WO2008106874A1

WO2008106874A1 - Two node fault handling method and system for two loop-span rpr

Info

Publication number: WO2008106874A1
Application number: PCT/CN2008/070224
Authority: WO
Inventors: Suping Zhai; Yan Wang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-03-08
Filing date: 2008-01-31
Publication date: 2008-09-12
Also published as: CN101262399A; CN101262399B

Abstract

A two node fault handling method and system for two loop-span RPR, which belongs to network communications field, are provided. The method includes: two resilient protection ring intersect between two loop-span node, when two fault node appear on one loop of the two RPR loops, when the fault of one fault node is recovered, the non loop-span node adjacent to the fault recovering node notices the loop-span node that the fault has been recovered; the loop-span node switches the operating state after apperceiving that the fault has been recovered, after switching the operating state, notices the non loop-span node adjacent to the fault recovering node that the state has been switched; the non loop-span node adjacent to the fault recovering node makes the operating state recover to normal state. The system includes: loop-span node and non loop-span node. The method and system may provide flux protection mechanism when two fault node occurred at a same time, so, when one fault node of them is recovered, it can avoid loop circuit.

Description

TECHNICAL FIELD The present invention relates to the field of network communication technologies, and in particular, to a cross-ring RPR two-point fault processing method and system. A resilient packet ring (RPR) is a packet ring network technology used as an access/aggregation bearer network in a metropolitan area network. From the network point of view, its characteristics are: Double-loop structure can achieve carrier-class 50ms traffic protection; Provide 2. 5G, 10G optical port; is a link layer protocol, compatible with 802.1 D/Q bridge. From the perspective of the RPR device, its main features are: support unicast/multicast/broadcast address; support multiple quality of service (QoS, Qua ty of Service) for different services; use flexible two-way, one-way transmission, And link/node failure wraparound, evasion mechanism, bandwidth on the ring can be effectively utilized; support fair algorithm to ensure that burst traffic does not occupy normal traffic bandwidth; topology automatic discovery mechanism guarantees plug-and-play function of RPR site, no need Manual configuration; support for operation and maintenance (0AM, Opera t ion and Management). The RPR shown in Figure 1 is a reverse double-loop topology. The outer ring is the Outer Ring and the inner ring is the Inner Ring. Both the outer ring and the inner ring transmit data packets and control packets.

The maturity of RPR technology has promoted the use of RPR technology as a packet network technology for metropolitan area networks in actual networking. The use of ring networking can save fiber, which is very practical in situations where the number of users is not large or the network size is not very large. The need for RPR cross-ring applications has gradually emerged during use. A typical application scenario is a cross-ring networking scheme for access rings and aggregation rings.

In the RPR cross-ring networking solution, in addition to solving the problem of how to avoid loops, it is also necessary to consider the traffic protection mechanism and the fault recovery mechanism when the cross-ring node/link fails. As shown in Figure 2, when two RPR rings intersect, the RPR device at the ring intersection is called a cross-ring node, as shown in Figure 2, the cross-ring node 1 and the cross-ring node 2 The RPR device that is not at the ring intersection is called a non-cross-ring node, as shown in Figure 2 for non-cross-ring node 1, non-cross-ring node 1, non-cross-ring node 3, and non-cross-ring node 4. If the two nodes across the ring are not controlled across the ring node 1 and the cross-ring node 2, loop problems are likely to occur. The existing RPR cross-ring schemes include the following three: RVR cross-ring scheme based on virtual tuvian VLAN (Virtual Tua l Loca l Area Network) or specific RPR domain, time-to-live (TTL)-based RPR cross-ring scheme , and Hash-based Hash-based RPR cross-ring scheme. However, in the process of implementing the present invention, the inventor has found that the above-mentioned prior art has at least the following problems: As shown in FIG. 3, in the RPR cross-ring networking solution, when one of the rings simultaneously has two fault points, wherein A fault point is located between two RPR cross-ring nodes. In this case, the prior art does not have a flow protection mechanism, and further, when one of the fault points is recovered, there is no loop avoidance mechanism. Summary of the invention

In view of this, the technical problem to be solved by the embodiments of the present invention is to provide a cross-ring RPR two-point fault processing method and system, which are used to simultaneously generate two fault points on one RPR ring, wherein one fault point is located in two A traffic protection mechanism is provided between the cross-ring nodes, and then, when one of the fault points is recovered, the loop is effectively avoided.

The object of the invention is achieved by the following technical solutions:

A cross-ring RPR two-point fault processing method, the method comprising:

Two resilient packet ring RPRs intersect at two cross-ring nodes. When two fault points occur on one of the RPR rings, one fault point is located between the two cross-ring nodes, and the cross-ring node performs State switching to protect the ring and cross-ring traffic;

When one of the fault points fails to recover, the non-cross-ring node adjacent to the fault recovery point notifies the cross-ring node that the fault has been recovered;

The cross-ring node senses the switching operation state after the fault is recovered, and after the working state is switched, notifying the non-cross-ring node state switching of the fault recovery point is completed;

The non-cross-ring node adjacent to the fault recovery point restores the working state to a normal state.

Meanwhile, the embodiment of the present invention further provides a cross-ring RPR two-point fault processing system, which is applied to two Elastic packet ring RPR, and the two RPR rings intersect at two cross-ring nodes. When two fault points occur simultaneously on one of the RPR rings, one of the fault points is located between the two cross-ring nodes. The system includes:

The cross-ring node is configured to perform state switching to protect the local ring and the cross-ring traffic when the two-point fault occurs; and after detecting failure of one of the fault points, switch the working state, and after the working state is switched, Notifying that the state of the non-cross-ring node adjacent to the fault recovery point is switched;

The non-cross-ring node is configured to notify the cross-ring node that the fault has been recovered after the fault of the adjacent fault point is recovered; and return the working state to the normal state according to the state switching completion notification of the cross-ring node. .

In the embodiment of the present invention, when a two-point failure occurs in the cross-ring RPR, one of the fault points is located between the two RPR cross-ring nodes, and the two cross-ring nodes are switched in state. Traffic that can effectively protect this ring and cross-ring is not lost.

Further, when one of the faults recovers, the non-cross-ring node adjacent to the fault recovery point notifies the cross-ring node that the fault has been recovered, and the cross-ring node senses that the fault is restored and completes the state switch and notifies the fault recovery point adjacent to the fault. After the non-cross-ring node state is switched, the non-cross-ring node adjacent to the fault recovery point returns to the normal forwarding state after receiving the notification, which can effectively avoid the loop. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural diagram of a single RPR ring networking in the prior art;

2 is a schematic diagram of communication of a cross-ring RPR network in the prior art;

3 is a schematic diagram of a two-point failure of a cross-ring RPR occurring at the same time according to an embodiment of the present invention;

4 is a schematic diagram of an RPR cross-ring scheme based on a VLAN or a specific RPR domain according to an embodiment of the present invention; FIG. 5 is a schematic diagram of a loop generated when a fault occurs in the case where two faults occur simultaneously in the embodiment of the present invention;

FIG. 6 is a flowchart of a fault processing according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION In order to make the objects, technical solutions and advantages of the present invention more comprehensible, the present invention will be further described in detail below with reference to specific embodiments.

When two RPR rings intersect, they intersect at two cross-ring nodes. When one of the two RPR rings has two fault points, one fault point is located between the two RPR cross-nodes. At this time, the traffic protection mechanism provided by the embodiment of the present invention is: Two cross-ring nodes perform state switching to protect the traffic of the ring and the ring. When one of the fault points is restored, the loop avoidance mechanism provided by the embodiment of the present invention is: the non-cross-ring node adjacent to the fault recovery point notifies the cross-ring node that the fault has been recovered, and the cross-ring node senses that the fault is recovered after the switchover. Working state, after the working state is switched, the sending status is completed after the confirmation is completed. When the non-cross-ring node adjacent to the fault recovery point receives the status switching completion confirmation, the original fault protection status (Wrap or s teer ing) ) Revert to normal forwarding state.

If the adjacent RPR node of the fault recovery point is a cross-ring node, when the fault recovers, the cross-ring node can perceive the fault recovery and then initiate the state switch. When the nodes at both ends of the fault recovery point are cross-ring nodes and non-cross-ring nodes, after the fault is recovered, the non-cross-ring node notifies another cross-ring node, that is, a cross-ring node that is not adjacent to the fault recovery point. The fault has been restored. In order to explain the embodiments of the present invention in more detail, the following three detailed RPR cross-ring schemes are respectively described in detail.

Embodiment 1: A fault handling method of an RPR cross-ring scheme based on a VLAN or a specific RPR domain.

First, this embodiment first introduces an RPR cross-ring scheme based on a VLAN or a specific RPR domain. As shown in Figure 4, traffic is classified into different protection groups according to different services according to VLANs or specific RPR domains, such as Group1 and Group2. For all traffic of Group1, the cross-ring node CI is responsible for cross-ring forwarding. For all traffic of Group2, the cross-ring node C2 is responsible for cross-ring forwarding. In this way, the formation of the loop is avoided, because the same traffic can only be forwarded from one of the cross-ring nodes to the other ring, and does not return from the other cross-ring node to the original ring; Load sharing can reduce the processing power requirements of cross-ring nodes. Referring to Figure 6, when a cross-ring RPR two-point failure occurs, the operation is as follows:

100: When a two-point fault occurs, the two cross-ring nodes perform state switching to protect the traffic of this ring and the cross-ring.

When two faults occur, the adjacent RPR nodes RB1 and RB2 of the fault recovery point become protected (wrap or s teer ing). As shown in Figure 3, in order to ensure that each node on the ring can communicate with any node on the other ring, the two cross-ring nodes RI 1 and RI 2 become active and are responsible for forwarding all the files. At this time, both cross-ring nodes are in the active state with respect to the same protection group.

200: When a fault point is recovered, the cross-ring node is notified that the fault has been recovered.

When one of the faults is recovered, as shown in FIG. 5, the present embodiment takes the failure point recovery between the non-cross-ring node 1 and the non-cross-ring node 2 as an example. At this time, the non-cross-ring node 1 and the non-cross-ring node 2 can be quickly perceived, has been implemented in the RPR protocol, and will not be described here. Because cross-ring node 1 and cross-ring node 2 are still responsible for forwarding all messages, there is a loop across the ring. To avoid the occurrence of a cross-ring loop as shown in FIG. 5, the loop avoidance mechanism provided by the embodiment of the present invention is:

Specifically, the non-cross-ring node adjacent to the fault recovery point can notify the cross-ring node that the fault has been recovered by sending a fault recovery notification message. The non-cross-ring node 1 and the non-cross-ring node 2 adjacent to the fault recovery point respectively send a failure recovery notification message, where the packet is a broadcast packet, which may be extended based on the existing RPR control packet. Or use the newly defined RPR control message.

To prevent the loss of the fault recovery notification packet from being sent, you can send one or more fault recovery notification packets. If it is specified to be sent three times in a cycle at a certain time interval.

300: After the fault recovery is sensed, the cross-ring node switches the working state, and after the working state is switched, the state of the non-cross-ring node cross-ring node adjacent to the fault recovery point is notified that the state of the cross-ring node has been switched. Specifically, when the cross-ring node is adjacent to the fault recovery point, the fault recovery may be perceived by itself. When the cross-ring node is not adjacent to the fault recovery point, the fault is sent according to the non-cross-ring node adjacent to the fault recovery point. The recovery notification packet senses the fault recovery, and then switches the working state across the ring node, and the working state is switched. After completion, the status of the non-cross-ring node cross-ring node adjacent to the fault recovery point can be notified by sending a status switch completion confirmation message. This embodiment is based on a VLAN or a specific RPR domain RPR cross-ring scheme. Compared with the same protection group, after the state switchover, the final state of the two cross-ring nodes is a master and a standby under normal conditions, see Figure 3. In this embodiment, the cross-ring node RI 1 is in the active state, and the cross-ring node RI2 is in the standby state. In this case, the traffic of the protection group is only forwarded by the cross-ring node RI 1 , and the cross-ring node R 12 is no longer responsible. Forwarding traffic of this protection group does not form a loop. The status switching completion acknowledgement packet is a broadcast packet, and may be extended on the basis of the existing RPR control packet, or the newly defined RPR control packet may be used.

Further, in order to prevent the transmission of the status switching completion confirmation message loss, the status confirmation completion message may be sent once or more. If it is specified to be sent three times in a cycle at a certain time interval.

The above is an example where the nodes adjacent to the fault recovery point are non-cross-ring nodes, as shown in Figure 3, RB1 and RB2. In this case, when the fault is recovered, the cross-ring node receives the neighboring from the fault recovery point. After the failure recovery advertisement message of the non-cross-ring node, the state switch is started; if it is the failure point recovery between the cross-ring nodes, as shown in RI 1 and RI 2 in Figure 3, the two cross-ring nodes can sense the fault. Point recovery, and then start the state switch of the cross-ring node, at this time, the two cross-ring nodes do not need to send the failure recovery notification message.

400: When the non-cross-ring node adjacent to the fault recovery point receives the status switch completion notification, it returns to the normal state (norma l) from the original protection state (wrap or s teer ing).

Embodiment 2: A fault processing method of a Hash-based RPR cross-ring scheme.

First, this embodiment first introduces the RPR cross-ring scheme based on Ha sh. Two cross-ring nodes form a protection group, and the protection group configures member 0 and member 1. Member 0 is only responsible for forwarding data traffic with a Hash value of 0. Member 1 is only responsible for forwarding data traffic with a Ha sh value of 1. The Hash calculation is calculated on a per-flow basis, that is, the Hash value is obtained by using a certain algorithm for a specific domain of each message. This solution can also solve the loop problem of the cross-ring and implement load sharing.

The processing flow is the same as that in the first embodiment, except that the identification of the state of the cross-ring node is different. That is, when two points of failure occur simultaneously, the two cross-ring nodes in the first embodiment are used by a primary one under normal conditions. The state and the standby state are all switched to the active state. The two cross-ring nodes in this embodiment are switched from the normal 0 or 1 state to the 0/1 state, that is, regardless of the Ha sh value is 0 or 1. The cross-ring nodes forward all the packets. Similarly, after one of the faults is recovered, the two cross-ring nodes in this embodiment are switched from the 0/1 state to the normal state, one of which is in the 0 state and one in the 1 state. Embodiment 3: A fault processing method for a TTL-based RPR cross-ring scheme. First, this embodiment first introduces a TTL-based RPR cross-ring scheme. TTL: The value of TTL determines the maximum number of hops that a data frame is forwarded on the RPR ring. Each time a node passes, the TTL value is decremented by one, when TTL is effective to avoid loops. Referring to FIG. 2, if the TTL of the cross-ring traffic forwarded from the cross-ring node 1 is set to 1, the TTL of the cross-ring traffic forwarded from the cross-ring node 2 is also set to 1, and load balancing can also be implemented. The processing flow is the same as that in the first embodiment, except that the identification of the state of the cross-ring node is different. The state of the cross-ring node includes the whole-loop forwarding state and the TTL-average forwarding state. When the cross-ring node is in the whole-loop forwarding state, the TTL value is the total number of the local ring nodes minus 1, and the packet is sent to the ring. When the cross-ring node is in the TTL-average forwarding state, the TTL value is set on the two cross-ring nodes to satisfy the sum of the TTL values of the two cross-ring nodes minus the total number of the ring nodes minus 1, so that the packet is sent. Go to all nodes on this ring. When two faults occur at the same time, the two cross-ring nodes in the first embodiment are switched from the active state and the standby state in the normal state to the active state. The two cross-ring nodes in this embodiment are Under normal circumstances, the TTL average forwarding state is switched to the full-loop forwarding state, so that the packets forwarded from the cross-ring node can reach all the nodes on the ring. Similarly, after one of the faults is recovered, the two cross-ring nodes in this embodiment are switched from the full-loop forwarding state to the TTL-average forwarding state in the normal case.

Meanwhile, the embodiment of the present invention further provides a cross-ring RPR two-point fault processing system, which is applied to two resilient packet ring RPRs, and two RPR rings intersect at two cross-ring nodes, and one of the RPR rings simultaneously appears. When two fault points are located, one fault point is located between two cross-loop nodes. The system specifically includes: a cross-ring node, configured to perform state switching to protect the ring and the cross-ring when the two points of the fault occur. After the failure of one of the fault points is detected, the working state is switched, and after the working state is switched, the state of the non-cross-ring node adjacent to the fault recovery point is notified to be switched;

The non-cross-ring node is configured to notify the cross-ring node that the fault has been recovered after the fault of the adjacent fault point is recovered; and return the working state to the normal state according to the state switching completion notification of the cross-ring node.

The working principle is basically the same as the method described, and will not be described here. In the embodiment of the present invention, when a two-point failure occurs in the cross-ring RPR, one of the fault points is located between the two RPR cross-ring nodes, and the two cross-ring nodes are switched in state. Traffic that can effectively protect this ring and cross-ring is not lost.

Further, when one of the faults recovers, the cross-ring node senses that the fault has been recovered, completes the state switch, and notifies the non-cross-ring node of the fault recovery point that the state transition is completed, and the non-cross-loop node adjacent to the fault recovery point is up to After receiving the notification, the normal forwarding state is restored, and the loop can be effectively avoided.

Further, the method disclosed in the embodiment of the present invention is applicable to three RPR cross-ring solutions, namely: an RPR cross-ring scheme based on a VLAN or a specific RPR domain, a TTL-based RPR cross-ring scheme, and a Ha sh-based RPR cross-ring scheme. , can provide a unified processing method for three different RPR cross-ring schemes.

Throughout the specification, the preferred embodiments and examples shown are to be considered as illustrative and not limiting.

Claims

Claim

A cross-ring RPR two-point fault processing method, the method comprising: two resilient packet ring RPRs intersecting two cross-ring nodes, when two fault points occur simultaneously on one of the RPR rings, a fault point is located between the two cross-ring nodes, and the cross-ring node performs state switching to protect the local ring and the cross-ring traffic;

The method according to claim 1, wherein the step of notifying the non-cross-ring node adjacent to the fault recovery point that the fault has been recovered by the cross-ring node comprises: the fault recovery point adjacent to the fault recovery point The non-cross-ring node sends at least one failure recovery advertisement message to the cross-ring node.

The method according to claim 2, wherein the step of detecting, by the cross-ring node, the switching operation state after the fault recovery comprises: when the cross-ring node is not a node adjacent to the fault recovery point And the cross-ring node receives a failure recovery notification message from the non-cross-ring node adjacent to the fault recovery point, and then switches the working state.

The method according to claim 1, wherein the step of notifying the non-cross-ring node of the fault recovery point that the cross-ring node has completed the state transition includes: sending the at least one state by the cross-ring node The handover completion acknowledgement message is sent to the non-cross-ring node adjacent to the fault recovery point.

The method according to any one of claims 1 to 4, wherein the method is applicable to any of the following RPR cross-ring schemes: based on a virtual local area network (VLAN) VLAN or a specific RPR domain-based RPR cross-ring solution, based on The RPR cross-ring scheme for survival time TTL, and the RPR cross-ring scheme based on hash Ha sh.

The method according to claim 5, wherein when the method is based on a virtual local area network (VLAN) VLAN or an RPR cross-ring scheme of a specific RPR domain, the cross-ring node performs state switching to protect the ring and The step of the cross-ring traffic is specifically as follows: The two cross-ring nodes are switched to the active state, and are responsible for forwarding all the packets.

The method according to claim 6, wherein the step of the cross-ring node sensing the switching operation state after the fault recovery is specifically: after the two cross-ring nodes sense the fault recovery, one of the Switch to the standby state and the other to remain in the active state.

The method according to claim 5, wherein when the method is based on an RPR cross-ring solution with a time-to-live TTL, the step of performing state switching to protect the local ring and the cross-ring traffic is specifically : The two cross-ring nodes are switched to the full-loop forwarding state.

The method according to claim 8, wherein the step of the cross-ring node sensing that the fault is restored after the fault is restored is specifically: the two cross-ring nodes sense that the fault is restored after being switched to The TTL is divided into forwarding states.

The method according to claim 5, wherein when the method is based on a hash Ha sh RPR cross-ring scheme, the step of the cross-ring node performing state switching to protect the local ring and the cross-ring traffic Specifically, the two cross-ring nodes are switched to a 0/1 state.

The method according to claim 10, wherein the step of the cross-ring node sensing that the fault is restored after the fault is restored is specifically: after the two cross-ring nodes sense the fault recovery, One of them switches to the 0 state and the other switches to the 1 state.

12. A cross-ring RPR two-point fault processing system, characterized in that it is applied to two resilient packet ring RPRs, and the two RPR loops intersect at two cross-ring nodes, when two of the RPR rings simultaneously appear And a fault point is located between the two cross-ring nodes; the system includes: the cross-ring node, configured to perform state switching to protect the ring when the two-point fault occurs And cross-ring flow; after sensing the failure of one of the fault points, the working state is switched, and after the working state is switched, the non-cross-ring node state of the fault recovery point is notified to be switched; the non-cross-ring node, The method is configured to notify the cross-ring node that the fault has been restored after the fault of the adjacent fault point is recovered; and return the working state to the normal state according to the state switching completion notification of the cross-ring node.