Early Review of draft-ietf-bfd-stability-18
review-ietf-bfd-stability-18-opsdir-early-mishra-2025-04-08-00

Request Review of draft-ietf-bfd-stability-17
Requested revision 17 (document currently at 18)
Type Early Review
Team Ops Directorate (opsdir)
Deadline 2025-04-04
Requested 2025-03-06
Requested by Reshad Rahman
Authors Ashesh Mishra , Mahesh Jethanandani , Ankur Saxena , Santosh Pallagatti , Mach Chen
I-D last updated 2025-05-15 (Latest revision 2025-04-07)
Completed reviews Yangdoctors Early review of -13 by Ebben Aries (diff)
Secdir Early review of -13 by Christian Huitema (diff)
Yangdoctors IETF Last Call review of -08 by Ebben Aries (diff)
Rtgdir IETF Last Call review of -17 by Ben Niven-Jenkins (diff)
Opsdir Early review of -18 by Gyan Mishra
Assignment Reviewer Gyan Mishra
State Completed
Request Early review on draft-ietf-bfd-stability by Ops Directorate Assigned
Posted at https://mailarchive.ietf.org/arch/msg/ops-dir/hRAMMKLZFD6QVq9hEcLenbvIv8o
Reviewed revision 18
Result Not ready
Completed 2025-04-08
review-ietf-bfd-stability-18-opsdir-early-mishra-2025-04-08-00
Summary:

This document describes extensions to the Bidirectional Forwarding Detection
(BFD) protocol to measure BFD stability. Specifically, it describes a mechanism
for detection of BFD packet loss.

Major issues:
None

Minor issues:
Section 7 describes the stability Yang model.  It references RFC 9314 BGP Yang
model for lacp, lag, sh, mh, mpls but does not mention SR-MPLS or SRv6 which
should be included as data planes stability that should be supported with this
draft.  Section 6.2 talks about out of order packet.  I wonder if with the null
authentication header with the sequence number counter that could be used for
sequencing and ordering of packets over lag or ECMP. As BFD control packets are
not stateful as is with TCP as long as packet is received on far end it does
not matter what path is taken. I agree out of order packets are not lost
packets as long as the BFD packet is received by far end. In case of lag with
lacp bundle with BFD over bundle member, there is a micro BFD session on each
bundle member.  For ECMP it’s a single BFD session across all paths if S-BGD is
used and if running IGP OSPF or ISIS as BFD registered client then a single BFD
session exists between the ingress PE or VM compute node and egress PE or VM
compute node.  In that case their is no OOO BFD control plane.

Nits:
None