Re: [AVT] iPhone streaming Internet-Draft posted

[John Lazzaro <john.lazzaro at gmail.com>]

From: Alex Giladi <alex.giladi at gmail.com>
> David,
> But why not re-use RTSP, just embedding it into HTTP?
> Alex.

This was proposed back in 2001 in MMUSIC, and did not
reach consensus, see the snippet below from the MMUSIC
minutes of IETF 51:


10. Tunneling RTSP/RTP/RTCP in HTTP (draft-gentric-avt-rtsp-http-00.txt)
=====================================================

RTSP describes a TCP-based streaming mode.  This includes interleaved
RTP/RTCP packets.  The draft proposal is to extend this to HTTP-only
firewalls.

Source of proposal: Internet Streaming Media Alliance.

The basic proposal is to use HTTP to create a channel in each
direction.  The authors are looking for more ideas and thoughts on how
to proceed.

Melinda Shore <mshore at cisco.com> expressed her disagreement with the
proposal, because it raises serious security concerns.  Its whole
thrust is to violating site security policy.  It would be more
consistent with network policy to use Jonathan's SIP approach.  If the
draft is accepted, HTTP might become characterized as "Horrible
Trashcan Transport Protocol".  Jonathan Rosenberg noted that it is too
late to salvage HTTP's reputation: RFC 3093 "IP Over HTTP" already
describes how to do it.  Mark Handley also expressed his concern with
the security implications.  Port 554 is allocated for RTSP; managers
can open it if they want to.  Apparently some firewall vendors already
block strange uses of HTTP.  Site administrators are aware of this
sort of tunneling and are asking firewall vendors for controls.

Joerg Ott ruled that the responses he had heard make it clear that the
proposal is going nowhere in the MMUSIC WG.

-- 
John Lazzaro
http://www.cs.berkeley.edu/~lazzaro
john [dot] lazzaro [at] gmail [dot] com