Inter-Domain P2MP Path Computation via Forward Search
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Solution Overview
Problem
Existing routing methods in Multiprotocol Label Switching (MPLS) networks, particularly for Point-to-Multipoint (P2MP) Traffic Engineering (TE) Label Switched Paths (LSPs) across multiple domains, face challenges in determining the shortest path without requiring a pre-defined sequence of domains and may not guarantee the shortest path across multiple domains.
Innovation Solution
The implementation of a Forward Search Path Computation (FSPC) procedure using multiple Path Computation Elements (PCEs, which computes the shortest path by cooperating to determine the best path from a source node to multiple destination nodes across multiple domains without relying on a pre-defined sequence of domains, utilizing extensions to the Path Computation Element Communication Protocol (PCEP) for supporting the forward search procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pre-defined sequence of domains (core tree) is used to compute P2MP LSP paths, then the routing computation can be simplified and domains can be managed independently, but the path computed may not be the shortest path across multiple domains
Solution Approach 1:
The patent segments the P2MP LSP computation into multiple P2P LSP computations, each handled by a different PCE responsible for a specific domain. Each PCE computes the shortest path segment within its domain, and these segments are combined to form the complete P2MP path. This segmentation allows independent domain management while still achieving global optimality through coordinated computation.
Solution Approach 2:
The patent introduces a new dimension to path computation by extending PCEP protocols to support inter-domain P2MP computations. Instead of computing paths within a single domain hierarchy, the system operates across multiple domain dimensions, allowing PCEs to exchange path information and coordinates across domain boundaries to find the globally optimal path.
2Manufacturing precision
If multiple PCEs are used to compute paths across multiple domains, then the shortest path can be guaranteed, but the coordination and communication overhead between PCEs increases
Solution Approach 1:
The patent applies preliminary action by having PCEs pre-compute and store shortest path information within their respective domains before inter-domain computation. When a P2MP path request arrives, PCEs can quickly exchange pre-computed path segments and coordinates rather than performing full path computations across all domains, significantly reducing coordination overhead while maintaining optimality.
Solution Approach 2:
The patent introduces an intermediary role where boundary PCEs act as mediators between domains. These boundary PCEs receive path requests, coordinate with internal PCEs to obtain optimal path segments, and then relay this information to adjacent domains. This intermediary approach simplifies the coordination complexity by creating a structured communication hierarchy among PCEs.
3Adaptability or versatility
If traditional RSVP-TE is used for P2MP LSP establishment, then domain independence can be maintained, but the path computation cannot guarantee shortest path across domain boundaries
Solution Approach 1:
The patent makes PCEs universal entities that can perform both intra-domain and inter-domain path computations. Instead of having separate mechanisms for domain-independent routing and optimal path computation, the PCE architecture provides multi-functionality by handling both scenarios through protocol extensions, maintaining domain independence while achieving global path optimality.
Data Source
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AI summary
An apparatus associated with a first domain, the apparatus comprising a processor configured to compute a portion of a Point-to-Multipoint (P2MP) path, wherein the P2MP path spans a plurality of domains including the first domain, wherein the apparatus does not require knowledge of a core tree of domains to compute the portion of the P2MP path.