Subject: [MMUSIC] RE: How to indicate the RTSP client to use TCP transport instead of UDP?

From: lazzaro <[email-masked]>
Date: Wed, 2 Aug 2006 14:10:03 -0700

> From: "Andrew Large" <[email-masked]>
>
> My recollection is that QuickTime doesn't support normal RTSP  
> interleaving.  Instead, they only support HTTP tunneling, which  
> "tunnels" RTSP over two HTTP sockets (one persistent socket opened  
> with a GET and one transient socket that is opened with POST and  
> potentially closed and re-opened on every request).  To the best of  
> my knowledge, this HTTP tunneling approach has not been  
> incorporated into any of the standards.

[...]

> From: Kylin Wei <[email-masked]>
> I think that Realplayer should support RTP over TCP. Realplayer has  
> a “RTSP transport configuration” option. From that we can see that  
> firstly it will attempt to use UDP for all media content. If it  
> can’t get media data within 4000 milliseconds, it will change to  
> use TCP. Finally, it will attempt to use HTTP transport if it still  
> can’t get media data within 4000 milliseconds. But I can’t sure  
> whether the configuration will work.

	Historically, at least, RFCs with titles like "Apple QuickTime's Method
for HTTP Interleaving over RTSP" were envisioned so that the RFC series
could be a repository for documenting existing protocols that were  
not suitable
for the standards-track (as I recall, an attempt to standardize HTTP
tunneling in AVT or MMUSIC a few years ago never made it to WG item).

	Maybe we should start encouraging those sorts of RFCs
from companies with de-facto-standard variant RTSP implementations.
While these RFCs couldn't be WG items, we could informally review
them here, I would think ... if middleboxes are going to be
inspecting QuickTime and Realplayer, it's in everyone's interest
that those middleboxes aren't guessing about the underlying protocol.

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

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From: "Jaehwan Kim" <[email-masked]>
Date: Fri, 4 Aug 2006 17:48:38 +0900

Only thing I can find from Apple.com is "Tunnelling RTSP and RTP through
HTTP", not HTTP tunneling over RTSP. (see
http://developer.apple.com/quicktime/icefloe/dispatch028.html)

The reason why Apple uses tunneling is to overcome the firewall/NAT
situation. If it is true, it could be discussed in BEHAVE...
(Maybe London meeting in 2001, MMUSIC had very strong negative voice on
this kind of solution. However, now we have BEHAVE...)

Or do you think that it is worth wile to discuss some MMUSIC related
de-facto standard which has not been handled here just because of out of
scope?

Kind Regards,
Jaehwan 

John Lazzaro Wrote:
> a "RTSP transport configuration" option. From that we can see that  
> can't get media data within 4000 milliseconds, it will change to  
> can't get media data within 4000 milliseconds. But I can't sure  

	Historically, at least, RFCs with titles like "Apple QuickTime's
Method

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From: lazzaro <[email-masked]>
Date: Fri, 4 Aug 2006 09:04:00 -0700

> http://developer.apple.com/quicktime/icefloe/dispatch028.html)

A typo on my part, the title you quoted was my intention ...

This is the sort of documentation I was hoping existed ...

> this kind of solution. However, now we have BEHAVE...)

I'm not directly involved so I'll leave this to others to discuss ...

---
John Lazzaro