Subject: [Webtransport] Comment(s) on draft-vvv-webtransport-overview

From: Bernard Aboba <[email-masked]>
Date: Tue, 19 Nov 2019 19:11:19 +0800

Reading the WebTransport Protocol Framework, a few questions came to mind.

Section 3

"Since this data can be replayed by attackers, it MUST NOT be used unless
the client has explicitly requested 0-RTT"

[BA] While draft-pauly-quic-interface has the concept of "Send Idempotent"
which makes data eligible for sending under 0-RTT keys, the WebTransport
API (https://wicg.github.io/web-transport/) has no equivalent.  Is support
for 0-RTT a desired feature?

Section 4

"All transport protocols MUST provide datagrams, unidirectional and
bidirectional streams i order to make the transport protocols
easily interchangeable."

[BA] Are there a set of requirements for "fallback transport" as well?

5.

"buffers for them should be small and prioritized over stream data"

[BA] Are you envisaging absolute priority here (e.g. datagrams can starve
out stream data)?

"In general, the transport should not apply aggregation algorithms (e.g.,
Nagle's algorithm [RFC0896]) to datagrams."

 [BA] draft-pauly-quic-datagram Section 5 says "This frame SHOULD be sent
as as soon as possible, and MAY be coalesced with other frames".  Are there
situations in which coalescing/aggregation is envisaged to be desirable so
that API support is needed?  Also was this intended to be SHOULD NOT?

NITs

1. Introduction

Where should comments be sent?  Presumably to [email-masked] and/or
a github repo?

1.1

s/in practice, its user/in practice, its use/

2.

"a mechanism such as ICE [RFC8445] can be used"

[BA] You might want to refer to ICE consent [RFC7675] instead of ICE.  But
since this is the WebTransport Protocol Framework (e.g. client/server) I'm
not sure why ICE need be mentioned.

7.

"the client must not be able to distinguish"

[BA] should this be MUST NOT?

---

From: Victor Vasiliev <[email-masked]>
Date: Tue, 26 Nov 2019 09:16:34 -0500

Hello Bernard,

Thank you for the comments!

On Tue, Nov 19, 2019 at 7:11 PM Bernard Aboba <[email-masked]>
wrote:

> API (https://wicg.github.io/web-transport/) has no equivalent.  Is
> support for 0-RTT a desired feature?
>

Indeed.  We could add it, but I am not sure it's worth it at this point in
time.

> [BA] Are there a set of requirements for "fallback transport" as well?

Those requirements do apply to fallback transport, however the datagrams
would obviously end up being reliable.

5.
> [BA] Are you envisaging absolute priority here (e.g. datagrams can starve

That was roughly my initial thought.  I suspect that we would want a better
scheme; #33 and #62 on the API repo have more detailed discussion of this.

> that API support is needed?  Also was this intended to be SHOULD NOT?

I can imagine coalescing to be a part of the API.  I have some ideas on how
to do this; filed https://github.com/WICG/web-transport/issues/79.

> NITs
>
> 1. Introduction
>
> Where should comments be sent?  Presumably to [email-masked]
> and/or a github repo?
>

Added a link into the preamble for all documents.

> s/in practice, its user/in practice, its use/

Fixed.

> not sure why ICE need be mentioned.
This was a clarifying example.  Changed wording.

> [BA] should this be MUST NOT?

There's already a MUST NOT above, this is just clarifying text.

  -- Victor.