PCE BIER-TE Path Computation via PCEP Extensions
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Solution Overview
Problem
Existing techniques for computing and setting up Bit Index Explicit Replication Traffic/Tree Engineering (BIER-TE) paths are inefficient and lead to difficulties in path computation and setup within BIER-TE domains, primarily due to partial solutions that rely on BIER explicit route objects, causing inefficiencies.
Innovation Solution
The implementation of extensions to the Path Computation Element Protocol (PCEP) using type length value (TLV) structures and sub-TLV structures allows a Path Computation Element (PCE) to create BIER-TE paths by receiving and processing PCEP messages to determine ingress nodes and compute optimal BIER-TE paths within BIER-TE domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing techniques for computing BIER-TE paths are used, then path computation can be performed, but the computation efficiency is low and setup difficulties arise due to reliance on partial BIER explicit route objects
Solution Approach 1:
The patent introduces new PCEP message types (PCReq, PCRep, PCRpt) with extended parameters specifically for BIER-TE path computation. These messages include fields for BIER-TE domain identification, root node specification, and bitstring parameters, transforming the computation process from generic routing to specialized BIER-TE optimization, thereby improving computation efficiency while maintaining clear protocol structures
Solution Approach 2:
The patent introduces a dedicated Path Computation Element (PCE) as an intermediary component that centralizes the BIER-TE path computation function. This PCE receives computation requests from network elements, performs the complex path calculations using the new PCEP protocols, and returns optimized paths, thereby separating the computation complexity from the network elements and reducing their setup complexity
2Loss of information
If BIER explicit route objects are used for path computation, then some path information can be obtained, but the solution is partial and leads to inefficiencies in path setup
Solution Approach 1:
The patent segments the path computation process into distinct phases handled by specific PCEP messages: PCReq for requesting path computation with complete BIER-TE parameters, PCRep for returning the computed path information, and PCRpt for reporting path setup status. This segmentation ensures complete path information is exchanged efficiently without relying on partial BIER explicit route objects, resolving both information completeness and setup efficiency requirements
Data Source
AI summary
A method is implemented by a first PCE controlling a BIER-TE domain. The method comprises receiving a first path computation element protocol (PCEP) message from a path computation component (PCC) running on each egress network node, where the first PCEP message contains a multicast group and a multicast source; obtaining an ingress node based on the multicast group and the multicast source; computing a BIER-TE path from the ingress node to each egress network node; sending a second PCEP message to the ingress node for the ingress node to create the BIER-TE path to transport packets for the multicast group and the multicast source; and receiving a third PCEP message from a PCC running on the ingress node, where the third PCEP message includes a status of the BIER-TE path.