SRV6 Service Chain Failover Using Secondary SID Bypass
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Solution Overview
Problem
In service chain technologies, traffic interruption occurs when a link between a service function forwarder (SFF) and a service function (SF) is faulty, particularly in scenarios where the SF is not aware of segment routing (SR-unaware), leading to unreliable service delivery.
Innovation Solution
Implement a method where a service function forwarder (SFF) updates the destination address field of a packet to a secondary segment identifier (SID) when a link fault occurs, allowing the packet to be bypassed to another SFF, using End-type SIDs to avoid complex configuration and potential traffic loops, thereby ensuring continuous service delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SFF directly forwards packets to the SF when a link fault occurs, then the service chain operates normally, but traffic interruption occurs when the link is faulty
Solution Approach 1:
The patent pre-configures multiple SIDs (primary and secondary) for each SFF-SF link before faults occur. When a link fault is detected, the SFF has already prepared alternative SIDs to immediately switch to, avoiding complex real-time routing calculations and ensuring rapid failover without traffic interruption
Solution Approach 2:
The patent changes the forwarding parameter (SID) from a fixed primary SID to a dynamic selection between primary and secondary SIDs based on link status. This parameter change allows the system to adapt to fault conditions by switching SIDs, thereby maintaining service continuity while managing forwarding complexity through predefined options
2Reliability
If the SFF uses complex protection mechanisms to prevent traffic interruption, then service reliability improves, but device complexity increases
Solution Approach 1:
The patent segments the protection mechanism into independent SID pairs (primary and secondary) for each SFF-SF link. This segmentation allows each link to have its own simple backup mechanism without requiring complex global coordination, reducing overall configuration complexity while maintaining high reliability through distributed, independent protection segments
Solution Approach 2:
The patent introduces SIDs as intermediary elements that mediate between the SFF and SF. These SIDs act as simple, standardized interfaces that encapsulate the complexity of link protection, allowing the SFF to forward packets using straightforward SID-based routing while the underlying complex protection logic remains hidden in the SID management system
3Duration of action of stationary object
If the SFF bypasses packets to alternative SFFs using secondary SIDs, then traffic continuity is maintained, but packet routing complexity increases
Solution Approach 1:
The patent pre-establishes secondary SIDs and their corresponding alternative SFF mappings before any faults occur. When a link fails, the SFF simply switches to using the pre-configured secondary SID, which already contains all the routing information needed to reach the alternative SFF. This eliminates the need for complex real-time routing calculations and maintains simple forwarding logic while ensuring service continuity
Data Source
AI summary
This application provides a service chain fault protection method, an apparatus, a device, a service chain fault protection system, and a storage medium, and relates to the field of communications technologies. In this application, in an SRV6 static service chain scenario, when a link between an SF network element and an SFF accessed by the SF network element is faulty, a secondary SID is introduced to update a destination address field of a packet header of a packet to the secondary SID, so that the packet is bypassed, based on the secondary SID, to another SFF accessed by the SF network element, thereby implementing fault protection in the link between the SFF and the SF network element.