Subject: [Webtransport] Use Cases (was Choosing the transport)

From: Bernard Aboba <[email-masked]>
Date: Wed, 22 Jul 2020 20:26:29 -0700

Victor said:

""Back when the original idea of WebTransport was forming, the hope was to
implement and ship all four of those, since they all fit different use
cases better.   After talking more to the people at IETF, it sounds like
four transports is a bit too much, and we should settle on two (one over
QUIC, and one over TCP)."

[BA]  This is a good question to ask, given some of the sentiments toward
simplicity that were expressed at IETF 107 as well as IETF 106.

However, since the four proposals "all fit different use cases better", it
would seem hard to answer the question without reference to the use cases.

The WEBTRANS WG Charter envisaged use cases as being developed along with
the requirements:

"To assist in the coordination with owners of the WebTransport API, the group
will initially develop an overview document containing use cases and
requirements in order to clarify the goals of the effort."

Since the current Overview Document doesn't include use cases,  at this
point, the best list we have is the one presented at IETF 106 (slide 12):

   -

   Machine learning
   -

   Web games
   -

   Live streaming
   -

   Cloud gaming
   -

   Remote desktop
   -

   Web chat

The division of these use cases between QuicTransport and Http3/Http2
transport is not stated on Slide 12, but on slide 15, the following use
cases were indicated as suitable for QuicTransport:

   - Video games on the Web
   - Real-time media

Can we assume that "Video games" corresponds to the "Cloud Gaming" use
case, but perhaps not the "Web games" use case? Does "realtime media"
correspond to the "machine learning" or "live streaming" use cases, or does
it refer to interactive communications (e.g. conferencing)?

Also on Slide 15, the following were indicated as suited for
Http3Transport:

   - General Web applications
   - Web Chat
   - Push Notifications

Are these the only use cases enabled by Http3Transport, or are there
others?