, the receiving port 803 may be, for example, connected to one or more antennas in first network node 111. In other embodiments, the first network node 111 may receive information from another structure in the communications system 100 through the receiving port 803. Since the receiving port 803 may be in communication with the processing circuitry 801, the receiving port 803 may then send the received information to the processing circuitry 801. The receiving port 803 may also be configured to receive other information.

[0224] The processing circuitry 801 in the first network node 111 may be further configured to transmit or send information to e.g., the second network node 112, the communications device 130, the third network node 701, the fourth network node 702, the radio network node 140, another network node or communications device, and / or another structure in the communications system 100, through a sending port 804, which may be in communication with the processing circuitry 801 , and the memory 802.

[0225] Those skilled in the art will also appreciate that the units comprised within the first network node 111 described above as being configured to perform different actions, may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 801 , perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0226] The first network node 111 may be configured to perform any of the Actions described in relation to Figure 4, Figure 7a and / or Figure 7b, e.g., by means of the processing circuitry 801 within the first network node 111 , configured to perform any of such actions.

[0227] Also, in some embodiments, different units comprised within the first network node 111 may be configured to perform the different actions described above, implemented as one or more applications running on one or more processors such as the processing circuitry 801.

[0228] Thus, the methods according to the embodiments described herein for the first network node 111 may be respectively implemented by means of a computer program 805 product, comprising instructions, i.e. , software code portions, which, when executed on at least one processing circuitry 801 of the first network node 111 , cause the first network node 111 to carry out the actions described herein as performed by the first network node 111. The computer program 805 product may be stored on a computer-readable storage medium 806. The computer-readable storage medium 806, having stored thereon the computer program 805, may comprise instructions which, when executed on at least one processing circuitry 801 of the first network node 111 , cause the first network node 111 to carry out the actions described herein, as performed by the first network node 111. In some embodiments, the computer-readable storage medium 806 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 805 product may be stored on a carrier containing the computer program 805 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 806, as described above.

[0229] The first network node 111 may comprise a communication interface configured to facilitate, or an interface unit to facilitate, communications between the first network node 111 and other nodes or devices, e.g., the second network node 112, the communications device 130, the third network node 701, the fourth network node 702, the radio network node 140, another network node or communications device, and / or another structure in the communications system 100. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

[0230] Circuitry may be understood herein as a hardware component.

[0231] Hence, embodiments herein also relate to the first network node 111 , operative to operate in the communications system 100. The first network node 111 may comprise the processing circuitry 801 and the memory 802, said memory 802 containing instructions executable by said processing circuitry 801 , whereby the first network node 111 is further operative to perform the actions described herein in relation to the first network node 111, e.g., in Figure 4, Figure 7a and / or Figure 7b.

[0232] Figure 9 depicts an example of the arrangement that the second network node 112 may comprise to perform the method described in Figure 5, Figure 4, Figure 6a, Figure 6b, Figure 7a and / or Figure 7b. The second network node 112 may be understood to be for handling the measurement of the delay. The second network node 112 is configured to operate in the core network 101 of the communications system 100.

[0233] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the second network node 112 and will thus not be repeated here. For example, the indication, that is, the second indication, may be configured to comprise one or more session reporting rules.

[0234] In Figure 9, an optional component is indicated with dashed lines.

[0235] The second network node 112 is configured to receive, from the first network node 111 configured to operate in the core network 101 of the communication system 100, the indication. The indication is configured to indicate to measure the delay in the flow of data configured to have the first QoS between the second network node 112 and the communication device 130. The indication is configured to indicate to measure the delay by sending the first packet to the communication device 130, from the first IP address to be allocated by the second network node 112 and receiving, by the second network node 112 on the first IP address, the second packet in response to the first packet from the communication device 130. The communications device 130 is configured to communicate via the communications system 100.

[0236] The second network node 112 is also configured to send the another indication to the first network node 111. The another indication is configured to indicate the response to the indication configured to be received from the first network node 111.

[0237] In some embodiments, the second network node 112 may be configured to measure the delay as one of the following: the first difference between the first timestamp of the sending of the first packet by the second network node 112, and the second timestamp of arrival of the second packet from the communication device 130 as configured to be received by the second network node 112, the second difference between the first timestamp and the third timestamp of arrival of the first packet at the communication device 130, and the third difference between the fourth timestamp of the sending of the second packet by the communication device 130, and the second timestamp.

[0238] In some embodiments, the second network node 112 may be configured with the following four configurations.

[0239] In some embodiments, the second network node 112 may be configured to send the first packet from the IP address configured to be allocated to the communication device 130, based on the indication configured to be received, that is, the second indication.

[0240] In some embodiments, the second network node 112 may be configured to receive, at the IP address configured to be allocated, the second packet from the communication device 130 in response to the first packet.

[0241] In some embodiments, the second network node 112 may be configured to determine the delay based on at least one of the first difference, the second difference and the third difference.

[0242] In some embodiments, the second network node 112 may be configured to output the additional indication of the delay configured to be determined.

[0243] In some embodiments, one of the following may apply. In a group of embodiments, the first packet may be configured to be the ICMP Echo request and the second packet may be configured to be the ICMP Echo response, and the first timestamp may be configured to be of the sending of the ICMP Echo request by the second network node 112 and the second timestamp may be configured to be of the arrival of the first Echo response to the Echo request from the communication device 130 as configured to be received by the second network node 112. In another group of embodiments, the first packet may be configured to be the ICMP Timestamp request and the second packet may be configured to be the ICMP Timestamp response, and one of the following may apply: the first timestamp may be configured to be of the sending of the Timestamp request by the second network node 112, the second timestamp may be configured to be of the arrival of the Timestamp response from the communication device 130 at the second node 112, the third timestamp may be configured to be of the arrival of the Timestamp request at the communication device 130, and the fourth timestamp may be configured to be of the sending of the Timestamp response from the communication device 130 to the second network node 112.

[0244] In some embodiments wherein the first QoS may be configured to be in the uplink and the flow of data may be configured to have the first QoS, or the second QoS, in the downlink, the measurement may be configured to be performed in the uplink and in the downlink, the indication may be configured to indicate that the second network node 112 may have to: report back to the first network node 111 the IP address configured to be allocated and refrain from marking reflective in the first packet, and the another indication may be configured to indicate the IP address configured to be allocated, the second network node 112 may be configured to allocate the IP address based on the indication configured to be received.

[0245] In some embodiments, the indication may be configured to indicate the measurement may have to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet. In such embodiments, the second network node 112 may be configured to refrain from indicating the IP address configured to be allocated in the another indication.

[0246] In some embodiments, the second network node 112 may be configured to send the first indication to the first network node 111. The first indication may be configured to indicate the capability of the second network node 112 to measure the delay by sending the first packet, and receiving on the first IP address, the second packet in response to the first packet.

[0247] In some embodiments, one or more of the following may apply: the indication may be configured to be comprised in the PFCP Session Establishment or Modification request, the another indication may be configured to be comprised in the PFCP Session Establishment or Modification response, the first network node 111 may be configured to manage the SMF, the second network node 112 may be configured to manage the UPF, the communications system 100 may be configured to be the 3FPP network, the communications system 100 may be configured to be the 5G System, and the core network 101 may be configured to be the 5G Core Network.

[0248] The embodiments herein in the second network node 112 may be implemented through one or more processors, such as a processing circuitry 901 in the second network node 112 depicted in Figure 9, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the second network node 112. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the second network node 112.

[0249] The second network node 112 may further comprise a memory 902 comprising one or more memory units. The memory 902 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the second network node 112.

[0250] In some embodiments, the second network node 112 may receive information from, e.g., the first network node 111 , the communications device 130, the third network node 701 , the fourth network node 702, the radio network node 140, another network node or communications device, and / or another structure in the communications system 100, through a receiving port 903. In some embodiments, the receiving port 903 may be, for example, connected to one or more antennas in second network node 112. In other embodiments, the second network node 112 may receive information from another structure in the communications system 100 through the receiving port 903. Since the receiving port 903 may be in communication with the processing circuitry 901 , the receiving port 903 may then send the received information to the processing circuitry 901. The receiving port 903 may also be configured to receive other information.

[0251] The processing circuitry 901 in the second network node 112 may be further configured to transmit or send information to e.g., the first network node 111 , the communications device 130, the third network node 701, the fourth network node 702, the radio network node 140, another network node or communications device, and / or another structure in the communications system 100, through a sending port 904, which may be in communication with the processing circuitry 901 , and the memory 902.

[0252] Those skilled in the art will also appreciate that the units comprised within the second network node 112 described above as being configured to perform different actions, may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 901 , perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0253] The second network node 112 may be configured to perform any of the Actions described in relation to Figure 5, Figure 4, Figure 6a, Figure 6b, Figure 7a and / or Figure 7b, e.g., by means of the processing circuitry 901 within the second network node 112, configured to perform any of such actions.

[0254] Also, in some embodiments, different units comprised within the second network node 112 may be configured to perform different actions described above, implemented as one or more applications running on one or more processors such as the processing circuitry 901.

[0255] Thus, the methods according to the embodiments described herein for the second network node 112 may be respectively implemented by means of a computer program 905 product, comprising instructions, i.e. , software code portions, which, when executed on at least one processing circuitry 901 of the second network node 112, cause the second network node 112 to carry out the actions described herein, as performed by the second network node 112. The computer program 905 product may be stored on a computer-readable storage medium 906. The computer-readable storage medium 906, having stored thereon the computer program 905, may comprise instructions which, when executed on at least one processing circuitry 901 of the second network node 112, cause the second network node 112 to carry out the actions described herein, as performed by the second network node 112. In some embodiments, the computer-readable storage medium 906 may be a non-transitory computer- readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 905 product may be stored on a carrier containing the computer program 905 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 906, as described above.

[0256] The second network node 112 may comprise a communication interface configured to facilitate, or an interface unit to facilitate, communications between the second network node 112 and other nodes or devices, e.g., the first network node 111 , the communications device 130, the third network node 701, the fourth network node 702, the radio network node 140, another network node or communications device, and / or another structure in the communications system 100. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

[0257] Circuitry may be understood herein as a hardware component.

[0258] Hence, embodiments herein also relate to the second network node 112, operative to operate in the communications system 100. The second network node 112 may comprise the processing circuitry 901 and the memory 902, said memory 902 containing instructions executable by said processing circuitry 901, whereby the second network node 112 is further operative to perform the actions described herein in relation to the second network node 112, e.g., in Figure 5, Figure 4, Figure 6a, Figure 6b, Figure 7a and / or Figure 7b.

[0259] Embodiments herein may also comprise the communications system 100 comprising one or more of: the first network node 111 configured as described in relation to Figure 8 and the second network node 112 configured as described in relation to Figure 9.

[0260] When using the word "comprise" or “comprising”, it shall be interpreted as non- limiting, i.e. , meaning "consist at least of".

[0261] The embodiments herein are not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention.

[0262] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0263] As used herein, the expression “at least one of:” followed by a list of alternatives separated by commas, and wherein the last alternative is preceded by the “and” term, may be understood to mean that only one of the list of alternatives may apply, more than one of the list of alternatives may apply or all of the list of alternatives may apply. This expression may be understood to be equivalent to the expression “at least one of:” followed by a list of alternatives separated by commas, and wherein the last alternative is preceded by the “or” term.

[0264] Any of the terms processor and circuitry may be understood herein as a hardware component.

[0265] As used herein, the expression “in some embodiments” has been used to indicate that the features of the embodiment described may be combined with any other embodiment or example disclosed herein.

[0266] As used herein, the expression “in some examples” has been used to indicate that the features of the example described may be combined with any other embodiment or example disclosed herein.

[0267] REFERENCES

[0268] 1. 3GPP TS 29.244 v18.5.0 (March 2024): Interface between the Control Plane and the User Plane nodes

[0269] 2. 3GPP TS 29.564 v18.4.0 (March 2024): 5G System; User Plane Function Services; Stage 3

[0270] 3. RFC 792 Internet Control Message Protocol

[0271] 4. RFC 4443 Internet Control Message Protocol for IPv6

Claims

CLAIMS:

1. A computer-implemented method, performed by a first network node (111), the method being for handling measurement of a delay, the first network node (111) operating in a core network (101) of a communications system (100), the method comprising: sending (404), to a second network node (112) operating in the core network (101) of the communication system (100), an indication to measure the delay in a flow of data having a first Quality of Service, QoS, between the second network node (112) and a communication device (130), by sending a first packet to the communication device (130), from a first Internet Protocol, IP, address to be allocated by the second network node (112) and receiving, by the second network node (112) on the first IP address, a second packet in response to the first packet from the communication device (130), wherein the communications device (130) communicates via the communications system (100), and receiving (405) another indication from the second network node (112), the another indication indicating a response to the indication sent by the first network node (111).

2. The method according to claim 1, wherein the second network node (112) is to measure the delay as one of: a first difference between a first timestamp of the sending of the first packet by the second network node (112), and a second timestamp of arrival of the second packet from the communication device (130) as received by the second network node (112), a second difference between the first timestamp and a third timestamp of arrival of the first packet at the communication device (130), and a third difference between a fourth timestamp of a sending of the second packet by the communication device (130), and the second timestamp.

3. The method according to claim 2, wherein one of: the first packet is an Internet Control Message Protocol, ICMP, Echo request and the second packet is an ICMP Echo response, and wherein the first timestamp is of the sending of the ICMP Echo request by the second network node (112) and the second timestamp is of the arrival of a first Echo response to the Echo request from the communication device (130) as received by the second network node (112),the first packet is an ICMP Timestamp request and the second packet is an ICMP Timestamp response, and wherein one of: the first timestamp is of the sending of the Timestamp request by the second network node (112), the second timestamp is of the arrival of the Timestamp response from the communication device (130) at the second node (112), the third timestamp is of the arrival of the Timestamp request at the communication device (130), and the fourth timestamp is of the sending of the Timestamp response from the communication device (130) to the second network node (112).

4. The method according to any of claims 1-3, wherein the first QoS is in the uplink and the flow of data has the first QoS, or a second QoS, in the downlink, the measurement is to be performed in the uplink and in the downlink, the indication indicates that the second network node (112) is to: report back to the first network node (111) the allocated IP address and refrain from marking reflective in the first packet, wherein the another indication indicates the allocated IP address and wherein the method comprises: determining (406), based on the received another indication, one or more rules to be used by the communication device (130) to send the second packet in reply to the first packet, the one or more rules indicating a flow to be used by the communication device (130) to send the reply to the allocated IP address, and sending (407) a further indication towards the communication device (130), the further indication indicating the determined one or more rules.

5. The method according to any of claim 1-3, wherein the indication indicates the measurement is to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet, and wherein the another indication lacks an indication of the allocated IP address.

6. The method according to any of claims 1-5, the method comprising: receiving (401) a first indication from the second network node (112), the first indication indicating a capability of the second network node (112) to measure the delay by sending the first packet, and receiving on the first IP address, the second packet in response to the first packet, selecting (402) the second network node (112) to measure the delay based on the indicated capacity, anddetermining (403) one or more flows to be measured by the second network node (112), and wherein the indication sent to the second network node (112) is a second indication, and wherein the second indication is based on the determined one or more flows to be measured.

7. The method according to any of claims 1-6, wherein one or more of: the indication is comprised in a PFCP Session Establishment or Modification request, the another indication is comprised in a PFCP Session Establishment or Modification response, the first network node (111) manages a Session Management Function, SMF, the second network node (112) manages a User Plane Function, UPF, the communications system (100) is a Third Generation Partnership Project network, the communications system (100) is a Fifth Generation, 5G, System, and the core network (101) is a 5G Core Network.

8. A computer-implemented method, performed by a second network node (112), the method being for handling measurement of a delay, the second network node (112) operating in a core network (101) of a communications system (100), the method comprising: receiving (502), from a first network node (111) operating in the core network (101) of the communication system (100), an indication to measure the delay in a flow of data having a first Quality of Service, QoS, between the second network node (112) and a communication device (130), by sending a first packet to the communication device (130), from a first Internet Protocol, IP, address to be allocated by the second network node (112) and receiving, by the second network node (112) on the first IP address, a second packet in response to the first packet from the communication device (130), wherein the communications device (130) communicating via the communications system (100), and sending (504) another indication to the first network node (111), the another indication indicating a response to the indication received from the first network node (111).

9. The method according to claim 8, wherein the second network node (112) is to measure the delay as one of:a first difference between a first timestamp of the sending of the first packet by the second node (112), and a second timestamp of arrival of the second packet from the communication device (130) as received by the second network node (112), a second difference between the first timestamp and a third timestamp of arrival of the first packet at the communication device (130), and a third difference between a fourth timestamp of a sending of the second packet by the communication device (130), and the second timestamp.

10. The method according to claim 9, the method comprising: sending (505) the first packet from the allocated IP address to the communication device (130), based on the received indication, receiving (506), at the allocated IP address, the second packet from the communication device (130) in response to the first packet, determining (507) the delay based on at least one of the first difference, the second difference and the third difference, outputting (508) an additional indication of the determined delay.

11. The method according to any of claims 9-10, wherein one of: the first packet is an Internet Control Message Protocol, ICMP, Echo request and the second packet is an ICMP Echo response, and wherein the first timestamp is of the sending of the ICMP Echo request by the second network node (112) and the second timestamp is of the arrival of a first Echo response to the Echo request from the communication device (130) as received by the second network node (112), the first packet is an ICMP Timestamp request and the second packet is an ICMP Timestamp response, and wherein one of: the first timestamp is of the sending of the Timestamp request by the second network node (112), the second timestamp is of the arrival of the Timestamp response from the communication device (130) at the second node (112), the third timestamp is of the arrival of the Timestamp request at the communication device (130), and the fourth timestamp is of the sending of the Timestamp response from the communication device (130) to the second network node (112).

12. The method according to any of claims 8-11, wherein the first QoS is in the uplink and the flow of data has the first QoS, or a second QoS, in the downlink, the measurement is to be performed in the uplink and in the downlink, the indication indicates that the second network node (112) is to: report back to the first network node (111) the allocated IP address and refrain from marking reflective in the first packet, wherein the another indication indicates the allocated IP address and wherein the method comprises: allocating (503), the IP address based on the received indication.

13. The method according to any of claims 8-11, wherein the indication indicates the measurement is to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet, and wherein the second network node (112) refrains from indicating the allocated IP address in the another indication.

14. The method according to any of claims 8-13, the method comprising: sending (501) a first indication to the first network node (111), the first indication indicating a capability of the second network node (112) to measure the delay by sending the request with the first packet and receiving on the first IP address, the second packet in response to the first packet.

15. The method according to any of claims 8-14, wherein one or more of: the indication is comprised in a PFCP Session Establishment or Modification request, the another indication is comprised in a PFCP Session Establishment or Modification response, the first network node (111) manages a Session Management Function, SMF, the second network node (112) manages a User Plane Function, UPF, the communications system (100) is a Third Generation Partnership Project network, the communications system (100) is a Fifth Generation, 5G, System, and the core network (101) is a 5G Core Network.

16. A first network node (111), for handling measurement of a delay, the first network node (111) being configured to operate in a core network (101) of a communications system (100), the first network node (111) being configured to: send, to a second network node (112) configured to operate in the core network (101) of the communication system (100), an indication to measure the delay in aflow of data configured to have a first Quality of Service, QoS, between the second network node (112) and a communication device (130), by sending a first packet to the communication device (130), from a first Internet Protocol, IP, address to be allocated by the second network node (112) and receiving, by the second network node (112) on the first IP address, a second packet in response to the first packet from the communication device (130), wherein the communications device (130) is configured to communicate via the communications system (100), and receive another indication from the second network node (112), the another indication being configured to indicate a response to the indication configured to be sent by the first network node (111).

17. The first network node (111) according to claim 16, wherein the second network node (112) is configured to measure the delay as one of: a first difference between a first timestamp of the sending of the first packet by the second network node (112), and a second timestamp of arrival of the second packet from the communication device (130) as configured to be received by the second network node (112), a second difference between the first timestamp and a third timestamp of arrival of the first packet at the communication device (130), and a third difference between a fourth timestamp of a sending of the second packet by the communication device (130), and the second timestamp.

18. The first network node (111) according to claim 17, wherein one of: the first packet is configured to be an Internet Control Message Protocol, ICMP, Echo request and the second packet is configured to be an ICMP Echo response, and wherein the first timestamp is configured to be of the sending of the ICMP Echo request by the second network node (112) and the second timestamp is configured to be of the arrival of a first Echo response to the Echo request from the communication device (130) as configured to be received by the second network node (112), the first packet is configured to be an ICMP Timestamp request and the second packet is configured to be an ICMP Timestamp response, and wherein one of: the first timestamp is configured to be of the sending of the Timestamp request by the second network node (112), the second timestamp is configured to be of the arrival of the Timestamp response from the communication device (130) at the second node (112),the third timestamp is configured to be of the arrival of the Timestamp request at the communication device (130), and the fourth timestamp is configured to be of the sending of the Timestamp response from the communication device (130) to the second network node (112).

19. The first network node (111) according to any of claims 16-18, wherein the first QoS is configured to be in the uplink and the flow of data is configured to have the first QoS, or a second QoS, in the downlink, the measurement is configured to be performed in the uplink and in the downlink, the indication is configured to indicate that the second network node (112) is to: report back to the first network node (111) the IP address configured to be allocated and refrain from marking reflective in the first packet, wherein the another indication is configured to indicate the IP address configured to be allocated and wherein the first network node (111) is configured to: determine, based on the another indication configured to be received, one or more rules to be used by the communication device (130) to send the second packet in reply to the first packet, the one or more rules being configured to indicate a flow to be used by the communication device (130) to send the reply to the IP address configured to be allocated, and send a further indication towards the communication device (130), the further indication being configured to indicate the one or more rules configured to be determined.

20. The first network node (111) according to any of claim 16-18, wherein the indication is configured to indicate the measurement is to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet, and wherein the another indication is configured to lack an indication of the IP address configured to be allocated.

21. The first network node (111) according to any of claims 1-5, configured to: receive a first indication from the second network node (112), the first indication being configured to indicate a capability of the second network node (112) to measure the delay by sending the first packet, and receiving on the first IP address, the second packet in response to the first packet, select the second network node (112) to measure the delay based on the capacity configured to be indicated, anddetermine one or more flows to be measured by the second network node (112), and wherein the indication configured to be sent to the second network node (112) is configured to be a second indication, and wherein the second indication is configured to be based on the one or more flows to be measured configured to be determined.

22. The first network node (111) according to any of claims 16-21, wherein one or more of: the indication is configured to be comprised in a PFCP Session Establishment or Modification request, the another indication is configured to be comprised in a PFCP Session Establishment or Modification response, the first network node (111) is configured to manage a Session Management Function, SMF, the second network node (112) is configured to manage a User Plane Function, UPF, the communications system (100) is configured to be a Third Generation Partnership Project network, the communications system (100) is configured to be a Fifth Generation, 5G, System, and the core network (101) is configured to be a 5G Core Network.

23. A second network node (112), for handling measurement of a delay, the second network node (112) being configured to operate in a core network (101) of a communications system (100), the second network node (112) being configured to: receive, from a first network node (111) configured to operate in the core network (101) of the communication system (100), an indication to measure the delay in a flow of data configured to have a first Quality of Service, QoS, between the second network node (112) and a communication device (130), by sending a first packet to the communication device (130), from a first Internet Protocol, IP, address to be allocated by the second network node (112) and receiving, by the second network node (112) on the first IP address, a second packet in response to the first packet from the communication device (130), wherein the communications device (130) is configured to communicate via the communications system (100), and send another indication to the first network node (111), the another indication being configured to indicate a response to the indication configured to be received from the first network node (111).

24. The second network node (112) according to claim 23, wherein the second network node (112) is configured to measure the delay as one of: a first difference between a first timestamp of the sending of the first packet by the second node (112), and a second timestamp of arrival of the second packet from the communication device (130) as configured to be received by the second network node (112), a second difference between the first timestamp and a third timestamp of arrival of the first packet at the communication device (130), and a third difference between a fourth timestamp of a sending of the second packet by the communication device (130), and the second timestamp.

25. The second network node (112) according to claim 24, being configured to: send the first packet from the IP address configured to be allocated to the communication device (130), based on the indication configured to be received, receive, at the IP address configured to be allocated, the second packet from the communication device (130) in response to the first packet, determine the delay based on at least one of the first difference, the second difference and the third difference, output an additional indication of the delay configured to be determined.

26. The second network node (112) according to any of claims 23-25, wherein one of: the first packet is configured to be an Internet Control Message Protocol, ICMP, Echo request and the second packet is configured to be an ICMP Echo response, and wherein the first timestamp is configured to be of the sending of the ICMP Echo request by the second network node (112) and the second timestamp is configured to be of the arrival of a first Echo response to the Echo request from the communication device (130) as configured to be received by the second network node (112), the first packet is configured to be an ICMP Timestamp request and the second packet is configured to be an ICMP Timestamp response, and wherein one of: the first timestamp is configured to be of the sending of the Timestamp request by the second network node (112), the second timestamp is configured to be of the arrival of the Timestamp response from the communication device (130) at the second node (112), the third timestamp is configured to be of the arrival of the Timestamp request at the communication device (130), andthe fourth timestamp is configured to be of the sending of the Timestamp response from the communication device (130) to the second network node (112).

27. The second network node (112) according to any of claims 23-26, wherein the first QoS is configured to be in the uplink and the flow of data is configured to have the first QoS, or a second QoS, in the downlink, the measurement is configured to be performed in the uplink and in the downlink, the indication being configured to indicate that the second network node (112) is to: report back to the first network node (111) the IP address configured to be allocated and refrain from marking reflective in the first packet, wherein the another indication is configured to indicate the IP address configured to be allocated and wherein the second network node (112) is configured to: allocate the IP address based on the indication configured to be received.

28. The second network node (112) according to any of claims 23-26, wherein the indication is configured to indicate the measurement is to be performed in the uplink and in the downlink on the same flow of data, and to mark reflective in the first packet, and wherein the second network node (112) is configured to refrain from indicating the IP address configured to be allocated in the another indication.

29. The second network node (112) according to any of claims 23-28, configured to: send a first indication to the first network node (111), the first indication being configured to indicate a capability of the second network node (112) to measure the delay by sending the request with the first packet and receiving on the first IP address, the second packet in response to the first packet.

30. The second network node (112) according to any of claims 23-29, wherein one or more of: the indication is configured to be comprised in a PFCP Session Establishment or Modification request, the another indication is configured to be comprised in a PFCP Session Establishment or Modification response, the first network node (111) is configured to manage a Session Management Function, SMF, the second network node (112) is configured to manage a User Plane Function, UPF,the communications system (100) is configured to be a Third Generation Partnership Project network, the communications system (100) is configured to be a Fifth Generation, 5G, System, and the core network (101) is configured to be a 5G Core Network.

31. A communications system (100) comprising one or more of: a first network node (111) according to any of the claims 16-22, and a second network node (112) according to any of the claims 23-30.

32. A computer program (805), comprising instructions which, when executed on at least one processing circuitry (801) of a first network node (111), cause the first network node (111) to carry out the method according to any of claims 1-7.

33. A computer-readable storage medium (806), having stored thereon a computer program (805), comprising instructions which, when executed on at least one processing circuitry (801) of a first network node (111), cause the first network node (111) to carry out the method according to any of claims 1-7.

34. A computer program (905), comprising instructions which, when executed on at least one processing circuitry (901) of a second network node (112), cause the second network node (112) to carry out the method according to any of claims 8-15.

35. A computer-readable storage medium (906), having stored thereon a computer program (905), comprising instructions which, when executed on at least one processing circuitry (901) of a second network node (112), cause the second network node (112) to carry out the method according to any of claims 8-15.

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