Communication system, router, program, and communication management method

Abstract

To provide a communication system.SOLUTION: In a communication system, an SRGW includes: an IP prefix of a subordinate network; and a table storage part that stores a corresponding table of an SRv6 SID of a Locator+Function length that is shorter than the length of the IP prefix corresponding to the IP prefix. A PE includes: an SID generation part that generates an SID containing one part of an address of a destination positioned at the subordinate of the SRGW and header information; and a packet transmission part that transmits an SRv6 packet containing the SID to the SRGW. The SRGW also includes a packet generation part that specifies the IP prefix corresponding to the SID contained in the SRv6 packet by referring to the corresponding table in the case where the SRv6 packet is received from the PE, specifies the address of the destination by using the IP prefix and one part of the address of the destination contained in the SID, and generates a packet by using the address specified and the header information.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a communication system, a router, a program, and a communication management method. [Background technology]

[0002] Patent Document 1 describes a forwarding device that performs forwarding processing using protocols such as Segment Routing IPv6 (SRv6) and Multi-Protocol Label Switching (SR-MPLS). [Prior art document] [Patent documents] [Patent Document 1] JP 2020-174231 A Summary of the Invention [Means for solving the problem]

[0003] According to an embodiment of the present invention, a communication system is provided. The communication system may include a first router and a second router. The first router may have a table storage unit that stores a correspondence table between an IP prefix of a network under the first router and an SRv6 SID having a Locator+Function length shorter than the IP prefix length corresponding to the IP prefix. The second router may have a SID generation unit that generates an SID including a part of an address of a destination located under the first router and header information of a packet to be transmitted to the destination. The second router may have a packet transmission unit that transmits an SRv6 packet including the SID generated by the SID generation unit to the first router. The first router may have a packet generation unit that, when receiving the SRv6 packet from the second router, refers to the correspondence table to identify an IP prefix corresponding to the SID included in the SRv6 packet, identifies the address of the destination using the identified IP prefix and a part of the destination address included in the SID, and generates a packet to be sent to the destination using the identified address and the header information included in the SID.

[0004] In the communication system, the first router may be a PE router that converts an SRv6 packet conforming to SRv6 into a GTP-U packet conforming to GTP-U, the table storage unit may store the correspondence table between the IP prefix of a RAN under the first router and the SRv6 SID, the second router may have a route information receiving unit that receives UE route information including a gNB address of a gNB to which a UE is connected, advertised by a controller, the SID generation unit may generate the SID including a portion of the gNB address and the header information, and the packet generation unit may identify the gNB address using an IP prefix corresponding to the SID included in the SRv6 packet and a portion of the gNB address included in the SID, and may generate a GTP-U packet to be transmitted to the gNB using the identified gNB address and the header information. The SID generation unit may generate the SID including a portion of the gNB address and the header information including a TEID, QFI, and RQI included in the UE route information, and the packet generation unit may generate the GTP-U packet using the identified gNB address and the TEID, QFI, and RQI included in the header information.The first router may have an advertisement unit that advertises an ISD (Interwork Segment Discovery) route, and the ISD route indicates GTP6.E.Reduced as SID Behavior in a BGP attribute that stores an SRv6 SID, and when a prefix length of an IP prefix of an actual RAN including an IP prefix corresponding to the SID is shorter than an Arg.Mob.Session length compared to an SID Locator / Function length, an IP prefix having the same length as the Locator / Function length of the SID and the Arg.Mob.Session length, including a stuff area for the second router to embed an Arg.Mob.Session in the SID, may be stored in an NLRI, and the SID generation unit may generate an SRv6 SID by detecting that the gNB address included in the UE route information is included in the IP prefix stored in the NLRI of the ISD route received from the first router including the stuff area, and When the Behavior of an SID indicates GTP6.E.Reduced, the SID may be generated by storing an Arg.Mob.Session consisting of the header information including the TEID, the QFI, and the RQI included in the UE route information in the Argument area within the SID, and storing the value of the gNB address in the same bit position as the remaining bits in the remaining Argument bits.When the packet generation unit receives an SRv6 packet having a GTP6.E.Reduced SID as an active SID, it may obtain the Arg.Mob.Session from the SID, identify the gNB address from the IP prefix including the stuff area and the value of the gNB address in the same bit position as the remaining bits, and obtain the TEID, the QFI, and the RQI from the Arg.Mob.Session.The first router may include a table management unit that deletes a pair of the RAN IP prefix and the corresponding SRv6 SID from the correspondence table when a route having a destination prefix including a RAN IP prefix having a stuff area for embedding Arg.Mob.Session from a VRF connected to the gNB is lost or reachability to the IP prefix is ​​lost, and the advertising unit may perform a withdrawal route advertisement for an ISD route having the RAN IP prefix in its NLRI when the pair of the RAN IP prefix and the corresponding SRv6 SID is deleted from the correspondence table. In any of the communication systems, the first router may further include a table registration unit that automatically generates one or more IP prefixes longer than the Locator+Function length of the SRv6 SID by the Arg.Mob.Session length as IP prefixes to be registered in the correspondence table using configuration information specifying one or more destination prefixes from route information registered in the VRF connected to the gNB and the Locator+Function length of the SRv6 SID set in the first router, automatically generates SRv6 SIDs corresponding to each of the automatically generated IP prefixes, and registers them in the correspondence table. The communication system may further include the controller.

[0005] According to one embodiment of the present invention, a router is provided. The router may include a table storage unit that stores a correspondence table between an IP prefix of a network under the router and an SRv6 SID with a Locator+Function length shorter than the IP prefix length corresponding to the IP prefix. The router may include a packet generation unit that, when receiving an SRv6 packet from another router, includes an SID including a part of an address of a destination under the router and header information of a packet to be sent to the destination, refers to the correspondence table, and uses the IP prefix corresponding to the SID included in the SRv6 packet and a part of the address of the destination included in the SID to identify the address of the destination, and generates a packet to be sent to the destination using the identified address and the header information included in the SID.

[0006] According to one embodiment of the present invention, there is provided a program for causing a computer to function as the router.

[0007] According to one embodiment of the present invention, there is provided a communication management method executed by a router. The communication management method may include a storage step of storing, in a table storage unit, a correspondence table between an IP prefix of a network under the router and an SRv6 SID having a Locator+Function length shorter than the IP prefix length corresponding to the IP prefix. The communication management method may include a packet generation step of, when receiving from another router an SRv6 packet including an SID including a part of an address of a destination located under the router and header information of a packet to be sent to the destination, referring to the correspondence table, specifying the address of the destination using the IP prefix corresponding to the SID included in the SRv6 packet and a part of the address of the destination included in the SID, and generating a packet to be sent to the destination using the specified address and the header information included in the SID.

[0008] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0009] [Figure 1] 1 illustrates a schematic configuration example of a communication system 10. [Diagram 2] 2 is an explanatory diagram for roughly explaining a processing flow in the communication system 10. FIG. [Diagram 3] FIG. 11 is an explanatory diagram for explaining an example of a GTP6.E.Reduced SID. [Figure 4] FIG. 11 is an explanatory diagram for explaining GTP6.E.Reduced SID. [Diagram 5] FIG. 11 is an explanatory diagram for explaining GTP6.E.Reduced SID. [Figure 6] 4 shows an example of a functional configuration of a conversion unit 450. [Figure 7] 2 illustrates an example of a functional configuration of a PE router 220. [Figure 8] An example of the hardware configuration of a computer 1200 functioning as an SRGW 400, a PE router 220, or an N4BGPC 300 is shown in schematic form. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0011] In a mobile network using SRv6, a function called End.M.GTP6.E is known that converts SRv6-compliant SRv6 packets into GTP-U packets that comply with GTP-U (GPRS Tunneling Protocol for User Plane). End.M.GTP6.E can convert the header of a packet from SRv6 to GTP-U / IPv6, for example, by using the gNB (gNodeB) address stored in the LastSID (Segment ID) of the SRH (SR Header). However, depending on the limitations of the hardware capabilities of the PE (Provider Edge) router that implements End.M.GTP6.E, it may be difficult to extract the gNB address stored in the LastSID of the SRH, and it may not be possible to configure the destination IPv6 address of the GTP-U packet.

[0012] In contrast, in one embodiment of the communication system 10 according to the present embodiment, for example, a function is provided that can achieve the restoration of all bits of the destination gNB address after GTP-U conversion, and the TEID (Tunnel Endpoint IDentifier), QFI (QoS Flow Identifier), and RQI (Reflective QoS Indication) of the GTP-U header with only one SID. Such a function may be referred to as End.M.GTP6.E.Reduced (GTP6.E.Red when omitted). GTP6.E.Red can reduce the limitations on the hardware capabilities to be implemented. This can contribute to realizing packet conversion from SRv6 to GTP-U with more hardware.

[0013] FIG. 1 illustrates an example of a configuration of a communication system 10. The communication system 10 includes a Segment Routing Gateway (SRGW) 400. The SRGW 400 may be called a Provider Edge (PE) router. The SRGW 400 may be an example of a first router. The communication system 10 may include a PE router 220. The PE router 220 may be an example of a second router. The communication system 10 may include an N4 Border Gateway Protocol Controller (N4BGPC) 300. The N4BGPC 300 may be an example of a controller. The SRGW 400, the PE router 220, and the N4BGPC 300 may be disposed in a Segment Routing Network (SRNW) 20.

[0014] The SRGW 400 may have a function of converting an SRv6 packet compliant with SRv6 received from an IP network into a GTP-U packet compliant with GTP-U. The SRGW 400 may have a function of converting a GTP-U packet compliant with GTP-U received from a mobile network into an SRv6 packet compliant with SRv6.

[0015] The N4BGPC 300 executes processing related to route control. The N4BGPC 300 may issue instructions related to route control to the SRGW 400. The N4BGPC 300 may issue instructions related to route control to the PE router 220.

[0016] 1, the SRNW 20 is provided with virtual routing and forwarding (VRF) circuits 202, 204, 206, and 208. Routers that realize each VRF are not shown. The SRGW 400 may include a VRF 210.

[0017] The VRF 202 is connected to a Session Management Function (SMF) 110. The VRF 204, VRF 206, and VRF 208 are connected to a User Plane Function (UPF) 120. The VRF 210 is connected to the gNB 130. The VRF 210 may be connected to the gNB 130 via a switch or a router. Although one VRF 210, one gNB 130, and one UE 40 are illustrated in FIG. 1, the numbers of the VRFs 210, the gNBs 130, and the UEs 40 are not limited to this.

[0018] The N4BGPC 300 acquires information related to the mobile network from the SMF 110. The N4BGPC 300 acquires, for example, Packet Forwarding Control Protocol (PFCP) session information of the UE 40 from the SMF 110.

[0019] The PFCP session information includes, for example, an address of the UE 40. The PFCP session information includes, for example, an address of the gNB 130 accommodating the UE 40. The PFCP session information includes, for example, an address of the UPF 120 corresponding to the UE 40. The PFCP session information includes, for example, a network instance corresponding to the UE 40. The network instance is, for example, an access network instance, information corresponding to slice identification information capable of identifying a slice corresponding to the UE 40 in a mobile network. The slice identification information is, for example, Single-Network Slice Selection Assistance Information (S-NSSAI). The PFCP session information may include an access network instance. The PFCP session information may include a core network instance. The core network instance is, for example, information corresponding to DN identification information capable of identifying a DN.

[0020] The SRGW 400 includes a conversion unit 410 and a conversion unit 450. The conversion unit 410 has a function of converting a packet conforming to GTP-U into an SRv6 packet conforming to SRv6. The conversion unit 410 may have a function of GTP4.D. The conversion unit 410 may have a function of GTP6.D.

[0021] The conversion unit 450 has a function of converting a packet conforming to SRv6 into a GTP-U packet conforming to GTP-U. The conversion unit 450 may have a function of GTP4.E. The conversion unit 450 may have a function of GTP6.E. In this embodiment, the conversion unit 450 may function as GTP6.E.Red.

[0022] In this embodiment, the N4BGPC 300 executes route setting for relaying communication between a UE (User Equipment) 40 connected to the gNB 130 and a communication partner connected to the DN 30. The communication partner of the UE 40 may be any communication device, such as any server on the Internet.

[0023] 2 is an explanatory diagram for roughly explaining the flow of processing in the communication system 10. Here, an example of the flow of processing after the SRGW 400 stores the correspondence table 480 and the N4BGPC 300 transmits the UE route information of the UE 40 to the PE router 220 will be described.

[0024] The correspondence table 480 registers an IP prefix of a radio access network (RAN) under the control of the SRGW 400 and an SRv6 SID having a Locator+Function length shorter than the IP prefix length that corresponds to the IP prefix. The correspondence table 480 may include a plurality of combinations of IP prefixes and SRv6 SIDs.

[0025] As an example, when the terminal address is 2001:0db8:0123:4567:89ab:cdef:0123:4567 and the network to which the terminal is connected is 2001:0db8:0123:4567:: / 64, normally, 2001:0db8:0123:4567:: / 64 is advertised to the network. However, in the communication system 10 according to the present embodiment, when the Locator+Function length of the SRv6 SID of the SRGW 400 is 48 bits, 2001:0db8:0123:4567:89ab:cd00:: / 88 is advertised. 2, for the RAN IP prefix 2001:0db8:0123:4567:89ab:cd00:: / 88, fc00:0123:4567:: / 48 is registered in the correspondence table 480 as the Locator+Function of the 48-bit SRv6 SID. In this way, when the SRGW 400 receives the SRv6 SID fc00:0123:4567:: / 48, it can extract 2001:0db8:0123:4567:89ab:cd00:: / 88 by referring to the correspondence table 480. In this example, it is necessary to include the last 40 bits of the terminal address in the SRv6 SID to restore the terminal address, but it is possible to freely use the other parts.

[0026] As in this example, the IP prefix to be registered in the correspondence table 480 may be registered with a prefix length longer than the IP prefix of the network to which the gNB 130 is connected. The SRv6 SID corresponding to the IP prefix to be registered in the correspondence table 480 may be set manually by an administrator. Or, it may be set from outside. The SRGW 400 may automatically generate the SRv6 SID corresponding to the IP prefix to be registered in the correspondence table 480. The SRGW 400 may automatically generate one or more IP prefixes longer than the Locator+Function length of the SRv6 SID by the Arg.Mob.Session length as the IP prefix to be registered in the correspondence table 480, using setting information that specifies one or more destination prefixes from the route information registered in the VRF 210 and the Locator+Function length of the SRv6 SID set in the SRGW 400. The SRGW 400 may automatically generate an SRv6 SID corresponding to each of the automatically generated IP prefixes and register the SRv6 SIDs in the correspondence table 480 .

[0027] In this example, first, the SRGW 400 advertises a BGP-MUP SAFI Interwork Segment Discovery Route (sometimes referred to as an ISD route). The ISD route indicates GTP6.E.Reduced as SID Behavior for the SRv6 SID stored in the BGP attribute storing the SRv6 SID, and when the actual RAN IP Prefix length including the RAN IP Prefix corresponding to the SID is shorter than the Arg.Mob.Session length compared to the SID Locator+Function length, the RAN IP Prefix of the same length as the Locator+Function+Arg.Mob.Session length of the SID including a stuff area for embedding the Arg.Mob.Session may be stored in the NLRI.

[0028] When a route having a destination prefix including a RAN IP prefix having a stuff area for embedding Arg.Mob.Session from VRF210 is lost, or reachability to the IP prefix is ​​lost, SRGW400 may delete the pair of the RAN IP prefix and the corresponding SRv6 SID from correspondence table 480 and perform a withdrawal route advertisement (withdrawal) of the ISD route having the RAN IP prefix in its NLRI.

[0029] When the gNB address included in the UE route information received from N4BGPC300 is included in the IP prefix stored in the NLRI of the ISD route received from SRGW400 including the stuff area, and the SRv6 SID indicates GTP6.E.Reduced as Behavior, the PE router 220 stores the Argument area in the SID containing the Argument.Mob.Session consisting of the TEID, QFI, and RQI included in the UE route information received from N4BGPC300, and when there are remaining Argument bits, the PE router 220 generates a GTP6.E.Reduced SID for transmitting a packet addressed to the UE 40 to the SRGW400 by storing the value of the gNB address in the same bit position as the remaining bits. When the gNB address included in the UE route information received from N4BGPC300 is not included in the IP prefix stored in the NLRI of the ISD route received from SRGW400 including the stuff area, the PE router 220 does not generate a GTP6.E.Reduced SID using the SRv6 SID of the ISD route.

[0030] When SRGW400 receives an SRv6 packet from PE router 220 having GTP6.E.Reduced SID as the active SID, it obtains Arg.Mob.Session from the SID, obtains the complete gNB address from the RAN IP prefix including the value of the stuff field for embedding the Arg.Mob.Session corresponding to the SID and the value of the gNB address in the same bit position as the remaining bits, sets the gNB address as the destination address of the GTP-U packet, and obtains the values ​​of TEID, QFI, and RQI from Arg.Mob.Session to generate a GTP-U packet and send it to gNB130.

[0031] 3 is an explanatory diagram for explaining an example of GTP6.E.Reduced SID. In order to convert an SRv6 packet into a GTP-U packet, the conversion unit 450 of the SRGW 400 needs to extract a 128-bit gNB address and a 40-bit parameter of the GTP-U packet from one 128-bit SID, but since it is 168 bits in total, it cannot be directly included in the 128-bit SID. Therefore, in the communication system 10 according to this embodiment, a correspondence table 480 is used.

[0032] Normally, the prefix length of IPv6 is 64 bits, and normally, a 64-bit prefix (actual prefix) is advertised. In contrast, in the communication system 10, when the Locator+Function length of the GTP6.E.Reduced SID is 48 bits, the actual prefix is ​​advertised including a 24-bit stuff area to enable later extraction of the 40-bit Arg.Mob.Session.

[0033] The PE router 220 generates a GTP6.E.Reduced SID by storing a 40-bit Argument field and the lower 40 bits of the gNB address included in the UE route information. The PE router 220 includes the TEID, QFI, and RQI included in the UE route information received from the N4BGPC 300 in the Arg.Mob.Session.

[0034] The upper 88 bits of the gNB address can be obtained by referring to the correspondence table 480 based on the Locator+Function of the GTP6.E.Reduced SID, as shown by the dashed line in FIG. 3. The lower 40 bits of the gNB address are stored at the end of the GTP6.E.Reduced SID, so the conversion unit 450 can obtain a 128-bit gNB address from these. In addition, the conversion unit 450 can also obtain information on the Arg.Mob.Session. The conversion unit 450 can generate a GTP-U packet in which the obtained 128-bit gNB address is set as the destination address and the TEID, QFI, and RQI obtained from the Arg.Mob.Session are set.

[0035] 4 is an explanatory diagram for explaining the outline of the GTP6.E.Reduced SID. Here, the case where the stuff area is included in the NLRI of the ISD root will be explained.

[0036] When the size of Locator+Function of SID502 in the ISD route is b, the size of Argument is 128-b. When the length of the RAN IP Prefix corresponding to the SID is a, the conversion unit 450 stores, in the ISD route, RAN IP Prefix 504 of the same length as the length of Locator+Function+Arg.Mob.Session of SID508 (i.e., b+40), including a stuff area (40-a+b) for embedding Arg.Mob.Session in the NLRI.

[0037] When the gNB address included in the UE route information received from N4BGPC300 is included in the IP prefix stored in the NLRI of the ISD route received from SRGW400 including a stuff area, the PE router 220 stores Arg.Mob.Session consisting of the TEID, QFI, and RQI included in the UE route information received from N4BGPC300 in the Argument area, and generates SID508 by storing the value of the gNB address 506 in the same bit position as the remaining bits (128-40-b) in the remaining bits.

[0038] FIG. 5 is an explanatory diagram for explaining the outline of GTP6.E.Reduced SID. Here, we will explain the case where the stuff area is not included in the NLRI of the ISD root. If the size of the argument is secured, there is no need to include the stuff area.

[0039] In the example shown in Figure 5, the RAN IP Prefix length corresponding to the SID is a, the size of the Locator+Function of SID512 in the ISD route is a-40, the size of the Argument is 128-(a-40), the size of the Locator+Function of SID518 is a-40, and the size of the Arg.Mob.Session is 40, so the stuff area is 40-a+(a-40)=0 and no stuff area is required.

[0040] 6 illustrates an example of a functional configuration of the conversion unit 450. The conversion unit 450 includes a storage unit 452, an advertising unit 454, a packet receiving unit 456, a packet generating unit 458, a packet transmitting unit 460, and a table management unit 462. It is not essential that the conversion unit 450 includes all of these units.

[0041] The storage unit 452 stores various information. The storage unit 452 stores a correspondence table 480 between an IP prefix of a network under the SRGW 400 and an SRv6 SID with a Locator+Function length shorter than the IP prefix length that corresponds to the IP prefix. The storage unit 452 may store a correspondence table 480 between an IP prefix of a RAN under the SRGW 400 and an SRv6 SID with a Locator+Function length shorter than the IP prefix length that corresponds to the IP prefix. The storage unit 452 may be an example of a table storage unit.

[0042] The advertisement unit 454 advertises the ISD route of the BGP-MUP SAFI. The ISD route indicates GTP6.E.Reduced as SID Behavior for the SRv6 SID stored in the BGP attribute that stores the SRv6 SID, and when the actual IP prefix length including the IP prefix corresponding to the SID is shorter than the Arg.Mob.Session length compared to the SID Locator+Function length, the ISD route may store an IP prefix of the same length as the Locator+Function length+Arg.Mob.Session length of the SID, including a stuff area for embedding the Arg.Mob.Session, in the NLRI.

[0043] The packet receiving unit 456 receives an SRv6 packet from the PE router 220. For example, the packet receiving unit 456 receives from the PE router 220 an SRv6 packet having an SID that includes a part of the address of a destination located under the SRGW 400 and header information of a packet to be transmitted to the destination, the SRv6 packet being generated by the PE router 220.

[0044] When the packet receiving unit 456 receives an SRv6 packet from the PE router 220, the packet generating unit 458 refers to the correspondence table 480 stored in the storage unit 452 to identify an IP prefix corresponding to the SID included in the SRv6 packet. The packet generating unit 458 identifies a destination address using the identified IP prefix and a part of the destination address included in the SID included in the SRv6 packet. The packet generating unit 458 generates a packet to be transmitted to the destination using the identified address and header information included in the SID included in the SRv6 packet.

[0045] Also, for example, the packet receiving unit 456 receives from the PE router 220 an SRv6 packet having an SID including a part of the gNB address of the gNB 130 to which the UE 40 is connected and header information, which is generated by the PE router 220. The packet generating unit 458 may specify the gNB address using an IP prefix corresponding to the SID included in the SRv6 packet and a part of the gNB address included in the SID included in the SRv6 packet. The packet generating unit 458 may generate a GTP-U packet to be transmitted to the gNB using the specified gNB address and the header information. The packet generating unit 458 may generate a GTP-U packet using the specified gNB address and the TEID, QFI, and RQI included in the header information. The packet generating unit 458 may generate a GTP-U packet with the specified gNB address as a destination address and with the TEID, QFI, and RQI included in the header information set.

[0046] The packet transmitting unit 460 transmits the packets generated by the packet generating unit 458. The packet transmitting unit 460 transmits the GTP-U packets generated by the packet generating unit 458.

[0047] When a route having a destination prefix including a RAN IP prefix having a stuff area for embedding Arg.Mob.Session from VRF 210 connected to gNB 130 is lost, or reachability to the IP prefix is ​​lost, the table management unit 462 may delete the pair of the RAN IP prefix and the corresponding SRv6 SID from the correspondence table 480. When the pair of the RAN IP prefix and the corresponding SRv6 SID is deleted from the correspondence table 480, the advertisement unit 454 may perform a withdrawal route advertisement of an ISD route having the RAN IP prefix in its NLRI.

[0048] The table management unit 462 may execute registration in the correspondence table 480. For example, the table management unit 462 may automatically generate one or more IP prefixes that are longer than the Locator+Function length of the SRv6 SID by the Arg.Mob.Session length as IP prefixes to be registered in the correspondence table 480, using configuration information that specifies one or more destination prefixes from route information registered in the VRF 210 connected to the gNB 130 and the Locator+Function length of the SRv6 SID set in the SRGW 400. The table management unit 462 may automatically generate SRv6 SIDs corresponding to the automatically generated IP prefixes, and register them in the correspondence table 480.

[0049] 7 shows an example of a schematic functional configuration of the PE router 220. The PE router 220 includes a storage unit 222, a route information receiving unit 224, a SID generating unit 226, and a packet transmitting unit 228.

[0050] The route information receiving unit 224 receives UE route information of the UE 40. The route information receiving unit 224 receives, for example, UE route information including a gNB address of a gNB to which the UE 40 is connected, advertised by the N4BGPC 300. The route information receiving unit 224 stores the received UE route information in the storage unit 222.

[0051] The route information receiving unit 224 receives the ISD route from the SRGW 400. The route information receiving unit 224 stores the received ISD route in the storage unit 222.

[0052] The SID generation unit 226 generates an SID including a part of the address of a destination located under the SRGW 400 and header information of a packet to be transmitted to the destination. For example, the SID generation unit 226 generates an SID including a part of the destination gNB address and header information including the TEID, QFI, and RQI included in the UE route information received by the route information reception unit 224. When the IP prefix of the ISD route received from the SRGW 400 and the gNB address included in the UE route information completely match, the generated SID does not need to include a part of the gNB address.

[0053] When the Behavior of the SRv6 SID of the ISD route received by the route information receiving unit 224 from the SRGW 400 indicates GTP6.E.Reduced, the SID generating unit 226 may generate an SID by storing Arg.Mob.Session in the Argument area in the SID and storing the value of the gNB address at the same bit position as the remaining bit in the remaining Argument bits. The Arg.Mob.Session may be configured by header information including the TEID, QFI, and RQI included in the UE route information. When the packet receiving unit 456 receives an SRv6 packet having the GTP6.E.Reduced SID as the active SID, the packet generating unit 458 of the conversion unit 450 may obtain the Arg.Mob.Session from the SID, identify the gNB address from the IP prefix including the stuff area and the value of the gNB address at the same bit position as the remaining bit, and obtain the TEID, QFI, and RQI from the Arg.Mob.Session.

[0054] The packet transmitting unit 228 transmits an SRv6 packet including the SID generated by the SID generating unit 226. The packet transmitting unit 228 transmits the SRv6 packet to the SRGW 400.

[0055] 8 is a schematic diagram showing an example of a hardware configuration of a computer 1200 functioning as an SRGW 400, a PE router 220, or an N4BGPC 300. A program installed in the computer 1200 can cause the computer 1200 to function as one or more "parts" of an apparatus according to the present embodiment, or cause the computer 1200 to execute operations or one or more "parts" associated with the apparatus according to the present embodiment, and / or cause the computer 1200 to execute a process or steps of the process according to the present embodiment. Such a program can be executed by the CPU 1212 to cause the computer 1200 to execute specific operations associated with some or all of the blocks of the flowcharts and block diagrams described herein.

[0056] The computer 1200 according to this embodiment includes a CPU 1212, a RAM 1214, and a graphics controller 1216, which are connected to each other by a host controller 1210. The computer 1200 also includes input / output units such as a communication interface 1222, a storage device 1224, a DVD drive, and an IC card drive, which are connected to the host controller 1210 via an input / output controller 1220. The DVD drive may be a DVD-ROM drive, a DVD-RAM drive, etc. The storage device 1224 may be a hard disk drive, a solid state drive, etc. The computer 1200 also includes a legacy input / output unit such as a ROM 1230 and a keyboard, which are connected to the input / output controller 1220 via an input / output chip 1240.

[0057] The CPU 1212 operates according to a program stored in the ROM 1230 and the RAM 1214, thereby controlling each unit. The graphic controller 1216 acquires image data generated by the CPU 1212 into a frame buffer or the like provided in the RAM 1214 or into itself, and causes the image data to be displayed on the display device 1218.

[0058] The communication interface 1222 communicates with other electronic devices via a network. The storage device 1224 stores programs and data used by the CPU 1212 in the computer 1200. The DVD drive reads programs or data from a DVD-ROM or the like and provides them to the storage device 1224. The IC card drive reads programs and data from an IC card and / or writes programs and data to an IC card.

[0059] The ROM 1230 stores therein a boot program or the like that is executed by the computer 1200 upon activation, and / or a program that depends on the hardware of the computer 1200. The input / output chip 1240 may also connect various input / output units to the input / output controller 1220 via a USB port, a parallel port, a serial port, a keyboard port, a mouse port, and the like.

[0060] The programs are provided by a computer-readable storage medium such as a DVD-ROM or an IC card. The programs are read from the computer-readable storage medium, installed in the storage device 1224, the RAM 1214, or the ROM 1230, which are also examples of computer-readable storage media, and executed by the CPU 1212. Information processing described in these programs is read by the computer 1200, and brings about cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be constructed by implementing operations or processing of information according to the use of the computer 1200.

[0061] For example, when communication is performed between the computer 1200 and an external device, the CPU 1212 may execute a communication program loaded in the RAM 1214 and instruct the communication interface 1222 to perform communication processing based on the processing described in the communication program. Under the control of the CPU 1212, the communication interface 1222 reads transmission data stored in a transmission buffer area provided in the RAM 1214, the storage device 1224, a DVD-ROM, or a recording medium such as an IC card, and transmits the read transmission data to the network, or writes reception data received from the network to a reception buffer area or the like provided on the recording medium.

[0062] Furthermore, the CPU 1212 may cause all or a necessary portion of a file or database stored in an external recording medium such as the storage device 1224, a DVD drive (DVD-ROM), an IC card, etc. to be read into the RAM 1214, and perform various types of processing on the data on the RAM 1214. The CPU 1212 may then write back the processed data to the external recording medium.

[0063] Various types of information, such as various types of programs, data, tables, and databases, may be stored in the recording medium and undergo information processing. The CPU 1212 may perform various types of processing on the data read from the RAM 1214, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search / replacement, etc., as described throughout this disclosure and specified by the instruction sequence of the program, and write back the results to the RAM 1214. The CPU 1212 may also search for information in a file, database, etc. in the recording medium. For example, when a plurality of entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored in the recording medium, the CPU 1212 may search for an entry whose attribute value of the first attribute matches a specified condition from among the plurality of entries, read the attribute value of the second attribute stored in the entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

[0064] The above-described programs or software modules may be stored in a computer-readable storage medium on the computer 1200 or in the vicinity of the computer 1200. In addition, a recording medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet can be used as a computer-readable storage medium, thereby providing the programs to the computer 1200 via the network.

[0065] The blocks in the flowcharts and block diagrams in the present embodiment may represent stages of a process in which an operation is performed or "parts" of an apparatus responsible for performing the operation. Particular stages and "parts" may be implemented by dedicated circuitry, programmable circuitry provided with computer-readable instructions stored on a computer-readable storage medium, and / or a processor provided with computer-readable instructions stored on a computer-readable storage medium. The dedicated circuitry may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. The programmable circuitry may include reconfigurable hardware circuits, such as, for example, field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), and the like, including AND, OR, XOR, NAND, NOR, and other logical operations, flip-flops, registers, and memory elements.

[0066] A computer-readable storage medium may include any tangible device capable of storing instructions that are executed by a suitable device, such that a computer-readable storage medium having instructions stored thereon comprises an article of manufacture that includes instructions that can be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of computer-readable storage media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, and the like. More specific examples of computer-readable storage media may include floppy disks, diskettes, hard disks, random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), electrically erasable programmable read-only memories (EEPROMs), static random access memories (SRAMs), compact disk read-only memories (CD-ROMs), digital versatile disks (DVDs), Blu-ray disks, memory sticks, integrated circuit cards, and the like.

[0067] The computer readable instructions may include either assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk®, JAVA®, C++, etc., and conventional procedural programming languages ​​such as the “C” programming language or similar programming languages.

[0068] Computer readable instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, or to a programmable circuit, either locally or over a local area network (LAN), a wide area network (WAN), such as the Internet, etc., to cause the processor of the general purpose computer, special purpose computer, or other programmable data processing apparatus, or to a programmable circuit, to execute the computer readable instructions to generate means for performing the operations specified in the flowcharts or block diagrams. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, etc.

[0069] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0070] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before" or "prior to," and that the process may be performed in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, it does not mean that the process must be performed in this order. [Explanation of symbols]

[0071] 10 communication system, 20 SRNW, 30 DN, 40 UE, 110 SMF, 120 UPF, 130 gNB, 202, 204, 206, 208, 210 VRF, 220 PE router, 222 memory unit, 224 route information receiving unit, 226 SID generating unit, 228 packet transmitting unit, 300 N4BGPC, 400 SRGW, 410 conversion unit, 450 conversion unit, 452 memory unit, 454 advertisement unit, 456 packet receiving unit, 458 packet generating unit, 460 packet transmitting unit, 462 table management unit, 480 correspondence table, 502 SID, 504 RAN IP Prefix, 506 gNB address, 508 SID, 512 SID, 514 RAN IP Prefix, 516 gNB address, 518 SID, 1200 Computer, 1210 host controller, 1212 CPU, 1214 RAM, 1216 graphic controller, 1218 display device, 1220 input / output controller, 1222 communication interface, 1224 storage device, 1230 ROM, 1240 input / output chip

Claims

1. a first router; The second router Equipped with The first router a table storage unit that stores a correspondence table between an IP prefix of a network under the first router and an SRv6 SID having a Locator+Function length shorter than the IP prefix length corresponding to the IP prefix; The second router an SID generator that generates an SID including a part of an address of a destination located under the first router and header information of a packet to be transmitted to the destination; a packet transmission unit that transmits an SRv6 packet including the SID generated by the SID generation unit to the first router; having a packet generating unit which, when receiving the SRv6 packet from the second router, refers to the correspondence table to identify an IP prefix corresponding to the SID included in the SRv6 packet, identifies an address of the destination using the identified IP prefix and a part of the address of the destination included in the SID, and generates a packet to be transmitted to the destination using the identified address and the header information included in the SID; A communication system comprising:

2. The first router is a PE router that converts an SRv6 packet conforming to SRv6 into a GTP-U packet conforming to GTP-U; The table storage unit stores the correspondence table between an IP prefix of a RAN under the first router and the SRv6 SID, The second router has a route information receiving unit that receives UE route information including a gNB address of a gNB to which the UE is connected, advertised by the controller; The SID generation unit generates the SID including a part of the gNB address and the header information, The packet generation unit identifies the gNB address using an IP prefix corresponding to the SID included in the SRv6 packet and a part of the gNB address included in the SID, and uses the identified gNB address and the header information to generate a GTP-U packet to be transmitted to the gNB. The communication system of claim 1.

3. The SID generation unit generates the SID including a part of the gNB address and the header information including the TEID, QFI, and RQI included in the UE route information, The communication system according to claim 2, wherein the packet generation unit generates the GTP-U packet using the identified gNB address and the TEID, the QFI, and the RQI contained in the header information.

4. The first router has an advertisement unit that advertises an Interwork Segment Discovery (ISD) route, The ISD route indicates GTP6.E.Reduced as SID Behavior in the BGP attribute storing the SRv6 SID, and when the IP prefix length of the actual RAN including the IP prefix of the RAN under the first router corresponding to the SID is shorter than the Arg. Mob. Session length compared to the SID Locator / Function length, stores an IP prefix of the same length as the Locator / Function length of the SID and the Arg. Mob. Session length, including a stuff area for the second router to embed the Arg. Mob. Session in the SID, in the NLRI; The SID generation unit generates the SID by storing an Arg. Mob. Session consisting of the header information including the TEID, the QFI, and the RQI included in the UE route information in an Argument area in the SID, and storing the value of the gNB address at the same bit position as the remaining bit in the remaining Argument bit, when the gNB address included in the UE route information is included in the IP prefix stored in the NLRI of the ISD route received from the first router including the stuff area, and the Behavior of the SRv6 SID indicates GTP6. E. Reduced, The packet generation unit, when receiving an SRv6 packet having a GTP6. E. Reduced SID as an active SID, acquires the Arg. Mob. Session from the SID, identifies the gNB address from the IP prefix including the stuff area and the value of the gNB address at the same bit position as the remaining bit, and acquires the TEID, the QFI, and the RQI from the Arg. Mob. Session. The communication system according to claim 3.

5. The first router is a table management unit that deletes a pair of the RAN IP prefix and the corresponding SRv6 SID from the correspondence table when a route having a destination prefix including a RAN IP prefix having a stuff area for embedding an Arg. Mob. Session from a VRF connected to the gNB is lost or when reachability to the IP prefix is ​​lost. Equipped with The communication system according to claim 4 , wherein the advertisement unit performs a withdrawal route advertisement of an ISD route having the RAN IP prefix in its NLRI when a pair of the SRv6 SID corresponding to the RAN IP prefix is ​​deleted from the correspondence table.

6. The first router uses configuration information specifying one or more destination prefixes from route information registered in the VRF connected to the gNB and the Locator+Function length of the SRv6 SID set in the first router to automatically generate one or more IP prefixes longer than the Locator+Function length of the SRv6 SID by the Arg. Mob. Session length as an IP prefix to be registered in the correspondence table, and automatically generates SRv6 SIDs corresponding to each of the automatically generated IP prefixes and registers them in the correspondence table. The communication system of claim 2 further comprising:

7. A communication system according to claim 2 , further comprising the controller.

8. A router, a table storage unit that stores a correspondence table between an IP prefix of a network under the router and an SRv6 SID having a Locator+Function length shorter than the IP prefix length corresponding to the IP prefix; a packet generating unit which, when receiving from another router an SRv6 packet including an SID including a part of an address of a destination located under the router and header information of a packet to be transmitted to the destination, refers to the correspondence table, and uses an IP prefix corresponding to the SID included in the SRv6 packet and a part of the address of the destination included in the SID to identify the address of the destination, and generates a packet to be transmitted to the destination using the identified address and the header information included in the SID; A router comprising:

9. A program for causing a computer to function as the router according to claim 8.

10. 1. A method of managing communications performed by a router, comprising: a storage step of storing in a table storage unit a correspondence table between an IP prefix of a network under the router and an SRv6 SID having a Locator+Function length shorter than the IP prefix length corresponding to the IP prefix; a packet generation step of, when receiving from another router an SRv6 packet including an SID including a part of an address of a destination located under the router and header information of a packet to be transmitted to the destination, specifying the address of the destination by referring to the correspondence table, using an IP prefix corresponding to the SID included in the SRv6 packet and a part of the address of the destination included in the SID, and generating a packet to be transmitted to the destination by using the specified address and the header information included in the SID; A communication management method comprising:

Images