Route Target Constraint for Seamless MPLS Route Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In seamless MPLS networks, access nodes face limitations in storing labeled BGP routes, particularly when using segment routing techniques, as they cannot employ LDP Downstream-on-Demand label advertisements to request label binding information from downstream routers, leading to inefficiencies in route filtering and scalability.
Innovation Solution
Access nodes utilize a route target extended community or constraint to request label binding information from downstream ABRs, generating BGP messages with address-specific route targets to filter routes effectively across the network, enabling efficient route propagation and reducing the need for extensive route storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access nodes store all labeled BGP routes to ensure complete route availability, then route reachability is improved, but memory capacity and storage burden increase significantly
Solution Approach 1:
The patent applies preliminary action by having access nodes send route target constraints to ABRs in advance, before actual route lookup is needed. The ABR pre-filters routes based on these constraints and returns only the relevant subset, eliminating the need for access nodes to store all routes while ensuring complete route availability when needed.
2Quantity of substance
If access nodes filter routes locally to reduce storage requirements, then memory usage is reduced, but filtering precision and route selection accuracy deteriorate
Solution Approach 1:
The patent introduces the ABR as an intermediary that performs the actual route filtering. The access node sends route target constraints to the ABR, which then filters its complete route table and returns only the precise matching routes. This intermediary approach allows local nodes to use minimal memory while maintaining high filtering precision through the ABR's comprehensive route knowledge.
3Productivity
If LDP Downstream-on-Demand is used to request label bindings, then route request efficiency is improved, but device complexity increases due to protocol requirements
Solution Approach 1:
The patent changes the parameter space by using BGP route target constraints instead of LDP Downstream-on-Demand mechanisms. This substitution maintains route request efficiency by allowing on-demand route retrieval while operating within the simpler BGP protocol framework that access nodes already support, avoiding the need for additional LDP protocol complexity.
Data Source
AI summary
Techniques are described for using route target constraint to filter routes advertised to a node in a seamless Multiprotocol Label Switching (MPLS) network. For example, a first router of a first network may generate a first border gateway protocol (BGP) message to advertise routing information for a first node of the first network, the first BGP message indicating a transport class and specifying an address-specific route target, the transport class comprising one or more tunnels to the first node that share common characteristics. In response to receiving a second BGP message originated by second node of a second network, the second BGP message comprising the address-specific route target, the first router sends the first BGP message to a second router of the second network for sending to the second node to cause the second node to import the routing information.