Ethernet Ring Protection Differentiating PE Direct Failures
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Solution Overview
Problem
The ITU-T G.8032 Ethernet Ring Protection protocol lacks mechanisms to differentiate between provider edge (PE) direct failures and ring partition failures in Ethernet Virtual Private Networks (E-VPN), leading to inefficient handling of failures and inadequate triggering of protection actions.
Innovation Solution
A method is introduced to distinguish between PE direct failures and ring partition failures by processing indications from multiple sources, including R-APS messages and BGP Ethernet Segment routes, allowing for efficient triggering of fast protection actions based on the nature of the failure, such as setting the local number of links field to zero in Designated Forwarder election attributes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If G.8032 protocol is used for Ethernet ring protection, then fast fail-over is provided for link or port failures, but the protocol cannot differentiate between PE direct failures and ring partition failures leading to inefficient failure handling
Solution Approach 1:
The patent segments the failure detection mechanism into two distinct paths: one for PE direct failures (using BGP PIC functionality) and one for ring partition failures (using G.8032 R-APS messages). This segmentation allows each failure type to be handled with the appropriate protection mechanism, resolving the contradiction between fast fail-over and failure type differentiation.
Solution Approach 2:
The patent introduces an intermediary mechanism that correlates BGP routing information with G.8032 R-APS failure messages. This intermediary correlation process enables the system to distinguish between PE direct failures and ring partition failures by analyzing whether BGP routes are affected, thereby providing both fast fail-over and accurate failure type identification.
2Reliability
If E-VPN BGP PIC functionality is used for PE direct failures, then backup PE node can forward traffic, but the mechanism cannot identify reachable MAC addresses behind PEs during ring partition failures
Solution Approach 1:
The patent implements feedback by using BGP routing information to inform the failure handling process. When a G.8032 failure message is received, the system checks BGP routing tables to determine whether the failure is a PE direct failure (where BGP PIC applies) or a ring partition failure (where MAC address information is lost). This feedback loop enables appropriate action based on the failure type.
Solution Approach 2:
The patent performs preliminary action by pre-establishing BGP routing information and MAC address bindings before failures occur. When failures happen, this pre-collected information is immediately available to determine the failure type and guide the protection switching action, enabling fast and accurate response without losing MAC address reachability information.
3Device complexity
If no differentiation mechanism is implemented, then protocol complexity is reduced, but proper protection actions are not triggered efficiently for each failure type
Solution Approach 1:
The patent makes the existing G.8032 and BGP mechanisms multi-functional by enabling them to serve both their original purposes and failure type differentiation. The BGP routing information serves both route advertisement and failure type identification, while G.8032 R-APS messages serve both failure notification and trigger for protection actions. This universality adds differentiation capability without significantly increasing protocol complexity.
Data Source
AI summary
In one embodiment, a method includes obtaining a first indication from a first source included in an Ethernet ring and obtaining a second indication from a second source associated with a provider edge (PE) node The method also includes determining when the first indication and the second indication are indicative of a direct failure of the PE node and determining when the first indication and the second indication are indicative of a ring partition failure associated with the Ethernet ring. The direct failure of the PE node is identified when it is determined that the first indication and the second indication are indicative of the direct failure of the PE node, and the ring partition failure associated with the Ethernet ring is identified when it is determined that the first indication and the second indication are indicative of the ring partition failure associated with the Ethernet ring.