WO2008011781A1

WO2008011781A1 - A method and node to detect neighbor node on resilient package ring

Info

Publication number: WO2008011781A1
Application number: PCT/CN2007/001608
Authority: WO
Inventors: Jian Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-07-18
Filing date: 2007-05-17
Publication date: 2008-01-31
Also published as: CN101110752B; CN101110752A

Abstract

A method and node to detect neighbor node on RPR are disclosed. In this method, a topology table is maintained in a node, which can be used for making sure if a neighbor node is connecting directly with the said node. The method wins the merit of converging in 50 ms, which overcomes the problem of low detecting speed over control plane, at the same time, bad connectivity problem, low scalability problem and additional bandwidth engrossment can be avoided well.

Description

Method and network node for sensing neighbor connectivity on resilient packet ring This application claims to be filed on July 18, 2006, with the Chinese Patent Office, application number 200610061720.4, and the invention name is "a resilient packet ring to sense neighbor connectivity. The priority of the Chinese Patent Application, the entire disclosure of which is incorporated herein by reference.

Technical field

The present invention relates to the field of network communication technologies, and in particular, to a method and a network node for sensing neighbor connectivity on an elastic packet ring.

Background technique

With the development of network communication technology, various new generations of metropolitan area network technologies emerge one after another. Among them, RPR (Resilient Packet Ring) technology combines the intelligence of IP (Internet Protocol) and the economics of Ethernet. Features such as flexibility and scalability, while absorbing the advantages of high bandwidth efficiency of fiber ring network, fast protection of 50ms (milliseconds), and automatic discovery of network topology, providing a good networking solution for broadband IP metropolitan area networks. Compared with traditional MAC (Media Access Control), RPR's most attractive feature is carrier-class reliability, which not only limits the processing of data-oriented services, but also forms more processing. Integrated transport solution for business delivery.

As shown in Figure 1, RPR is a ring network composed of packet switching nodes. Adjacent nodes are connected by a pair of optical fibers. Similar to SDH (Synchronous Digital Hierarchy) topology, RPR network topology It is based on two oppositely transmitted rings, each of which operates at the same rate. Different from SDH, both rings of RPR can transmit data, and the two rings are called 0 ring and 1 ring respectively. The data transmission direction of the 0 ring on the RPR is clockwise, and the direction of the 1 ring is counterclockwise. Each RPR node uses the 48-bit MAC address used in the Ethernet as the address identifier.

RPR provides 50ms of source routing protection. Under normal circumstances, both fibers of the RPR are working fibers. When a fiber break or node failure occurs, the node fiber ingress physical layer device detects an error and notifies the MAC layer of the error, and sends a control signaling packet to notify other nodes; after receiving the control signaling packet, these nodes will Perform topology auto-discovery and transfer all services to the active ring. According to the RPR protocol, this ring protection switching is completed within 50ms, so its topology convergence is also completed within 50ms. In an IP network, the connectivity of the interface network is a very important feature. Fast and reliable access to neighbor connectivity, fast convergence for IGP (Interior Gateway Protocol), various FRR (Fast Re-route), VRRP (Virtual Router Redundancy Protocol) ) The switching technology is very important. In the current technology, there are two main methods for detecting connectivity of an interface network neighbor: slow detection through the upper layer of the control plane protocol and fast detection through the forwarding plane.

The slow detection of the upper layer of the control plane protocol includes the IGP hello packet, the link-layer protocol (Peer-to-Point Protocol), and other QoS packets of the reliability protocol such as VRRP. . This type of detection packet needs to be sent and received by a CPU (Central Process Unit) running on the routing control plane. Therefore, the transmission and reception frequency has a large P-control system, which is basically a second-level detection. If the detection rate is increased, Then the CPU pressure on the control plane is very large. For example, the neighboring detection of the ISIS (Intermediate System-to-Intermediate System) protocol sends a hello packet for 10 seconds (seconds). If the Hello packet is not received for 4 consecutive times, the neighbor connectivity is considered to be lost. The typical configuration of the advertised VRRP packet is that Is is sent once. If the VRRP packet is not received for three consecutive times, the connectivity with the peer device is considered to be lost. The disadvantage of this method is that the detection speed is too slow, usually takes 3 seconds to 90 seconds. This time is unacceptable for real-time services that require a 50ms switch.

The fast detection of the forwarding plane detects the connectivity of neighbors through protocols such as BFD (Bidirectional Forward Detection). The hello packet of the BFD is sent directly through the forwarding plane. The sending and receiving speed is very fast. You can send a hello packet in 10 ms. If the connection fails for three consecutive times, the neighbor connectivity is lost. This detection method can meet the speed requirements, but there are still some shortcomings: BFD packets need to occupy a lot of bandwidth. Usually, a BFD test needs to occupy nearly 64k (thousands of bits) of bandwidth. In addition, the BFD protocol standard is still in the draft stage. The standardization degree and interoperability of the protocol have certain limitations. Moreover, the BFD protocol needs to be established between two neighbors. For the ring topology of RPR, there is a scalability problem.

Summary of the invention

In view of the above problems in the prior art, the embodiments of the present invention provide a method and a device for sensing neighbor connectivity on an elastic packet ring, which can quickly obtain connectivity of the ring neighbors within 50 ms while avoiding the problem of occupying extra bandwidth. . An embodiment of the present invention provides a method for sensing neighbor connectivity on an elastic packet ring, including: obtaining a topology table after convergence of the elastic packet ring;

The connectivity of the neighbor node is determined by whether the topology table includes an address identifier of a neighbor node. An embodiment of the present invention further provides a network node, where the network node includes:

a topology table unit, configured to obtain a topology table after the convergence of the elastic packet ring;

And a detecting unit, configured to determine connectivity of the neighbor node by whether the topology table includes an address identifier of a neighboring node.

According to the technical solution provided by the foregoing embodiment of the present invention, when the neighbor connectivity detection is initiated or when the topology changes, the specified neighbor node address is searched in the generated topology table after the network topology is converged. Identification, detecting neighbor connectivity. Because the elastic packet protocol can ensure that the topological fast convergence can be completed within 50ms after each topology change, the fast detection of the adjacent connectivity is realized, and the problem of slow detection speed of the upper control plane protocol layer is solved.

At the same time, it can be seen from the technical solution provided above that the embodiment of the present invention fully utilizes the function of the flexible packet ring protocol itself, does not need to occupy extra bandwidth, and has good scalability.

DRAWINGS

Figure 1 is a schematic diagram of RPR ring network communication;

2 is a flowchart of a first embodiment of a method for sensing neighbor connectivity according to the present invention; a flowchart of a node address;

4 is a topological structural diagram of an RPR ring network in an application example of the present invention;

FIG. 5 is a schematic diagram of a first variation of an RPR ring network topology in an application example of the present invention; FIG. 6 is a schematic diagram of two variants of an RPR ring network topology in an application example of the present invention; FIG. 7 is an application example of the present invention. A third variation diagram of the RPR ring network topology; FIG. 8 is a schematic structural diagram of an embodiment of a network node in the present invention.

detailed description

In the embodiment of the present invention, according to the elastic packet ring network, it is ensured that topology convergence is completed within 50 ms, and a topology table reflecting the current topology structure is generated in each RPR ring node, and the topology table is searched for connectivity. The address identifier of the neighbor node that is sexually detected to determine connectivity with the neighbor node.

In an embodiment of the present invention, the node needs to be perceived or detected on a node of an elastic packet ring. The connectivity of a node to one of its neighbors. The node first searches for the MAC address of the neighbor node that needs to be aware of connectivity in the topology table of the current resilient packet ring. If it can be found, it has connectivity, otherwise it has no connectivity. At the same time, the MAC address of the neighboring node is associated with the RPR ring, and the associated information is saved, indicating that the MAC address is the MAC address of the associated node on the RPR ring. The association between the MAC address of the neighboring node and the resilient packet ring can be saved in the network device.

The specific steps are shown in Figure 2, including:

Step S210: The upper layer application of the node specifies an elastic packet ring that needs to find connectivity, and specifies a MAC address of a neighbor node that needs to perform connectivity detection.

Step S220: Find a topology table of the elastic packet ring on the node according to the specified resilient packet ring. Step S230: Check whether the elastic packet topology table completes convergence. If the convergence is complete, perform step S240, otherwise wait for topology convergence. Afterwards, step S240 is performed;

Step S240: Search for the MAC address of the specified neighbor node in the topology table, if it is found, it has connectivity, otherwise it does not have connectivity.

If the neighbor node specified on the node that needs to be aware of connectivity has connectivity, the specified neighbor node can be associated with the corresponding elastic packet ring and the associated information is saved. The association indicates that the neighbor node is on the elastic packet ring.

When searching for the MAC address of the specified neighboring node in the topology table, the topology table may be traversed sequentially, or the topology table may be searched by a hash (HASH) method, and other methods may be utilized by those skilled in the art. The search is performed without departing from the scope of the invention.

The topology table of the node usually includes a ring topology table (or east table) and a ring topology table (or a west table), and the process of searching for the MAC address of the neighbor node in the topology table by sequentially traversing. It may have the flow shown in Figure 3, including:

I. Starting from the first hop entry of the ring topology table of the elastic packet ring;

II. First, it is necessary to check the reachability and validity of the elastic packet ring entry, which can be determined by the validity field and the reachability field in the elastic packet ring topology table. If the check fails, go to Step III; otherwise, check whether the MAC address in the Elastic Packet Ring Topology entry and the MAC address of the neighbor node to be detected are identical. If they are the same, the search succeeds, indicating connectivity; otherwise, Step 2 of the next-hop table of the ring topology table, and perform step II until the last entry of the ring topology table. If it is still not found, perform step ΠΙ; III. Starting from the first hop entry of the 0-ring topology table of the elastic packet ring;

IV. Check the reachability and validity of the elastic packet ring entry. If the check fails, the connectivity is not provided. Otherwise, the MAC address in the elastic packet ring topology entry and the MAC address of the neighbor node to be detected are compared. If they are the same, they have connectivity. Otherwise, they go to the next hop entry. Step IV is executed until the last entry of the 0-ring topology table. If it is still not found, it does not have connectivity.

Of course, the above search process can also be searched from the 0-ring topology table.

In addition, neighbor connectivity tables can be constructed from topology tables and neighbor nodes that specify perceptual connectivity. The neighbor connectivity table includes the address identifier of the neighbor node that needs to be aware of connectivity, the resilient packet ring associated with the neighbor node, and the current connectivity of the neighbor node learned from the topology table. Of course, other related information may also be included.

In the second embodiment of the present invention, when the topology of the resilient packet ring network changes, the elastic packet protocol can obtain topology change information and notify all nodes on the ring to perform topology convergence again. After convergence, the convergence is generated. The topology table of the resilient packet ring looks up the MAC address of the neighbor node that needs to be aware of connectivity. If it can be found, the connectivity to the neighbor node is normal; otherwise, the connectivity to the neighbor node fails. The address of the neighbor node that needs to be aware of connectivity at this time is the MAC address of the associated node.

In the second embodiment, the process of searching for the MAC address in the topology table is the same as the search process in the first embodiment.

If a neighbor connectivity table is constructed, each time the topology changes, neighbor nodes that have an association relationship with the elastic packet ring whose topology changes may be found in the neighbor connectivity table, and these neighbor nodes may be topologically The neighbor nodes that change the connectivity; after the topology is converged, the connectivity of the neighbor nodes is refreshed according to the topology table, that is, if the convergence topology table includes the MAC address of one of the neighbor nodes, the neighbor node The connectivity is normal; otherwise the connectivity of the neighbor node fails.

In this embodiment, the topology change includes: the networking structure, the node on the elastic packet ring, or the link fault occurs. The topology changes, and the node inserts or withdraws the elastic packet ring.

A person skilled in the art can understand that all or part of the steps in implementing the above method embodiments can be completed by a program instructing related hardware, and the program can be stored in a readable storage medium, and the program can be executed when executed. All or part of the steps in the above method embodiments are included. Said The storage medium may be a read only memory, a random access memory, a magnetic disk, an optical disk, or the like.

In order to further understand the above two embodiments of the sensory connectivity method of the present invention, the following will be further described in conjunction with the application examples.

Referring to Figure 4, in the RPR ring network shown, it is assumed that the connectivity of neighbor R5 nodes is detected on the R1 node. According to the method in the foregoing embodiment, after the network is formed, the R1 node will form its own topology table due to the network topology discovery. The basic information is as follows:

R1 MAC address 00.e0.fc.10.00.al

R2 MAC address 00.e0.fc.10.00.a2

R3 MAC address 00.e0.fc.10.00.a3

R4 MAC address 00.e0.fc.10.00.a4

R5 MAC address 00.e0.fc.10.00.a5

R6 MAC address 00.e0.fc.10.00.a6

The R1 node finds the MAC address of the neighbor R5 in its own topology table 00.e0.fc.10.00.a5, which can be found, so the connectivity between R1 and neighbor R5 is normal.

Referring to Figure 5, when the link between R5 and R6 fails, the RPR detects the fault and notifies all nodes on the ring to perform topology convergence again. When the R1 node topology is converged, its topology information is as follows:

R1: MAC address 00.e0.fc.10.00.al

R2: MAC address 00.e0.fc.10.00.a2

R3: MAC address 00.e0.fc.10.00.a3

R4: MAC address 00.e0.fc.10.00.a4

R5: MAC address 00.e0.fc.10.00.a5

R6: MAC address 00.e0.fc.10.00.a6

The R1 node still has the MAC address of the R5 node in its own topology table, so the connectivity between R1 and neighbor R5 is still normal.

Referring to Figure 6, after the link between R5 and R6 and the link between R3 and R4 are faulty at the same time or in succession, the RPR detects the fault and notifies all nodes on the ring to perform topology convergence again. When the R1 node topology is converged, its topology information is as follows:

R1: MAC address 00.e0.fc.10.00.al R2: MAC address 00.e0.fc.10.00.a2

R3: MAC address 00.e0.fc.10.00.a3

R6: MAC address 00.e0.fc.10.00.a6

The R1 node cannot find the MAC address of the R5 node in its own topology table, so the connectivity between R1 and neighbor R5 fails.

Referring to Figure 7, after the R5 node fails, the RPR protocol detects the fault and notifies all nodes on the ring to re-top topology convergence. When the R1 node topology is converged, its topology information is as follows:

R1: MAC address 00.e0.fc.10.00.al

R2: MAC address 00.e0.fc.10.00.a2

R3: MAC address 00.e0.fc.10.00.a3

R4: MAC address 00.e0.fc.10.00.a4

R6: MAC address 00.e0.fc.10.00.a6

In the present invention, an embodiment of a network node connected to an elastic packet ring may have the structure shown in FIG. The network node includes a topology table unit 810 and a detection unit 820. The topology table unit 810 is configured to obtain a topology table after the convergence of the elastic packet ring on the network node, for example, by the topology table unit 810 when the connectivity detection is initiated for the first time. To determine whether the elastic packet ring converges and read the converged topology table. The detecting unit 820 searches the topology table acquired by the topology table unit 810 for the address identifier of the neighbor node that needs to be aware of connectivity, and if found, determines that the neighbor node has connectivity, and if not found, determines that the neighbor node does not have connectivity. Sex.

Generally, the topology table includes a 0 ring table and a ring table of the elastic packet ring. When the detecting unit 820 does not find the address identifier of a neighbor node in the two tables, it is determined that the neighbor node has no connectivity. The address identifier of the neighbor node usually adopts the MAC address of the neighbor node. The unit 830 monitors whether the elastic packet ring in which the network node is located has a topology change, and sends an indication to the topology table unit 810 and the detecting unit 820 respectively when the change occurs, indicating that the topology table unit obtains the updated information after the elastic packet ring converges. The topology table indicates that the detecting unit refreshes the connectivity of the neighbor nodes according to the updated topology table. The detection unit 820 may further include a connectivity table storage module 822 and a connectivity table maintenance module 821 in consideration of convenience of implementation. The connectivity identifier is stored in the connectivity table storage module 822, and the association relationship between the neighboring node and the resilient packet ring is stored. After the topology table unit 810 obtains the topology table after the elastic packet ring convergence, the connectivity table maintenance module 821 finds the address identifier of the neighbor node that has an association relationship with the elastic packet ring in the connectivity table storage module 822, and In the topology table, it is found whether there is an address identifier of the associated neighbor node, and if found, the neighbor node is determined to have connectivity, and if not found, the neighbor node is determined to have no connectivity; and the topology update notification unit 830 is received. After the indication, the connectivity table maintenance module 821 repeats the above process to update the current connectivity of the associated neighbor node. In addition, the current connectivity of the associated neighbor node may be saved in the connectivity table storage module, and maintained by the connectivity table maintenance module 821.

In summary, the embodiment of the present invention determines the connectivity with the neighbor node by looking up the address identifier of the neighbor node to be detected in the topology table, and fully utilizes the characteristics of the protocol convergence within 50 ms of the elastic packet ring itself, thereby solving the upper layer control. The problem of slow detection at the plane protocol level, without interoperability problems and scalability issues, does not require additional bandwidth.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed by the present invention. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

Rights request

A method for sensing neighbor connectivity on an elastic packet ring, comprising: obtaining a topology table after convergence of the elastic packet ring;

The connectivity of the neighbor node is determined by whether the topology table includes an address identifier of a neighbor node.

The method for sensing neighbor connectivity on the resilient packet ring according to claim 1, wherein the method further includes:

Obtaining a topology table updated after convergence when the topology of the elastic packet ring changes;

The connectivity of the neighbor node is re-determined by whether the updated topology table includes an address identifier of a neighbor node.

The method for sensing neighbor connectivity on the resilient packet ring according to claim 2, wherein the method further comprises: storing an address identifier of the neighbor node that needs to be aware of connectivity and its association with the resilient packet ring. relationship.

The method for sensing neighbor connectivity on the resilient packet ring according to claim 3, wherein the re-determining the connectivity of the neighbor node comprises:

And searching for an address identifier of the neighboring node that is associated with the resilient packet ring in which the topology change occurs; and determining connectivity of the neighboring node that is associated with the resilient packet ring according to the address identifier.

The method for sensing neighbor connectivity on an elastic packet ring according to claim 2, wherein: the topology change comprises a network structure change, or a link failure, or a node failure, or a node insertion/:out The internet.

The method for sensing neighbor connectivity on an elastic packet ring according to any one of claims 1 to 5, wherein the determining the connectivity of the neighbor node comprises: searching in the converged topology table. The address identifier of the neighbor node, if found, has connectivity, otherwise it does not have connectivity.

7. The method for sensing neighbor connectivity on an elastic packet ring according to claim 6, wherein the address identifier of the neighbor node in the topology table after convergence is searched by sequential traversal or hashing.

The method for sensing neighbor connectivity on an elastic packet ring according to claim 7, wherein the topology table comprises a first table and a second table; wherein the first table is an elastic packet ring The ring table is a ring table of the elastic packet ring; or, the first table is a ring table of the elastic packet ring, and the second table is a ring table of the elastic packet ring.

The method for sensing the neighboring connectivity on the resilient packet ring according to claim 8, wherein the locating the address identifier of the neighboring node by the sequential traversal comprises:

Search from the first hop entry of the first table;

Check the reachability and validity of the first table entry. If the check fails, go to the next step to find the second table. Otherwise, compare the address identifier in the first table entry with the address identifier of the neighbor node. If they are the same, they have connectivity. If they are different, continue to compare the next hop entry until the last entry of the first table.

Search from the first hop entry of the second table;

Checking the reachability and validity of the second table entry. If the check fails, the connectivity is not provided. Otherwise, the address identifier in the second table entry is compared with the address identifier of the neighbor node. If they are the same, Connectivity, if different, continue to compare the next hop entry until the last entry in the second table; if there is no entry identified by the same address, there is no connectivity.

The method for sensing neighbor connectivity on a resilient packet ring according to claim 1, wherein the address identifier of the neighboring node is a MAC address of the neighboring node.

A network node, connected to the elastic packet ring, and comprising:

The network node according to claim 11, wherein the network node further includes a topology update notification unit, configured to indicate that the topology table unit obtains convergence after the topology of the elastic packet ring changes The updated topology table, and the indication detection unit re-determines the connectivity of the neighbor nodes.

The network node according to claim 11 or 12, wherein the detecting unit comprises:

a connectivity table storage module, configured to store an address identifier of a neighbor node that needs to be aware of connectivity and an association relationship with the resilient packet ring;

The connectivity table maintenance module is configured to determine the current connectivity of the neighbor node according to whether the topology table of the resilient packet ring convergence includes an address identifier of a neighbor node having an association relationship.

The network node according to claim 11, wherein: the topology table includes a ring table and a ring table of the elastic packet ring; and the address identifier of the neighbor node is a MAC address of the neighbor node.