BFD Protocol Extension for Unnumbered MPLS Interfaces

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Solution Overview

Problem

The Bidirectional Forwarding Detection (BFD) protocol is unable to function within Multi-Protocol Label Switching (MPLS) networks that include unnumbered interfaces or links, as it lacks a mechanism for identifying and managing these interfaces, which are essential for rapid network failure detection and alternate path restoration.

Innovation Solution

The introduction of a newly defined interface identifier (IF-ID) sub-object within BFD protocol messages enables BFD support for unnumbered IP interfaces, allowing for the establishment and management of BFD sessions across unnumbered interfaces by using a unique value to identify each interface, facilitating rapid network failure detection and corrective actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If BFD protocol is used in MPLS networks with unnumbered interfaces, then rapid network failure detection is enabled, but the protocol cannot identify or manage interfaces without IP addresses

Engineering Contradiction:

Improvenetwork failure detection capabilityVSAvoidinterface identification capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an Interface Identifier (IF-ID) sub-object as an intermediary element within BFD control packets. This IF-ID acts as a mediator that enables interface identification in unnumbered interfaces by carrying a unique identifier (such as a data link layer address or locally significant identifier) in the BFD protocol messages, allowing BFD sessions to be established and tracked without relying on IP addresses.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a unique interface identifier is added to BFD protocol messages, then interface identification is enabled, but the protocol complexity increases

Engineering Contradiction:

Improveunnumbered interface supportVSAvoidBFD protocol structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The IF-ID sub-object is nested within the existing BFD control packet structure as an optional parameter. This nesting approach allows the interface identification functionality to be integrated into the existing BFD protocol framework without requiring a complete protocol redesign. The IF-ID is embedded as a sub-element that can be included or excluded based on network requirements, maintaining backward compatibility while adding new functionality.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS10044610B2System, method and apparatus providing bi-directional forwarding detection support to unnumbered IP interfaces

Publication Date: 2018.08.07 ALCATEL LUCENT SA

AI summary

A system, method and apparatus providing BFD support to unnumbered IP Interfaces in MPLS networks using a newly defined interface identifier (IF-ID) sub-object included within one or more BFD protocol messages to extend the use of BFD protocol to unnumbered IP interfaces.