BGP Session Migration Between Routers

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Solution Overview

Problem

Current network routing protocols face challenges in migrating Border Gateway Protocol (BGP) sessions between routers without causing service disruptions, leading to downtimes of several minutes, which violates service-level agreements and affects customer satisfaction.

Innovation Solution

The method involves migrating the TCP connection, exchanging routing state, moving routing protocol configuration, and migrating the underlying IP link between routers using a router grafting processor, which performs a coordinated sequence of operations to transfer the BGP session seamlessly, ensuring transparency and minimal disruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If BGP session migration is performed using existing routers and routing protocols, then network equipment can be upgraded and new services deployed, but service disruptions occur resulting in downtime of several minutes

Engineering Contradiction:

Improvenetwork upgrade capabilityVSAvoidservice continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a BGP session migration mechanism that acts as an intermediary process between the old and new router configurations. The migration controller coordinates the transfer of BGP sessions from the first router to the second router, using TCP connection state transfer and route advertisement coordination to bridge the transition period and prevent service disruption.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary actions by establishing the BGP session on the second router before fully decommissioning the first router. The migration process pre-configures the new router with necessary routing information and TCP connection states, ensuring that the session is already prepared to take over without interruption when the switch occurs.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If BGP session migration is performed using existing protocols, then router changes can be made, but downtime of several minutes occurs violating service-level agreements

Engineering Contradiction:

Improverouter deployment flexibilityVSAvoidsession downtime

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent replaces the traditional mechanical BGP session establishment process with a software-based state transfer mechanism. Instead of physically reconfiguring routers and waiting for BGP handshakes (which takes minutes), the system uses TCP connection state export/import and coordinated route advertisements to instantly transfer session state, substituting the slow mechanical process with a fast software operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes key parameters of the BGP session migration process by transferring TCP connection states and route advertisement timings rather than performing traditional BGP session establishment. This parameter-based approach allows the session to be migrated by copying state parameters (TCP sequence numbers, route tables) rather than re-negotiating the entire session, dramatically reducing migration time.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If traditional BGP session migration is used, then network changes can be implemented, but service disruptions affect customer satisfaction

Engineering Contradiction:

Improvenetwork modification capabilityVSAvoidservice disruption impact

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements beforehand cushioning by preparing the second router with all necessary BGP session state information before the actual migration. The migration controller pre-transfers TCP connection states, route tables, and session parameters to the second router, creating a cushion of preparedness that absorbs the transition impact and prevents service disruption during the switch from the first to the second router.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS8806032B2Methods and apparatus to migrate border gateway protocol sessions between routers

Publication Date: 2014.08.12 AT&T INTELLECTUAL PROPERTY I L P

AI summary

Methods and apparatus to migrate border gateway protocol sessions between routers are disclosed. An example method to migrate a border gateway protocol session from a first router to a second router disclosed herein comprises exporting a connection state to migrate a transport control protocol connection supporting the border gateway protocol session with a session endpoint from the first router to the second router, and after the transport control protocol connection has been migrated to the second router, announcing, from the first router to the second router, routes contained in an exported routing information base associated with the session endpoint, the second router to process the routes to migrate handling of the border gateway protocol session with the session endpoint to the second router.