Router Advertisement Caching for Network Failover

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Solution Overview

Problem

In IPv6 networks, client devices may experience prolonged downtime when a router fails, as they need to receive a new router advertisement (RA) to switch to a different router, during which time they cannot communicate on the network.

Innovation Solution

Implementing a controller that caches router advertisements (RAs) and uses this caching mechanism to quickly determine router failures and facilitate failover, allowing for immediate network access and load balancing across multiple routers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If client devices wait for new router advertisements to switch routers after a failure, then they can maintain routing table accuracy, but network downtime increases

Engineering Contradiction:
Improverouting table accuracyVSAvoidnetwork downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The controller pre-generates and caches router advertisement messages for multiple potential routers before failures occur. When a router fails, the controller can immediately send cached RA messages to client devices without waiting for new RAs from remaining routers, thus reducing downtime while maintaining routing accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller acts as an intermediary between routers and client devices. It intercepts router advertisement messages, caches them, and selectively forwards them to client devices based on router status. This intermediary function allows the system to decouple the timing of RA generation from RA delivery, enabling faster failover responses

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If multiple routers are used for load balancing, then network performance improves, but router failure detection and failover complexity increases

Engineering Contradiction:
Improvenetwork performanceVSAvoidfailover mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The controller automatically monitors router status by attempting to send data to each router and detecting failures when no response is received. It self-manages the caching of RAs for multiple routers and automatically selects appropriate cached RAs to send to client devices, eliminating the need for complex manual failover configurations

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The controller creates and maintains copies (caches) of router advertisement messages for multiple routers. These cached copies can be rapidly deployed to client devices without requiring actual communication with the routers themselves, simplifying the failover mechanism while supporting multiple routers for load balancing

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3316559B1Router advertisement caching
Publication Date: 2019.06.19 HEWLETT PACKARD ENTERPRISE DEV LP
  • EP3316559B1 patent drawingFigure 1
  • EP3316559B1 patent drawingFigure 2
  • EP3316559B1 patent drawingFigure 3

AI summary

Example implementations relate to router advertisement caching. A controller may comprise a processing resource and a memory resource storing machine-readable instructions to cause the processing resource to perform a number of actions. For instance, the controller may cache a router advertisement (RA) from a router, select, in response to a client device associating with the controller, the cached RA from the router, and unicast the RA from the router to the client device.