Inter-Chassis Port Role Switching for E-Tree Convergence
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Solution Overview
Problem
EVPN technology is not optimized for E-Tree configurations with dual-homed root nodes, leading to significant control message exchanges and longer convergence times during failures in dual-homed E-Tree topologies with Active/Standby or Active/Active redundancy.
Innovation Solution
Introduction of an inter-chassis port between two PE nodes that dynamically changes its role from root to leaf or vice versa based on the status of the root port in the data plane, eliminating the need for control plane involvement and utilizing existing Layer 2 data plane mechanisms for faster convergence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EVPN control plane is used for E-Tree with dual-homed root node, then routing control and redundancy are achieved, but convergence time increases due to significant control message exchanges
Solution Approach 1:
The patent extracts the role assignment logic from the EVPN control plane and implements it directly in the data plane. The inter-chassis port dynamically changes its role (root/leaf) based on data plane detection of root port status, eliminating the need for control plane message exchanges during role transitions and achieving millisecond-level convergence
Solution Approach 2:
The patent introduces an inter-chassis port as an intermediary between the two PEs in the cluster. This port acts as a mediator that dynamically assumes root or leaf role based on the status of root ports, enabling fast failover without involving the EVPN control plane while maintaining proper E-Tree routing behavior
2Reliability
If EVPN control plane is used for E-Tree with dual-homed root node, then proper routing control is achieved, but device complexity increases due to multiple route type exchanges
Solution Approach 1:
The patent extracts the essential function of role assignment from the complex EVPN control plane machinery and implements it through simple data plane mechanisms. The inter-chassis port monitors root port status and automatically adjusts its role without requiring EVPN route exchanges, significantly reducing control plane complexity while maintaining routing control
Solution Approach 2:
The system implements self-service by allowing the inter-chassis port to autonomously determine its role based on local detection of root port status. The data plane mechanisms automatically handle role transitions without external control plane intervention, eliminating the need for complex EVPN routing protocols while maintaining proper E-Tree behavior
Data Source
AI summary
A Provider Edge (PE) node includes a plurality of ports including an inter-chassis port to a second PE node, a port connected to a root node, and one or more ports connected to leaf nodes, wherein the plurality of ports are in an Ethernet Tree (E-Tree), and wherein the root node is dual-homed to the PE node and the second PE node; switching circuitry configured to switch traffic between the plurality of ports; and circuitry configured to designate the inter-chassis port as one of a leaf node and a root node in the E-Tree instance, and manage a designation of the inter-chassis port based on a status of the port connected to the root node. The designation is changed in a data plane instead of in a control plane.