Double-Ascription PE Fast Convergence via BFD Tunnel Detection
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Solution Overview
Problem
Current MPLS TE FRR techniques fail to achieve fast end-to-end service convergence when a terminal node of the tunnel fails, resulting in prolonged service disruption and reduced reliability, with convergence times exceeding 1 second and being dependent on the number of MPLS VPN private network routes.
Innovation Solution
A method and apparatus for fast converging end-to-end services by setting and detecting routing and tunnel state information for multiple tunnels in a double-ascription PE, using techniques like BFD and tunnel fast convergence to select and forward services through available tunnels, independent of the number of MPLS VPN routes, thereby reducing malfunction detection time to less than 500ms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If MPLS TE FRR technique is used for service fast switching, then service switching time can be reduced to less than 50ms, but end-to-end service convergence time exceeds 1 second when terminal node fails
Solution Approach 1:
The patent pre-configures backup routing information in the forwarding table before failure occurs. When a terminal node fails, the double-ascription PE can immediately switch to the pre-configured backup route without waiting for route recalculation, thus reducing end-to-end service convergence time to under 1 second while maintaining the fast switching capability of MPLS TE FRR
Solution Approach 2:
The patent introduces BFD (Bidirectional Forwarding Detection) as an intermediary detection mechanism that independently monitors tunnel status. BFD provides fast failure detection (within 50ms) that is separate from the routing protocol, enabling the PE to quickly detect terminal node failures and trigger the backup routing switch without waiting for IGP convergence
2Reliability
If standard MPLS L3 VPN techniques are used for route advertisement, then routing information can be propagated between PEs, but convergence time increases significantly with the number of MPLS VPN private network routes
Solution Approach 1:
The patent extracts the failure detection function from the routing protocol and implements it through BFD as a separate mechanism. This allows failure detection to occur independently of the number of MPLS VPN routes, so convergence time remains under 1 second regardless of the scale of the VPN network
Solution Approach 2:
The patent pre-establishes backup routing information in the forwarding table before failure occurs. This preliminary configuration enables immediate switch to backup routes upon failure detection, making the convergence process independent of the number of routes that need to be advertised and processed by the routing protocol
Data Source
Figure 1~2
AI summary
A method for fast converging an end-to-end service and a Provider Edge (PE) includes: setting routing information of at least two tunnels in a double-ascription PE of a remote Customer Edge (CE), wherein, the two tunnels are from the double-ascription PE of the remote CE to the PE connected with the remote CE; detecting tunnel states to obtain state information of the tunnels; the double-ascription PE obtaining available routing information and routing information of the at least two tunnels, and forwarding the service according to the available routing information. The double-ascription PE of the remote CE can directly forward the service according to the pre-configured routing information of other tunnels when the current tunnel is unavailable, such as a terminal node of the current tunnel is abnormal, thereby avoids the procedure of re-selecting the route, and increases the end-to-end service convergence speed and improves the service reliability.