BIER-PIM Boundary Source Discovery for Multicast Routing
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Solution Overview
Problem
In mixed protocol computer networks, particularly those incorporating Bitwise Index Explicit Replication (BIER) and Protocol Independent Multicast (PIM), there is a lack of efficient mechanisms for determining the upstream BIER router to send PIM or IGMP messages, leading to potential traffic duplication and increased state maintenance overhead.
Innovation Solution
Storing a metric and proxy address of a boundary router on the border between BIER and PIM domains, and using these to determine the best path for multicast join signaling, thereby optimizing routing and reducing traffic duplication and state information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PIM or IGMP messages are sent in mixed protocol networks without effective source discovery, then multicast routing can be established, but traffic duplication occurs and state maintenance overhead increases
Solution Approach 1:
The patent performs source discovery before establishing multicast routing. Boundary routers proactively discover active sources by receiving PFM messages from PIM domains, storing source information and metrics in advance. This preliminary action enables downstream BIER routers to efficiently determine the best upstream BIER router when multicast join signaling is needed, avoiding traffic duplication and reducing state maintenance overhead.
2Adaptability or versatility
If traditional PIM multicast services run through BIER core, then multicast routing is facilitated, but determination of upstream BIER router becomes ineffective
Solution Approach 1:
The patent introduces boundary routers as intermediaries between PIM domains and BIER domains. These boundary routers perform source discovery by receiving PFM messages from PIM domains and translating/mapping source information into BIER domain routing information. This intermediary mechanism enables effective upstream BIER router determination while maintaining protocol compatibility between PIM and BIER domains.
3Device complexity
If source discovery is not implemented in mixed protocol networks, then system complexity is reduced, but confidence in message routing efficiency decreases
Solution Approach 1:
The patent implements a self-service source discovery mechanism where boundary routers automatically receive PFM messages from PIM domains, extract source information, and populate local data structures with source-to-border-router mappings. This self-service approach enables routers to autonomously determine the best upstream BIER router based on stored metric information, providing reliable and confident routing decisions without requiring complex centralized control or manual configuration.
Data Source
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AI summary
A disclosed method is performed at a first boundary node bordering a BIER domain. The method includes receiving a message associated with a source and group for multicast from outside the BIER domain. The method further includes generating an encapsulated message based on the message, a metric, and a first proxy address of the first boundary node. The method also includes forwarding the encapsulated message through the BIER domain to at least one second boundary node bordering the BIER domain and connectable to the first boundary node. The first boundary node additionally triggers the at least one second boundary node to decapsulate the encapsulated message for forwarding out of the first domain and store a record including the source, the group, the metric representing the cost of the first boundary node to the source, and the first proxy address on the at least one second boundary node.