BGP-Free Core Rerouting via Context Labels
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Solution Overview
Problem
Edge routers in BGP-free core networks face challenges in rapidly rerouting data traffic after a failure occurs without BGP reconvergence, as they do not employ the BGP protocol and need to handle millions of IP address prefixes.
Innovation Solution
A method where a first provider edge router detects the unavailability of a second provider edge router, allocates a mirror forwarding table, and sends repair information to a BGP-free core router to add a context label, enabling the core router to reroute data packets to a backup provider edge router, allowing instantaneous rerouting without BGP reconvergence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BGP protocol is used by core routers for traffic rerouting, then routing reliability is improved, but device complexity increases due to handling millions of IP address prefixes
Solution Approach 1:
The patent extracts BGP protocol operations from core routers by introducing a dedicated backup router that handles BGP reconvergence. Core routers remain BGP-free and simple, while the backup router absorbs the complexity of BGP processing and coordinate failover, thus reducing device complexity in the core network while maintaining routing reliability.
Solution Approach 2:
The backup router acts as an intermediary between edge routers and core routers. It receives BGP updates from edge routers, processes routing information, and coordinates failover without requiring core routers to understand BGP protocol, thereby simplifying core router device complexity while ensuring routing reliability through coordinated backup mechanisms.
2Reliability
If BGP reconvergence is performed after edge router failure, then routing correctness is ensured, but loss of time increases due to reconvergence delay
Solution Approach 1:
The backup router pre-loads BGP routing tables and maintains synchronized routing information with edge routers before failures occur. When a failure is detected, the backup router can immediately take over and redirect traffic without waiting for BGP reconvergence, thus reducing loss of time while ensuring routing correctness through pre-positioned routing information.
Solution Approach 2:
The backup router creates a copy of the BGP routing tables and forwarding information from edge routers. This copied routing data enables the backup router to immediately assume responsibility for traffic forwarding after failure detection, eliminating the delay associated with waiting for BGP reconvergence while maintaining routing correctness through accurate routing table replication.
3Reliability
If backup router mechanism is implemented, then reliability is improved through failover capability, but device complexity increases due to additional routing tables and labels
Solution Approach 1:
The backup router performs multiple functions: it acts as a BGP client receiving updates from edge routers, maintains routing tables, processes failover coordination, and redirects traffic. By consolidating these multiple functions into a single backup router, the system achieves high reliability through failover capability while managing device complexity through functional consolidation rather than distributing complexity across multiple components.
4Ease of operation
If context labels are added to data packets, then ease of operation is improved through simplified rerouting, but loss of information increases due to additional packet processing requirements
Solution Approach 1:
Context labels are added only at specific points in the packet path (at the backup router) rather than throughout the entire network. The labels provide localized identification information that simplifies rerouting decisions at the backup router without requiring extensive packet processing or modification at intermediate core routers, thus improving ease of operation while minimizing loss of information through targeted labeling.
Data Source
AI summary
In one embodiment, a method comprises detecting, by a first provider edge router, a second provider edge router providing reachability to a prescribed destination address prefix via a protected next hop address; allocating, by the first provider edge router, a mirror forwarding table associated with the second provider edge router and identifying a destination used by the second provider edge router for reaching the prescribed destination address prefix; and the first provider edge router sending repair information to a Border Gateway Protocol (BGP)-free core network router in the core network, the repair information enabling the BGP-free core network router to add a context label and reroute a received data packet to the first provider edge router if the second provider edge router is unavailable, the context label enabling the first provider edge router to identify the destination in the rerouted data packet for delivery to the destination address prefix.