Re: [rtcweb] A problem with both A and B

Christer Holmberg <christer.holmberg@ericsson.com> Tue, 21 May 2013 08:57 UTC

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From: Christer Holmberg <christer.holmberg@ericsson.com>
To: Kevin Dempsey <kevindempsey70@gmail.com>, Emil Ivov <emcho@jitsi.org>
Thread-Topic: [rtcweb] A problem with both A and B
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Date: Tue, 21 May 2013 08:57:30 +0000
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Subject: Re: [rtcweb] A problem with both A and B
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Hi,

> In cases where each m= line has a different port, when a new SSRC is received usually it is either discarded (when latched to a pre exisiting SSRC stream that does not stop) or is treated as replacing the previous SSRC.
>
> When multiplexing is being used it is not obvious whether the new SSRC is replacing a previous one, or is another separate stream.
>
> I think that in the multiplex case we need something like a virtual destination port in each RTP packet, such as a RTP header extension or even UDP over UDP!

Perhaps.

But, then we talk more about how to identify/demux a stream, once it has been added.

We would still need to answer whether the actual addition of a new stream requires a SDP O/A transaction :)

Regards,

Christer



On 21.05.13, 10:38, Christer Holmberg wrote:
> Hi,
>
>>> If adding a new stream means adding a new SSRC, within an
>>> existing m-, then it is also an SDP O/A issue - bundle or no
>>> bundle.
>>
>> Why is that?
>
> Because, even WITHOUT bundle, you have to answer whether adding a new
> SSRC (or, whatever mechanism we use to identify a stream) within an
> existing m- line requires an SDP O/A transaction or not.
OK, I guess I took your statement to mean that adding and removing SSRCs
to m= lines is a matter that cannot be handled without SDP O/A which I
think it isn't (and which is what this thread started with).

I obviously agree that it is not a bundle-specific issue.

Emil

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