WO2012048585A1

WO2012048585A1 - Switching method and router

Info

Publication number: WO2012048585A1
Application number: PCT/CN2011/076077
Authority: WO
Inventors: 翟洪军; 龚协丰
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-10-15
Filing date: 2011-06-21
Publication date: 2012-04-19
Also published as: CN102447615A

Abstract

The present invention discloses a switching method and router, wherein the switching method includes: an Alternate router detects whether a master router is out of service according to a fast detection session established between the Alternate router and the master router, wherein the Alternate router is selected from backup routers; after detecting that the master router has been out of service, the Alternate router switches from an Alternate state to a master state and switches to be a new master router. The present invention solves the problem in the prior art of fast switching when the master router fails.

Description

TECHNICAL FIELD The present invention relates to the field of network communications, and in particular to a handover method and a router. BACKGROUND With the increasing popularity of the Internet (Internet), people are becoming more and more dependent on the network, and the reliability of the network has become a key factor in today's local area networks. To this end, the IETF has developed VRRP (Virtual Router Redundancy Protocol). The protocol is applied to Layer 3 switches and routers to provide faster and more efficient redundancy fault tolerance for terminal systems that rely on the default gateway for external network access, and enhances the reliability of the LAN gateway. VRRP works as follows: Two or more routers are grouped together to form a virtual router (or VRRP backup group), and provide a consistent virtual IP (Internet Protocol) and virtual MAC (Media Access Control). , Media Access Control) Address. A host in the local area network accesses the external network by designating the virtual IP as the default next hop. At any time, only one router in the backup group is responsible for forwarding data between the internal and external, called the primary router or the master, and the other routers are used as backup routers or backup routers. The primary router declares its existence by periodically sending a keep-alive message, and the alternate route detects the state of the primary router by receiving the keep-alive message. If the keep-alive message is not received within a few consecutive cycles (seconds), the standby router considers that the primary router has failed and initiates the primary router. The optimal standby router (including: the highest priority or the same priority but the primary IP address is the largest) will become the new primary router and take over the packet forwarding of the original primary router, thus ensuring the smooth communication between the local area network and the external network. . The second-level keep-alive packet sending period causes the detection and switching time of the VRRP faulty router to be second-order, which is far from satisfying the millisecond requirement of real-time services such as voice. To speed up fault detection, you can speed up the detection of faults by speeding up the transmission of keep-alive packets between the VRRP master and backup routers, or by using techniques such as BFD (bidirectional forwarding detection). And the switching speed of the device to meet the needs of real-time business. However, these technologies bring new problems while meeting real-time business needs. The principle of the method for establishing a BFD session is as follows: The BFD session is established between the VRRP master and backup routers to detect the status of the active router. The purpose of the change. In VRRP, when the primary router fails, the primary router migrates from one device to another. For a VRRP backup group with multiple routers, you need to establish a BFD session between any two routers in the backup group to detect the status of the primary router. In this way, a full mesh BFD session needs to be established in a VRRP backup group that includes multiple routers. This not only consumes a lot of bandwidth, but also increases the burden on the device (especially the primary router). More importantly, when the VRRP backup group includes more than two routers, the status of the active router is detected through the BFD session. This does not guarantee that the primary router fails. For example, as shown in Figure 1, LAN devices (Hl, H2, H3, and H4) are connected through Layer 2 switches. Router A, Router B, and Router C form a virtual router. Router A is the primary router. The status of the active router is quickly detected. Both Router B and Router C establish a BFD session with Router A. At some point, Router A has failed. After several tens of milliseconds, Router B and Router C have discovered the fault almost simultaneously, and then expand the selection of the primary router by sending a keep-alive message. Assume that Router B first sends keep-alive packets to the network, and the MAC table of the switch is updated, that is, the egress port that reaches the virtual router virtual MAC is changed to port B. After Router C has placed its keep-alive packet in the buffer queue of the sending port, the VRRP module receives the keep-alive packet of Router B (for example, process scheduling or system load, etc.). Subsequently, the keep-alive message of the router C is sent to the network, the MAC table of the switch is updated again, and the port C becomes the egress port of the virtual MAC. Because Router B has a higher priority, it is selected as the new primary router, but the packets sent to the virtual router are sent by the switch to Router C (do not bear the packet forwarding work), resulting in interruption of internal and external network access. . This problem can only be solved after the next keep-alive of Router B. This takes at least 1 second, which is difficult to meet the needs of real-time services. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a handover method and a router, which solve the problem of fast handover when a primary router fails in the prior art. According to an aspect of the present invention, a handover method is provided, including: an Alternate router detects whether a primary router fails by a fast detection session established with a primary router, wherein the alternate router is from the standby router. Elected; After detecting that the primary router has failed, the Alternate router transitions from the Alternate state to the active state and switches to the new primary router. Before the Alternate router detects the failure of the primary router through a fast detection session established with the primary router, the following includes: the primary router initiates an alternate router election, elects the optimal standby router as an alternate router; the primary router establishes and A fast detection session between Alternate routers. The primary router initiates an alternate router election, electing the optimal standby router as

The Alternate router includes: the primary router periodically sends keep-alive messages, and sends an alternate router election request message to the standby router to initiate an alternate router election; the standby router returns a response report of the alternate router election request message to the primary router. The response message carries the priority and/or the primary IP address of the standby router; the primary router elects the backup router with the highest priority as the alternate router, or, in the case of the same priority, the primary router The standby router with the largest primary IP address is elected as the alternate router; the standby router with the highest priority or the largest primary IP address is switched from the standby state to the alternate state and switched to the alternate router. Before the active router establishes a fast detection session with the alternate router, the method includes: the primary router negotiates the session type and the fast detection session parameter negotiation, and negotiates with the alternate router to quickly detect the session. Type and parameters; The fast detection session between the primary router and the alternate router includes: After the negotiation succeeds, the active router establishes a fast detection session with the alternate router according to the negotiated type and parameters. In the foregoing method, the method further includes: if the establishment fails or the negotiation fails, the alternate router transitions from the alternate state to the standby state and re-switches to the standby router; the standby router listens to the keep-alive message sent by the primary router; If the keep-alive packet from the active router is not received within the time, the standby router initiates the election of the primary router, elects the optimal standby router as the new primary router, and enters the primary router to initiate the election of the alternate router to elect the optimal backup. The router acts as a step 4 of the alternate router. After the Alternate router transitions from the Alternate state to the active state and switches to the new primary router, the new primary router enters the primary router to initiate an alternate router election, and the optimal standby router is elected as the Alternate router. Fast detection sessions include, but are not limited to, bidirectional forwarding detection (BFD) sessions, synchronous digital hierarchy (SDH) sessions, and heartbeat sessions. According to another aspect of the present invention, a router is provided, comprising: a detecting module, configured to be established between a router and an active router in a case where the router is an alternate router Quickly check the session to detect whether the primary router is invalid. The Alternate router is elected from the standby router. The switching module is set to be in the case that the router is an alternate router. After the detection module detects that the primary router is invalid, The Alternate state transitions to the active state and switches to the primary router. The router further includes: a transceiver module configured to initiate an alternate router election when the router is the primary router, and elect the backup router with the highest priority as the alternate router or when the priority is the same, the election primary IP address is the largest. The standby router acts as an alternate router; the module is set up to establish a fast detection session with the alternate router after the transceiver module elects the alternate router, so that the alternate router detects the failure of the router through the fast detection session; wherein, the switching module also sets In the case that the router is the primary router, after the detection module detects that the router has failed, it switches from the primary state to the standby state and switches to the standby router. The router further includes: a negotiation module, configured to quickly detect a session type negotiation packet and a fast detection session parameter negotiation packet, and negotiate a fast detection session with the alternate router, respectively, before the establishment module establishes a fast detection session with the alternate router. The type and parameters of the setup module are set to establish a fast detection session with the alternate router according to the negotiated type and parameters. With the present invention, a fast detection session is established only between the master router and the alternate router, and a fast detection session is not required between any two routers in the backup group. Therefore, the primary router in the prior art is solved. The fast switching problem at the time of failure ensures that sub-second fast switching between the primary and backup routers is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a schematic diagram of detecting a state of a primary router by using a BFD session in a VRRP according to the related art; FIG. 2 is a flowchart of a handover method according to an embodiment of the present invention; FIG. 3 is a flowchart according to a preferred embodiment of the present invention. State transition diagram of the router in VRRP; 4 is a flow chart of a switching method of a preferred embodiment of the present invention; FIG. 5 is a flow chart showing a state change of a Backup router according to a preferred embodiment of the present invention; FIG. 6 is a flow chart showing a state change of an alternate router according to a preferred embodiment of the present invention. Figure 7 is a flow chart showing the state change of the master router according to a preferred embodiment of the present invention; Figure 8 is a schematic diagram of a router in accordance with an embodiment of the present invention; and Figure 9 is a schematic diagram of a router in accordance with a preferred embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. In order to solve the problem that the related art may consume a large amount of bandwidth and increase the burden on the device, and when the VRRP backup group includes more than two standby routers, the state of the primary router is simply detected through the BFD session, and the primary router cannot be guaranteed to be invalid. The VRRP active/standby router is implemented by the VRRP protocol, which is an enhanced virtual redundant router protocol (ERRRP). The method of fast switching, the EVRRP mainly includes:

(1) The VRRP state extension expands an Alternate state in addition to the original Initialize, Backup, and Master states of the VRRP router. The router in the Alternate state (called the Alternate router) will detect the status of the master router by detecting the session quickly (that is, detecting whether the primary router is invalid). When it finds that the master router is faulty (that is, it fails), it immediately takes over its work. , that is, switch to the new primary router.

(2) The extension of the protocol packet, in addition to the existing VRRP Advertisement message (that is, the keep-alive message), the Alternate router election request message (Alternate Request) is extended, and the response of the Alternate router election request message is extended. The message (Alternate Reply), the session type negotiation type (Session Type Negotiate), and the session parameter Negotiate are quickly detected. The format of the various extended messages can be determined according to actual needs. 2 is a flow chart of a handover method according to an embodiment of the present invention, including the following steps: Step S202, the Alternate router detects whether the primary router is invalid through a fast detection session established between the primary router and the master router, wherein the alternate router is elected from all current backup routers; Step S204, After detecting that the primary router has failed, the alternate router switches from the alternate state to the primary state (as shown in Figure 3) and switches to the new primary router. In this embodiment, a fast detection session is established only between the master router and the alternate router, and no fast detection session is established between any two routers in the backup group. Therefore, the related technologies may consume a large amount of bandwidth. And the problem of increasing the burden on the device, so that only one fast detection session is established in a VRRP backup group, the bandwidth occupation is small, and the burden on the device (especially the standby router) is alleviated. In addition, the present embodiment also solves the problem of fast switching when the primary router fails in the prior art, thereby ensuring fast sub-second fast switching between the primary and secondary routers. As shown in FIG. 4, the switching method according to the preferred embodiment of the present invention includes the following specific processing steps. In step S402, the backup router listens for the keep-alive message sent by the master router. In step S404, the backup router determines whether the keep-alive message from the master router is received within a certain period of time. If not, the master router election is initiated, and the process proceeds to step S406; if yes, the process goes to step S402. Specifically, the standby router initiates an election of the primary router, and elects the optimal backup router as the new master router (as shown in FIG. 3, being elected as a new router, that is, switching from the standby state to the master state). The optimal standby router refers to the standby router with the highest priority or the standby router with the largest primary IP address in the case of the same priority. Step S406, the new master router initiates an alternate router election, and elects an optimal standby router as an alternate router. As above, the optimal standby router refers to the standby router with the highest priority or the standby router with the largest primary IP address in the case of the same priority. For example, the step S406 includes the following steps 1-4: Step 1: The new master router sends a periodic keep-alive packet (that is, periodically sends the keep-alive message), and sends an alternate request message (Alternate router election request packet) to the backup router to initiate the alternate router. After the backup router 4 owes the Alternate Request 4 message, it responds to the Alternate Reply message. The Alternate Reply message carries the information such as the priority and the primary IP address of the standby router. Step 3: New The primary router elects the optimal backup router as the alternate router accordingly; Step 4, the optimal standby router (ie, the elected standby router) transitions from the standby state to the alternate state (as shown in FIG. 3) and Switch to the Alternate router. Obviously, in step 1-2, the active router can also use other types of packets to initiate an alternate router election. The backup router can also respond to other types of messages to carry information such as its own priority and primary IP address. Complete the election. Step S408: The Master Router and the Alternate Router negotiate a fast detection by sending a Session Type Negotiate message (a fast detection session type 10 message) and a Session Parameters Negotiate message (fast detection session parameter negotiation message). The type and parameters of the session. If the negotiation is successful, go to step 4 to gather S410; otherwise, go to step 4 to gather S418. Step S410, a fast detection session is established between the master router and the alternate router. If the session establishment is successful, the process proceeds to step S412, otherwise, the process goes to step S418. Specifically, the master router and the alternate router establish a fast detection session according to the negotiated type and parameters of the fast detection session. It is worth noting here: In the VRRP backup group, only the fast detection session between the master router and the alternate router is established. That is, the master router only establishes a fast detection session with the alternate router. Step S412, the Alternate router detects the status of the master router (ie, detects whether the master router is invalid or fails) through the fast detection session established in step S410 with the master router, and proceeds to step S414. This step 4 S S412 corresponds to step 4 S202 in FIG. In step S414, if the master router is found to be invalid, the process goes to step S416, otherwise the process goes to step S412. In step S416, the Alternate router is promoted to the master router. As shown in FIG. 3, its state is also changed from the Alternate state to the Master state, and the process goes to step S406. The above step 4 gathers S414-step 4 gathers S416 corresponding to step 4 gathers S204 in FIG. Step 4 gathers S418, and the Alternate router falls back to the Backup router, as shown in Figure 3. The state also transitions from the Alternate state to the Backup state; Go to step S402. In the embodiment shown in FIG. 2 and FIG. 4, the fast detection session may be a fast failure detection session such as a BFD session, an SDH (Synchronous Digital Hierarchy) session, or a heartbeat session. The above-mentioned preferred embodiment of the present invention enhances the VRRP protocol (ie, the EVRRP protocol), and adds an alternate state to the VRRP state. The router in the alternate state is the most qualified of all the backup routers to replace the master router. A Backup router. During the active/standby switchover or fast detection, the master router dynamically establishes a fast detection session with the alternate router. Through this session, the alternate router can quickly detect the failure of the master router and immediately take over the work of the master router (ie, switch As the main router), the fast switching of the faulty device is realized, and the switching speed of the device is improved. In addition, in the above preferred embodiment, the fast detection session between the master router and the alternate router is automatically established through negotiation, and the maintenance burden of the network administrator is not increased, so the maintenance is simple. Moreover, the type and parameters of the fast detection session are determined through negotiation, and the implementation can be extended as needed, thereby having better scalability. It should be noted that the EVRRP protocol proposed by the embodiment of the present invention can be compatible with the standard VRRP protocol. The device supporting the EVRRP protocol sends a standard VRRP packet in addition to the EVRRP extension packet. Therefore, in the environment where the EVRRP device and the VRRP device are interconnected, the device works according to the standard VRRP mechanism. In the environment where only the EVRRP device is used, the device dynamically establishes a fast detection session mechanism to implement the faulty device. Fast switching in seconds. As shown in the foregoing embodiment of FIG. 2 and FIG. 4, as shown in FIG. 3, the EVRRP state of each router in the VRRP backup group according to the preferred embodiment of the present invention includes the following four states: (1) Initial state: The initial state of the EVRRP router. In this state, the device does not process any message. When the Startup event occurs, the router will transition to the Master according to whether its own priority is 255. Backup

(2) Backup (standby or backup) status: The router in this state does not perform any data packet forwarding, but it will listen to the keep-alive packets of the master router, listen and reply to the alternate router election and fast detection. Session negotiation 4 (including fast detection session type negotiation 4 和 and fast detection session parameter negotiation message). Participate in the Alternate router, if it wins, it will transition to the Alternate state; otherwise, it will detect the keep-alive of the Master router in the Backup state;

(3) Alternate (prepared) status: The router in this state does not forward packets, but detects the status of the master through a fast detection session. If the master fails, it is promoted to the master. Otherwise, it continues to listen to the master. status;

(4) Master (active) status: The router in this state is responsible for the actual 4 艮 text forwarding work, and periodically sends keep-alive messages to declare their existence. At the same time, it is also responsible for initiating the election of the alternate router, establishing the fast detection session, and sending a fast detection keep-alive message through the established fast detection session, so that the alternate router can utilize the established fast detection session and receive the fast detection and keep alive. The text is used to check whether the status of the master router is invalid or has failed. Among them, except for the Initial state, as long as the Shutdown event is received in any other state, it will immediately fall back to the Initial state. The flow of the state change of the Backup Router, the Alternate Router, and the Master Router will be respectively described below with reference to FIG. 5, FIG. 6, and FIG. As shown in FIG. 5, the state change process of the Backup router according to the preferred embodiment of the present invention includes the following steps: S 502 - Step 4 S S520. Step S502: Listening to the protocol packet, and listening to the keep-alive message of the master router and the alternate election request message initiated by the master router. After receiving the keep-alive message, the Master keep-alive timer will be reset. Step S504: If the master keep-alive timer expires (that is, the keep-alive message of the master router is not received within consecutive cycles), the master router is considered to be invalid, and the process proceeds to step S506, otherwise, the process proceeds to step 4, S512. Step S506: The master router is selected, and the backup router sends the keep-alive message to the outside to initiate the election of the master router. Step S508: If the winning is selected, the optimal Backup router will select the winning in the Master. If it wins, proceed to step S510; otherwise, go to step S502. Step S510: Switch to the Master state, and the selected router will send the virtual

Free ARP 4 for IP and virtual MAC, update the MAC table of the interactive machine and the ARP table of the host. Then, the router ends the Backup process and enters the state processing flow of the Master router as shown in FIG. 7. Step S512: If the Alternate router election message is received, proceed to step S514, otherwise, go to step 4 to gather S502. Step S514: For the received Alternate router election request message, replying to the response message, wherein the response message carries information such as its current priority and primary IP address. Step S516-S518: After the primary router elects the optimal standby router as the alternate router according to the alternate notification request message and the alternate response message of the backup router, the standby router determines whether the alternate election wins. If the election is won in the Alternate election, Then, proceed to step S520, otherwise, go to step S502. Step S520: Promote from the standby router to the alternate router, switch from the standby state to the alternate state, end the processing flow of the backup router, and enter the state processing flow of the alternate router as shown in FIG. 6. As shown in FIG. 6, for the alternate router, the state change process includes the following steps S602-S616. Step S602: Negotiating the type of the session and the parameters required for establishing the session by interacting with the Master Router by using a Session Type Negotiate message and a Session Parameters Negotiate message. Step S604: If the agreement is reached with the master for the session type and the parameter (that is, the negotiation is successful), the process continues to step S606, otherwise, the process proceeds to step 4 to S616. Step S606: A fault fast detection session (ie, a fast detection session) is established between the Alternate router and the master router according to the negotiated session type and parameters required for establishing the session. Step S608: The Alternate router detects the status of the master router by quickly detecting the session. If the fast keep-alive message is received through the fast detection session, the fast keep-alive timer is reset. Step S610: If the fast keep-alive timer expires, that is, the fast keep-alive packet is not received within consecutive fast detection periods, the Alternate router considers that the master router has expired, and if it fails, continues to step 4 to gather S612, otherwise, Up to step 4 gathers S614. Step S612: After the master router finds that the master router is invalid, it will immediately migrate to the master state, and take over the master's 4 艮 text forwarding work, end the status processing process of the alternate router, and enter the process flow of the master router as shown in FIG. 7 . . Step S614: After the Alternate router establishes a fast detection session with the master router, the Alternate router still detects the keep-alive message and the alternate router election/response message. If the sender of the packet is found to be better in the preemptive mode (that is, the priority is higher, or the priority is the same but the primary IP address is larger), it indicates that there is a router superior to the master in the network, and the process proceeds to step S616. Otherwise, go to step 4 to gather S608. Step 4: S616: Remove the fast detection session with the master router, abandon its own identity, and roll back to the backup state, and enter the state processing flow of the backup router as shown in Figure 5. As shown in FIG. 7, the state change process of the master router includes the following steps S702-S722. Step S702: Check whether there is a fault fast detection session between the router and the alternate router. Step S704: If there is a fast detection session with the alternate router, the Alternate router already exists in the network, and the process goes to step S716, otherwise the process continues to step S706. Step S706: The Master router initiates an alternate router election by sending an Alternate Request message. After receiving the 4 essays, the Backup Router will respond to the Alternate Reply 4 message. Using the information carried in the above two types of packets, the optimal router will be elected as an alternate router. Step S708: If a backup router is elected as an alternate router, step 4 is continued to S710, otherwise, the process proceeds to step 4 to S716. Step S710: Negotiate with the Alternate router to establish a session type and a required parameter of the fault fast detection session. In the ten business operators, Session Type Negotiate and Session Parameters Negotiate are used. Step S712: If the Master and the Alternate agree on the type and parameters of the fast detection session (ie, the negotiation is successful), proceed to step S714, otherwise, go to step S716. Step S714: Establish a fault fast detection session with the alternate router according to the negotiated session type and parameters. Step S716: Sending a VRRP keep-alive message and detecting a session keep-alive message, and listening to the message of the keep-alive message, the alternate reply, and the like sent by other routers. By comparing the priority and the primary IP address with the priority and primary IP address carried in these 4 messages (ie, the priority of the sender and the primary IP address of the message), it is possible to check whether there is a better network. router. Step S718: If it is the preemption mode and finds that there is a better router on the network, proceed to step S720, otherwise, go to step 4 to S716. Step S720: Removing the fault fast detection session established between the router and the alternate router. Step S722: Roll back to the Backup state, abandon the Master identity, and return to the Backup state, and enter the state processing flow of the Backup router as shown in FIG. 5. 8 is a router in a VRRP backup group according to an embodiment of the present invention. The router (also referred to as an EVRRP router) includes: a detecting module 10, configured to be in a case where the router is an alternate router (ie, in an Alternate state), Detecting whether the primary router is invalid through a fast detection session established with the primary router, wherein the alternate router is elected from all the standby routers; and the switching module 20 is configured to be in the case that the router is an alternate router (ie, In the Alternate state, after the detection module 10 detects that the primary router has failed, it transitions from the Alternate state to the active state and switches to the primary router. In actual implementation, in order to implement the election of the alternate router and establish a fast detection session between the primary router and the alternate router, the router may further include: a transceiver module 30, configured to be in the case that the router is the primary router (ie, In the master state, the election of the alternate router is initiated, and the optimal standby router is elected as the alternate router. The establishing module 40 is configured to establish a fast detection session with the alternate router after the transceiver module 30 elects the alternate router to make the alternate. The router can detect whether the status of the router is invalid through the fast detection session. The switching module 20 is further configured to enable the router to be used from the primary device after the detection module 10 detects that the router is invalid. The state transitions to the standby state and switches to the standby router. The transceiver module 30 is further configured to periodically send a keep-alive message when the router is the primary router, and initiate an alternate router election by sending an alternate router election request to all the backup routers; When the router is a standby router (that is, in a standby state), the response packet of the received alternate router election request message is returned to the primary router, where the response packet carries its own priority and / or the primary IP address is such that the primary router elects the backup router with the highest priority as the alternate router or if the priority is the same, the standby router with the largest primary IP address is elected as the alternate router; wherein, the highest priority The standby router with the highest level or primary IP address transitions from the standby state to the alternate state and switches to the alternate router. In order to enable a fast detection session between the master router and the alternate router, the router may further include: a negotiation module 50 configured to quickly detect the session type before the establishment module 40 establishes a fast detection session with the alternate router. The negotiation packet and the fast detection session parameter negotiation packet negotiate with the alternate router for the types and parameters of the fast detection session. The establishment module 40 is configured to establish an Alternate router according to the negotiated type and parameters after the negotiation module 50 negotiates successfully. A quick detection session between. If the establishment module 40 fails to establish a fast detection session or the negotiation module 50 fails to negotiate the type and parameter of the fast detection session, the switching module 20 is further configured to switch from the alternate state to the standby state when the router is an alternate router. Switch back to the standby router. The transceiver module 30 in the router is further configured to listen to the keep-alive message sent by the active router if the router is the backup router, and if the keep-alive message from the active router is not received within a certain period of time, Initiating the election of the primary router, electing the optimal standby router as the new primary router, and entering the step of initiating the election of the alternate router and electing the optimal standby router as the alternate router. Among them, the optimal means that the highest priority is given or the primary IP address is the largest when the priorities are the same. The fast detection session may be a fast fault detection session such as a BFD session, an SDH session, or a heartbeat session. As shown in FIG. 9, in the actual implementation process, the transceiver module 30 and the switching module 20 can be implemented by the packet transceiver module 901, the VRRP protocol module 902, and the VRRP state management module 903. The negotiation module 50 can be quickly detected. The session management module 904 is implemented, and the detection module 10 and the establishment module 40 can be implemented by the fault fast detection module 905. The specific functions of each function module are as follows: The packet sending and receiving module 901 is configured to receive and send data packets, protocol packets, and fault detection packets. For the received packet, the module forwards the packet or distributes the packet to the VRRP packet transmission module 902 or the fault fast detection module 905 according to the packet type. For the packets from the VRRP packet sending and receiving module 902 and the fault fast detecting module 905, the module is properly encapsulated and sent out from the corresponding outgoing port. In addition, the receiving and sending of the module message is also affected by the control information of the VRRP state management module 903;

The VRRP packet sending and receiving module 902 is configured to complete the receiving and sending of the VRRP standard protocol packet and the extended protocol (or EVRRP protocol) packet in the present invention. The protocol messages related to the module include: VRRP keep-alive 4, EVRRP Alternate Request/Reply 4 and Session Type/Parameters Negotiate 4. By analyzing the protocol from the 4 收发 transceiver module 901, the protocol state machine and the fault fast detection session are respectively controlled. The module also constructs a protocol packet according to the state of the router, and sends the protocol packet to the packet transceiver module 901 to complete the protocol packet transmission.

The VRRP state management module 903 is configured to be responsible for the state management of the VRRP router, such as electing an Alternate router from the Backup router and upgrading the Alternate router to the Master. The factors affecting VRRP state management include VRRP packet transmission and reception (from VRRP packet transmission and reception module 902) and fast detection of session management information (from fast detection session management module 904). Conversely, the status information of the router affects the sending and receiving of VRRP packets, data packets, and detection packets, and the management of the fast detection session. The fast detection session management module 904 is configured to complete the negotiation of the fast detection session type and session parameters. And the fault fast detection module 905 is notified to establish or tear down the fast detection session. The session state affects the state transition of the VRRP router. The fault fast detection module 905 is set to quickly detect the establishment, maintenance, and teardown of the session, and check the status of the peer device. If a device failure is found, the fast detection session management module 904 is notified, which in turn affects the state of the VRRP router. From the above description, it can be seen that the present invention achieves the following technical effects:

The master router selects an optimal router as the alternate router in the backup router, and establishes a fault fast detection session between the two by negotiation. Through this session, the Alternate router can detect the status of the master router in real time. Once the master router fails, the Alternate router will immediately take over the work of the master router to meet the needs of real-time services. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claims A method of switching, including:

The standby Alternate router detects whether the primary router is invalid through a fast detection session established between the primary router and the primary router, wherein the alternate router is elected from the standby router;

After detecting that the primary router fails, the Alternate router transitions from the Alternate state to the active state and switches to the new primary router. The method according to claim 1, wherein before the Alternate router detects whether the primary router is invalid through a fast detection session established between the primary router and the primary router, the method further includes:

The primary router initiates an election of an alternate router, and elects an optimal standby router as an alternate router;

The primary router establishes the fast detection session with the alternate router. The method according to claim 2, wherein the primary router initiates an election of an alternate router, and the election of the optimal standby router as an alternate router includes:

The primary router periodically sends a keep-alive message, and initiates the alternate router election by sending an alternate router election request message to the backup router; the standby router returns the same to the primary router. The response message of the Alternate router election request message, where the response message carries the priority and/or the primary IP address of the standby router;

The primary router elects the backup router with the highest priority as the Alternate router, or, in the case of the same priority, the primary router elects the backup router with the largest primary IP address as the alternate router;

The standby router with the highest priority or the largest primary IP address transitions from the standby state to the alternate state and switches to the alternate router.

4. The method according to claim 2, wherein

Before the primary router establishes the fast detection session with the alternate router, the method further includes: the primary router separately negotiates the session type negotiation and quickly detects the session parameter negotiation packet, and the The Alternate router negotiates the type and parameters of the fast detection session;

The fast detecting session between the primary router and the alternate router includes: after the negotiation succeeds, the primary router establishes the relationship with the alternate router according to the negotiated type and parameter. Quickly detect sessions.

5. The method according to claim 4, further comprising:

If the establishment fails or the negotiation fails, the Alternate router switches from the Alternate state to the standby state and switches back to the standby router.

The standby router listens to the keep-alive message sent by the primary router; if the keep-alive message from the primary router is not received within a certain period of time, the standby router initiates election of the primary router, and the election The optimal standby router acts as the new primary router, and enters the primary router to initiate an alternate router election, and elects the optimal standby router as an Alternate router.

6. The method according to claim 1, wherein after the Alternate router transitions from the Alternate state to the active state and switches to the new primary router, the new primary router enters the primary router to initiate an alternate router. Election, the step of electing the optimal backup router as an alternate router.

The method according to any one of claims 1 to 6, wherein the fast detection session includes but is not limited to: a bidirectional forwarding detection BFD session, a synchronous digital system SDH session, a heartbeat session.

8. A type of router, including:

a detecting module, configured to detect, by using a fast detection session established between the router and the primary router, whether the primary router is invalid, wherein the alternate router is from the standby router. Elected

The switching module is configured to switch from the alternate state to the active state and switch to the primary router after the detecting module detects that the primary router fails after the router is an alternate router.

9. The router according to claim 8, further comprising:

The transceiver module is configured to initiate an alternate router election when the router is the primary router, and elect the standby router with the highest priority as the alternate router or elect the standby router with the largest primary IP address as the alternate when the priorities are the same. Router

Establishing a module, configured to: after the transceiver module elects an alternate router, establish a fast detection session with the alternate router to enable the alternate router to detect whether the router is invalid through the fast detection session; The switching module is further configured to switch from the active state to the standby state and switch to the standby router after the detecting module detects that the router fails after the router is the primary router.

The router according to claim 9, further comprising: a negotiation module, configured to quickly detect a session type negotiation report before the establishing module establishes the fast detection session with the alternate router And quickly detecting a session parameter negotiation message, and negotiating, with the Alternate router, the type and parameter of the fast detection session;

After the negotiation of the negotiation module is successful, the establishing module is configured to establish the fast detection session with the alternate router according to the negotiated type and parameter.