Edge Router Prefix Grouping for Core Rerouting
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Solution Overview
Problem
Existing data network solutions for rerouting data packets around a failed edge router are inefficient, often requiring waiting for routing protocols to converge or maintaining large and complex routing tables that depend on the number of prefixes in the network.
Innovation Solution
A system and method where edge routers determine and advertise repair next-hops and labels to core routers, allowing for immediate rerouting of data packets without relying on routing protocol convergence or extensive routing table maintenance, by grouping prefixes and assigning repair paths and labels to reduce the burden on core routers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If core routers wait for routing tables to be updated after BGP or IGP re-converges, then routing accuracy is improved, but rerouting speed deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing backup next-hop information in the core routing table before any failure occurs. When an edge router fails, the core router can immediately use the pre-computed backup next-hop without waiting for routing protocol convergence, thus achieving both fast rerouting and accurate routing decisions.
2Loss of information
If core routers learn all prefixes reachable by each edge router, then routing completeness is improved, but routing table complexity increases
Solution Approach 1:
The patent applies the taking out principle by extracting only the essential backup next-hop information from the complete routing data and storing it in the core routing table. Instead of maintaining the full prefix-to-edge-router mapping in the core, only the critical backup next-hop pointers are kept, reducing routing table complexity while preserving routing completeness through the backup information.
3Measurement precision
If routing tables are maintained dependent on the number of prefixes, then routing accuracy is improved, but maintenance difficulty increases
Solution Approach 1:
The patent applies preliminary action by pre-computing the backup next-hop information during normal operation and storing it in the core routing table. This eliminates the need for real-time computation and maintenance of complex prefix-dependent routing tables during failures, significantly reducing maintenance difficulty while preserving routing accuracy through the pre-computed backup information.
Data Source
AI summary
In one embodiment, a method includes determining, by an edge router, a plurality of prefixes reachable by the edge router, each prefix indicating a range of Internet Protocol (IP) addresses. The method further includes grouping, by the edge router, the plurality of prefixes into one or more groups, wherein each group is associated with a particular repair edge router and the prefixes in each particular group are reachable by both the edge router and the particular repair edge router associated with the particular group. The method further includes communicating instructions, from the edge router to a core router, to send data packets associated with the prefixes in each particular group to the particular edge router associated with the particular group if the edge router becomes unreachable.