Merged mtrie Structure for Multi-Topology Routing

Solution Overview

Problem

Current forwarding database structures face significant memory and hardware overhead in supporting multi-topology routing, particularly in incremental forwarding modes, due to the need for multiple prefix trees and successive lookups, which can slow down routers and increase costs.

Innovation Solution

A method is introduced to construct a forwarding database using a merged mtrie structure that allows a single lookup by providing pointers between topologies, enabling an initial class-based de-multiplexing operation and subsequent longest prefix match lookup, thereby reducing the need for multiple sequential lookups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple prefix trees are used to support multi-topology routing, then routing functionality is improved, but memory and hardware overhead increase

Engineering Contradiction:

Improvemulti-topology routing supportVSAvoidmemory overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges multiple topology-specific prefix trees into a single unified prefix tree structure. Instead of maintaining separate prefix trees for each topology, the invention combines them into one shared structure that all topologies can utilize, thereby reducing memory overhead while preserving multi-topology routing capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The unified prefix tree structure serves multiple topologies simultaneously, making it a universal data structure that performs the function of multiple individual prefix trees. This multi-functional approach allows a single structure to support routing decisions across different topologies without requiring separate dedicated structures for each.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple prefix trees are used for multi-topology routing, then routing functionality is improved, but hardware overhead increases

Engineering Contradiction:

Improvemulti-topology routing supportVSAvoidhardware overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple topology-specific prefix trees into a single unified prefix tree structure. Instead of maintaining separate prefix trees for each topology, the invention combines them into one shared structure that all topologies can utilize, thereby reducing memory overhead while preserving multi-topology routing capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The unified prefix tree structure serves multiple topologies simultaneously, making it a universal data structure that performs the function of multiple individual prefix trees. This multi-functional approach allows a single structure to support routing decisions across different topologies without requiring separate dedicated structures for each.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If successive lookups are performed in multiple prefix trees, then routing accuracy is improved, but router performance deteriorates

Engineering Contradiction:

Improverouting accuracyVSAvoidrouter performance

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent merges multiple topology-specific prefix trees into a single unified prefix tree structure. Instead of maintaining separate prefix trees for each topology, the invention combines them into one shared structure that all topologies can utilize, thereby reducing memory overhead while preserving multi-topology routing capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent pre-organizes routing information from multiple topologies into a single unified prefix tree structure before routing decisions are needed. This preliminary organization allows the router to perform a single lookup operation rather than multiple sequential lookups, improving routing performance while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7969995B2Method and apparatus for constructing a forwarding database for a data communications network

Publication Date: 2011.06.28 CISCO TECHNOLOGY INC

AI summary

A method of constructing a forwarding database for a data communications network comprising a plurality of network components and supporting at least first and second topologies having one or more common network components is described. The forwarding database includes at least first and second database structures having records including forwarding information for data destined for related network components in the respective topologies. Each database structure has a plurality of elements including a pointer to one of a succeeding element or a record including said forwarding information. The method comprises the step, performed at a constructing network component of identifying a network component common to the first and second topologies for which a record exists in the second database structure. The method further comprises the step of including a pointer from the related element in the first database structure to a corresponding element or record in the second database structure.