BIER D-BFR Election Automates Bitmask Assignment

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Solution Overview

Problem

In Bit Index Explicit Replication (BIER) networks, the automated assignment of bitmask (BM) length and position, as well as tree type, becomes non-trivial with a large number of receivers or independent BIER trees, requiring either centralized or distributed approaches that increase protocol complexity and scalability concerns.

Innovation Solution

A method where network devices participate in an election process to determine a designated BFR, which then determines and advertises the elected BM length and tree type, and assigns unique BM positions to bit forwarding egress routers, ensuring all receivers can support the distribution tree and BM length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a centralized approach is used to assign BM positions and determine BM length, then the assignment process is simplified, but scalability is reduced and protocol complexity increases

Engineering Contradiction:

Improveprotocol complexityVSAvoidscalability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a distributed election mechanism where BFRs autonomously participate in elections to determine the D-BFR and autonomously determine BM length and tree type based on advertised capabilities. This self-service approach eliminates the need for centralized assignment, reducing protocol complexity while maintaining scalability as networks can dynamically adapt to changing topologies and receiver requirements without centralized coordination

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically adapts BM length and tree type based on real-time network conditions and receiver capabilities through the election process. The D-BFR determines these parameters based on advertised maximum BM lengths and supported tree types from participating BFRs, allowing the network to flexibly respond to changing requirements rather than relying on static centralized assignment

Inventive Principle:

Principle #15Dynamics

2Quantity of substance

If the number of receivers increases, then network coverage is improved, but automated assignment of BM positions becomes non-trivial and requires complex centralized or distributed approaches

Engineering Contradiction:

Improvenumber of receiversVSAvoidassignment complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

Each BFR autonomously advertises its maximum BM length capability and supported tree types, and the D-BFR automatically determines the appropriate BM length and tree type based on these advertisements. This self-service mechanism handles large numbers of receivers without requiring complex centralized assignment logic, as the system leverages the inherent capabilities of participating routers

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system changes the BM length parameter dynamically based on the capabilities of participating BFRs. The D-BFR determines the elected BM length by evaluating advertised maximum BM lengths from all participating BFRs, allowing the network to scale to accommodate large numbers of receivers by adjusting the BM length parameter rather than requiring complex assignment algorithms

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If distributed approach is used for BM assignment, then scalability is improved, but protocol complexity increases due to election process

Engineering Contradiction:

ImprovescalabilityVSAvoidprotocol complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

BFRs perform preliminary actions by advertising their maximum BM length capabilities and supported tree types before the actual BM assignment occurs. This preliminary exchange of capability information simplifies the subsequent determination process, allowing the D-BFR to make informed decisions about BM length and tree type without requiring complex real-time negotiations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback through the advertisement mechanism where BFRs provide information about their capabilities (maximum BM length, supported tree types) to the D-BFR. This feedback loop enables the D-BFR to determine appropriate BM length and tree type parameters that are compatible with all participating BFRs, achieving scalability through structured information exchange rather than complex protocols

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10439928B2Automated determination of tree attributes and assignment of receiver identifiers by distributed election in multicast architectures relying on packets identifying intended receivers

Publication Date: 2019.10.08 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Exemplary methods include a first network device participating in an election process to determine a designated bit forwarding router (D-BFR). The methods include in response to determining the first network device is elected to be the D-BFR, performing D-BFR operations comprising assigning one or more bitmask positions (BMPs) to one or more bit forwarding egress routers (BFERs) and advertising the assigned one or more BMPs. The method may further include one or more of determining an elected bitmask (BM) length based on maximum local BM lengths advertised by other BFRs and determining an elected tree type based on supported tree types advertised by other BFRs.