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Re: HTTbis spec size, was: Rechartering HTTPbis

From: Ted Hardie <ted.ietf@gmail.com>
Date: Mon, 6 Feb 2012 13:07:41 -0800
Message-ID: <CA+9kkMBL=fm-BQu3=7+ewhRJR0HA6T3=pNsaEOge+DxAXQ6U2g@mail.gmail.com>
To: Henrik Nordström <henrik@henriknordstrom.net>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
2012/2/6 Henrik Nordström <henrik@henriknordstrom.net>:
> mån 2012-02-06 klockan 11:03 -0800 skrev Ted Hardie:

> And DTLS is not by definition unreliable. It may be used alike over
> unreliable transports such as UDP or over reliable message transports
> such as SCTP. The reliability of the delivery in DTLS is a property of
> it's underlying transport, not the DTLS protocol as such.
>

"Datagram transport does not require or provide reliable or in-order
   delivery of data.  The DTLS protocol preserves this property for
   payload data.  "

The major point of DTLS is that it works without a reliable transport; its
advantages over TLS are there.  At least as I understand it, it also does not
guarantee this property when run over any transport.   It might, for example,
deliver data out of order even when the underlying transport will re-transmit
to get in-order delivery; it depends on the implementation to determine when
the data is passed up.

> HTTP is a request/response message exchange protocol. At the high level
> message level it's pretty ignorant about the transport.
>

I suspect it gets to be ignorant about the transport in part because it gets
to assume certain things about the transport.  If you change those things,
I think the applications that are built on top of HTTP may want new tools from
HTTP (or they will each have to build those same tools for themselves).  This
is particularly the case for applications where non-idempotent methods are
used.

regards,

Ted
Received on Monday, 6 February 2012 21:11:54 GMT

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