Re: [rtcweb] JSEP: Order of m- lines in multiple PeerConnections

Christer Holmberg <> Fri, 18 October 2013 04:59 UTC

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From: Christer Holmberg <>
To: "Cullen Jennings (fluffy)" <>
Thread-Topic: JSEP: Order of m- lines in multiple PeerConnections
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Date: Fri, 18 Oct 2013 04:59:21 +0000
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Subject: Re: [rtcweb] JSEP: Order of m- lines in multiple PeerConnections
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Hi Cullen,

My question is how it would be done when creating the new PC, so I don't think replacing UPDATE with REPLACE would solve the problem :)

Also, the usage of a new PC can also be used for serial forking. But, that is not the issue.



Sent from my Sony Ericsson Xperia arc S

"Cullen Jennings (fluffy)" <> wrote:

Perhaps in the parallel forking section, we should replace UPDATE with "INVITE with replaces" . Would that work ?

Alternatively we could just remove the parallel forking section.

On Oct 16, 2013, at 5:16 AM, Christer Holmberg <> wrote:

> Hi,
> Any comments on this issue? I’d like to have some e-mail discussions before Vancouver.
> I’d also like it to be listed as an issue – unless, of course, I have missed something, and it really isn’t an issue :)
> Regards,
> Christer
> From: [] On Behalf Of Christer Holmberg
> Sent: 30. syyskuuta 2013 11:08
> To:
> Subject: [rtcweb] JSEP: Order of m- lines in multiple PeerConnections
> Hi,
> JSEP talks about the usage of multiple PeerConnection to support forking, i.e. for each new forked leg (SIP: early dialog) a new PeerConnection is created.
> As has been indicated, as each new PeerConnection will have its own set of address properties, ICE properties etc, so a new Offer will have to be created and sent to inform the remote about the new properties.
> So far so I good.
> I also assume that the same camera/mic/etc sources are connection to each PeerConnection, so the number of m- lines in the Offer of the new PeerConnection should be the same.
> However, according the 3264, the ORDER of the m- lines also need to be kept the same.
> So, my question is: how can I ensure that the order of the m- lines in an Offer for a new PeerConnection is the same as in an Offer for an old PeerConnection?
> Regards,
> Christer