RFC 8214, "Virtual Private Wire Service Support in Ethernet VPN", August 2017Source of RFC: bess (rtg)
Errata ID: 7562
Publication Format(s) : TEXT
Reported By: Alexander ("Sasha") Vainshtein
Date Reported: 2023-07-13
Section 3.1 says:
In a multihoming All-Active scenario, there is no Designated Forwarder (DF) election, and all the PEs in the ES that are active and ready to forward traffic to/from the CE will set the P Flag.
It should say:
In a multihoming All-Active scenario, there is no Designated Forwarder (DF) election, and all the PEs in the ES that are active and ready to forward traffic to/from the CE SHOULD set the P Flag.
The original text in the RFC does not express any requirement level ("will" is not a recognized IETF term for expressing requirement levels as defined in RFC 2119). The new test replaces "will" with "SHOULD".
SHOULD and not MUST is proposed to avoid potential issues with implementations that did not set P flag in the L2 Attributes Extended Community in All-Active multi-homing scenarios (since this was not required) and would suddenly become non-compliant if the text were changed to from "will" to MUST.