[tsvwg] Intdir early review of draft-ietf-tsvwg-nqb-23

[Benson Muite via Datatracker <[e-mail]>]

Reviewer: Benson Muite
Review result: On the Right Track

I am an assigned INT directorate reviewer for <draft-ietf-tsvwg-nqb-24.txt>.
These comments were written primarily for the benefit of the Internet Area
Directors. Document editors and shepherd(s) should treat these comments just
like they would treat comments from any other IETF contributors and resolve
them along with any other Last Call comments that have been received. For more
details on the INT Directorate, see
https://datatracker.ietf.org/group/intdir/about/ .

Based on my review, if I was on the IESG I would ballot this document as NO
OBJECTION.

SUMMARY:
The draft introduces a differentiated services code point for traffic where
latency is important. The primary focus is for applications such as IoT and
video conferencing.  However, the threshold for low bit rate assumes network
connectivity at least as good as provided by 5G mobile networks. Many places in
the world still have 4G and even 3G networks.  Remote locations may only be
served by satellite.  Many IoT applications are not latency sensitive, but are
low bit rate - for example environment recording applications - but it is
probably not good to differentiate these from latency sensitive low bit rate
applications such as sending remote terminal input.  Many video conferencing
applications (for example Meetecho) offer possibilities to turn of video feeds
and just have audio and screen sharing.  6G is also being developed and when
deployed will likely take time to replace 4G and 5G, so some more thought on
thresholds for NQB PHB is needed.

SPECIFIC COMMENTS:

In section 4.1 500Kb/s is quite high on 4G mobile networks, typically what is
used for video conferencing and can saturate end point link bandwidth.  Would
expect this to also be high for satellite links. For IoT applications and voice
probably 50Kb/s is sufficient.

Informative reference [SA-5G] is an ETSI document that has several versions,
possibly the latest version 18.5.0 is the one being referred to.

Should there be references for Cubic and BBR in the introduction, perhaps
RFC8312 for Cubic and https://github.com/google/bbr for BBR,as the draft
https://datatracker.ietf.org/doc/html/draft-cardwell-iccrg-bbr-congestion-control-02
has expired.