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Re: HTTP 1.1 --> 2.0 Upgrade

From: Willy Tarreau <w@1wt.eu>
Date: Mon, 20 Aug 2012 12:36:11 +0200
To: Roberto Peon <grmocg@gmail.com>
Cc: Phillip Hallam-Baker <hallam@gmail.com>, Julian Reschke <julian.reschke@gmx.de>, Yoav Nir <ynir@checkpoint.com>, "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>
Message-ID: <20120820103611.GF11752@1wt.eu>
Hi Roberto,

On Mon, Aug 20, 2012 at 03:23:32AM -0700, Roberto Peon wrote:
> For port 80:
> What WebSockets has done on port 80 with upgrade seems basically fine. The
> part that is unfortunate is that it requires about as much time as doing
> the TLS handshake (an additional round-trip).

As we suggested in our network-friendly draft, its possible to send multiple
GET requests at once during the handshake by passing the list of URIs in a
dedicated header. It basically allows us not to waste the round trip.

> Having the data in DNS could short-circuit this, but shouldn't be a
> dependency.

The DNS requires a round trip anyway and it currently where time is wasted
in mobile environments.

> I still do like the idea of "alternate-protocol", which is extremely poorly
> described in the SPDY spec. The idea of alternate-protocol was that the
> server adds the header detailing the protocol, port, and negotiation
> mechanism. The client, if it understands it, may attempt in parallel one of
> the alternate protocols. This allows a switch of protocol and port, and a
> possible upgrade (no guarantee, given that HTTP offers plaintext and is
> 100% completely insecure) to using TLS for HTTP schemes, assuming both
> client and server agree to do it. This is separate from an upgrade,
> however, in that the new protocol is spoken over a new connection which is
> used only after it is established (with the previous connection remaining
> in use until supplanted), and thus the transfer of resources is not blocked
> by application-layer handshakes at any point in time.

Maybe this could still be done over the established connection using an
Upgrade ? However, I'd hope we avoid announcing IP and ports in exchanges,
as it will cause the NAT mess we managed to avoid for years with HTTP and
which made other protocols disappear.

Regards,
Willy
Received on Monday, 20 August 2012 10:36:46 GMT

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