SDP

All posts tagged SDP

webrtcH4cKS: ~ The Minimum Viable SDP

Posted by Philipp Hancke on March 31, 2015
Posted in: Guide.
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3 comments

One evening last week, I was nerd-sniped by a question Max Ogden asked:

That is quite an interesting question. I somewhat dislike using Session Description Protocol (SDP)  in the signaling protocol anyway and prefer nice JSON objects for the API and ugly XML blobs on the wire to the ugly SDP blobs used by the WebRTC API.

The question is really about the minimum amount of information that needs to be exchanged for a WebRTC connection to succeed.

 WebRTC uses ICE and DTLS to establish a secure connection between peers. This mandates two constraints: ...  Continue reading

webrtcH4cKS: ~ SDP: The worst of all worlds or why compromise can be a bad idea (Tim Panton)

Posted by Tim Panton on January 20, 2014
Posted in: Standards.
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As WebRTC implementations and field trials evolve, field experience is telling us there are still a number of open issues to make this technology deployable in the real world and the fact that we would probably do some things differently if we started all over again. As an example, see the recent W3C discussion What is missing for building (WebRTC) real services or Quobis‘ CTO post on WebRTC use of SDP.

Tim Panton, contextual communications consultant at Westhawk Ltd,  has gone through some of these issues. During the last couple of years we had the chance to run some workshops together and have some good discussions in the IETF and W3C context. Tim’s expertise is very valuable and I thought it would be a good idea to have him here to share some of his experiences with our readers. It ended up as a rant. ...  Continue reading

webrtcH4cKS: ~ Anatomy of a WebRTC SDP (Antón Román)

Posted by Victor Pascual on January 14, 2014
Posted in: Guide.
Tagged: , , .
4 comments

Editor note: see the updated version of this post here.

As described in previous posts, WebRTC does not specify a particular signalling model other than the generic need to exchange Session Description Protocol (SDP) media descriptions in the offer/answer fashion.

During the last few months, my friend  Antón Román (CTO of Quobis) and I spent a lot of time with our team figuring out how to manipulate and adapt the SDP’s generated by web browsers to make them compatible with the different server/gateway technologies we’re working with.

As WebRTC makes use of new mechanisms but also existing ones that have seen few  deployment in real networks to date. SDP’s generated by Web Browsers are more complex and contain a number of new attributes that are unfamiliar in SIP or IMS networks. In the following post, Antón analyses the anatomy of a WebRTC SDP, giving a detailed description of what all those lines do. ...  Continue reading

webrtcH4cKS: ~ Updated: Why the WebRTC API has it wrong – Interview with WebRTC Object API (ORTC) co-author Iñaki Baz

Posted by Chad Hart on August 26, 2013
Posted in: Standards.
Tagged: , , , .
8 comments

Updated 25 Aug 2013 –  some minor edits fixing some ORTC API references and added ORTC sample code.

In my post on WebRTC standardization I mentioned that one of the controversial points of discussion in the W3C context was whether the SDP Offer/Answer model and the current API provided the level of flexibility a wide range of WebRTC use cases would require. In order to avoid the endless and repetitive discussions that have already occurred on this topic, developers unsatisfied with the current API have just announced an alternative to the existing WebRTC API. This new proposal is called WebRTC Object API, motivation behind it is presented in this IETF draft and some example code can be found on GitHub. Note that this is not the first time an alternative API aiming to provide more control to web developers has been proposed- Microsoft’s CU-RTC-Web introduced last year took a similar approach by introducing an alternative along with a working prototype. ...  Continue reading