BGP Router Originator ID Loop Detection
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Solution Overview
Problem
Conventional BGP route loop detection methods are unreliable in networks with route reflectors due to the prohibition of inserting the router's autonomous system identifier into the AS_PATH attribute list, leading to inaccurate best-path calculations and resource wastage from processing redundant advertisements.
Innovation Solution
Implementing a method where a router checks for the originator identifier in received path advertisements and modifies them to include its own identifier as a BGP_AGGREGATOR attribute, allowing for efficient detection and avoidance of routing loops by distinguishing between original and redundant advertisements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a route reflector inserts its autonomous system identifier into the AS_PATH attribute list for loop detection, then routing loop detection reliability is improved, but best-path calculation accuracy deteriorates due to unnecessary identifier inclusion
Solution Approach 1:
The patent segments the loop detection function from the best-path calculation function by introducing a separate originator identifier attribute. This allows loop detection to operate independently without contaminating the AS_PATH attribute that is used for best-path calculation, thus resolving the contradiction between detection reliability and calculation accuracy.
Solution Approach 2:
The patent introduces an intermediary mechanism (the originator identifier attribute) that mediates between the need for loop detection and the requirement for accurate best-path calculation. This intermediary carries loop detection information without interfering with the AS_PATH-based path selection process.
2Loss of information
If a route reflector processes all received route advertisements, then routing information completeness is improved, but computational resource consumption increases due to redundant processing
Solution Approach 1:
The patent applies preliminary action by checking the originator identifier attribute before performing full route advertisement processing. This preliminary check allows the route reflector to identify and discard redundant advertisements early in the process, preventing wasteful computational resource consumption while maintaining routing information completeness.
Solution Approach 2:
The patent implements discarding and recovering by enabling the route reflector to discard redundant route advertisements that have already been processed, as identified through the originator identifier attribute. This prevents unnecessary reprocessing while ensuring that valid routing information is retained and propagated.
Data Source
AI summary
In an embodiment, a method comprises: receiving, at a data packet router, a path advertisement comprising information about an available path; determining whether the path advertisement comprises an originator identifier of an originator of the available path; in response to determining that the path advertisement comprises the originator identifier of the originator of the available path, determining whether the originator identifier of the available path is a router identifier of the data packet router, and in response to determining that the originator identifier of the available path is the router identifier of the data packet router, not accepting the path advertisement; wherein the method is performed by one or more processors of the data packet router.