System of network switch

Abstract

The present disclosure describes a system comprising: a first network switch and a second network switch, the first network switch and the second network switch each comprising a plurality of ports for coupling to one or more devices; wherein the first network switch is communicatively coupled with the second network switch; wherein the first network switch, based on receiving a network frame at its port, is configured to: process the network frame based on a content of the network frame and a first set of rules to determine network frame forwarding information for the network frame; adding metadata to the network frame based on a result of the processing; forwarding the network frame with the added metadata to the second network switch; wherein the second network switch, based on receiving the network frame, is configured to read the metadata and process the network frame based on the network frame forwarding information as determined by the first network switch.

Description

Technical Field

[0001] The present disclosure relates to a system including a first network switch and a second network switch, wherein the first network switch is communicatively coupled to the second network switch. The present disclosure also relates to a system including a plurality of network switches. The present disclosure also relates to a method of operating the system. Background Art

[0002] Network switches can be coupled together to form a single system. This concept is known as switch stacking. Ensuring that a system's network switches work effectively and efficiently as a single system presents challenges. Summary of the invention

[0003] According to a first aspect of the present disclosure, a system is provided, comprising:

[0004] a first network switch comprising a plurality of ports for coupling to one or more devices;

[0005] a second network switch comprising a plurality of ports for coupling to one or more devices;

[0006] wherein the first network switch is communicatively coupled to the second network switch;

[0007] wherein the first network switch is configured based on receiving a network frame at a first port among the plurality of ports to:

[0008] processing the network frame based on content of the network frame and a first set of rules of the first network switch to determine network frame forwarding information for the network frame;

[0009] adding metadata to the network frame based on a result of the processing of the network frame forwarding information defining the network frame;

[0010] forwarding the network frame with the added metadata to the second network switch, provided that an address of the network frame is reachable at or via the second network switch;

[0011] The second network switch is configured based on receiving the network frame from the first network switch to:

[0012] The metadata is read, and the network frame is processed based on the network frame forwarding information of the network frame as determined by the first network switch.

[0013] In one or more embodiments, the second network switch is configured, based at least on receiving the network frame from the first network switch, to process the network frame based on the network frame forwarding information of the network frame as determined by the first network switch, and then the second network switch processes the network frame based on the content of the network frame and a second rule set of the second network switch.

[0014] In one or more embodiments, the network frame forwarding information determined by the processing performed by the first network switch includes:

[0015] The metadata includes instructions for causing the second network switch to perform the change.

[0016] In one or more embodiments, the change of the VLAN tag includes one or both of a change of a VLAN identifier field and a change of a priority code point field.

[0017] In one or more embodiments, the network frame forwarding information determined by the processing by the first network switch specifies:

[0018] Quality of service, and wherein the second network switch is configured to process the network frame based on the quality of service determined by the first network switch.

[0019] In one or more embodiments, the network frame forwarding information determined by the processing performed by the first network switch includes a timestamp specifying when the network frame was received by the first network switch. In one or more embodiments, the network frame forwarding information determined by the processing performed by the first network switch includes a timestamp specifying when the network frame was transmitted from the first network switch. In one or more embodiments, the network frame forwarding information determined by the processing performed by the first network switch includes a request for the second network switch to reply with a second network frame, the request including a timestamp indicating when the second network switch received and / or transmitted the network frame.

[0020] In one or more embodiments, the network frame forwarding information determined by the processing performed by the first network switch includes port mirroring instructions, and wherein the second network switch is configured to create a copy of the network frame based on the port mirroring instructions for forwarding according to the port mirroring instructions.

[0021] In one or more embodiments, the second network switch is configured to include the added metadata in the copy of the network frame.

[0022] In one or more embodiments, the system includes a third network switch, the third network switch including a plurality of ports for coupling to one or more devices, the third network switch being communicatively coupled to the second network switch, wherein the second network switch is configured to:

[0023] based on the network frame being destined for a device among the one or more devices coupled to the plurality of ports, removing the metadata and forwarding the network frame to the device; and

[0024] Based on the network frame being destined for a device coupled to the third network switch, the metadata is retained and the network frame is forwarded to the third network switch.

[0025] In one or more embodiments, the second network switch is provided with a second rule set defining one or more rules to process the metadata added by the first network switch.

[0026] In one or more embodiments, the system includes a management device configured to program the first set of rules for the first network switch and the second set of rules for the second network switch.

[0027] In one or more embodiments, the metadata is added to a header of the network frame or to a tail of the network frame.

[0028] In one or more embodiments, the first network switch being configured to forward the network frame with the added metadata comprises one or more of the following:

[0029] Forwarding based on the MAC address of the network frame;

[0030] forwarding based on an IP address specified in the content of the network frame;

[0031] forwarding to a particular one of the plurality of ports based on an indication in the network frame that the network frame is part of a stream, wherein the particular one of the ports is established by an earlier received network frame or a predetermined rule; and

[0032] The forwarding is performed based on one or more fields in the header or payload of the network frame.

[0033] According to a second aspect of the present disclosure, there is provided a vehicle-based network comprising the system according to the first aspect.

[0034] According to a third aspect of the present disclosure, a method for processing a network frame in a system is provided, comprising: a first network switch, the first network switch comprising a plurality of ports for coupling to one or more devices; a second network switch, the second network switch comprising a plurality of ports for coupling to one or more devices; and wherein the first network switch is communicatively coupled to the second network switch; wherein the method comprises:

[0035] receiving, by the first network switch, a network frame at a first port of the plurality of ports;

[0036] processing the network frame by the first network switch based on content of the network frame and a first rule set of the first network switch to determine a network frame forwarding rule for the network frame;

[0037] adding, by the first network switch, metadata to the network frame based on a result of the processing of the network frame forwarding information defining the network frame;

[0038] forwarding the network frame with the added metadata to the second network switch through the first network switch, provided that an address of the network frame is reachable at or via the second network switch;

[0039] receiving the network frame from the first network switch via the second network switch;

[0040] reading the metadata via the second network switch; and

[0041] The network frame is processed by the second network switch based on the network frame forwarding information of the network frame as determined by the first network switch.

[0042] In one or more examples, the method includes: processing the network frame by the second network switch based at least on receiving the network frame from the first network switch and based on the network frame forwarding information of the network frame as determined by the first network switch, and then the second network switch processes the network frame based on the content of the network frame and a second rule set of the second network switch.

[0043] Although the present disclosure allows various modifications and alternative forms, its details have been shown in the drawings by way of example and will be described in detail. However, it should be understood that other embodiments other than the specific embodiments described are also possible. All modifications, equivalents and alternative embodiments falling within the spirit and scope of the appended claims are also encompassed.

[0044] The above discussion is not intended to present every example embodiment or every implementation within the scope of the current or future claim sets. The accompanying drawings and the following detailed description also illustrate various example embodiments. The various example embodiments can be more fully understood by considering the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] One or more embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0046] Figure 1 An example embodiment of a system including a plurality of network switches communicatively coupled together is shown;

[0047] Figure 2 shows an example network frame; and

[0048] Figure 3 A flow chart illustrating an example method is shown. DETAILED DESCRIPTION

[0049] The described embodiments relate to a system including a plurality of network switches (also referred to as bridges) that are communicatively coupled together to form a network. The plurality of network switches may be configured to operate together as a single logical network switch. Thus, the network switches of the system may be centrally controlled by a single management device. In other examples, a plurality of management devices or hosts may be provided, and in some examples, the management devices may share management functions of the system. In some examples, the system may be viewed as including a plurality of stacked network switches or a distributed switch architecture.

[0050] Figure 1 An example system 100 is shown. In this example, the system 100 provides at least part of an automotive communication network for a vehicle, but the application has a wider range of applications. In this example, the system includes a first network switch 101, a second network switch 102, a third network switch 103, and a fourth network switch 104. Each of the network switches 101 to 104 includes a plurality of ports for coupling to one or more devices. In this example, each switch has six ports, but other numbers of ports may exist, and each switch does not necessarily need the same number of ports as another network switch. In general, each switch has multiple ports to support different topologies. The first network switch 101 is shown as having six ports 101A to 101F. Similarly, the second network switch 102 is shown as having six ports 102A to 102F. In this example, the third and fourth network switches also have six ports, but for clarity, only some of the ports are marked.

[0051] Ports 101A-F, 102A-F, 103B, 103E, 104A, 104D are configured to be coupled to one or more devices, thereby enabling the devices to communicate. For example, the fourth port 101D of the first network switch 101 is shown coupled to a local host 105, which may include a single device such as a sensor or a vehicle subsystem. The fourth port 104D of the fourth network switch 104 is shown coupled to a remote host 106. The remote host 106 may host multiple devices, all of which communicate via the fourth port 104D of the fourth network switch 104.

[0052] The first network switch 101 is communicatively coupled to the second network switch by means of a connection between the sixth port 101F of the first network switch and the fifth port 102E of the second network switch 102. The second network switch 102 is communicatively coupled to the third network switch 103 by means of a connection between the sixth port 102F of the second network switch and the fifth port 103E of the third network switch 103. The fourth network switch 104 is communicatively coupled to the second network switch 102 by means of a connection between the fourth port 102D and the first port 104A. In some examples, dedicated network switch coupling ports using any desired protocol may be provided to couple network switches. And, other topologies are possible. In summary, in this example, at least one of the multiple ports of each network switch 101 to 104 is communicatively coupled to a port of another switch of the system 100.

[0053] Each network switch 101 to 104 may have a processor or other hardware configured to provide a conventional data packet / network frame switching function of a network switch or bridge. The processor may include a CPU, an ASIC, or an FPGA for performing the switching function. Each network switch 101 to 104 may include a processor for configuring the network switch and hardware for performing the conventional data packet / network frame switching function. Each network switch 101 to 104 may include a memory for storing a forwarding database. As will be known to those skilled in the art, the forwarding database may maintain a record of a destination address (e.g., a MAC and / or IP address of a device coupled to each port) so that the network switch may forward a network frame received at one of its ports to a different port in its port so that the network frame arrives at a device addressed by the network frame or arrives at another network switch in the network switch, and the other network switch further forwards the network frame to its destination. In other examples, the forwarding database may maintain a record of a specific combination of a header or specific fields of a frame, including a payload, for forwarding a decision to a specific port. The term network frame is used to refer to the protocol data unit processed by a network switch, but it should be understood that the example network switch may perform switching at layer 3 and thus the term network frame is intended to cover network packets and switched at layers 2, 3, or even 4 or higher of the OSI model.

[0054] Generally speaking, a network switch may also perform network function processing on network frames passing through the network switch. Network function processing may include processing virtual local area network (VLAN) tags and / or performing traffic management functions. For example, a network switch may assign or determine a priority for a network frame, and based on the priority, may forward the network frame before or after another network frame. Network function processing may be a quality of service related function. For example, a network switch may process information related to the transmission priority and / or discard resilience of a network frame (i.e., how discardable a frame is based on the level of congestion experienced on a queue). Therefore, in some examples, a network switch may be required to maintain a large register defining network function rules to process network frames in order to perform its network function processing role. Moreover, when the network function rules change, a management device is required to update the registers in each network switch, which may be inefficient. In addition, memory and / or processing resources in a network switch are limited, and therefore ensuring efficient use of memory and processing resources is a challenge. In addition, the system 100 may be part of a vehicle, and according to the software defined vehicle (SDV) concept, the updating of network switch functionality may be a mandatory feature. Such updates may be driven by feature updates (on-demand functionality) or in response to problem resolution, as may be typical in an Intrusion Detection and Prevention System (IDPS).

[0055] Returning to this example, the first network switch 101 may receive the network frame 110 or data packet, for example, at its first port 101A. We will describe the actions performed by the system 100 of the embodiment of the present invention based on the first switch receiving the network frame. However, it should be understood that any one of the plurality of network switches 101 to 104 may first receive the network frame into the system 100.

[0056] The first network switch 101, for example, receives network frames only at the first port 101A, and is configured to process the network frames in addition to providing packet / frame switching to forward the network frames to a different one of its multiple ports 101B to 101E based on a destination address (e.g., MAC or IP address) specified in the network frame / packet. The first network switch 101 may receive the network frame from a device coupled to the port 101A, but in other examples, the first network switch 101 may receive the network frame from another network switch.

[0057] Specifically, the first network switch 101 is configured to process the network frame based on the content of the network frame and the first rule set of the first network switch to determine network frame forwarding information of the network frame.In addition to determining which port of the network switch the network frame should be forwarded to, the network frame forwarding information is also determined.

[0058] This frame forwarding information may define: the addition or modification of a VLAN tag; the addition or modification of a field specifying a priority of a network frame; the addition or modification of a field specifying discardability of a network frame; the addition and / or modification of one or more timestamps to a network frame indicating, for example, a reception time or a forwarding time of a network frame; forwarding a network frame to one or more hosts; mirroring of a network frame to be performed at a different one of the network switches; and / or other functions other than determining an egress port for a network frame. Examples of such processing are described below in the examples.

[0059] The first network switch 101 is configured to add metadata to the network frame based on the result of the processing. Therefore, the metadata defines or specifies the network frame forwarding information determined for the network frame. In the present example, the metadata is added to the header of the network frame. However, in other examples, the metadata may be added to the tail of the network frame. The metadata may include an index for referencing a predefined action stored in the memory of the second network switch 102 or any other network switch 103, 104 of the system. The metadata may include instructions that can be executed by the second network switch with or without reference to a lookup table. Specifically, in some examples, the metadata may be processed without reference to a large number of lookup tables, and alternatively, a small database may be used to process specific actions as indicated by the metadata.

[0060] The first network switch 101 is configured to perform its forwarding function based on the destination address specified in the network frame (usually a MAC address or an IP address or a VLAN ID) or one or more other fields as mentioned above. Therefore, by convention, the first network switch 101 will determine or be programmed with which destination addresses can be reached from each of its multiple ports 101A to 101E with the help of a forwarding database.

[0061] In this example, the first network switch 101 may forward the network frame with the added metadata to the second network switch 102 via ports 101F and 102E, provided that the address of the network frame is reachable at or via the second network switch. The metadata may be added in the header or trailer. The MAC address may specify a device coupled to one of the ports of the second network switch 102. Alternatively, the MAC address may specify a device coupled to a third network switch 103 or a fourth network switch 104, and the second network switch 102 will be configured to forward the network frame to the third network switch 103 or the fourth network switch 104.

[0062] When the second network switch 102 receives the network frame, the second network switch 102 is configured to read the metadata added by the first network switch and process the network frame based on the network frame forwarding information of the network frame as determined by the first network switch 101. In some examples, the second network switch can be programmed to execute any instructions contained in the metadata. In other examples, the second network switch 102 can include predetermined information, such as a second set of rules for interpreting the metadata and performing any predefined actions that may be required.

[0063] Thus, in one or more examples, rather than requiring a comprehensive second set of rules (e.g., equivalent to the first set of rules) to determine what the network frame forwarding information should be, the second network switch 102 uses the output of the processing performed by the first network switch, i.e., the network frame forwarding information, to process the network frame. Thus, in this example, the processing performed by the first network switch 101 that first receives the network frame does not need to be performed again by the second network switch 102. Thus, processing resources are used more efficiently. Additionally, the network frame forwarding information may include one or more instructions to be executed by the second network switch 102. Thus, the first network switch 101 is provided with a mechanism for instructing the second network switch 102 or any other network switch 103, 104 of the system 100 to execute any network frame it determines is required.

[0064] Thus, the second network switch 102 is configured to process the network frame based on metadata (i.e., in addition to the processing performed on port forwarding based on the destination address) based on at least receiving the network frame from another network switch of the system, and then the second network switch processes the network frame based on the content of the network frame and the second network switch's comprehensive second rule set. In this way, network frames received from other network switches in the system 100 (or at least one or more of the switches of the system 100) are processed based on metadata, while network frames received from ports (e.g., 102A to 102C) that are not coupled to another network switch can be processed so that the second network switch 102 is configured to determine network frame forwarding information (e.g., in addition to the processing performed on port forwarding based on the destination address or other fields). It has been found that the second rule set can be more space-efficient when including information for carrying instructions included in the metadata rather than independently processing the network frame. In addition, the rule sets of network switches 101 to 104 can be defined based on the location of the network switches in the system 100. Thus, the rule set for each network switch 101-104 may include only rules applicable to network frames that the network switch may encounter, such as from devices coupled to its ports. The manner in which other network switches in the system should process the frame may be provided in the network frame forwarding information provided in the metadata.

[0065] In some examples, even if the second network switch 102 is configured or capable of determining network frame forwarding information corresponding to the network frame forwarding information defined in the metadata, the second network switch 102 is configured to simply process the network frame according to the metadata.

[0066] This functionality may have additional benefits for different network topologies. For example, if the first network switch 101 is coupled to a modem or a telematics unit, the first network switch 101 may be at a higher risk of attack. Therefore, the first rule set of the first network switch 101 may need to be more comprehensive, and the processing performed by the first network switch 101 may need to be more robust. However, once the processing is performed, the network frame forwarding information of the metadata may simply instruct other network switches 102 to 104 how to process the network frame without the need to reprocess the network frame.

[0067] It should be understood that the first network switch can apply this functionality to all or some network frames. For example, in some network implementations, the network frame may need to be forwarded based on the source or destination MAC address or other layer 2 mark of the network frame, that is, the frame is bridged, such as defined in IEEE 802.1Q. Additional processing can be applied to such frames. In some examples, the network frame may be an Internet Protocol data packet, and therefore the IP data packet may need to be forwarded based on the source or destination IP address or other layer 3 mark (i.e., IP routing). Additional processing can be applied to such frames. In some examples, the network frame may need to be forwarded to a specific one of a plurality of ports based on an indication in the network frame that the network frame is part of a stream, wherein the specific one of the ports is established by an earlier received network frame or a predetermined rule (i.e., stream forwarding). Additional processing can be applied to one or more frames or all frames of such frames of the stream. It should be understood by those skilled in the art that network frame forwarding can be performed based on more than MAC or IP addresses or replaceable fields.

[0068] We will now describe several examples of processing that may be performed by the first network switch 101 and therefore determine what network frame forwarding information. It should be appreciated that the processing may involve one or a combination of the following examples.

[0069] In a first example, the network frame forwarding information determined by the processing performed by the first network switch may relate to a VLAN. For example, the network frame forwarding information may include instructions to change or add a virtual local area network VLAN tag of the network frame. Thus, the metadata may include instructions for the second network switch 102 or other switches 103, 104 of the system 100 to perform the change. The VLAN tag may include changes to the VLAN identifier field and / or the priority code point field. Thus, the processing may include VLAN ID re-tagging or PCP re-tagging.

[0070] In a second example, the network frame forwarding information determined by the processing performed by the first network switch 101 specifies the quality of service. Therefore, the second network switch 102 or other switches 103, 104 of the system 100 are configured to process the network frame based on the quality of service determined by the first network switch. Therefore, the processing can derive an implicit priority from a field of the network frame, such as when exiting a queue.

[0071] In a third example, the network frame forwarding information determined by the processing performed by the first network switch 101 specifies a timestamp indicating when the network frame is received by the first network switch 101. The timestamp may be added in response to an instruction contained in the network frame or a determination that the network frame is of a particular type. In some examples, the timestamp added by the first network switch may be used by the second network switch when forwarding the network frame to a device coupled to the second network switch 102 (e.g., the time at which the second network switch 102 subsequently receives the network frame). In one or more embodiments, the network frame forwarding information determined by the processing performed by the first network switch includes a timestamp specifying when the network frame is transmitted from the first network switch (e.g., transmitted to the second network switch). The timestamp may be added in response to an instruction contained in the network frame or a determination that the network frame is of a particular type. In some examples, the timestamp added by the first network switch may be used by the second network switch when forwarding the network frame to a device coupled to the second network switch 102. In one or more embodiments, the network frame forwarding information determined by the processing performed by the first network switch includes a request for the second network switch to reply with a second network frame, the request including a timestamp indicating when the second network switch transmitted the network frame. Thus, the first network switch 101 may receive a network frame from a device or host coupled to one of its ports. Subsequently, based on instructions from the host, or based on the nature of the network frame received by the first network switch 101 from the host, the first network switch 101 may be configured to determine the network frame forwarding information and add corresponding metadata including instructions to cause a different network switch (e.g., the second network switch 102) to report back to the host a timestamp indicating when the network switch (e.g., the second network switch 102) received and / or transmitted the network frame. Thus, when the second network switch 102 transmits the network frame on its forward trip, the second network switch 102 is configured to execute the instructions in the metadata by generating a second network frame addressed to the host and possibly including in the metadata a timestamp indicating when the second network switch 102 transmitted the network frame on its forward trip (e.g., to a different host or another network). The timestamp may thus indicate when the network frame was transmitted from one of the egress ports of the second network switch 102. Such instructions may also be executed by any additional network switch of the system 100, provided that the network frame is forwarded through the additional network switch of the system 100. Providing metadata indicating or collecting timestamps from the network switches of the system 100 may be advantageous for management of the system 100, as described in the third example.

[0072] In a fourth example, the network frame forwarding information determined by the processing performed by the first network switch 101 includes a port mirroring instruction. Thus, rather than the first network switch 101 creating a copy of the network frame for mirroring purposes, the second network switch or other switches 103, 104 of the system are configured to create a copy of the network frame based on the port mirroring instructions contained in the metadata. The second network switch may then forward the network frame and its copy according to one or more rules or as defined in the port mirroring instructions. This is advantageous because the creation of the mirrored frame can be delayed until it reaches the desired network switch of the system 100, rather than routing multiple mirrored frames through the network switches 101, 102, 103, 104 of the network.

[0073] The network frame forwarding information may include instructions for a network switch directly coupled with respect to the first network switch 101 (e.g., network switch 102) or for an indirectly coupled network switch (e.g., third network switch 103 or fourth network switch 104). Thus, the second network switch may be configured to include the added metadata in the network frame when it forwards the network frame to the egress port. In addition, if metadata has been generated, the metadata may be retained in any mirror copy.

[0074] In some examples, the second network switch 102 may be configured to remove the metadata based on the destination of the network frame being a device coupled to the plurality of ports 102A to 102C and forward the network frame to the device. However, if the destination of the network frame is a device coupled to a different network switch, such as for forwarding to ports 102D and 102F, the second network switch may retain the metadata when forwarding the network frame to ports 102D, 102F of the other network switches 103, 104.

[0075] The system 100 may include one management device (although there may be more than one) configured to program or update a first rule set for the first network switch 101 and a second rule set for the second network switch 102, as well as corresponding rule sets for the other network switches 103, 104. Programming of changes may be made more efficient by configuring the rule sets to follow instructions in metadata rather than each switch processing a network frame. Thus, an over-the-air update may only require updating a subset of the network switches.

[0076] Figure 2Two example network frame formats 200 and 201 are shown. Metadata may be provided in a header (before the payload), such as in field 203 of the first example frame format. In the second example frame format 201, metadata is provided in a trailer (after the payload), such as in field 204. Other fields shown include: a destination address 205, such as a MAC destination address or other layer 2 address; a source address, such as a MAC source address or other layer 2 address; an OSI layer 2 header 207, which may include information such as a VLAN tag; a payload 208, which may include data with an OSI layer 3 header (such as IP related fields); and a frame check sequence 209. In some examples, metadata is carried in both the header field 203 and the trailer field 204 of the same network frame. In one or more examples, the metadata specifies an index, such as a number, corresponding to a desired action that should be performed by the receiving network switch. Thus, the rule set may be compact and perform actions based on instructions indicated by metadata or by an index referencing such instructions.

[0077] Figure 3 An example method for processing network frames in a system including a plurality of network switches, each of which includes a plurality of ports for coupling to one or more devices, is shown. Figure 1 The method comprises:

[0078] Receiving 301 a network frame at a first port of a plurality of ports by a first network switch;

[0079] processing 302 the network frame by the first network switch based on content of the network frame and a first rule set of the first network switch to determine a network frame forwarding rule for the network frame;

[0080] adding 303, by the first network switch, metadata to a network frame based on a result of said processing of said network frame forwarding information defining the network frame;

[0081] forwarding 304 the network frame with the added metadata to a second network switch through the first network switch, provided that an address of the network frame is reachable at or via the second network switch;

[0082] receiving 305 a network frame from the first network switch via the second network switch;

[0083] Reading 306 metadata via a second network switch; and

[0084] The network frame is processed 307 by the second network switch based on network frame forwarding information of the network frame as determined by the first network switch.

[0085] Unless a specific order is explicitly stated, the instructions and / or flow chart steps in the above figures may be performed in any order. Moreover, those skilled in the art will recognize that although an example instruction set / method has been discussed, the materials in this specification may be combined in a variety of ways to produce other examples and should be understood within the context provided in this detailed description.

[0086] In some example embodiments, the instruction set / method steps described above are implemented as functions and software instructions embodied as an executable instruction set, which is implemented on a computer or a machine programmed and controlled with the executable instructions. Such instructions are loaded for execution on a processor (e.g., one or more CPUs). The term processor includes a microprocessor, a microcontroller, a processor module or subsystem (including one or more microprocessors or microcontrollers), or other control or computing devices. A processor may refer to a single component or multiple components.

[0087] In other examples, the instruction sets / methods shown herein and the data and instructions associated therewith are stored in corresponding storage devices, which are implemented as one or more non-transitory machine or computer readable or computer usable storage media. Such one or more computer readable or computer usable storage media are considered to be part of an article (or product). An article or product may refer to any manufactured single component or multiple components. One or more non-transitory machine or computer usable media as defined herein do not include signals, but such one or more media may be able to receive and process information from signals and / or other transient media.

[0088] Example embodiments of the materials discussed in this specification may be implemented in whole or in part through network, computer or data-based devices and / or services. These may include the cloud, the Internet, an intranet, a mobile device, a desktop computer, a processor, a lookup table, a microcontroller, a consumer device, an infrastructure, or other enabling devices and services. As may be used herein and in the claims, the following non-exclusive definitions are provided.

[0089] In one example, one or more instructions or steps discussed herein are automated. The term automation or automatic (and similar variations thereof) means the use of computers and / or mechanical / electrical devices to control the operation of equipment, systems and / or processes without the need for human intervention, observation, effort and / or decision making.

[0090] It should be understood that any components that are said to be coupled may be coupled or connected directly or indirectly. In the case of indirect coupling, additional components may be placed between the two components that are said to be coupled.

[0091] In this specification, example embodiments have been presented based on a selected set of details. However, one of ordinary skill in the art will appreciate that many other example embodiments including different selected sets of these details may be practiced. It is intended that the appended claims cover all possible example embodiments.

Claims

1. A system, characterized in that: include: a first network switch comprising a plurality of ports for coupling to one or more devices; a second network switch comprising a plurality of ports for coupling to one or more devices; wherein the first network switch is communicatively coupled to the second network switch; wherein the first network switch is configured based on receiving a network frame at a first port among the plurality of ports to: processing the network frame based on content of the network frame and a first set of rules of the first network switch to determine network frame forwarding information for the network frame; adding metadata to the network frame based on a result of the processing of the network frame forwarding information defining the network frame; forwarding the network frame with the added metadata to the second network switch, provided that an address of the network frame is reachable at or via the second network switch; The second network switch is configured based on receiving the network frame from the first network switch to: The metadata is read, and the network frame is processed based on the network frame forwarding information of the network frame as determined by the first network switch.

2. The system according to claim 1, characterized in that The second network switch is configured, based at least on receiving the network frame from the first network switch, to process the network frame based on the network frame forwarding information of the network frame as determined by the first network switch, and then the second network switch processes the network frame based on the content of the network frame and a second rule set of the second network switch.

3. A system according to any of the preceding claims, characterised in that The network frame forwarding information determined by the processing performed by the first network switch includes: The metadata includes instructions for causing the second network switch to perform the change.

4. The system according to claim 3, characterized in that The change of the VLAN tag includes one or both of a change of a VLAN identifier field and a change of a priority code point field.

5. A system according to any of the preceding claims, characterised in that The network frame forwarding information determined by the processing by the first network switch specifies: Quality of service, and wherein the second network switch is configured to process the network frame based on the quality of service determined by the first network switch.

6. A system according to any of the preceding claims, characterised in that The network frame forwarding information determined by the processing by the first network switch includes one or more of the following: a timestamp specifying when the network frame was received by the first network switch; a timestamp specifying when the network frame was transmitted from the first network switch; A request for the second network switch to reply with a second network frame, the request including a timestamp indicating when the second network switch transmitted the network frame.

7. A system according to any one of the preceding claims, characterised in that The network frame forwarding information determined by the processing by the first network switch includes port mirroring instructions, and wherein the second network switch is configured to create a copy of the network frame based on the port mirroring instructions for forwarding in accordance with the port mirroring instructions.

8. The system according to claim 7, characterized in that The second network switch is configured to include the added metadata in the copy of the network frame.

9. A car-based network, characterized in that Comprising a system according to any one of claims 1 to 8.

10. A method for processing a network frame in a system, comprising: a first network switch comprising a plurality of ports for coupling to one or more devices; a second network switch, the second network switch comprising a plurality of ports for coupling to one or more devices; and wherein the first network switch is communicatively coupled to the second network switch; wherein the method comprises: receiving, by the first network switch, a network frame at a first port of the plurality of ports; processing the network frame by the first network switch based on content of the network frame and a first rule set of the first network switch to determine a network frame forwarding rule for the network frame; adding, by the first network switch, metadata to the network frame based on a result of the processing of the network frame forwarding information defining the network frame; forwarding the network frame with the added metadata to the second network switch through the first network switch, provided that an address of the network frame is reachable at or via the second network switch; receiving the network frame from the first network switch via the second network switch; reading the metadata via the second network switch; and The network frame is processed by the second network switch based on the network frame forwarding information of the network frame as determined by the first network switch.

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