Router Dead Interval Adaptation for Network Failure Detection

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Solution Overview

Problem

Current network protocols, such as OSPF, take too long to recover from network element failures due to high bandwidths and large data loss during unstable situations, as they rely on static timer settings that do not adapt to network conditions, leading to potential false alarms and increased recovery times.

Innovation Solution

A method to dynamically adjust the router dead interval based on the average arrival interval of status-indicating packets, using normal data packets as indicators of router health, and incorporating congestion monitoring to minimize false alarms and reduce recovery time by dynamically varying the router dead interval.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a static router dead interval is used in current network protocols, then the protocol implementation is simple, but the failure detection time is long and false alarms increase during network instability

Engineering Contradiction:
Improvefailure detection timeVSAvoidprotocol complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the router dead interval adaptive rather than static. The system continuously monitors the arrival intervals of status-indicating packets and dynamically adjusts the dead interval based on observed network conditions. This allows the protocol to respond to changing network states, reducing false alarms during instability while maintaining simplicity through automated adaptation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using the actual arrival intervals of status-indicating packets to adjust the router dead interval. The system measures the time between packet arrivals, compares this to the current dead interval setting, and adjusts the dead interval accordingly. This closed-loop feedback mechanism optimizes failure detection accuracy without requiring complex manual configuration.

Inventive Principle:
Principle #23Feedback

2Speed

If the router dead interval is reduced to detect failures faster, then failure detection speed improves, but false alarms increase due to packet loss during unstable situations

Engineering Contradiction:
Improvefailure detection speedVSAvoidfalse alarm rate
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system dynamically adjusts the router dead interval based on observed packet arrival patterns rather than using a fixed value. During stable periods, the dead interval can be shorter for faster detection. During unstable periods with packet loss, the system automatically increases the dead interval to avoid false alarms, thus resolving the contradiction between speed and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of router dead interval from a static value to a dynamic value that adapts to network conditions. By monitoring the actual arrival intervals of status packets and adjusting the dead interval parameter accordingly, the system optimizes both detection speed and reliability based on current network state.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If normal data packets are used as status indicators, then the monitoring overhead is minimized, but the ability to distinguish actual router failures from packet loss is reduced

Engineering Contradiction:
Improvemonitoring efficiencyVSAvoidfailure detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent makes normal data packets serve multiple functions: both their primary data transmission role and a secondary role as status indicators for router health monitoring. By analyzing the arrival intervals of these multi-functional packets, the system achieves monitoring without additional overhead while maintaining accuracy through intelligent analysis of packet timing patterns.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the packets' own arrival timing information to monitor router status without requiring separate monitoring mechanisms. The packets essentially monitor themselves by providing timing data that reveals router health status, eliminating the need for dedicated status packets or additional monitoring infrastructure.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP1980063B1Method of operating a network
Publication Date: 2017.12.20 BRITISH TELECOM PLC
  • EP1980063B1 patent drawingFigure 1~2
  • EP1980063B1 patent drawingFigure 3
  • EP1980063B1 patent drawingFigure 4

AI summary

An Internet Protocol router device (10) for use in a data network comprising a plurality of nodes (10, 20, 30), wherein packets of data are sent from one node in the network to another on a hop by hop basis. The router includes: a data store (14) for storing a routing table indicating the next hop destination for a received packet on the basis of the ultimate destination specified by the received packet; a digital processor (13) operable to maintain the routing table on the basis of communications received from neighbouring router devices (20, 30) within the network; and a timer (15) for timing the length of time elapsed since last receiving a communication, or a communication of a type which is one of a subset of the possible types of communication, from each of one or more of the router device's neighbours; wherein the data store (14) is further operable to store in respect of each of said one or more of the router device's neighbours a router dead interval; and the digital processor (13) is further operable to compare said length of time elapsed with the corresponding router dead interval in respect of each of said one or more of the router device's neighbours and to ascertain that the corresponding router device is no longer operating correctly if the comparison indicates that a length of time equal to or greater than the router dead interval has elapsed without receiving a said communication, or a said communication of a type which is one of a subset of the possible types of communication, from said neighbouring router device; the router device being characterised in that the digital processor (13) is further operable to dynamically vary the or each router dead interval in accordance with one or more properties of the network.