RFC 8966, "The Babel Routing Protocol", January 2021

Errata ID: 7373
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT, PDF, HTML
Reported By: Daniel Gröber
Date Reported: 2023-02-27
Held for Document Update by: Gunter Van de Velde
Date Held: 2024-10-30

Section 3.8.2.2. says:

Additionally, since metric computation does not necessarily coincide
with the delay in propagating updates, a node might receive an
unfeasible update from a currently unselected neighbour that is
preferable to the currently selected route (e.g., because it has a
much smaller metric); in that case, the node SHOULD send a unicast
seqno request to the neighbour that advertised the preferable update.

It should say:

Additionally, since metric computation does not necessarily coincide
with the delay in propagating updates, a node might receive an
unfeasible update from a currently unselected neighbour that would
lead to the received route becoming selected were it feasible. In that
case, the node SHOULD send a unicast seqno request to the neighbour
that advertised the preferable update.

Notes:

As currently written the text does not recommend sending a seqno request when no route is currently selected because ".. that is preferable to the currently selected route" implies a selected route as a precondition.

We recommend reinstating some of the RFC6126 wording instead. (Thanks to Juliusz for pointing this out)

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