Method and system for using IS-IS for SPB in the context of a service provider network

Abstract

A system and method are disclosed for using Intermediate System to Intermediate System IS-IS as a control plane for Shortest Path Bridging SPB in a network, the network including at least one Service Provider Network SPN (101) and at least two Backbone Edge Bridges BEB (121 i ), and at least two Backbone Edge Bridges BEB (121 i ) being connected to the SPN (101). The method includes the BEBs, and the BEBs are configured to: form adjacencies between BEBs through LAN hellos, elect one of the BEBs as the designated IS DIS, and simulate a pseudo-node, all BEBs create and flood non-pseudo-node level-1 LSPS, the DIS creates and floods pseudo-node level-1 LSPS, and periodically sends a Complete Sequence Number PDU CSNP to other BEBs, and run Shortest Path First (SPF) to calculate the shortest paths between BEBs in the network.

Description

Technical Field

[0001] The present technology relates to data processing, and more particularly to a method and system for using an intermediate system to an intermediate system as a control plane for shortest path bridging in a network including a service provider network. Background Art

[0002] Intermediate System to Intermediate System (IS-IS), defined in ISO / IEC 10589, is a routing protocol used to efficiently move information within a network by determining the best route for packets through a packet switching network. IEEE 802.1aq Shortest Path Bridging (SPB) enables multipath routing in Ethernet mesh networks by using IS-IS as a control plane protocol. This technology allows all paths to be active, supports equal-cost paths, and provides shortest path forwarding in Ethernet mesh networks. "IS-IS for SPB" uses enhanced IS-IS to distribute topology information in the form of additional type-length values ​​(TLVs) and new network layer protocol identifiers (NLPIDs) containing multicast and topology attributes, making it an OSI Layer 2 efficient routing protocol that operates by reliably flooding link state information throughout the network of ISs (Intermediate Systems), such as switches and routers. IS-IS for SPB provides fast convergence, high link efficiency, and supports large Layer 2 topologies.

[0003] In general, the present technology is intended to adapt IS-IS for SPB routing protocol to the requirements of using IS-IS for the control plane in a network involving ISs connected to a Service Provider Network (SPN), including forming multiple adjacencies between ISs and shortest path calculations between ISs with SPNs.

[0004] The subject matter discussed in the background section should not be assumed to be prior art simply because it is mentioned in the background section. Similarly, problems mentioned in the background section or associated with the subject matter in the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches. Summary of the invention

[0005] The implementation of the present technology is based on the developer's understanding of the shortcomings associated with the prior art, especially the limitation of multiple adjacencies between ISs in IS-IS for SPB routing protocol. Eliminating these limitations requires, in particular:

[0006] - arranged to exchange Local Area Network (LAN) Hellos between ISs rather than Point-to-Point (P2P) Hellos, thereby affecting adjacency formation;

[0007] -arranged to treat multi-access links as pseudonodes to perform efficient link state protocol data unit (LSP) flooding and minimize bandwidth consumption, including by creating specific LSPs as pseudonode LSPs to represent the multi-access network;

[0008] - arranging different LSP flooding between the configuration of the P2P link and one of the multi-access links; and

[0009] - Arrangement of the shortest path calculation also differs between the configuration of the P2P link and one of the multi-access links.

[0010] In one aspect, various embodiments of the present technology provide a method for using an intermediate system to intermediate system IS-IS as a control plane for a shortest path bridge SPB in a network, the network comprising at least one service provider network SPN and at least two backbone edge bridges BEB, the at least two backbone edge bridges BEB (121 i ) is connected to the SPN, the method comprising:

[0011] - forming an adjacency by each of the at least two BEBs with each other of the at least two BEBs by periodically sending a Local Area Network LAN IS-IS Hello IIH and listening to a LAN IIH received from each other of the at least two BEBs;

[0012] -Select one of the BEBs among at least two BEBs as the designated ISDIS to simulate a pseudo node;

[0013] - creating, by each of the at least two BEBs, a non-pseudonode level 1 LSP, listing the pseudonode as a neighbor of the non-pseudonode level 1 LSP, and flooding the non-pseudonode level 1 LSP to each other of the at least two BEBs;

[0014] - creating, by the DIS, a pseudonode level 1 LSP, listing the DIS and each of the other BEBs of the at least two BEBs as neighbors of the pseudonode level 1 LSP, and flooding the pseudonode level 1 LSP to each of the other BEBs of the at least two BEBs;

[0015] - after forming the adjacency, a complete sequence number PDU CSNP is sent by the DIS to each other of the at least two BEBs; and

[0016] - A shortest path first SPF is run by each of the at least two BEBs to calculate the shortest path in the network from each of the at least two BEBs itself to each other of the at least two BEBs.

[0017] In one embodiment of the method, the LAN IIH is sent to the level 1 IS multicast address with a LAN ID consisting of the system ID of the DIS plus an octet long unique ID assigned by the DIS.

[0018] In another embodiment of the method, the pseudonode represents a multi-access link, and the pseudonode level 1 LSP lists all SPB nodes connected to the multi-access link.

[0019] In yet another embodiment of the method, sending the CSNP by the DIS is performed periodically.

[0020] In another embodiment of the method, IS-IS for SPB records a list of all hops except pseudonodes during SPF calculation from one BEB to another BEB, and the list is used with the ECT mask to block the link when SPF finds equal cost multipath ECMP.

[0021] In another embodiment of the method, there is a TLV in the LAN IIH, the TLV includes the following fields: Type (1 byte) - 252, Length (1 byte) - 4, and Value - 4 byte Circuit ID.

[0022] In another embodiment of the method, the rate at which the LAN IIH is sent by the DIS is more than twice the rate at which the LAN IIH is sent by each other of the at least two BEBs.

[0023] In another embodiment of the method, the sending LAN IIH is sent to the multicast MAC address 01-80-C2-00-00-14.

[0024] In another embodiment of the method, the CSNP sent by the DIS is sent to the multicast MAC address 01-80-C2-00-00-14.

[0025] In another aspect, various embodiments of the present technology provide a backbone edge bridge BEB, when the backbone edge bridge BEB is connected to a service provider network SPN, wherein at least another BEB is also connected to the service provider network SPN, and in the service provider network SPN, an intermediate system to intermediate system IS-IS is used as a control plane for the shortest path bridge SPB, the backbone edge bridge BEB is configured to perform the following operations:

[0026] - forming an adjacency with at least one other BEB by periodically sending a LAN IS-IS Hello IIH and listening to LAN IIHs received from at least one other BEB;

[0027] -Select the backbone edge bridge BEB itself or at least other BEBs as the designated ISDIS to simulate a pseudo node;

[0028] - Create a non-pseudonode level 1 LSP, list the pseudonode as a neighbor of the non-pseudonode level 1 LSP, and flood the non-pseudonode level 1 LSP to at least other BEBs;

[0029] -If selected as DIS:

[0030] - creating a pseudonode level 1 LSP, listing the DIS and at least one other BEB as neighbors of the pseudonode level 1 LSP, and flooding the pseudonode level 1 LSP to at least one other BEB; and

[0031] - after forming an adjacency, sending the full sequence number PDU CSNP to at least the other BEB; and

[0032] - Run Shortest Path First SPF to calculate the shortest path from the Backbone Edge Bridge BEB itself to at least one other BEB in the network.

[0033] In one embodiment, the BEB is configured to send the LAN IIH to the level 1 IS multicast address with a LAN ID consisting of the system ID of the DIS plus an octet long unique ID assigned by the DIS.

[0034] In another embodiment of the BEB, the pseudonode represents a multi-access link, and the BEB is configured to, when elected as a DIS, send a pseudonode level 1 LSP listing all SPB nodes connected to the multi-access link.

[0035] In yet another embodiment, the BEB is configured to support a TLV present in the LAN IIH, the TLV comprising the following fields: Type (1 byte) - 252, Length (1 byte) - 4, and Value - 4 byte Circuit ID.

[0036] In yet another embodiment, the BEB is configured to send the LAN IIH to the multicast MAC address 01-80-C2-00-00-14.

[0037] In yet another embodiment, the BEB (121i) is configured to send the CSNP to the multicast MAC address 01-80-C2-00-00-14 when elected as the DIS.

[0038] In the context of this specification, unless explicitly stated otherwise, "Service Provider Network" or "SPN" is intended to include the core network or backbone infrastructure through which a business entity or organization provides services such as network access and bandwidth availability for sale to customers. This core network or backbone infrastructure, including edge or access points, consists of switching equipment that transports multicast IS-IS for SPB packets and enables Layer 2 connectivity between customer networks connected to the edge or access points.

[0039] In the context of this specification, unless explicitly stated otherwise, a computing system may refer to, but is not limited to, an “electronic device,” “operating system,” “system,” “computer-based system,” “controller unit,” “monitoring device,” “control device,” and / or any combination thereof suitable for the relevant task at hand.

[0040] In the context of this specification, the expression "FPGA" is intended to include field programmable gate array computing systems available on the market at the time of filing this patent application, such as reference Xilinx VU9P or Intel Stratix V, and any subsequently available equivalent technologies, regardless of their names, contained in computing system hardware programmed with software.

[0041] In the context of this specification, the expression "processor" is intended to include a single dedicated processor, a single shared processor, or multiple separate processors, some of which may be shared. In some aspects of the present technology, the processor may be, for example, a general-purpose processor such as a central processing unit (CPU), a processor dedicated to a specific purpose, or a processor implemented in an FPGA. Other conventional and / or custom hardware may also be included.

[0042] In the context of this specification, unless otherwise expressly specified, the expression "memory" is intended to include random access memory systems available on the market at the time of filing this patent application, as well as any subsequent available equivalent technologies, regardless of their names, included in computing system media for storing digital information. An example of such a memory may be a quad data rate (QDR) static random access memory (SRAM).

[0043] In the context of this specification, the functional steps shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software.

[0044] Still in the context of this specification, "a" computer-readable medium and "the" computer-readable medium should not be interpreted as the same computer-readable medium. On the contrary, and whenever appropriate, "a" computer-readable medium and "the" computer-readable medium may also be interpreted as a first computer-readable medium and a second computer-readable medium.

[0045] In the context of this specification, unless explicitly stated otherwise, the words "first", "second", "third" etc. are used as adjectives only to distinguish the nouns they modify rather than to describe any specific relationship between these nouns.

[0046] The implementations of the present technology each have at least one of the above-mentioned purposes and / or aspects, but not necessarily all of these purposes and / or aspects. It should be understood that some aspects of the present technology that have been obtained from attempting to achieve the above-mentioned purpose may not meet the purpose and / or may meet other purposes not specifically listed herein.

[0047] Additional and / or alternative features, aspects, and advantages of implementations of the present techniques will become apparent from the following description, drawings, and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] For a better understanding of the present technology as well as other aspects and further features, reference is made to the following description which will be used in conjunction with the accompanying drawings, in which:

[0049] Figure 1 illustrates an exemplary network topology in which the present technology may be implemented;

[0050] Figure 2 The diagram illustrates a scenario of tunneling packets through a provider backbone bridge;

[0051] Figure 3 Depicts computing systems that can be used to implement methods and processes according to the present technology; and

[0052] Figure 4 Computer-implemented method steps according to the present technology are depicted.

[0053] It should be noted that, unless otherwise expressly stated herein, the drawings are not drawn to scale. In addition, the same elements from one figure to the next share the same reference numerals. DETAILED DESCRIPTION

[0054] The examples and conditional language listed herein are primarily intended to help the reader understand the principles of the present technology, rather than to limit its scope to such specific listed examples and conditions. It should be understood that a person skilled in the art may design a variety of arrangements that, although not explicitly described or shown herein, still embody the principles of the present technology and are included within its spirit and scope.

[0055] In addition, to facilitate understanding, the following description may describe a relatively simplified implementation of the present technology. Those skilled in the art will appreciate that various implementations of the present technology may have greater complexity.

[0056] In some cases, examples that are considered helpful for modifications of the present technology may also be set forth. This is done solely to aid understanding, and again is not intended to limit the scope of the present technology or set forth the limits of the present technology. These modifications are not an exhaustive list, and those skilled in the art may make other modifications while still falling within the scope of the present technology. Furthermore, where examples of modifications are not set forth, it should not be construed that any modification is impossible and / or that what is described is the only way to implement that element of the present technology.

[0057] In addition, all statements herein listing the principles, aspects, and implementations of the present technology and specific examples thereof are intended to encompass their structural and functional equivalents, whether they are currently known or developed in the future. Thus, for example, it will be understood by those skilled in the art that any block diagram herein represents a conceptual view of an illustrative circuit that embodies the principles of the present technology. Similarly, it should be understood that any diagram, flow chart, state transition diagram, pseudocode, etc. represents a variety of processes that can be fully represented in a non-transient computer-readable medium and thus executed by a computer or processor, whether or not such a computer or processor is explicitly shown.

[0058] Software modules, or simply modules implying software, may be represented herein as any combination of diagram elements or other elements indicating the execution of process steps and / or textual descriptions. Such modules may be executed by hardware as explicitly or implicitly shown. Furthermore, it should be understood that a module may include, for example, but not limited to, computer program logic, computer program instructions, software, stacked pieces, firmware, hardware circuitry, or combinations thereof that provide the desired capabilities.

[0059] With this basic knowledge in place, we will now consider some non-limiting examples to illustrate various implementations of aspects of the present technology.

[0060] Figure 1 1 illustrates an exemplary network topology in which the present technology may be implemented. SPN 101 has a corresponding SPB network-to-network (NNI) port 111. i The number i of backbone edge bridges (BEBs) 121 connected to it i Each BEB121 i With corresponding access port 131 i The BEB connects the customer network to the SPN.

[0061] Before any shortest path tree calculations are performed, the network topology must first be discovered. Adjacency in IS-IS for SPB routing protocol is ensured by periodic IS-IS Hello (IIH) packets exchanged between ISs. Each IS then sends an LSP containing information about adjacent ISs and associated networks, which is flooded between all ISs. Each IS builds a database of the network topology and aggregates the flooded network information. IS-IS for SPB routing protocol treats SPNs such as SPN101 (multi-access and local area network (LAN)) as virtual pseudo nodes.

[0062] In order to Figure 1 The network topology forms the SPB backbone, each BEB 121 i It is necessary to form adjacencies with all other BEBs connected to SPN 101, and shortest path calculations between ISs need to be performed with SPN 101. By periodically sending IIH packets, each IS (such as BEB 121 i ) forms an adjacency with each of the other BEBs. BEB 121 i One of the ISs is selected as the designated IS (DIS) and plays the role of a pseudonode or simulates a pseudonode. The DIS also sends periodic complete sequence number PDUs (CSNPs, with PDU as "protocol data unit") to inform other ISs about all LSPs in the IS database. IS-IS for SPB currently supports only P2P adjacencies: therefore, pseudonodes and links from pseudonodes to pseudonodes are not considered part of the IS-IS Shortest Path First (SPF) calculation and are simply avoided if present in the physical topology. According to the prior art, adapting IS-IS for SPB to the needs of forming multiple adjacencies between ISs and shortest path calculations between ISs with SPNs solves the following problems:

[0063] Adjacency formation :

[0064] On a multi-access interface, a LAN IIH may be exchanged. The LAN IIH carries precedence over the P2P IIH and the LAN ID (a combination of the DIS's system ID plus an octet-long unique ID assigned by the DIS). The format of a LAN IIH may be as follows (the length of the field is indicated in brackets):

[0065]

[0066] Packet Type - Specific fields for LAN IIH may be as follows:

[0067] -Circuit Type: Indicates whether this circuit is Class 1 only, Class 2 only, or both (Class 2 or backbone areas are not applicable to this technology)

[0068] -Source ID: The system ID of the originator

[0069] -Hold Time: Indicates how long to wait for the IIH from this IS before declaring it exhausted and removing its adjacency

[0070] -PDU length: the length of the entire PDU, fixed header, and type-length value (TLV)

[0071] - Priority: This 7-bit value specifies the priority for the DIS on the LAN (Class 1)

[0072] -LAN ID: The system ID of the DIS plus an octet-long unique ID assigned by the DIS for this IS

[0073] The TLVs may be as follows:

[0074] - Area Address (Type 1): (Defined in IS-IS for SPB) It contains the area address configured on the IS

[0075] -IS Adjacency (Type 6): (Defined in IS-IS for SPB) It contains the Backbone Media Access Control (B-MAC) address (System ID) of the Level 1 adjacency

[0076] -MT Port Capability TLV: (defined in IS-IS for SPB) It contains B-VLAN, Equal Cost Tree (ECT) mapping.

[0077] The IS-IS routing protocol TLV for SPB might be as follows:

[0078] - Area Address TLV: This TLV lists the set of area addresses configured on the originating IS. To form a level 1 adjacency, a common area address needs to be configured on both adjacent ISs. An IS can generate up to 255 LSPs, but this TLV should be in the first LSP (zero LSP), or

[0079] If the LSP is fragmented, this TLV should be in the first fragment. This is not relevant for pseudonode LSPs, so this should only be part of non-pseudonode LSPs. The Area Address TLV consists of the following

[0080] Field composition:

[0081] - Type (1 byte): 1

[0082] - Length (1 byte): The total length of the Value field

[0083] - Value: nx (1-byte address length + variable area address)

[0084] -IS Adjacency TLV: This TLV captures the list of adjacent Level 1 ISs. It consists of the following fields

[0085] composition:

[0086] - Type (1 byte): 6

[0087] - Length (1 byte): 1 byte + nx (system ID length) for n neighbors

[0088] - Value: nx (neighboring system ID)

[0089] When a LAN interface is enabled for IS-IS for SPB, the BEB may immediately send an IIH packet (specified as the all-level-1 IS multicast address) with a LAN ID consisting of the DIS's system ID plus an octet-long unique ID assigned by the DIS. It may also begin listening to the IIH to discover any connected adjacencies. Depending on its configuration, it may then run the DIS election process to determine if it qualifies to become a DIS on the multiaccess network.

[0090] The way a BEB receives an IIH depends on its configuration (interface type): a LAN IIH is transmitted on a LAN interface, and a P2PIIH is transmitted on a P2P interface, and if a BEB receives a LAN IIH on a P2P interface, or a P2P IIH on a LAN interface, the BEB does not process such an IIH. All IIHs received are checked for compliance with the configuration (same as in the case of a P2P link). The ID Length and Maximum Area Address fields in the received IIH must match the local values.

[0091] When a BEB receives an IIH packet, it checks for existing adjacencies with the transmitter. If the adjacency is known, it resets the hold time to the value in the received IIH. If the adjacency is unknown, the receiving BEB creates an adjacency and sets its state to initialized until a subsequent received IIH packet confirms bidirectional communication. The BEB includes the backbone MAC (B-MAC) addresses or system IDs of all neighbors on the LAN from which they received the IIH, allowing a simple mechanism to confirm bidirectional communication. Bidirectional communication is confirmed when a subsequent IIH received contains the receiving BEB's B-MAC address in the IS Adjacency TLV field. Otherwise, communication between the nodes is considered unidirectional and the adjacency remains in the initialized state. For the BEB to send or process received LSPs, the adjacency must be in the in and up state.

[0092] IS-IS for SPB selects (from the configuration) one of the Backbone Virtual LANs (B-VLANs) as the control B-VLAN, where all control packets are transmitted on this VLAN and tagged with the control bvlan (IEEE 802.1q). All SPB NNI ports 111 of the SPB nodes i , such as BEB 121 i ( Figure 1 ), is not only tagged with the control bvlan, but also tagged with other B-VLANs, IS-IS IIH may not be flooded to avoid packet loops. Therefore, where a control packet (multicast) is received, BEB 121 i It can be consumed without reflooding.

[0093] Pseudonode and Pseudonode LSP:

[0094] After adjacencies are determined, LSP flooding occurs. To enforce efficient LSP flooding and minimize bandwidth consumption, multi-access links can be modeled as pseudonodes. As the name suggests, these are virtual nodes whose role is played by the DIS elected for the LAN.

[0095] During the election process, only BEBs with normal adjacencies are considered. The DIS is elected based on the highest interface priority, where the highest B-MAC address blocks the link. The default interface priority is 64, which can be changed with configuration.

[0096] Therefore, each multi-access link can be represented by a pseudonode LSP generated by the DIS. The pseudonode LSP can list all SPB nodes connected to the multi-access link, which is represented by the extended IS reachability TLV. The pseudonode LSP consists of IS-IS for the SPB LSP header and one or more extended IS reachability TLVs - one extended IS reachability TLV for each IS neighbor on the multi-access network, as follows:

[0097] - TLVs in pseudonode LSPs: Standard extended IS reachability TLV (22) can be used to advertise all neighbors on the SPN and the metrics to reach those neighbors

[0098] - The Extended IS Reachability TLV (Type 22) supports extended metric values ​​of more than 3 bytes (e.g., to account for pseudonode metrics in the case where pseudonodes exist between neighbors), instead of the 1 byte of the IS Neighborhood TLV (Type 2). The format for this TLV may be as follows:

[0099] - Type (1 byte) - 22

[0100] - Length (1 byte) – the total length of the Value field

[0101] -Value-6-byte system ID + 1-byte pseudonode number

[0102] - Default metric of 3 bytes

[0103] -1 byte sub-TLV length

[0104] -0–244 bytes of sub-TLV

[0105] The 3 bytes of the metric field may be used to encode the metric as a 24-bit unsigned integer. The sub-TLV may be reserved as part of the present technology and may be used for MPLS traffic engineering purposes.

[0106] IS-IS LSP:

[0107] There is no backup DIS elected. Given the frequency of periodic database synchronization that occurs on broadcast links, this is not an issue with LSP flooding. If the current DIS fails, another IS is immediately elected to play this role. The DIS may transmit IIH packets more frequently (e.g., three times more frequently) than other ISs on the LAN. For example, the default IIH period for a DIS may be 3 seconds instead of 9 seconds for other nodes. This allows for rapid detection of DIS failures and immediate replacement.

[0108] Periodic database synchronization over broadcast links (periodic transmission of CSNPs by the DIS) allows preemption of an existing DIS without serious disruption of IS-IS operations. A DIS may no longer be a DIS if a new IS with a higher priority appears on the LAN and immediately takes over the DIS role upon connecting to the LAN, assuming pseudonode functionality.

[0109] TLVs in (LAN and P2P) IIH and (non-pseudonode) LSPs:

[0110] IS-IS over multiaccess uses several TLVs that are already defined in IS-IS for SPB. Some of them are optional. IS-IS over multiaccess for SPB also uses these TLVs and does not require additional TLVs to advertise any additional SPB IS-IS related information. The following table gives a summary of the TLVs:

[0111]

[0112]

[0113] As an illustration, we assume that Figure 1 : BEB 1 With B-MAC address M1, BEB 2 With B-MAC address M2, BEB 3With B-MAC address M3, and BEB 1 It is DIS. Since the value of TLV 22 is system ID + pseudo node number, BEB 1 A non-pseudonode LSP may show the following adjacencies:

[0114] M1.1 (“1” represents a pseudo node)

[0115] BEB 2 A non-pseudonode LSP may show the following adjacencies:

[0116] M2.1

[0117] BEB 3 A non-pseudonode LSP may show the following adjacencies:

[0118] M3.1

[0119] By BEB 1 The pseudonode LSP created may show the following adjacencies ("0" represents a non-pseudonode adjacency):

[0120] M1.0

[0121] M2.0

[0122] M3.0

[0123] Database synchronization:

[0124] The database synchronization process may be different from that performed over P2P links. In the case of P2P links, the CSNP may be sent only once, when the IS-IS adjacency is initialized, before LSPs are exchanged on the link. LSPs can be reliably exchanged over point-to-point links in a manner that ensures that all LSPs sent over the link from one end can be received at the other end. On multi-access links, the CSNP may be transmitted periodically by the DIS to compensate for the inherently unreliable LSP exchange process. When the DIS plays the role of a node or simulates a pseudonode, as an abstraction for representing a multi-access link as a network node, this may reduce the number of one-to-one communications in a broadcast environment, and as a result, reduce the amount of information exchanged when many nodes are interconnected in such an environment.

[0125] ISs connected to the same multi-access link can form adjacencies with each other by periodically sending IIHs to a multicast address called the AllL1IS MAC address (01-80-C2-00-00-14). Adjacency maintenance and database synchronization on multi-access links can be separate processes. On multi-access links, LSPs can also be multicast to the address AllL1IS, and DISs can also coordinate link state database synchronization by periodically multicasting CSNPs to the same multicast address.

[0126] Shortest path calculation:

[0127] The SPF calculation for unicast and multicast on multi-access links is similar to that for point-to-point links, but the SPF calculation on multi-access links needs to take into account pseudonode LSPs to create the shortest path tree on the multi-access link.

[0128] Each node's LSP (non-pseudonode LSP) lists the pseudonode as a neighbor on the multi-access link, and the pseudonode LSP lists all other nodes on the multi-access link as its neighbors. Therefore, the shortest path between 2 nodes on a multi-access link passes through the pseudonode.

[0129] IS-IS used for SPB records a list of all hops (nodes) during SPF calculation (a combination of bridge ID, system ID, and priority) from one node to another in lexicographic order. This list is used along with the ECT mask to block a link when SPF finds an equal-cost multipath (ECMP). SPF does not record pseudonodes in the list of hops, so pseudonodes may not be considered in ECMP link blocking.

[0130] Mac Table:

[0131] For example, assume that M1, M2, M3, and M4 are considered MAC addresses, and P1, P2, P3, and P4 are considered to be connected to the BEB, respectively. 1 , BEB 2 , BEB 3 and BEB 4 The BEB 1 The SPB MAC table on may look like this:

[0132]

[0133] Data plane:

[0134] MAC tunnel creation and MAC in packet encapsulation are not affected by this technique. Forwarding data with / in a service provider network is outside the scope of this technique.

[0135] As shown in the MAC table above, BEB 1 Can forward traffic to port P2 while sending traffic to BEB 2 , BEB 3 or BEB 4 How data is forwarded in an SPN is known and is not described as part of this technology.

[0136] According to the present technology, the encapsulation method in IEEE 802.1ah is supported, and basic data is forwarded using Provider Backbone Bridging (PBB). i ( Figure 1 ), the packet may be classified as SPB service based on the access port configuration (for example, if VLAN tag is 10, assign the packet to SPB service 1). At this point, the packet can tunnel Figure 2 The PBB network 200 is shown. The client frame can be transmitted by the BEB 121 i ("mac-in-mac" technology) encapsulated in the backbone mac address (B-MAC).

[0137] B-MAC is the individual MAC address (system MAC address) of the BEB. In addition, a new VLAN id called B-VID 201 can also be assigned to the frame. The customer frame further switched by the BCB (backbone core switch) 202 can use the B-MAC and B-VID, and the BCB 202 only learns the B-MAC instead of the customer MAC. This has two benefits: a reduction in the total number of MAC addresses and isolation of the backbone domain from the customer domain. The service instance limitation of the 4K s-VLAN can be solved by assigning a 24-bit instance number (I-SID) to the customer frame by the BEB. The I-SID is carried in the I-TAG field 203 of the encapsulated frame transmitted by the BEB.

[0138] PBB networks can use conventional bridging mechanisms, including the spanning tree protocol, for loop resolution within the backbone network. SPB-M can employ the same framework as above. The main difference is that instead of spanning tree, it uses IS-IS for SPB to create a shortest path tree for transmitting frames through the backbone network.

[0139] Limit multiple adjacencies between two SPB nodes:

[0140] IS-IS for SPB does not allow multiple adjacencies to exist between two switches running IS-IS for SPB to avoid loops. IS-IS selects the adjacency with the lowest circuit ID (interface id) on the IS with a higher system ID, and the IIH on other interfaces may be silently ignored, so that the adjacency will not be established. IS-IS for SPB uses a 3-way adjacency TLV (240) to understand the remote system circuit ID. The 3-way adjacency TLV carries information about the circuit ID of the IS-IS node on the P2P interface. According to the current technology, in order to announce the circuit ID of the multi-access interface, a TLV (IS-IS Circuit ID Announcement TLV) is introduced in the LAN IIH, which consists of the following fields:

[0141] - Type (1 byte) - 252

[0142] -Length (1 byte) - 4

[0143] - Value - 4-byte circuit ID

[0144] The above methods and process steps may be implemented in a computing system, examples of which, but not limited to, are about Figure 3 As will be appreciated by those skilled in the art, such a computing system may be implemented in any other suitable hardware, software and / or firmware, or a combination thereof, and may be a single physical entity, or several separate physical entities with distributed functionality.

[0145] In some aspects of the present technology, computing system 300 may include a variety of hardware components, including one or more single-core or multi-core processors, collectively represented by processor 301, solid-state drive 302, memory 303, and input / output interface 304. In this case, processor 301 may or may not be included in an FPGA. In some other aspects, computing system 300 may be an "off-the-shelf" general-purpose computing system. In some aspects, computing system 300 may also be distributed among multiple systems. Computing system 300 may also be specifically used for implementation of the present technology. As can be appreciated by those skilled in the art, multiple variations on how to implement computing system 300 can be envisioned without departing from the scope of the present technology.

[0146] Communications between the various components of the computing system 300 may be enabled by one or more internal and / or external buses 305 (e.g., a PCI bus, a Universal Serial Bus, an IEEE 1394 "FireWire" bus, a SCSI bus, a Serial ATA bus, an ARINC bus, etc.) to which the various hardware components are electrically coupled.

[0147] The input / output interface 304 may allow for enabling networking capabilities, such as wired access or wireless access. As an example, the input / output interface 304 may include a network interface, such as, but not limited to, a network port, a network plug-in, a network interface controller, etc. A number of examples of how the network interface is implemented will become apparent to those skilled in the art. According to embodiments of the present technology, the solid-state drive 302 may store program instructions, such as, for example, those portions of libraries, application programs, etc., suitable for being loaded into the memory 303 and executed by the processor 301 for methods and process steps according to the present technology.

[0148] Figure 4The steps of a method implemented by a computing system according to the present technology are depicted. In step 401, each BEB connected to a network including an SPN having IS-IS as a control plane for the SPB forms an adjacency with each other BEB connected to the SPN by periodically sending a LAN IIH. For example, BEB 121 i and SPN 101 can be as Figure 1 As shown. In step 402, each BEB participates in the election process of the DIS, and each BEB simulates a pseudonode by creating and flooding a pseudonode LSP. In step 403, each BEB connected to the SPN creates a non-pseudonode level 1 LSP, lists the pseudonode as a neighbor of the non-pseudonode level 1 LSP, and floods the non-pseudonode level 1 LSP to all other BEBs connected to the SPN. In steps 404 and 405 respectively: (i) the DIS creates a pseudonode level 1 LSP, lists itself and each of the other BEBs connected to the SPN as neighbors of the pseudonode level 1 LSP, and floods the pseudonode level 1 LSP to all other BEBs connected to the SPN, and (ii) once the formation of the adjacency in step 401 is completed, the CSNP is sent to all other BEBs connected to the SPN. In step 406, each BEB connected to the SPN runs SPF to calculate the shortest path in the network from each BEB itself to all other BEBs connected to the SPN.

[0149] Although the above implementations have been described and illustrated with reference to specific steps performed in a specific order, it should be understood that these steps can be combined, subdivided, or reordered without departing from the teachings of the present disclosure. At least some of the steps can be performed in parallel or in series. Therefore, the order and grouping of steps are not limitations of the present technology. It should be clearly understood that not all technical effects mentioned herein need to be enjoyed in each and every embodiment of the present technology.

[0150] Modifications and improvements to the above-described embodiments of the present technology will be apparent to those skilled in the art. The foregoing description is intended to be illustrative rather than restrictive. Therefore, the scope of the present technology is intended to be limited only by the scope of the appended claims.

Claims

1. A method for using an intermediate system to intermediate system (IS-IS) as a control plane for a shortest path bridge (SPB) in a network, the network comprising at least one service provider network (SPN) (101) and at least two backbone edge bridges (BEBs) (121 i ), the at least two backbone edge bridges BEB (121 i ) is connected to the SPN (101), the method include: - by periodically sending LAN IS-IS Hello IIH and listening to the at least two BEBs (121 i ) received by each of the other BEBs, from the at least two BEBs (121 i ) in each of the BEBs and the at least two BEBs (121 i ) forms an adjacency with every other BEB; - Select the at least two BEBs (121 i ) as a designated ISDIS, simulating a pseudo node; - by the at least two BEBs (121 i ) to create a non-pseudo node level 1 link state protocol data unit LSP for each of the BEBs in the BEBs, list the pseudo node as a neighbor of the non-pseudo node level 1 LSP, and flood the non-pseudo node level 1 LSP to the at least two BEBs (121 i ) every other BEB; - The DIS creates a pseudo node level 1 LSP, connecting the DIS and the at least two BEBs (121 i ) as a neighbor of the pseudo node level 1 LSP, and flooding the pseudo node level 1 LSP to the at least two BEBs (121 i ) every other BEB; - After forming the adjacency, the DIS sends a complete sequence number PDU CSNP to the at least two BEBs (121 i ) in each other BEB; as well as - by the at least two BEBs (121 i ) in each BEB runs the shortest path first SPF to calculate the path from the at least two BEBs (121) in the network. i ) to the at least two BEBs (121 i ), wherein the LAN IIH is sent to a level 1 IS multicast address with a LAN ID consisting of the system ID of the DIS plus an octet-long unique ID assigned by the DIS, It is characterized in that there is a type-length-value TLV in the LAN IIH, and the TLV includes the following fields: type-252, length-4, and value-4-byte circuit ID.

2. The method according to claim 1, in, The pseudonode represents a multi-access link, and the pseudonode level 1 LSP lists all SPB nodes connected to the multi-access link.

3. The method according to any one of claims 1 or 2, in, The sending of CSNP by the DIS is performed periodically.

4. The method according to any one of claims 1 or 2, in, IS-IS for SPB records a list of all hops except the pseudonode during SPF calculation from one BEB to another BEB, and wherein the list is used together with an equal cost tree ECT mask to block a connection when SPF finds an equal cost multipath ECMP.

5. The method according to any one of claims 1 or 2, in, The rate at which the LAN IIH is sent by the DIS is determined by the at least two BEBs (121 i ) at least twice the rate at which each other BEB in the LAN sends LAN IIH.

6. The method according to any one of claims 1 or 2, in, The outgoing LAN IIH is sent to the multicast MAC address 01-80-C2-00-00-14.

7. The method according to claim 6, in, The CSNP sent by the DIS is sent to the multicast MAC address 01-80-C2-00-00-14.

8. A backbone edge bridge BEB (121 i ), the backbone edge bridge BEB (121 i ) includes a processor (301), a solid state drive (302), a memory (303) and an input / output interface (304), when the backbone edge bridge BEB (121 i ) is connected to the service provider network SPN (101) through the input / output interface (304), in, At least one other BEB is connected to the service provider network SPN (101), and an intermediate system to intermediate system IS-IS is used as a control plane for the shortest path bridge SPB in the service provider network SPN (101), the backbone edge bridge BEB (121 i ) is configured to perform the following operations: - forming an adjacency with at least one other BEB by periodically sending a Local Area Network LAN IS-IS Hello IIH and listening to LAN IIHs received from at least one other BEB; - Select the backbone edge bridge BEB (121 i ) itself or at least one other BEB as a designated ISDIS, simulating a pseudo node; - creating a non-pseudonode level 1 link state protocol data unit LSP, listing the pseudonode as a neighbor of the non-pseudonode level 1 LSP, and flooding the non-pseudonode level 1 LSP to the at least other BEB; -If selected as the DIS: - creating a pseudo-node level 1 LSP, listing the DIS and the at least other BEB as neighbors of the pseudo-node level 1 LSP, and flooding the pseudo-node level 1 LSP to the at least other BEB; as well as - after forming the adjacency, sending the complete sequence number PDU CSNP to said at least other BEB; as well as - Run the shortest path first SPF to calculate the path from the backbone edge bridge BEB (121 i ) the shortest path from itself to said at least one other BEB; wherein the LAN IIH is sent to a level 1 IS multicast address with a LAN ID consisting of the system ID of the DIS plus an octet-long unique ID assigned by the DIS, Characterized in that the BEB(121 i ) is configured to: support the type-length-value TLV present in the LAN IIH, the TLV including the following fields: type-252, length-4, and value-4 bytes of circuit ID.

9. The backbone edge bridge BEB (121 according to claim 8 i ), in, The pseudonode represents a multi-access link, and the BEB is configured to, when elected as a DIS, send a pseudonode level 1 LSP listing all SPB nodes connected to the multi-access link.

10. The backbone edge bridge BEB (121) according to any one of claims 8 or 9. i ), the BEB (121 i ) is configured to send LAN IIH to multicast MAC address 01-80-C2-00-00-14.

11. The backbone edge bridge BEB (121) according to claim 10 i ), the BEB (121 i ) is configured to: when selected as the DIS, send the CSNP to the multicast MAC address 01-80-C2-00-00-14.

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