BIER Multicast Forwarding via Label-Based Intermediary Nodes

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Solution Overview

Problem

The deployment of BIER technology in multicast networks is hindered by high costs and complexity due to the need for node upgrades to identify and process bit strings in BIER headers.

Innovation Solution

An intermediate node in a P2MP-based BIER multicast tree supports P2MP forwarding by reading only the BIER label, allowing it to forward BIER packets without processing other data in the header, thereby reducing the need for hardware upgrades and simplifying deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If nodes are upgraded to support BIER technology for identifying and processing bit strings in BIER headers, then multicast forwarding capability is improved, but deployment cost and device complexity increase

Engineering Contradiction:
Improvemulticast forwarding capabilityVSAvoiddeployment complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism where the BIER header is processed only at the ingress router (BFIR), and intermediate routers simply forward packets based on the bit string without full BIER processing capability. This mediator approach allows standard routers to participate in BIER networks without upgrading their forwarding planes, thus reducing deployment complexity while maintaining multicast forwarding capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the BIER processing function into two parts: (1) BIER header processing and bit string manipulation at the ingress router, and (2) simple packet forwarding at intermediate routers. This segmentation allows intermediate routers to avoid complex BIER processing while still participating in the multicast distribution, reducing their device complexity and deployment burden.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If nodes are upgraded to support BIER technology for processing bit strings, then packet forwarding accuracy is improved, but deployment cost increases

Engineering Contradiction:
Improvepacket forwarding accuracyVSAvoiddeployment ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The ingress router acts as an intermediary that performs the complex BIER processing (bit string manipulation, next-hop determination) before packets enter the core network. Intermediate routers then simply forward packets based on this pre-processed information, maintaining forwarding accuracy while avoiding the need for expensive upgrades across the entire network.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by having the ingress router perform all complex BIER processing operations before packets are forwarded into the network. The bit string is computed and the forwarding path is determined in advance, so intermediate routers only need to perform simple label-based forwarding, thus maintaining accuracy while reducing deployment difficulty.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If intermediate nodes process only BIER label without other header data, then device complexity is reduced, but processing completeness may be affected

Engineering Contradiction:
Improveintermediate node complexityVSAvoidprocessing completeness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The ingress router serves as a mediator that performs complete BIER header processing and generates forwarding information that intermediate routers can rely on. This ensures that even though intermediate nodes process only the simplified label, the overall system maintains processing completeness and reliability through the upstream mediator's thorough processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The complete BIER processing is performed in advance at the ingress router before packets reach intermediate nodes. All necessary forwarding decisions and bit string manipulations are completed preliminarily, so intermediate nodes can reliably forward packets based on this pre-computed information without needing to perform additional processing, thus maintaining reliability while reducing their complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4120630B1Multicast data packet processing method, and apparatus
Publication Date: 2024.11.27 HUAWEI TECH CO LTD
  • EP4120630B1 patent drawingFigure 1
  • EP4120630B1 patent drawingFigure 2
  • EP4120630B1 patent drawingFigure 3

AI summary

This application provides a multicast data packet processing method, and an apparatus, and relates to the field of communications technologies, to reduce deployment costs and difficulty in deploying a BIER technology in a multicast network. The method and the apparatus are applied to a P2MP-based BIER multicast tree, and an intermediate node of the multicast tree supports to use P2MP to forward a BIER packet. The method includes: receiving a first multicast data packet, where a BIER header of the first multicast data packet includes a first label; obtaining a first forwarding entry based on the first label, where the first forwarding entry includes the first label, a first identifier, and a second identifier, the first identifier is used to identify the multicast tree, and the second identifier is used to instruct to perform P2MP forwarding on the packet; obtaining a second forwarding entry based on the first identifier, where the second forwarding entry includes the first identifier and a second label; and obtaining a second multicast data packet based on the second identifier, the second forwarding entry, and the first multicast data packet, and sending the second multicast data packet, where the second multicast data packet includes the second label.