Border Node Routing Information Propagation in IPe Networks

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Solution Overview

Problem

Routing problems occur when an Internet Protocol everywhere (IPe) network is extended over multiple Open Shortest Path First (OSPF) flooding domains, as existing link-state protocols struggle to maintain efficient propagation of routing information across different areas, leading to reachability issues for IPe devices moving between domains while retaining their network address.

Innovation Solution

Intelligent Area Border Routers (ABRs) observe routing information messages and independently determine whether to propagate them, using subnet checks and message reformatting, allowing IPe devices to remain reachable across OSPF areas without reconfiguring existing network devices or restructuring boundaries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If link-state protocols segment the network into multiple flooding domains to enable scaling, then network scalability is improved, but routing information propagation becomes unreliable across domain boundaries

Engineering Contradiction:

Improvenetwork scalabilityVSAvoidrouting information propagation

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

Area Border Routers (ABRs) serve as intermediary devices between different OSPF flooding domains. These ABRs receive routing information messages from one domain, process and reformat them, and propagate them to other domains. This intermediary mechanism enables reliable cross-domain routing information propagation while preserving the scalability benefits of network segmentation into multiple flooding domains.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If routing information is propagated extensively across all flooding domains, then IPe device reachability is improved, but processing overhead increases

Engineering Contradiction:

ImproveIPe device reachabilityVSAvoidprocessing overhead

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies local quality by making ABRs perform selective propagation of routing information based on local conditions. Each ABR independently evaluates whether to propagate received routing messages to adjacent domains using subnet checks and propagation decisions. This localized, intelligent propagation ensures IPe device reachability is maintained across domains while minimizing unnecessary processing overhead by avoiding blanket propagation of all routing information.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If existing link-state protocols are used without modification, then device compatibility is maintained, but IPe mobility across domains fails

Engineering Contradiction:

ImproveIPe mobilityVSAvoidprotocol complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Area Border Routers act as mediators that translate and adapt routing information for IPe mobility across OSPF domains. The ABRs receive standard link-state routing messages, perform subnet checks to determine if the message contains routing information for IPe devices, and selectively propagate these messages to adjacent domains. This intermediary approach enables IPe mobility functionality without requiring modifications to existing link-state protocols or end devices, thereby maintaining device compatibility while adding adaptability for IPe mobility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7860027B2Extending an IP everywhere network over a plurality of flooding domains

Publication Date: 2010.12.28 CISCO TECHNOLOGY INC

AI summary

In one embodiment, a border node receives a message that includes routing information indicating connection of a network device to a domain. The border node then updates a routing database with the routing information, and also uses a network address for the network device to determine whether to propagate the routing information.