Multicast Information Aggregation for Scalable BIER Forwarding
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Solution Overview
Problem
Existing multicast technologies face challenges in large-scale deployments due to the need for complex multicast forwarding state information maintenance and require specific capabilities in BIER edge devices, lacking universality and scalability.
Innovation Solution
A multicast information forwarding method and apparatus that creates a Bit Forwarding Egress Router (BFER) list and selects a Bit Forwarding Ingress Router (BFIR) node based on aggregation information, enabling BIER header encapsulation without extending multicast or PCE protocols, using a multicast information aggregation node to distribute this information across BIER sub-domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If standard extension methods are used for BIER multicast forwarding, then multicast service can be forwarded, but BIER edge devices require particular capabilities and the method lacks universality
Solution Approach 1:
The patent introduces a PCE (Path Computation Element) as an intermediary to compute and distribute BFER lists to BIER edge devices. The PCE centralizes the complexity of determining which egress routers should receive multicast traffic, allowing edge devices to simply forward packets based on received BFER lists without needing complex judgment capabilities themselves. This resolves the contradiction by moving complexity from edge devices to the intermediary PCE.
Solution Approach 2:
The patent extracts the complex logic of determining BFER membership from BIER edge devices and places it in the PCE. Edge devices only need to perform simple packet forwarding based on pre-computed BFER lists, while the PCE handles the complex tasks of receiving multicast group information, determining appropriate BFERs, and distributing the BFER lists. This separation extracts complexity away from edge devices, improving universality.
2Productivity
If PIM protocol is used for multicast forwarding, then multicast traffic can be forwarded, but intermediate nodes must maintain complex multicast flow forwarding state information
Solution Approach 1:
The patent extracts the multicast state information maintenance function from intermediate BIER routers and consolidates it in the PCE. BIER routers only maintain simple forwarding tables for BFR (BIER Forwarding Router) identification, while the PCE maintains the complex multicast group-to-BFER mappings and distributes BFER lists to edge devices. This extraction eliminates the need for intermediate nodes to maintain complex multicast state, improving forwarding efficiency.
Solution Approach 2:
The patent implements stateless BIER forwarding where routers automatically forward packets based on pre-computed BFER lists without needing to maintain or query multicast state information. The BIER header contains all necessary forwarding information (BFER list, BFR-id), allowing routers to self-service the forwarding decision without complex state maintenance, thus improving productivity.
Data Source
AI summary
A multicast information forwarding method includes receiving first aggregation information and second aggregation information, where the first aggregation information includes multicast source information and Bit Index Explicit Replication (BIER) information, and the second aggregation information includes multicast user information and BIER information of a network on the multicast user side; creating a Bit Forwarding Egress Router (BFER) list of a BFER of a BIER sub-domain and selecting a Bit Forwarding Ingress Router (BFIR) node of the BIER sub-domain; and distributing the BFER list and the multicast source information to one of the following: the BFIR node, a multicast source server supporting BIER encapsulation, or a multicast-source-server-directly-connected device supporting BIER encapsulation; and forward the multicast source information to the multicast user.