RFC Errata
RFC 8584, "Framework for Ethernet VPN Designated Forwarder Election Extensibility", April 2019
Source of RFC: bess (rtg)See Also: RFC 8584 w/ inline errata
Errata ID: 7811
Status: Verified
Type: Technical
Publication Format(s) : TEXT
Reported By: Luc André Burdet
Date Reported: 2024-02-15
Verifier Name: Gunter Van de Velde
Date Verified: 2025-02-10
Section .2 says:
Where: o DF(V) is defined to be the address Si (index i) for which Weight(V, Es, Si) is the highest; 0 <= i < N-1. o BDF(V) is defined as that PE with address Sk for which the computed Weight is the next highest after the Weight of the DF. j is the running index from 0 to N-1; i and k are selected values.
It should say:
Where: o DF(V) is defined to be the address Si (index i) for which Weight(V, Es, Si) is the highest; 0 <= i <= N-1. o BDF(V) is defined as that PE with address Sk for which the computed Weight is the next highest after the Weight of the DF. j is the running index from 0 to N-1; i and k are selected values.
Notes:
An observation was made while reviewing EVPN Port-Active draft pointing to a possible algorithm errata in RFC8584 ;
Basically, when evaluating the DF for HRW,
> * DF(Es) is defined to be the address Si (index i) for which
> Weight(Es, Si) is the highest; 0 <= i < N-1.
Here,
if N=1, no remotes: 0 <= i < 0 -- ERROR
if N=2, 1 peer: 0 <= i < 1 -> possible values are only 0 meaning index 1 (the peer)’s weight is not considered.
Logically, this should be 0 <= i <= N-1 or 0 <= i < N