Ethernet Ring Protection Switching for L2VPN Redundancy
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Solution Overview
Problem
Existing Layer 2 Virtual Private Network (L2VPN) topologies face complexity in achieving resilient site multi-homing with Ethernet frame looping conditions, and the spanning tree protocol lacks scalability and visibility in service provider networks.
Innovation Solution
Implementing the ITU-T G.8032 Ethernet ring protection switching protocol, which establishes a virtual channel between routing devices for redundancy, using conventional Ethernet path labeling and packet forwarding techniques to prevent loops and ensure sub-50 ms convergence time, while supporting dual-homing and active/standby redundancy modes without requiring configuration on customer equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spanning tree protocol is used to avoid looping conditions, then loop prevention is achieved, but scalability is poor and configuration visibility is lost
Solution Approach 1:
The patent segments the network into a ring topology with designated protection links, dividing the redundancy management into controlled segments rather than using a global spanning tree protocol. This allows localized protection switching without requiring complex global calculations.
Solution Approach 2:
The patent introduces an intermediary mechanism (protection switching protocol) that operates between network devices to coordinate redundancy. This intermediary enables automated protection switching with visible configuration and better scalability compared to spanning tree.
2Loss of time
If Ethernet ring protection switching is implemented, then convergence time is reduced to sub-50 ms, but protocol configuration complexity increases
Solution Approach 1:
The patent establishes protection links and designates backup paths in advance during normal operation. When a failure occurs, pre-configured protection mechanisms activate immediately without requiring real-time calculation, achieving sub-50 ms convergence.
Solution Approach 2:
The patent implements feedback mechanisms where network devices monitor link status and automatically trigger protection switching when failures are detected. This automated feedback loop reduces manual configuration complexity while maintaining fast convergence.
3Reliability
If dual-homing redundancy is provided, then reliability is improved, but Ethernet frame looping conditions occur
Solution Approach 1:
The patent introduces asymmetry into the redundant topology by designating specific links as protection links with directional blocking. This asymmetric configuration allows dual-homing connectivity while preventing symmetric loop paths that cause Ethernet frame looping.
Data Source
AI summary
In one embodiment, a first routing device establishes a virtual channel with a remote routing device in a G.8032 protocol Ethernet network ring. The first routing device and the remote routing device each being linked to a multi-homed routing device having Layer 2 connectivity to a core network. The multi-homed routing device is not configured with the G.8032 protocol. The first routing device identifies a link state from the first routing device to the multi-homed routing device. Layer 2 connectivity of the first routing device to the core network is controlled based upon the identified link state of the first routing device.