Inter-Domain TE-LSP Routing via Dynamic Reachability Retrieval
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Solution Overview
Problem
Current MPLS Traffic Engineering path computation techniques face challenges in computing inter-domain TE-LSPs due to limited network topology information across domain boundaries, leading to the inability to automatically steer traffic onto TE-LSPs within remote domains, which often requires cumbersome manual configuration.
Innovation Solution
A dynamic inter-domain reachability information retrieval technique using a request/response signaling exchange based on RSVP TE signaling messages, where a head-end node requests and receives routing information from target nodes along a TE-LSP, including address prefixes, next-hop addresses, and metrics, through new RSVP objects and TLVs, enabling the creation of a shadow table for route calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional MPLS Traffic Engineering path computation techniques are used, then path computation within a single domain is achieved, but inter-domain TE-LSP computation is not possible due to limited network topology information across domain boundaries
Solution Approach 1:
The patent introduces border routers as intermediary nodes that exchange reachability information between domains. Border routers receive routing information from remote domains through BGP updates and propagate this information to head-end nodes, enabling inter-domain TE-LSP computation without requiring full topology visibility across all domains.
Solution Approach 2:
The patent segments the network into multiple domains with domain boundary routers that manage reachability information exchange. Each domain maintains its own routing information while sharing essential reachability data with border routers, allowing distributed TE-LSP computation across domains without requiring complete global topology knowledge.
2Ease of operation
If manual configuration is used to steer traffic onto TE-LSPs in remote domains, then routing control is achieved, but configuration complexity and error potential increase
Solution Approach 1:
The patent enables head-end nodes to automatically compute and steer traffic onto TE-LSPs in remote domains by autonomously processing reachability information received from border routers. The system performs self-service routing decisions using dynamically acquired routing information, eliminating the need for manual configuration of remote domain paths.
Solution Approach 2:
The patent implements a feedback mechanism where border routers continuously update reachability information to head-end nodes through BGP routing updates. This feedback loop enables automatic adaptation to network changes and allows head-end nodes to dynamically compute optimal paths without manual reconfiguration when network conditions change.
3Adaptability or versatility
If complete routing information is exchanged between all domains, then full routing flexibility is achieved, but routing scalability deteriorates due to increased information exchange overhead
Solution Approach 1:
The patent extracts only the essential reachability information needed for TE-LSP computation from complete routing tables. Border routers share summarized reachability data with head-end nodes, enabling routing flexibility for traffic engineering while avoiding the overhead of exchanging complete routing information between all domains.
Solution Approach 2:
The patent applies partial action by exchanging only the necessary reachability information (destination prefixes, next hops, metrics) rather than complete routing tables. This selective information exchange provides sufficient routing flexibility for TE-LSP computation while maintaining scalability by avoiding excessive information transfer between domains.
Data Source
AI summary
A technique dynamically retrieves reachability information from a target node, including a tail-end or any intermediate node, along a traffic engineering (TE) label switched path (LSP) that spans multiple domains in a computer network. The interdomain information retrieval technique is illustratively based on a request/response signaling exchange whereby at least a portion of the reachability, i.e., routing, information maintained by the target node is propagated to a head-end node of the TE-LSP. The routing information may comprise a list of address prefixes reachable by the target node, but may optionally include next-hop and metric attributes associated with those prefixes. The head-end node uses the retrieved routing information to calculate routes reachable from the target node for insertion into its routing table.