EVPN VPWS FXC Local Switching Connectivity via Distributed LAG Coordination
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Solution Overview
Problem
Existing Ethernet Virtual Private Network (EVPN) Virtual Private Wire Service (VPWS) Flexible Cross-Connect (FXC) local switching connectivity fails to maintain reachability between client devices during inter-chassis Provider Edge network link failures, leading to service disruptions.
Innovation Solution
Implementing a distributed Link Aggregation Group (LAG) configuration across network elements, where the distribution state is coordinated based on detection of out-of-distribution members, ensuring that if one member of an Ethernet Segment Instance is out-of-distribution, associated members in a common VPWS service instance with a normalized Virtual Local Area Network (VLAN) Identifier change state accordingly, facilitating recovery through withdrawal of Ethernet Auto Discovery (AD) routes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If EVPN VPWS FXC local switching is implemented for multiplexing multiple Attachment Circuits, then service consolidation and routing efficiency are improved, but reachability between client devices is not maintained during inter-chassis link failures
Solution Approach 1:
The system segments the distributed LAG into multiple independent members belonging to different Ethernet Segment Instances (ESIs), where each member can be independently controlled. When an inter-chassis link fails, only the affected LAG member is withdrawn, while other members remain active to maintain client device reachability through alternative paths.
Solution Approach 2:
The system dynamically changes the distribution state parameter of individual LAG members based on link status. When a link failure is detected, the affected member's state is changed from in-distribution to out-of-distribution, triggering appropriate routing adjustments while maintaining other members' normal operation.
2Adaptability or versatility
If distributed LAG members are independently managed, then flexibility in handling partial failures is improved, but coordination complexity between members increases
Solution Approach 1:
The system implements feedback mechanisms where each LAG member monitors its own distribution state and reports status changes to the control plane. When a member transitions to out-of-distribution state, this feedback triggers automatic routing adjustments and ensures consistent state management across all members without requiring complex centralized coordination.
Solution Approach 2:
The system pre-configures multiple LAG members across different ESIs with defined distribution state relationships. When a failure occurs, the predetermined state coordination rules are automatically applied, eliminating the need for complex real-time decision-making and reducing coordination complexity.
Data Source
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AI summary
A network element (18, 200) configured to implement an Ethernet Virtual Private Network (EVPN) Virtual Private Wire Service (VPWS) Flexible Cross-Connect (FXC) local switching service includes a plurality of ports (208); and a switching fabric configured to switch traffic between the plurality of ports (208); wherein a set of ports is configured in a distributed Link Aggregation Group (LAG) with two nodes (12, 14), and an inter-chassis link configured with a second network element (20, 200), and wherein, responsive to a failure of the inter-chassis link, a distribution state of members in the distributed LAG is coordinated.