BIER Multicast Forwarding via Bit String Tunneling
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Solution Overview
Problem
Existing multicast forwarding technologies require multiple P2MP forwarding trees, leading to significant resource overheads and reduced forwarding efficiency, and can result in traffic packet loss due to insufficient bandwidth on forwarding paths.
Innovation Solution
A multicast forwarding method in a BIER multicast network that establishes a template tunnel from a head node device to multiple tail node devices, using bit string manipulation and bitwise operations to efficiently route multicast streams through intermediate nodes, reducing the need for multiple forwarding trees and optimizing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple P2MP forwarding trees are established for each multicast stream, then multicast delivery can be achieved, but resource overheads of node devices become relatively large
Solution Approach 1:
The patent merges multiple P2MP forwarding trees into a single BIER-based forwarding structure. Instead of establishing separate forwarding trees for each multicast stream, the system uses a unified BIER forwarding table that handles multiple streams simultaneously through bit string manipulation, significantly reducing the number of forwarding structures needed and lowering device resource overhead
Solution Approach 2:
The BIER forwarding mechanism serves multiple multicast streams through a universal forwarding structure. The forwarding table uses bit strings to represent multiple destination groups, allowing a single forwarding entry to handle traffic for multiple multicast groups, thereby reducing the overall complexity and resource consumption compared to dedicated forwarding trees for each stream
2Reliability
If multiple P2MP forwarding trees are established for each multicast stream, then specific multicast routing can be achieved, but forwarding efficiency is reduced
Solution Approach 1:
The patent replaces the mechanical process of traversing multiple forwarding tables and determining next hops for each multicast stream with a streamlined BIER forwarding mechanism. The system uses bit string matching and bitwise operations to determine forwarding actions in a single step, eliminating the iterative lookup process and significantly improving forwarding efficiency while maintaining accurate multicast routing
3Reliability
If multiple P2MP forwarding trees are used, then multicast stream routing is possible, but bandwidth on forwarding paths may be insufficient causing packet loss
Solution Approach 1:
The BIER forwarding system dynamically adapts to bandwidth constraints by optimizing the utilization of available network paths. The unified forwarding structure allows for more flexible load distribution across network links, enabling the system to dynamically adjust traffic routing to avoid congested paths and prevent packet loss, thereby improving reliability under bandwidth constraints
Data Source
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AI summary
A multicast forwarding method is disclosed. The method is applied to a BIER multicast network, and includes: establishing, by a head node device, a first tunnel; generating a first entry; obtaining bit string information of a first multicast stream, where the bit string information includes an identifier of a tail node device that the first multicast stream is expected to reach; determining whether first bit string map information includes the identifier, in the bit string information, of the tail node device that the first multicast stream is expected to reach; and forwarding, by the head node device, the first multicast stream to a first intermediate node device through the first tunnel when the head node device determines that the first bit string map information includes the identifier, in the bit string information, of the at least one tail node device that the first multicast stream is expected to reach.