SRv6 VPN SID Path Switching for PE Device Fault Recovery
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Solution Overview
Problem
In virtual private networks (VPNs), the current method of using bidirectional forwarding detection (BFD) between provider edge (PE) devices to detect faults in packet transmission paths leads to a high deployment of BFD, occupying excessive resources and increasing fault detection time.
Innovation Solution
The method involves configuring PE devices with specific SRv6 VPN SIDs, allowing for the establishment of alternative paths based on these SIDs, thereby eliminating the need for BFD between PE devices to detect faults. When a fault is detected, packets are switched through paths connected to PE devices with the same SRv6 VPN SID, enabling rapid path switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BFD is deployed between PE devices to detect faults in packet transmission paths, then fault detection capability is improved, but resource occupation and device complexity increase
Solution Approach 1:
The patent merges the fault detection function into the SRv6 VPN SID routing mechanism itself. By using the same SRv6 VPN SID for both primary and backup paths and leveraging the routing protocol's natural path selection behavior, fault detection and path switching are achieved without deploying separate BFD sessions between PE devices, thus reducing device complexity while maintaining reliability
Solution Approach 2:
The SRv6 VPN SID is made multi-functional, serving both as a path identifier and as a fault detection mechanism. The routing protocol automatically detects path availability through standard routing updates, eliminating the need for dedicated BFD fault detection functionality between PE devices
2Loss of time
If BFD is deployed on all PE devices to ensure quick fault detection on each path, then fault detection speed is improved, but resource occupation increases
Solution Approach 1:
The patent combines fault detection with the existing SRv6 routing update mechanism. When a path fails, the routing protocol naturally stops advertising routes through that path, and routers automatically switch to backup paths through standard routing convergence, eliminating the need for separate BFD resource deployment while maintaining quick fault detection
Solution Approach 2:
The routing system performs self-diagnosis through standard routing protocol operations. Routers monitor path availability through regular routing updates and automatically detect failures when routes are no longer advertised, enabling the system to self-manage fault detection without external BFD assistance
3Reliability
If multiple paths are established for multi-homed CE devices, then network reliability is improved, but path management complexity increases
Solution Approach 1:
The patent uses SRv6 VPN SID parameters to encode path information directly in the routing entries. By modifying the routing table structure to include SRv6 VPN SIDs that inherently encode both primary and backup path information, the system simplifies path management while maintaining multi-homing protection capabilities
Solution Approach 2:
The routing system pre-configures both primary and backup paths using SRv6 VPN SIDs before failures occur. When failures happen, routers already have backup routes ready in the routing table, enabling immediate path switching without complex real-time path management or selection algorithms
Data Source
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AI summary
This application discloses a route processing method and an apparatus, and a data transmission method and an apparatus. The route processing method is applied to a network that bears an SRv6-based VPN service. A first CE device and a second CE device belong to a same VPN, and an egress PE device includes a first PE device and a second PE device. The method includes: receiving, by the first PE device, a VPN route that includes a second SRv6 VPN SID and a third SRv6 VPN SID and that is sent by the second PE device; determining that the second SRv6 VPN SID is the same as a first SRv6 VPN SID; and establishing a second path based on the third SRv6 VPN SID, where when a first path directly connected to the first PE device and the second CE device is faulty, the second path is used by the first PE device to forward a packet to the second CE device. This can effectively reduce an amount of BFD configured on each PE.