Subject: [AVT] RTP streams Collisions

From: "Yuval Nissan" <[email-masked]>
Date: Tue, 2 Jan 2007 11:01:47 +0200

Hi,

We have encountered many times in the field the following scenario:

Few voice RTP streams are receiving in the same UDP port - only one of
them is the actual session, and the other exist because of troubles in
the network (for example there was a session before on the same port,
and the other side didn't close the stream). 

It is also important to mention that the sessions in our case are mainly
unicast.

Now, I don't think there is good way in the standards today that gives
simple answer which is the right stream (for all the different network
architectures).

SRTP for example can solve this issue, but of course it is overkill
solution. 

One suggestion that was raised by Ed in the past that can help in most
of the cases: 

http://www1.ietf.org/mail-archive/web/mmusic/current/msg01516.html

Please advice.

Yuval

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

---

From: "Oren Peleg" <[email-masked]>
Date: Tue, 2 Jan 2007 16:33:25 +0200

It looks also an over kill to use a STUN server for such a problem. The
idea is to only make sure that the SSRC is negotiated to avoid multiple
streams entering the same RTP decoder.

Oren P.

-----Original Message-----
From: Colin Perkins [mailto:[email-masked]] 
Sent: Tuesday, January 02, 2007 1:59 PM
To: Yuval Nissan
Cc: [email-masked]
Subject: Re: [AVT] RTP streams Collisions

On 2 Jan 2007, at 09:01, Yuval Nissan wrote:
> Few voice RTP streams are receiving in the same UDP port - only one  
> of them is the actual session, and the other exist because of  
> troubles in the network (for example there was a session before on  
> the same port, and the other side didn't close the stream).
>
>
> It is also important to mention that the sessions in our case are  
> mainly unicast.
>
>
> Now, I don't think there is good way in the standards today that  
> gives simple answer which is the right stream (for all the  
> different network architectures).
>
> One suggestion that was raised by Ed in the past that can help in  
> most of the cases:
>

Won't ICE solve this, along with similar issues due to forking?

Colin

---

From: "Oren Peleg" <[email-masked]>
Date: Wed, 3 Jan 2007 10:30:22 +0200

Its not good enough solution for startup since you want this to be
interoperable.

Oren P.

-----Original Message-----
From: Stephen Casner [mailto:[email-masked]] 
Sent: Tuesday, January 02, 2007 7:59 PM
To: Yuval Nissan
Cc: [email-masked]
Subject: Re: [AVT] RTP streams Collisions

> It is also important to mention that the sessions in our case are
mainly
> simple answer which is the right stream (for all the different network

It is the CNAME in RTCP that is intended to provide the binding of the
SSRC identifier to a meaninful identifier for the endpoint.

For unicast sessions, RTCP timing rules are more flexible, so you can
handle the startup.

                                                        -- Steve