Abstract

An alternative to the default Designated Forwarder (DF) selection algorithm in Ethernet VPNs (EVPNs) is defined. The DF is the Provider Edge (PE) router responsible for sending Broadcast, Unknown Unicast, and Multicast (BUM) traffic to a multihomed Customer Edge (CE) device on a given VLAN on a particular Ethernet Segment (ES). In addition, the ability to influence the DF election result for a VLAN based on the state of the associated Attachment Circuit (AC) is specified. This document clarifies the DF election Finite State Machine in EVPN services. Therefore, it updates the EVPN specification (RFC 7432).