BGP Route Originator Attribute for Faster Convergence
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Solution Overview
Problem
Current BGP network convergence is hindered by propagation delays in WITHDRAW messages, leading to unnecessary UPDATE messages and route dampening, which affects the speed and reliability of route convergence in networks.
Innovation Solution
Incorporating a route originator attribute in BGP WITHDRAW messages to identify the node that originated the withdrawn route, allowing receiving nodes to mark matching paths as ineligible for best path determination, thereby preventing the use of unreachable routes and reducing unnecessary route flapping and dampening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BGP WITHDRAW messages are propagated through the network, then route information is updated, but propagation delays cause unnecessary UPDATE messages and route flapping
Solution Approach 1:
The patent applies preliminary action by marking paths as ineligible for best path determination before the WITHDRAW message fully propagates through the network. When a node receives a WITHDRAW message, it immediately marks the associated paths as ineligible, preventing them from being selected as best paths even though the withdrawal may not yet be fully propagated to all nodes. This proactive marking prevents unnecessary route flapping and UPDATE messages that would occur if nodes waited for full propagation before updating their routing decisions.
2Reliability
If BGP nodes wait for full WITHDRAW message propagation before updating routes, then routing accuracy is maintained, but convergence speed decreases
Solution Approach 1:
The patent implements feedback by using the route originator attribute in WITHDRAW messages to provide specific information about which node originated the withdrawn route. Receiving nodes use this feedback information to immediately mark paths as ineligible for best path determination, rather than waiting for full propagation. The route originator attribute serves as feedback that enables nodes to make informed routing decisions locally, improving convergence speed while maintaining routing accuracy through the eligibility marking mechanism.
3Loss of information
If unnecessary UPDATE messages are sent during convergence, then route information is propagated, but network traffic and processing overhead increase
Solution Approach 1:
The patent applies preliminary anti-action by preemptively marking paths as ineligible for best path determination upon receiving a WITHDRAW message, before unnecessary UPDATE messages can be generated. This preliminary marking prevents other nodes from selecting ineligible paths as their best paths, thereby preventing the generation of cascading UPDATE messages. The route originator attribute enables this preliminary action by providing specific identification of the node that should mark paths as ineligible, stopping the propagation of unnecessary routing updates and reducing network processing overhead.
Data Source
AI summary
A method of improving convergence in networks that use path vector protocols. In one embodiment using Border Gateway Protocol (BGP) for inter-domain route and reachability communication, nodes that need to remove routes using EBGP NLRI announcements send BGP WITHDRAW messages containing a new route originator attribute that identifies an originator of a specified withdrawn route. A receiving node removes the specified route from its routing information base (RIB), and matches the originator to other paths in the RIB. Matching paths are marked as ineligible for consideration in a best path computation, thereby preventing the use of routes that are unreachable but not yet withdrawn by an originating node. The approach causes faster BGP convergence, reduces unnecessary route flapping, and alleviates unnecessary route dampening.