Re: SDP DataChannels

Looks like there are RTCP candidates in a Data Channel only 'connection' is that necessary ?
T.

On 3 Aug 2013, at 08:39, Eric Rescorla <ekr@rtfm.com> wrote:

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> On Sat, Aug 3, 2013 at 9:26 AM, piranna@gmail.com <piranna@gmail.com> wrote:
> Good to know it for reference, seems to be fairly more complicated (interesting to see the IP and ports of each one of the DataChannels...
> 
> 
> Those are the ICE candidates. It's kind of needed to set up the communications
> channel. The only reason you're not seeing them in Chrome is that Chrome
> does Trickle ICE and so sends them in a separate message.
> 
> -Ekr
>  
> El 03/08/2013 08:12, "Eric Rescorla" <ekr@rtfm.com> escribió:
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> On Sat, Aug 3, 2013 at 1:29 AM, piranna@gmail.com <piranna@gmail.com> wrote:
> I've just been able to generate an offer only with DataChannels (seems
> the fact that audio m-lines where added on Chrome due a bug on the
> mediaConstraints, and that was the reason why SDP strings were so
> long) and I've been able to dump the generated SDP, being now more
> confident that SDP is not the best format at least for this use case
> (only DataChannels). Could be any body explain me why there are so
> much (almost) duplicated lines? What are the essential ones? What are
> just the essential bits of data required to create this DataChannels?
> 
> It's probably better to look at the SDP from Firefox because Chrome doesn't
> currently implement the  data channel specification. Here is what the Firefox
> SDP looks like:
> 
> v=0
> o=Mozilla-SIPUA-25.0a1 12613 0 IN IP4 0.0.0.0
> s=SIP Call
> t=0 0
> a=ice-ufrag:9638f069
> a=ice-pwd:90f72795622bd286d75dde68d9b7e02f
> a=fingerprint:sha-256 7C:CE:6B:7A:D4:B0:2E:D7:0C:76:07:59:B5:9E:28:5C:14:6C:00:D7:E0:10:C6:CD:25:8B:4B:E8:1D:CC:FC:4F
> m=application 51189 DTLS/SCTP 5000 
> c=IN IP4 89.246.150.136
> a=fmtp:5000 protocol=webrtc-datachannel;streams=16
> a=sendrecv
> a=candidate:0 1 UDP 2113601791 10.0.1.158 53229 typ host
> a=candidate:1 1 UDP 1694236671 89.246.150.136 51189 typ srflx raddr 10.0.1.158 rport 53229
> a=candidate:0 2 UDP 2113601790 10.0.1.158 54571 typ host
> a=candidate:1 2 UDP 1694236670 89.246.150.136 55176 typ srflx raddr 10.0.1.158 rport 54571
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