Anycast Packet Forwarding With Virtual Nodes for Loop-Free Routing
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Solution Overview
Problem
In segment routing networks, the use of anycast nodes can lead to packet forwarding loops when a link failure occurs, causing packet failures due to nodes having the same IP address forwarding packets back to the faulty node.
Innovation Solution
Implement a method where first and second nodes with an anycast route determine a loop-free path by adding a virtual node to network topology information, setting virtual links, and using a loop-free path computation algorithm to avoid loops, ensuring packets are forwarded correctly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anycast nodes are configured with the same IP address and SID for reliability, then node redundancy is improved, but packet forwarding loops occur when link failures happen
Solution Approach 1:
The patent introduces a virtual node as an intermediary in the path computation process. When computing a loop-free path between anycast nodes, the virtual node acts as a mediator that prevents the computation from selecting paths that would create loops. The virtual node is added to the network topology temporarily during path computation, allowing the algorithm to identify and avoid loop-prone paths while maintaining the anycast configuration for reliability.
2Productivity
If nodes calculate minimum path cost based on encapsulated addresses, then routing efficiency is improved, but packets are forwarded to the faulty node causing loops
Solution Approach 1:
The patent performs preliminary path computation before actual packet forwarding. By pre-calculating loop-free paths using the virtual node technique and storing this path information, the system prepares routing decisions in advance. When packets need to be forwarded, the pre-computed loop-free path information is used directly, maintaining routing efficiency while preventing loops from occurring.
3Reliability
If loop-free path computation is implemented in anycast networks, then packet forwarding reliability is improved, but path computation complexity increases
Solution Approach 1:
The virtual node serves as a computational intermediary that simplifies the loop-free path computation problem. Instead of implementing complex loop-detection algorithms, the system adds a virtual node to the topology and uses standard shortest path algorithms. This intermediary approach transforms a complex loop-avoidance problem into a straightforward path computation task, reducing the actual computational complexity while improving reliability.
Data Source
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AI summary
Embodiments of the present invention provide a packet forwarding method and apparatus, and pertain to the field of communications technologies. The method includes: determining, by a first node, information about a loop-free path from the first node to a second node, where the first node and the second node are a pair of nodes having an anycast route; and when the first node receives a packet to be sent to a third node, if a link from the first node to the third node is faulty, forwarding, by the first node, the packet to the second node based on the information about the loop-free path, so as to forward the packet to the third node through the second node. According to this application, a success rate of packet sending can be improved.