Segment Routing Packet Reroute for Loop-Free Fast Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing Interior Gateway Protocol (IGP) Fast Reroute (FRR) technology forms packet forwarding loops when local forwarding policies conflict with IGP FRR during path computation, preventing its effective deployment.
Innovation Solution
A method and node for packet transmission that uses segment identifiers, specifically IPv6 addresses with a strict Shortest Path First (SPF) flag, to establish secondary paths dynamically when a next-hop node fails, avoiding reliance on local policies and ensuring loop-free forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secondary path is computed based on IGP FRR technology using SPF principle, then packet forwarding reliability is improved, but packet forwarding loops are formed when local policies conflict with IGP FRR
Solution Approach 1:
The patent applies dynamics by making the path computation method adaptable: when local policies exist on the secondary path, the system dynamically switches from SPF-based computation to constraint-based computation that respects local policies, thereby avoiding loops while maintaining reliability
Solution Approach 2:
The patent changes the computation parameters by introducing policy awareness into the path computation process. When local policies are detected, the computation parameters are adjusted to incorporate policy constraints, transforming the path selection from purely SPF-based to policy-compliant path selection
2Adaptability or versatility
If local forwarding policies are configured on nodes to redefine traffic paths, then traffic engineering flexibility is improved, but packet forwarding loops are formed during FRR operation
Solution Approach 1:
The patent applies preliminary anti-action by pre-detecting the presence of local policies on potential secondary paths before FRR activation. When such policies are detected, the system proactively adjusts the path computation method to avoid conflicts, preventing loop formation before it occurs
Solution Approach 2:
The patent introduces an intermediary mechanism that mediates between IGP FRR requirements and local policies. This intermediary layer checks for policy conflicts and selects appropriate computation methods, ensuring both traffic engineering flexibility and loop-free forwarding
3Reliability
If secondary paths are pre-established for all possible failures, then packet forwarding reliability is improved, but network resource consumption increases
Solution Approach 1:
The patent applies partial action by computing and establishing secondary paths only when actually needed (upon failure detection) rather than pre-establishing all possible paths. This reduces resource consumption while maintaining reliability through on-demand path computation
Solution Approach 2:
The system dynamically computes secondary paths based on actual failure conditions rather than maintaining static pre-computed paths for all scenarios. This dynamic approach reduces network resource consumption by activating path computation only when necessary
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
This application provides a method and a node for packet transmission in a network. A first path from a second node to a third node is established in the network, and the first path is established based on a first segment identifier of the third node. The method includes: receiving, by a first node, a second segment identifier sent by the third node; receiving, by the first node, a packet sent by the second node through the first path; determining, by the first node, that a next-hop node of the first node on the first path is faulty; and in response to the determining, by the first node, that a next-hop node of the first node on the first path is faulty, adding, by the first node, the second segment identifier to the packet, and sending the packet to the third node through a second path, where the second path is established by the first node based on the second segment identifier. According to the method, a loop is avoided in a packet sending process.