Incremental MRT-FRR Deployment via Network Segmentation
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Solution Overview
Problem
Existing IP networks lack effective fast reroute capabilities, particularly in large networks, as they require significant additional infrastructure and cannot provide 100% failure coverage due to the limitations of Loop-Free Alternates (LFA) and other IP Fast ReRoute (IPFRR) techniques.
Innovation Solution
The implementation of Maximally Redundant Tree Fast Re-Route (MRT-FRR) within islands of nodes in a network, which allows for incremental deployment by pre-calculating detour paths using a clean set of unimpacted nodes and extended island candidate nodes, enabling flexible endpoint selection based on configured optimization options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Loop-Free Alternates (LFA) is used for fast reroute, then implementation simplicity is improved, but failure coverage is insufficient
Solution Approach 1:
The patent segments the network into islands of MRT-capable nodes, allowing MRT-FRR to be deployed incrementally without requiring the entire network to support the technology. Each island can independently calculate and maintain detour paths using MRT, providing comprehensive failure coverage within the island while maintaining simplicity in implementation.
Solution Approach 2:
The patent pre-calculates detour paths using Maximally Redundant Trees (MRT) before failures occur. By pre-establishing alternative paths through the clean set of unimpacted nodes and extended island candidate nodes, the system ensures fast reroute capability is ready immediately when failures happen, improving both reliability and implementation efficiency.
2Reliability
If MRT-FRR is deployed throughout the entire network, then failure coverage is maximized, but deployment complexity and cost increase significantly
Solution Approach 1:
The patent divides the network into discrete islands of MRT-capable nodes, allowing selective deployment only where needed. This segmentation enables failure coverage to be maximized within each island while avoiding the complexity of implementing MRT-FRR across the entire network, particularly in large networks where full deployment would be prohibitively complex and costly.
Solution Approach 2:
Instead of requiring full network deployment, the patent applies MRT-FRR partially to specific islands containing failures that need protection. This partial action approach provides sufficient failure coverage for critical paths while avoiding the excessive complexity and cost of universal deployment throughout the entire network.
3Reliability
If all network elements support MRT-FRR, then maximum failure coverage is achieved, but infrastructure cost increases significantly
Solution Approach 1:
The patent segments the network into islands of MRT-capable nodes, allowing infrastructure investment to be concentrated only where failure coverage is most needed. This segmentation reduces the total quantity of network elements requiring MRT-FRR support compared to full network deployment, thereby reducing overall infrastructure cost while maintaining maximum failure coverage within the island.
Solution Approach 2:
The patent applies MRT-FRR with local quality by enabling it only in specific islands where failures occur or are anticipated, rather than uniformly across the entire network. This localized approach ensures maximum failure coverage in critical areas while avoiding unnecessary infrastructure expenditure in regions where MRT-FRR is not required.
4Reliability
If network topology is redesigned to be LFA friendly, then failure coverage is improved, but additional links and devices are required
Solution Approach 1:
The patent pre-calculates detour paths using MRT before failures occur, eliminating the need for pre-redesigning network topology to be LFA-friendly. By establishing alternative paths in advance through the clean set and extended island candidate nodes, the system achieves comprehensive failure coverage without requiring additional links or devices to be installed beforehand.
Solution Approach 2:
The patent creates virtual copies of path information through MRT data structures, allowing nodes to compute alternative paths without physically modifying the network topology. This copying approach enables failure coverage improvement through software-based path calculation rather than hardware topology redesign, avoiding additional infrastructure requirements.
Data Source
AI summary
A method supports incremental deployment of maximally redundant trees-fast reroute (MRT-FRR) by supporting MRT-FRR within an island of nodes in the network. A destination node and next hop failure selected to calculate detour paths. The clean set of nodes is calculated. The clean set of nodes is expanded with extended island candidate nodes that are reachable by a border node within the island via shortest path first (SPF) to the destination node that does not pass through the failed next hop. The extended island candidate nodes that are reachable by the border node within the island via SPF are part of an extended island. An MRT is calculated for each extended island candidate node. A candidate node is selected from the clean set of nodes according to a configured optimization option to serve as the endpoint of detour path to a destination node.