Ethernet Mesh Protection via Virtual Ring Segmentation
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Solution Overview
Problem
Current methods for preventing loops in Ethernet mesh networks are complex and do not achieve fast enough failure recovery times, unlike physical layer transport technologies like SONET/SDH, which can recover in 50 mSec or less.
Innovation Solution
Implementing a method that uses ring and sub-ring network primitives to model a mesh network, allowing for the application of ring protection schemes like ITU-T G.8032, which includes channel blocking and Failure Indication Messages to maintain loop-free traffic forwarding and rapid failure recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Spanning Tree Protocol (STP) is used to compute traffic forwarding paths through a mesh network, then loops are prevented, but failure recovery time increases to several seconds due to complete tree recomputation
Solution Approach 1:
The patent segments the mesh network into multiple virtual ring topologies. Each ring is independently managed with its own protection mechanism, allowing localized failure recovery without affecting the entire network. When a failure occurs, only the affected ring segment needs to recompute its forwarding paths, reducing recovery time from seconds to milliseconds.
Solution Approach 2:
The patent pre-computes protection paths and establishes virtual ring structures in advance before failures occur. Each node maintains pre-calculated alternative forwarding paths within its virtual ring, enabling immediate switch to protection paths upon failure detection without requiring complete network-wide recomputation.
2Loss of time
If two or more topologically diverse trees are computed from each node to every other node with working and protection trees, then failure recovery time is reduced, but device complexity increases due to computation of very large number of trees
Solution Approach 1:
Instead of computing multiple diverse trees for the entire mesh network, the patent segments the network into virtual rings where only two trees (working and protection) need to be computed per ring. This segmentation reduces the computational burden from exponential (multiple trees across entire mesh) to linear (two trees per ring segment).
Solution Approach 2:
The patent merges multiple mesh links into virtual ring structures, combining the protection functionality of multiple diverse trees into a single ring-based protection mechanism. This merging simplifies the overall computation while maintaining protection capabilities across the mesh network.
3Loss of time
If conventional Ethernet flooding and MAC learning functionality is used for traffic flow restoration, then traffic is restored quickly after FDB flush, but network topology must be ring-based rather than mesh
Solution Approach 1:
The patent introduces a virtual dimension by overlaying ring topologies on top of the physical mesh network. The virtual rings provide the structured protection mechanism needed for fast recovery, while the underlying physical mesh topology remains flexible and can be configured in various ways. This dimensional separation allows fast protection switching without constraining the physical topology.
Data Source
AI summary
A method of routing traffic through a packet network having a mesh physical topology. At least two types of network primitive are defined, each type of network primitive providing a respective model of traffic forwarding through at least two neighbor nodes of the network. A network model encompassing at least a portion of the network is constructed using a set of two or more interconnected network primitives. The network model has nodes and links corresponding to respective nodes and lines of the network. Respective forwarding information is computed for each node of the network model. For each node of the network model, the respective computed forwarding information is installed in a forwarding database of the corresponding node of the network, such that traffic is forwarded by each node of the network in accordance with the respective computed forwarding information.