SPB Edge Router Multicast Routing Across PIM Domains
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Solution Overview
Problem
Current technologies face challenges in supporting Protocol Independent Multicast—Sparse Mode (PIM-SM) over Shortest Path Bridging (SPB) networks, as conventional SPB networks lack knowledge of rendezvous points and rooted multicast trees, hindering efficient multicast traffic routing between multiple independent PIM-SM domains.
Innovation Solution
Configuring SPB edge routers as Rendezvous Points (RPs) to receive and process PIM Register Messages, forming data structures with multicast sender information, and allocating identifiers to construct multicast state within the SPB network, enabling efficient routing of multicast traffic across multiple domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional SPB networks are used without modification, then network simplicity is maintained, but multicast routing capability is lost
Solution Approach 1:
The patent enables SPB edge routers to perform dual functions: traditional SPB shortest path bridging and PIM-SM rendezvous point operations. By configuring edge routers as RPs, the network gains multicast routing capability while utilizing existing router infrastructure, avoiding the need for dedicated multicast hardware and reducing overall system complexity.
Solution Approach 2:
The patent introduces an intermediary mechanism where SPB edge routers act as bridges between PIM-SM domains and the SPB core network. These edge routers translate PIM register messages into ISIS-IPMC format for propagation through the SPB network, enabling multicast routing without modifying the core SPB protocol.
2Adaptability or versatility
If multiple independent PIM-SM domains are connected through SPB, then network scalability is improved, but protocol compatibility problems arise
Solution Approach 1:
The patent uses ISIS-IPMC protocol as an intermediary language between different PIM-SM domains. Edge routers translate incoming PIM register messages into ISIS-IPMC format for propagation across the SPB network, and translate outgoing ISIS-IPMC messages back to PIM format for local domain delivery, ensuring protocol compatibility across domains.
Solution Approach 2:
The patent segments the multicast routing function into domain-specific PIM operations at edge routers and core SPB operations using ISIS-IPMC. This segmentation allows each domain to maintain its independent PIM-SM operations while enabling inter-domain multicast through the standardized ISIS-IPMC interface in the SPB core.
3Adaptability or versatility
If PIM register messages are propagated through SPB network, then multicast routing is enabled, but message format incompatibility occurs
Solution Approach 1:
The patent introduces ISIS-IPMC message format as an intermediary representation for propagating multicast sender information through the SPB network. Edge routers translate PIM register messages into ISIS-IPMC format containing ISID, sender address, and group address, enabling standardized propagation while maintaining compatibility with both PIM and SPB protocols.
Data Source
AI summary
A method and apparatus for routing multicast data across multiple multicast routing domains connected by a shortest path bridging (SPB) network is presented. A Shortest Path Bridging (SPB) edge router of an SPB network connected to a PIM network is configured as a Rendezvous Point (RP). A message is received at the RP, and in response, the RP forms a first data structure including multicast sender information. The RP floods the SPB network with a second message containing the first data structure, allocates an Identifier to the multicast stream, and sends a second data structure with sender information. An edge router with multicast receive interest responds with the second data structure with multicast receive interest information. As a result, a receiver in a second network has knowledge of devices in a first network such that multicast traffic is able to be routed between different networks connected to the SPB network.