Method for realizing fast re-routing of label distribution protocol and label switch router

Abstract

The invention discloses an LSR (label switch router) for realizing the FRR (fast re-routing) of an LDP (label distribution protocol). The LSR comprises an IP FRR unit for establishing a backup route and an LDP FRR unit for establishing a backup LSP (label switch path) path, wherein the IP FRR unit is used for notifying a backup next hop LSR on the backup route computed by the local LSR, which takes the target LSR as the FEC (forwarding equivalence class), to the LDP FRR unit; and the LDP FRR unit is used for establishing the backup LSP according to the backup next hop LSR and an FEC-target LSR label sent by the backup next hop LSR. The invention also discloses a corresponding method. By establishing the backup LSP computed by the IP FRR and ensuring the consistence of the backup LSP and the backup route, and the LDP FRR can select the better path and avoid a bad path; and compared with the conventional LDP FRR, the LSR has flexible realization mode, and is free from relying on a backup interface manually configured by a user.

Description

technical field [0001] The present invention relates to the field of network communication technologies, in particular to a method for realizing LDP (Label Distribution Protocol, Label Distribution Protocol) FRR (Fast Reroute, fast rerouting) for an MPLS (Multiprotocol Label Switching, multi-protocol label switching) network and an LSR (Label Switching Router, label switching router). Background technique [0002] IP FRR (Internet Protocol, Internet Protocol) was originally proposed to meet the strict requirements of real-time services such as voice and video on the interruption time of network traffic. It calculates a loop-free backup route in advance, and directly uses the backup route when a fault is detected. Replace invalid routes, and use backup routes to guide forwarding before routes reconverge, so as to minimize traffic interruption time. [0003] At present, in the MPLS technology that is increasingly widely used in the IP basic network, in order to improve the re...

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Problems solved by technology

[0004] However, in the prior art, the implementation of LDP FRR generally relies on user manual configuration (backup interface) or some internal rules, and is not associated with the routing selection of IP FRR, which will bring the following two problems: first, due to Without the loop detection function in IP FRR, in a complex network, loops may appear in the backup LSP path selected by LDP FRR; second, because there is no route optimization function in IP FRR, when faced with multiple paths For selection, the backup LSP path selected by LDP FRR may not be a better path

like figure 1 In the FRR network including LSRs A to F shown, the main LSP path from A to D is A→B→D, which is consistent with the main route; on A, D is the FEC (Forwarding Equivalence Class, forwarding equivalence class, The next hop of the LDP LSP of FEC D is B, and by enabling LDP FRR using interface backup on A, if interface 3 is configured as the backup interface of interface 2, the next hop of the backup LSP of FEC D will be E, so When the link between A and B fails, the traffic of A→B will be switched to the backup LSP of A→E→F→B→D, which cannot be connected with the backup route A→C→B optimized by IP FRR calculation. → D stay consistent

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