VPLS External Loop Detection and Protection Requirements
Virtual Private LAN Service (VPLS) implementations, as defined in [RFC4761] and [RFC4762], are highly susceptible to layer-2 loops external to the PE customer-facing interface. Such loops impact performance and can have a detrimental affect on all VPLS traffic throughout the entire instance under certain conditions. Current Layer-2 loop detection and protection mechanisms do not function effectively here. This document describes the requirements for a protocol function to offer VPLS service providers a mechanism for detecting such layer-2 loops and facilitating configurable actions without the need for inter-operation with customer network protocols, other VPLS PEs or customer sourced frames.