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Last Call Review of draft-ietf-mops-streaming-opcons-10

Request Review of draft-ietf-mops-streaming-opcons
Requested revision No specific revision (document currently at 10)
Type Last Call Review
Team Internet Area Directorate (intdir)
Deadline 2022-05-06
Requested 2022-04-22
Requested by Éric Vyncke
Authors Jake Holland , Ali C. Begen , Spencer Dawkins
Draft last updated 2022-04-26
Completed reviews Intdir Last Call review of -10 by Tommy Pauly
Opsdir Last Call review of -10 by Linda Dunbar
Tsvart Last Call review of -10 by Michael Scharf
Artart Last Call review of -10 by Valery Smyslov
This is the first MOPS WG document and it has interesting contents for transport, Internet, ART, and operations. So, I will appreciate a last call review by your directorate.


Assignment Reviewer Tommy Pauly
State Completed
Review review-ietf-mops-streaming-opcons-10-intdir-lc-pauly-2022-04-26
Posted at
Reviewed revision 10
Result Ready with Nits
Completed 2022-04-26
Thanks to the authors for a well-written document. It is structured clearly,
and explains the space nicely.

I have a few nit comments that could improve the document further (written as
an IntArea review, but with some general nits as well):

- Section 3.2.1 says, "There are many reasons why path characteristics might
change suddenly...". It may be good to mention MTU changes as part of the path
changes, since changes in the maximum packet sizes supported by paths can be
disruptive to traffic (requiring new PMTUD, etc).

- There are places that could benefit from more citations. For example, Section
3.5 says, "Historical data shows that users consume more videos and at a higher
bit rate than they did in the past..." but does not explain what data this is.

- In Section 6.1 (on UDP), DNS queries are described as follows: "DNS, which is
often used to send a single-packet request to look up the IP address for a DNS
name, and return a single-packet response containing the IP address." I'm not
sure how valuable this example is for explaining UDP, but if it is kept, please
say that *multiple* packets are sent to get *multiple* addresses. With IPv6 and
IPv4, clients query for both A and AAAA records, and handle multiple addresses,
especially for IPv6.

- As a bit of transport commentary, I don't find the setup of Section 6
compelling. While UDP is a transport in a technical sense, for the purpose of
media, it is almost always a layer upon which the protocol doing the congestion
control work runs. To that end, QUIC is just another more standardized case of
this, just like SCTP over UDP. Rather than talking about "UDP's behavior" vs
"TCP's behavior", I suggest talking about how applications over UDP for media
behave vs applications over TCP for media behave.