Technical Summary
The Designated Forwarder (DF) in Ethernet Virtual Private Networks
(EVPN) is defined as the PE responsible for sending Broadcast,
Unknown unicast and Broadcast traffic (BUM) to a multi-homed device/
network in the case of an all-active multi-homing Ethernet Segment
(ES), or BUM and unicast in the case of single-active multi-homing.
The Designated Forwarder is selected out of a candidate list of PEs
that advertise the same Ethernet Segment Identifier (ESI) to the EVPN
network, according to the Default Designated Forwarder Election
algorithm. While the Default Algorithm provides an efficient and
automated way of selecting the Designated Forwarder across different
Ethernet Tags in the Ethernet Segment, there are some use cases where
a more 'deterministic' and user-controlled method is required. At
the same time, Service Providers require an easy way to force an on-
demand Designated Forwarder switchover in order to carry out some
maintenance tasks on the existing Designated Forwarder or control
whether a new active PE can preempt the existing Designated Forwarder
PE.
This document proposes a Designated Forwarder Election algorithm that
meets the requirements of determinism and operation control.
Working Group Summary
Was there anything in the WG process that is worth noting?
For example, was there controversy about particular points
or were there decisions where the consensus was
particularly rough?
Consensus seemed to be broad and no problems were found with the process.
Document Quality
Are there existing implementations of the protocol? Have a
significant number of vendors indicated their plan to
implement the specification? Are there any reviewers that
merit special mention as having done a thorough review,
e.g., one that resulted in important changes or a
conclusion that the document had no substantive issues? If
there was a MIB Doctor, Media Type, or other Expert Review,
what was its course (briefly)? In the case of a Media Type
Review, on what date was the request posted?
There was broad consensus for this document. One change was made at the last minute but there is no indication this affected consensus.
There is indication that there are active implementations of this draft.
Personnel
The Document Shepherd for this document is Stephane Litkowski. The
Responsible Area Director is Andrew Alston.