Re: [rtcweb] JSEP-06: How to create the second offer where only the port numbers are changed?

[Justin Uberti <[e-mail]>]

Agreed.


On Mon, Mar 3, 2014 at 6:35 AM, Christer Holmberg <
[e-mail]> wrote:

>  Fair enough, maybe some things can change. And, BUNDLE does not forbid
> changing values, but it does say that the offerer should be careful when
> doing so.
>
>
>
> Section 6.4.3:
>
>
>
> “The Offerer MAY modify any SDP parameter in a BAS Offer.
>
>
>
>    NOTE: It is important that the BAS Offer gets accepted by the
>
>    Answerer, so the Offerer needs to consider the necessity to modify
>
>    SDP parameters that could get the Answerer to reject the BAS Offer.
>
>    Removing "m=" lines, or reducing the number of codecs, in the BAS
>
>    Offer used for the is considered to have a low risk of being
>
>    rejected.”
>
>
>
> So, I guess what should be avoided is adding of new m- lines, new codecs,
> or anything which may trigger the answer to reject the offer.
>
>
>
> Regards,
>
>
>
> Christer
>
>
>
> *From:* Justin Uberti [mailto:[e-mail]]
> *Sent:* 03 March 2014 16:13
> *To:* Christer Holmberg
> *Cc:* [e-mail]
> *Subject:* Re: JSEP-06: How to create the second offer where only the
> port numbers are changed?
>
>
>
> But why is it a problem if other things change (e.g. a=remote-candidates
> is set)?
>
>
>
> On Mon, Mar 3, 2014 at 5:48 AM, Christer Holmberg <
> [e-mail]> wrote:
>
>  Hi,
>
>      As specified in BUNDLE, before the remote peer has indicated support
> of BUNDLE, all m- lines (including those within to a bundle group) must
> have unique port numbers.
>
> Then, when the remote peer has indicated support of BUNDLE, a second offer
> (called the BAS offer) needs to be sent, in which the same port number is
> assigned to all m- lines within a bundle group.
>
> My question is: how do I create the BAS offer? I don’t want to change
> anything – I just want to get an SDP with the BUNDLE port assigned to all
> m- lines. Is there a flag in createOffer() for that?
>
>    The implementation knows that any offers that are created after the
> BUNDLE answer should have the same port numbers. So, the app could push the
> createOffer button once it receives the answer if it wanted to ensure this
> happened immediately. Otherwise, there will be an onnegotiationneeded event
> once ICE completes, and the offer sent at that time will have the updated
> ports.
>
> When I call createOffer(), can I be ensure that *only* the port values
> will change?
>
>
>
> No. Why would this be necessary?
>
>
>
> Because the only thing I want to do is to send a new offer, with the same
> port number in each m- line. I don’t want anything else to change.
>
>
>
> Regards,
>
>
>
> Christer
>
>
>