Inter-domain TE-LSP IGP Extensions for Dynamic Routing
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Solution Overview
Problem
Current MPLS Traffic Engineering techniques face challenges in automatically steering traffic onto inter-domain TE-LSPs due to limited network topology information, leading to reliance on static or policy-based routing, which is cumbersome and prone to errors.
Innovation Solution
The technique propagates reachability information for a tail-end node of a TE-LSP across multiple domains using Interior Gateway Protocols (IGPs) like OSPF or IS-IS, employing novel sub-TLVs to convey remote reachability information from a target node to a head-end node, enabling dynamic route calculation and avoiding manual configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If static or policy-based routing is used for inter-domain TE-LSPs, then routing can be established without dynamic topology information, but manual configuration is required which is cumbersome and prone to errors
Solution Approach 1:
The system enables automatic route calculation by having routers propagate their own reachability information through IGP advertisements. Routers automatically compute and insert routes into their routing tables based on received advertisements, eliminating the need for manual static routing configuration while reducing configuration complexity.
2Extent of automation
If dynamic route calculation is implemented using IGP extensions, then automatic routing is achieved, but additional protocol extensions and information propagation mechanisms are required
Solution Approach 1:
The patent extends existing IGP protocols (OSPF, IS-IS) to serve multiple functions: traditional routing plus reachability information propagation for TE-LSPs. By making IGP advertisements carry both conventional routing information and extended reachability data, the system achieves automatic route calculation without requiring entirely new protocols, thus reducing overall system complexity.
Solution Approach 2:
The patent introduces target nodes as intermediaries that generate and propagate reachability information advertisements. These target nodes act as mediators between the TE-LSP tail-end nodes and head-end routers, enabling automatic route calculation by flooding reachability information throughout the network without requiring direct communication between all routers.
3Loss of information
If reachability information is propagated across domains using IGP, then remote reachability information becomes available for dynamic routing, but information must be transmitted across multiple domains which increases propagation complexity
Solution Approach 1:
The patent merges reachability information propagation with existing IGP advertisement mechanisms. By combining TE-LSP reachability data with standard IGP routing advertisements, the system propagates remote reachability information across domain boundaries using already-established inter-domain routing infrastructure, thus reducing propagation complexity while ensuring information availability.
Data Source
AI summary
A technique propagates reachability information for a tail-end node of a traffic engineering (TE) label switched path (LSP) to a head-end node of the TE-LSP in a computer network. The TE-LSP preferably spans multiple domains of the network such that the tail-end node resides in a domain that is different (remote) from the domain of the head-end node. The inter-domain information propagation technique employs an Interior Gateway Protocol (IGP) to transmit the remote reachability information from a target node residing in the same domain as the tail-end node to the head-end node. The head-end node uses the remote information to calculate routes, i.e., address prefixes and associated attributes, reachable from the tail-end node for insertion into its routing table.