W3C home > Mailing lists > Public > public-webrtc@w3.org > August 2013

Re: SDP DataChannels

From: Eric Rescorla <ekr@rtfm.com>
Date: Sat, 3 Aug 2013 13:45:51 +0200
Message-Id: <93E0408E-2A2A-4012-9407-F69B0AFD6E56@rtfm.com>
Cc: "piranna@gmail.com" <piranna@gmail.com>, public-webrtc <public-webrtc@w3.org>
To: tim panton <thp@westhawk.co.uk>


On Aug 3, 2013, at 10:11, tim panton <thp@westhawk.co.uk> wrote:

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

I noticed that too. I think it's a bug in ffox

Ekr

> On 3 Aug 2013, at 08:39, Eric Rescorla <ekr@rtfm.com> wrote:
> 
>> 
>> 
>> 
>> 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:
>>> 
>>>> 
>>>> 
>>>> 
>>>> 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
> 
Received on Saturday, 3 August 2013 11:46:23 UTC

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