Intermediate System Failure Recovery via Pre-computed Backup Paths

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Solution Overview

Problem

Current router recovery mechanisms consume significant computational resources and network bandwidth, leading to network instability and 'network flap' phenomena, which disrupt data traffic and are not transparent to neighboring systems.

Innovation Solution

An intermediate system suppresses detection of its reinitialization and queries neighboring systems for routing information to reconstruct its routing tables, reducing computational resource and bandwidth usage, and maintaining transparent operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If routers broadcast route update messages to detect and respond to failures, then network routing paths are recomputed to circumvent failed routers, but significant amounts of network bandwidth are commandeered for control traffic transmission

Engineering Contradiction:

Improverouting path availabilityVSAvoidnetwork bandwidth consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by pre-computing and storing backup routing paths before failures occur. When a router fails, the system can immediately switch to pre-computed backup paths without triggering broadcast storms, thus maintaining routing availability while avoiding excessive bandwidth consumption during failure recovery

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies preliminary anti-action by implementing mechanisms that prevent the propagation of failure detection messages throughout the network. By using localized failure containment and pre-established backup paths, the system counteracts the tendency toward widespread routing updates, thereby reducing control traffic bandwidth consumption while maintaining reliable routing

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If routers detect failure and begin route re-computation simultaneously, then routing paths are updated to circumvent failed routers, but processor time on the router's control plane is consumed reducing computational resources available for other management functions

Engineering Contradiction:

Improverouting path availabilityVSAvoidcomputational resource availability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-computing backup routing paths and storing them in advance. When failures occur, routers can switch to pre-computed paths without triggering simultaneous re-computation across the network, thereby maintaining routing availability while preserving computational resources for other management functions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies skipping by enabling routers to bypass the computationally intensive route re-computation process entirely when failures occur. By using pre-computed backup paths, the system rushes through the failure recovery process without consuming significant processor time, thus maintaining routing availability while preserving computational productivity

Inventive Principle:

Principle #21Skipping (Rushing through)

3Reliability

If routers announce new paths and subsequently receive messages invalidating those paths, then network flap occurs causing destinations to be unreachable for significant periods, but this phenomenon consumes computational resources and network bandwidth

Engineering Contradiction:

Improverouting path stabilityVSAvoidcomputational resource and bandwidth consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by pre-computing and validating backup routing paths before failures occur. This preliminary preparation ensures that when failures happen, routers can switch to validated backup paths without announcing and subsequently withdrawing paths, thereby eliminating network flap while maintaining routing stability and reducing resource consumption

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies blessing in disguise by converting the potentially harmful network flap phenomenon into a benefit. By using pre-computed backup paths with validated reachability, the system transforms what would be a destabilizing path announcement-withdrawal cycle into a stable, resource-efficient failover mechanism that improves overall routing reliability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS7760652B2Methods and apparatus for improved failure recovery of intermediate systems

Publication Date: 2010.07.20 EXTREME NETWORKS INC

AI summary

Methods and apparatus relating to intermediate system recovery to reduce the required amount of computational resources and network bandwidth to recover an intermediate system after an operational failure. The intermediate system conceals its operational failure from neighboring systems and queries them for information sufficient to simplify the reconstruction of its routing information. The intermediate system can interoperate with existing neighbor intermediate systems that have not implemented the invention allowing the benefit and convenience of incrementally deploying embodiments of the present invention. Embodiments of the present invention include but are not limited to intermediate systems that use IS-IS and BGP protocols.