WO2010102560A1 - Method, device and system for exiting graceful restart - Google Patents

Abstract

The present invention provides a method, device and system for exiting graceful restart. When a first timer of a restarter expires, the restarter exits graceful restart and sends a first notification message, which is used for notifying helpers to exit the graceful restart, to all neighbor helpers respectively. After receiving the first notification message, the neighbor helpers exit the graceful restart. When a second timer of a helper expires, the helper exits the graceful restart and sends a second notification message, which indicates that the helper has exited the graceful restart, to the neighbor restarter. After receiving the second notification messages of exiting graceful restart sent by all the neighbor helpers, the restarter exits the graceful restart. Thus, it is ensured that the restarter and helpers can exit graceful restart in time, and thereby the situation that the forwarding tables of both are not deleted in time resulting in forwarding block is avoided.

Description

 Method, device and system for exiting graceful restart This application claims to be filed on March 10, 2009 with the Chinese Patent Office, application number 200910127034.6, and the invention titled "A Method, Equipment and System for Exiting Elegant Restart" Priority of the application, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present invention relates to the field of network communication technologies, and in particular, to a method, device, and system for exiting graceful restart. BACKGROUND Multi-Protocol Label Switching (MPLS) can support multi-layer labeling and connection-oriented, and has good scalability, making it possible to provide various services to customers on a unified MPLS/IP infrastructure network architecture. . The Label Distribution Protocol (LDP) is a control protocol of MPLS. It is responsible for the classification of FEC (Forwarding Equivalence Class), the assignment of labels, and the establishment and maintenance of Label Switched Paths (LSPs). A series of operations.

 The Label Switched Router (LSR) can directly map the routing information of the network layer to the LSP of the data link layer through the LDP or the Constrained Route-Label Distribution Protocol (CR-LDP). And then establish an LSP on the network layer. The LSP can be established between two adjacent LSRs or terminated at the network egress node, so that label switching can be used on all nodes of the network.

 The MPLS architecture is described below with reference to the accompanying drawings. Referring to Figure 1, the figure shows a prior art MPLS architecture.

 The MPLS architecture is divided into a control plane 100 and a forwarding plane 200. The control plane 100 generates the LSP 102 through the signaling protocol unit 103, and simultaneously transmits the generated LSP 102 information to the tag information base 101 and the tag forwarding information base 201 of the forwarding plane 200. The forwarding plane 200 is used to guide the label forwarding information base 201 to forward control information.

The Graceful Restart (GR) means that when the control plane 100 of the Restarter restarts, the forwarding plane 200 keeps the label forwarding information base 201 unchanged. Label forwarding is not interrupted. Specifically, the control plane 100 is restarted. During the GR, the information in the tag information base 101 is marked with the "Stale" flag, but the tag forwarding information base 201 of the forwarding plane 200 is not notified, and the information of the tag forwarding information base 201 is made. Consistent with before rebooting. After the control plane 100 works normally, the LSP is regenerated, and the tag information base 101 and the tag forwarding information base 201 are updated. If the information in the tag information base 101 is not restored within the specified time, the LDP GR should be exited and the tag information that has not been recovered is deleted.

 RFC 3478 specifies that the Restarter starts an MPLS timer when the control plane restarts. Before the timer expires, the forwarding plane retains the label forwarding information before the control plane restarts, and the control plane performs label information recovery. After the timer expires, if there is still any tag information that has not been recovered, the forwarding plane deletes it.

 The helper starts a Reconnect timer. If the LDP session between the Helper and the Restarter is not re-established before the Reconnect timer expires, the Helper will exit the GR after the timeout and delete the related label information. If the LDP session is established before the timeout period, the helper deletes the Reconnect timer and then starts a recovery timer. After the Recovery timer expires, the GR is deleted and the unrecovered label information is deleted.

 The interval between the three timers can be configured by the user. The interval between the Reconnect timer and the Recovery timer is negotiated when the LDP session is established.

 The purpose of setting up the above three timers is to control the time when the Restarter and Helper exit GR. However, the time required for the LSR to recover all LSPs before restarting is not only related to the number of LSPs, but also related to the processing speed, network status, and topology of the router. In the actual application, the timers of the Restarter and the Helper are not synchronized. As a result, the forwarding entries of the two cannot be deleted in time.

 In summary, in the prior art, the Restarter and the Helper cannot be used to exit the GR in time by using the above three timers. SUMMARY OF THE INVENTION The embodiments of the present invention provide a method, a device, and a system for exiting graceful restart, which can control the Restarter and the Helper to exit LDP GR in time.

Embodiments of the present invention provide a method for exiting graceful restart, including: when the control plane is elegant When restarting, the restarting end starts the first timer; if the first timer expires, the restarting end exits gracefully restarting, and sends a first notification message to all neighboring assisting ends, respectively, to notify all neighboring neighbors to quit gracefully Restarting; if receiving the second notification message sent by all the neighboring assistants and exiting the graceful restart, the restarting terminal exits the graceful restart.

 The embodiment of the present invention further provides a method for exiting the graceful restart, including: when the control plane gracefully restarts, the assisting end starts the second timer; if the second timer expires, the assisting end exits gracefully restarting, and restarts to the neighbor The sending end sends the second notification message of the graceful restart; if the notification is sent by the neighboring restarting end, the assisting end exits the graceful restarting first notification message, and the assisting end exits the graceful restart.

 The embodiment of the present invention further provides a restarting end that exits the graceful restart, and includes: a first determining unit, a first notifying unit, a first detecting unit, and a first exiting unit;

 The first determining unit is configured to determine whether the first timer of the restarting end timeout and whether the restarting end receives the second notification that exits the graceful restart sent by all the neighboring assistants, and cancels the first exiting unit, When the first determining unit determines that the first timer of the restarting end timeout or determines that the restarting end receives the second notification message sent by all the neighboring assistance terminals, exiting the graceful restart;

 The first notification unit is configured to: when the first determining unit determines that the first timer of the restarting end timeout expires, send a first notification message that exits graceful restart to all neighboring assistance ends, and notify all neighbors The helper exits gracefully restarting.

 The embodiment of the present invention further provides an assisting end that exits the graceful restart, and includes: a second determining unit, a second notifying unit, and a second exiting unit;

 The second determining unit is configured to determine whether the second timer of the assisting end times out and whether the assisting end receives the first notification message that the neighboring restarting end sends the notification assisting end to exit the graceful restart;

 The second exiting unit is configured to: when the second determining unit determines that the second timer of the assisting end is timed out or the assisting end receives the notification sent by the neighboring restarting end, the assisting end exits the graceful restarting Exiting the graceful restart when a notification message is received;

The second notification unit is configured to: when the second determining unit determines that the second timer of the assisting end times out, send the second notification message that the assisting end exits the graceful restart to the neighboring restarting end. The embodiment of the invention further provides a system for exiting graceful restart, comprising: a restarting end and a assisting end;

 When the first timer of the restarting end timeout expires, the restarting end exits the graceful restart, and sends a first notification message to the neighboring assisting end to notify the assisting end to exit the graceful restart; the neighboring assisting end receives the first After a notification message, exit the graceful restart;

 When the second timer of the assisting end times out, the assisting end exits the graceful restart, and sends a second notification message that the assisting end exits the graceful restart to the neighboring restarting end; the restarting end receives all neighbors. After the assisting end sends the second notification message that exits the graceful restart, the graceful restart is exited.

 The above technical solution ensures that the restarting end and the assisting end can exit the graceful restart in time, so that the forwarding entries of the two are not deleted in time, and the forwarding fails. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural diagram of a prior art MPLS architecture;

 2 is a system structural diagram of a restart end and a help end according to an embodiment of the present invention;

 Figure 3 is a flow chart of the first embodiment of the method of the present invention;

 Figure 4 is a flow chart of a second embodiment of the method of the present invention;

 FIG. 5 is a structural diagram of a restart end in the embodiment of the present invention; FIG.

 FIG. 6 is a structural diagram of the assisting end in the embodiment of the present invention. The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. example. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

 Referring to FIG. 2, the figure is a system structure diagram of a restart end and a help end according to an embodiment of the present invention.

 The Restarter in the general network corresponds to multiple Helpers. As shown in Figure 2, one Restarter corresponds to three helpers, namely Helper 1, Helper 2, and Helper 3.

Method embodiment one: Referring to Figure 3, there is shown a flow chart of a first embodiment of the method based on the present invention.

 In this embodiment, the restarting end is taken as an example to illustrate the method for exiting the graceful restart of the present invention.

 S301: When the control plane gracefully restarts, the Restarter starts the first timer.

 In the embodiment of the present invention, the first timer started by the Restarter is an MPLS timer. Before the first timer expires, the forwarding plane retains the label forwarding information before the control plane restarts, and the control plane performs label information recovery. After the first timer expires, if there is no recovered label information, the forwarding plane deletes the label information that has not been recovered.

 S302a: If the first timer expires, the Restarter exits the GR and sends a first notification message to all neighboring helpers. The first notification message is used to notify the neighbor Helper to exit the GR.

 S302b: If the Restarter receives the second notification message sent by the neighboring helper, the Restarter exits the GR, where the second notification message is used to notify the Restarter, and the second notification message is sent.

Helper has quit GR.

 It should be noted that both S302a and S302b are the conditions for the Restarter to exit the GR, that is, the first timer expires and/or the second notification message of the exit GR sent by all neighbors Helper is received.

The Restarter needs to exit GR.

 Figure 2—The Restarter corresponds to multiple neighbors Helper as an example:

 If the first timer of the Restarter expires, the Restarter exits GR and sends Helper to Helper.

Helper2 and Helper3 send the first notification message to notify Helper 1, Helper2, and Helper3 to quit.

GR, that is, as long as the Restarter exits the GR, all neighbors of the Restarter Helper also need to exit the GR.

 If the Restarter receives the second notification message from the neighboring helper and exits the GR, for example, the Restarter only receives the second notification message from the GR sent by the Helper1, and the Restarter does not exit the GR; the Restarter needs to wait for the Receiver. After the second notification message of the GR is sent to the helper2 and the helper3, the Restarter exits the GR. That is, the Restarter needs to receive the second notification message from the neighboring helper to log out of the GR before exiting the GR.

 The method for exiting the GR provided by the present invention adds a notification message to the GR, so that the Restarter and all its neighbors helper can exit the GR in time, so that the forwarding entries of the two are not deleted in time, and the forwarding fails.

 S303: Delete the unrecovered tag information.

The unrecovered tag information is deleted in order to re-establish the tag information and is not affected by the pre-restart. Method Embodiment 2:

 Referring to Figure 4, there is shown a flow chart of a second embodiment of the method based on the present invention.

 In this embodiment, the method of exiting GR by the present invention is illustrated by taking the assisting end as an example.

 S401: When the control plane is restarted, the helper starts the second timer.

 S402a: If the second timer expires, the helper exits the GR and sends a second notification message to the neighbor Restarter that the helper exits the GR.

 S402b: If the notification sent by the neighbor Restarter is received, the helper exits the first notification message of the GR, and the Helper exits the GR.

 The above S402a and S402b are the conditions for the helper to exit the GR, that is, the second timer expires and/or the first notification message of the exit GR sent by the neighbor Restarter is received, and the helper needs to exit the GR.

 It should be noted that a helper exits the GR and sends only the second notification message of the exit GR to the neighbor Restarter. However, the neighbor Restarter does not exit the GR. The neighbor Restarter needs to receive the second notification message from the Helper to log out of the GR. If the helper receives the notification message of the GR that is sent by the neighboring Restarter, you need to log out of the GR. This ensures that the Restarter and the Helper exit the GR in time, so that the forwarding entries of the two are not deleted.

 S403: Delete the unrecovered tag information.

 The unrecovered tag information is deleted so that the tag information is not re-established and is not affected by the pre-restart.

 The following describes the specific process of Helper exiting GR according to the timer timeout.

 In this embodiment, the second timer is specifically a Reconnect timer and/or a Recovery timer.

 The helper first starts a Reconnect timer.

 If the LDP session between the Helper and the Restarter is not re-established before the Reconnect timer expires, the Helper will exit the GR after the timeout and delete the related label information.

 If the LDP session is set up before the Reconnect timer expires, the helper deletes the Reconnect timer and then starts a Recovery timer. After the Recovery timer expires, the device exits the GR and deletes the unrecovered label information. It should be noted that if the Recovery timer does not time out, the Helper remains working normally and does not exit.

GRe The first method of the foregoing method indicates that the first timer of the Restarter is timed out and/or the second notification message of the GR that is sent by the neighboring helper is received. The Restarter needs to quit the GR. The second timer of the helper times out and/or receives the neighbor Restarter. If the first notification message of the GR is sent, the helper needs to quit the GR. If the Restarter exits the GR and sends the first notification message to the helper to log out of the GR, the helper exits the GR when receiving the first notification message. The Restarter sends the second notification message of the GR to the Restarter. When the Restarter receives the second notification message, it is determined whether all the Helpers of the neighbors have quit the GR. When all the Helpers exit the GR, the Restarter exits the GR.

 The invention also provides a restart end that exits the GR.

 Restart side embodiment one:

 Referring to FIG. 5, the figure is a structural diagram of a restart end according to an embodiment of the present invention.

 The Restarter that exits the GR provided in this embodiment includes: a first determining unit 501, a first leaving unit 502, and a first notifying unit 503.

 The first determining unit 501 is configured to determine, when the control plane is restarted, whether the first timer started by the Restarter times out; if the first timer expires, sending the first timer to the first exiting unit 502 and the first notification unit 503 to timeout And the first determining unit 501 is configured to determine whether a second notification message sent by all neighboring helpers is received, the second notification message is used to notify the Restarter, and the helper that sends the second notification message has exited the GR.

 The first exiting unit 502 is configured to: when the first determining unit 501 determines that the first timer expires and/or when the first determining unit 501 receives the message of the second notification message sent by all the neighboring helpers, the GR is exited.

 The first notification unit 503 is configured to: after receiving the message that the first timer is sent by the first determining unit 501, send a first notification message to all neighboring helpers, where the first notification message is used to notify the neighboring helper to exit the GR.

The Restarter provided in this embodiment, when the first exit unit 502 receives the message that the first determining unit 501 times out, exits the GR, and the first notification unit 503 notifies all neighbors that the helper also exits the GR. This ensures that the Restarter and the Helper can log out of the GR in time when the first timer of the Restarter times out. When the first exit unit 502 receives the message that all the neighbor helpers sent by the first determining unit 501 exit the GR, the first exit unit 502 also exits the GR. This also ensures that the Restarter and Helper can exit the GR in time. In both cases, the forwarding entries of the Restarter and the Helper are not deleted in time, and the forwarding fails. The Restarter provided in this embodiment further includes a first deleting unit 504. After the first exiting unit 502 exits the GR, the first deleting unit 504 is configured to delete the unrecovered tag information. The unrecovered tag information is deleted in order to re-establish the tag information and is not affected by the pre-restart.

 The Restarter provided in the above embodiment can prevent the Restarter and the neighboring Helper from exiting the GR in time. This prevents the forwarding entries of the Restarter and the Helper from being deleted in time. The present invention also provides a helper that exits the GR.

 Assisted end example 1:

 Referring to FIG. 6, this figure is a structural diagram of an assisting end based on an embodiment of the present invention.

 The embodiment provides a helper that exits the GR, and includes: a second determining unit 601, a second exiting unit 602, and a second notifying unit 603.

 The second determining unit 601 is configured to determine whether the second timer started by the helper times out when the control plane is restarted, and send the second timer to the second exiting unit 602 and the second notifying unit 603 when the second timer expires. Timeout message.

 The second exiting unit 602 is configured to: when the second determining unit 601 determines that the second timer expires and/or the second determining unit 601 detects that the notification sent by the neighbor Restarter exits the first notification message of the GR, the GR is exited.

 The second notification unit 603 is configured to: when the second determining unit 601 determines that the second timer expires, send a notification message of exiting the GR to the neighbor Restarter, and notify the neighbor Restarter to exit the GR.

 It should be noted that when a helper exits the GR, only the notification message of the exit GR is sent to the neighbor Restarted. However, the neighbor Restarter does not exit the GR. If the helper receives the notification message of the exit GR sent by the neighbor Restarter, the J and J exit the GR. In this way, the Restarter and the Helper are allowed to log out of the GR in time, so that the forwarding entries of the two are not deleted in time and the forwarding fails.

 The following describes the specific process of Helper exiting GR according to the timer timeout.

 The helper first starts a Reconnect timer.

 If the LDP tongue between the Helper and the Restarter is not re-established before the Reconnect timer expires, the Helper will exit the GR after the timeout and delete the related label information.

If the LDP session is established before the Reconnect timer expires, the helper will When the LDP session is established, the Reconnect timer is deleted, and a recovery timer is started. After the Recovery timer expires, the GR is deleted and the unrecovered label information is deleted.

 The helper provided in this embodiment further includes a second deleting unit 604. After the second exit unit 602 exits the graceful restart, the second deleting unit 604 is configured to delete the unrecovered tag information. The unrecovered tag information is deleted so that the tag information is not re-established after it is re-established. This prevents the forwarding entries of the Restarter and Helper from being deleted in time. The present invention also provides a system for exiting GR.

 System embodiment one:

 Referring to Figure 2, there is shown a block diagram of a system based on an embodiment of the present invention.

 A system that exits graceful restart, including a restart end and a help end;

 When the first timer of the restarting end times out, the restarting end exits the graceful restart, and sends a notification to the neighboring assistants to notify the assisting end to exit the graceful restarting first notification message. After receiving the first notification message, the neighboring assisting end exits. The graceful restart;

 When the second timer of the assisting end times out, the assisting end exits the graceful restart, and sends a second notification message to the neighboring restarting end to cancel the elegant restarting of the graceful restart; the restarting end receives the graceful restart sent by all the neighboring assisting ends. After the second notification message, exit gracefully restart.

 It should be noted that, in this embodiment, a restarter Restarter and three neighboring assistants Helperl, Helper2, and Helper3 are used as an example. Generally, one Restarter corresponds to multiple Helpers, and is not limited to three.

 When the control plane restarts, the Restarter starts the first timer. If the first timer of the Restarter times out, the Restarter exits graceful restart; and the Restarter sends the first notification message to exit graceful restart to all neighbors Helper Helperl, Helper2, Helper3.

 After all the neighbors Helperl, Helper2, and Helper3 receive the first notification message, they exit the graceful restart. That is, as long as the Restarter exits the GR, all its neighbor Helpers also need to exit GR.

When the control plane restarts, the helper starts the second timer. If the second timer of the helper times out, the helper exits the GR; and the helper sends a second notification message that exits the GR to its neighbor. It should be noted that the above assistance end may be any one or more of Helperl, Helper2, and Helper3. For example, if only the timer of Helperl needs to exit GR, then Helperl sends a notification message to exit GR to Restart, but the Restarter does not need to exit GR after receiving the notification message. That is, when only one assisting end exits the GR, the other assisting end and the restarting end do not need to exit the GR. The Restarter needs to log out of the GR when it receives the notification message of graceful restart from all neighbors, Helperl, Helper2, and Helper3. That is, the restarter exits GR ₀ after all helpers exit the GR.

 After the Restarter and Helper exit GR, the unrecovered label information is deleted. The system for exiting the GR provided by the present invention, the timer expires and the notification message of the exiting GR is deleted from the GR, and the Restarter and the helper can be deleted from the GR in time to prevent the forwarding entries of the Restarter and the Helper from being deleted in time. There is no forwarding.

 It should be noted that the Restarter and the Helper in the foregoing system include specific units in the Restarter and Helper embodiments in the device embodiment.

 The method, device and system of the present invention are not only applied to the CR-LDP using a timer to control the signaling of the time of exiting the GR, but also applicable to the Resource Re-Servation Protocol (RSVP) using a timer. Signaling of the time to exit the GR.

 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 computer readable storage medium. The content of each embodiment of the aforementioned communication method may be included. The storage medium referred to herein is, for example, R0M/RAM, disk, optical disk, and the like.

 A person skilled in the art can understand that all or part of the steps of implementing the foregoing embodiments may be completed by a program instructing related hardware, and the program may be stored in a computer readable storage medium, and the program is executed. The method includes the following steps: The restarting end starts the first timer; if the first timer expires, exits the graceful restart, and sends a first notification message to all the neighboring assistants respectively, informing the neighboring assistants to exit the graceful restart And/or, if receiving the second notification message sent by all the neighbor assistance ends and exiting the graceful restart, exiting the graceful restart.

Claims

Rights request  1. A method for exiting graceful restart, characterized in that it comprises:  When the control plane gracefully restarts, the restart end starts the first timer;  If the first timer expires, the restarting end exits the graceful restart, and sends a first notification message to all the neighboring assistants to notify all the neighboring assistants to exit gracefully restarting; The second notification message of graceful restart is exited, and the restarter exits the graceful restart.  2. The method according to claim 1, further comprising: deleting the unrecovered tag information after the restarting end exits the graceful restart.  3. A method for exiting graceful restart, which is characterized by comprising:  When the control plane gracefully restarts, the assisting end starts the second timer;  If the second timer expires, the assisting end exits gracefully restarting, and sends a second notification message that the assisting end exits the graceful restart to the neighboring restarting end;  If the notification sent by the neighboring restarting end is received, the assisting end exits the first notification message of the graceful restart, and the assisting end exits the graceful restart.  The method according to claim 3, further comprising: deleting the unrecovered tag information after the assisting end exits the graceful restart.  A restarting end that exits the graceful restart, and includes: a first determining unit, a first notifying unit, a first detecting unit, and a first exiting unit;  The first determining unit is configured to determine whether the first timer of the restarting end timeout and whether the restarting end receives the second notification that exits the graceful restart sent by all the neighboring assistants, and cancels the first exiting unit, When the first determining unit determines that the first timer of the restarting end timeout or determines that the restarting end receives the second notification message sent by all the neighboring assistance terminals, exiting the graceful restart;  The first notification unit is configured to: when the first determining unit determines that the first timer of the restarting end timeout expires, send a first notification message that exits graceful restart to all neighboring assistance ends, and notify all neighbors The helper exits gracefully restarting.  The restarting end according to claim 5, further comprising a first deleting unit, configured to delete the unrecovered tag information after the first exiting unit exits the graceful restart. 7. A helper end that exits the graceful restart, and is characterized by comprising: a second determining unit, a second notification unit and a second exit unit;  The second determining unit is configured to determine whether the second timer of the assisting end times out and whether the assisting end receives the first notification message that the neighboring restarting end sends the notification assisting end to exit the graceful restart;  The second exiting unit is configured to: when the second determining unit determines that the second timer of the assisting end is timed out or the assisting end receives the notification sent by the neighboring restarting end, the assisting end exits the graceful restarting Exiting the graceful restart when a notification message is received;  The second notification unit is configured to: when the second determining unit determines that the second timer of the assisting end times out, send the second notification message that the assisting end exits the graceful restart to the neighboring restarting end.  The assistance terminal according to claim 7, further comprising a second deletion unit, configured to delete the unrecovered tag information after the second exit unit exits the graceful restart.  9. A system for exiting graceful restart, wherein the system includes a restart end and a help end;  When the first timer of the restarting end timeout expires, the restarting end exits the graceful restart, and sends a first notification message to the neighboring assisting end to notify the assisting end to exit the graceful restart; the neighboring assisting end receives the first After a notification message, exit the graceful restart;  When the second timer of the assisting end times out, the assisting end exits the graceful restart, and sends a second notification message that the assisting end exits the graceful restart to the neighboring restarting end; the restarting end receives all neighbors. After the assisting end sends the second notification message that exits the graceful restart, the graceful restart is exited.  The system according to claim 9, wherein the restarting end exits the graceful restart, and deletes the unrecovered label information; and/or, after the assisting end exits the graceful restart, the unrecovered label is removed. Information is deleted.