Segment Routing Error Message Delivery via Packet Rewriting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In segment routing networks, error handling is challenging due to the lack of per-flow routing states in nodes other than the ingress node, leading to issues with error message delivery and correlation, causing operational black holes and incorrect error message routing.
Innovation Solution
A method is introduced to generate error messages by rewriting packets to include the original destination address and removing the segment routing header, deriving a new segment routing header for the error message, and forwarding it to the correct source node, ensuring accurate error message delivery and correlation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If segment routing is implemented without per-flow routing states in transit nodes, then device complexity is reduced and scalability is improved, but error message delivery and correlation become unreliable
Solution Approach 1:
The ingress node performs preliminary actions by encoding the complete segment routing header with all segment identifiers and routing information before packets enter the segment routing domain. This preliminary encoding allows transit nodes to forward packets without maintaining per-flow state, while still enabling reliable error message delivery back to the source through the pre-established routing information in the SRH.
Solution Approach 2:
The segment routing header acts as an intermediary that carries routing information through the network without requiring transit nodes to maintain flow state. The SRH enables error messages to be routed back to sources by embedding destination information in the header itself, rather than requiring intermediate nodes to track flow states.
2Ease of operation
If segment routing headers are removed from error messages, then error message processing is simplified, but error message routing to the correct source becomes incorrect
Solution Approach 1:
The patent extracts and preserves only the essential routing information needed for error message delivery while removing unnecessary segment routing headers. Specifically, the ingress node's address is extracted and embedded in the error message, allowing simplified processing at transit nodes while maintaining accurate routing back to the source.
Solution Approach 2:
The segment routing header information is copied into the error message in a simplified form. The error message contains a copy of the necessary routing information (such as the ingress node address) rather than the complete original SRH, enabling both simplified processing and accurate routing.
Data Source
AI summary
Embodiments include generating an error message based on an error associated with a packet, adding to the error message an address of a node in a segment routing domain of a network to serve as a destination address of the error message, and adding a new segment routing header to the error message. Embodiments also include rewriting the packet where the rewriting includes replacing a destination address in the packet with a final destination address associated with the packet. Embodiments further include adding the rewritten packet to the error message, and forwarding the error message to the destination address of the error message. In specific embodiments, the rewriting the packet includes removing a segment routing header of the packet. More specific embodiments include deriving the new segment routing header from information in the packet.