Subject: Re: "Transport" field

From: Rob Lanphier <[email-masked]>
Date: Mon, 28 Jul 1997 11:47:09 -0700

At 02:22 PM 7/28/97 -0400, Mark Handley wrote:
>I believe this is independent of the transport protocol issue, and so
>you would probably want to use TCP-RTP/AVP or something similar rather
>than RTP/TCP.

Wouldn't the profile, once created, still be called RTP/xxx?  I'll agree
that there is a vacuum there, but why TCP-RTP/AVP?  Doesn't the first half
describe the protocol in general (RTP), and the second half describe the
implementation of the protocol (AVP or some other form, like an embedded
TCP version)?

Rob
---
Rob Lanphier               Voice: (206)674-2322         Fax: (206)674-2699
Program Manager-Protocols                         Email: [email-masked]
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---

From: Mark Handley <[email-masked]>
Date: Mon, 28 Jul 1997 16:55:38 -0400

>implementation of the protocol (AVP or some other form, like an embedded

I had been thinking of the RTP AV profile as kind of "transport
independent", but re-reading it, I see that isn't the case.  If you
want to use a different transport you have to define a whole new
profile.

It may be that the way RTP was split into base spec and profile chose
a poor separation once you start to choose to use RTP over different
transport protocols than UDP because much of what is in the current AV
profile is transport independent.  It would have been good to be able
to use the existing AV profile with different lower-layer transport
protocols.

So I guess you're right - you do need to define a whole new profile.
Yeuch!  Given this, RTP/TCP is not unreasonable.

BTW, I assume you *are* planning to use compressed RTP over the TCP
connection?  Otherwise you waste lots of bits unnecessarily.  

Of course it's still not a good idea to use TCP :-)

Mark