Imagine working at your desk, getting a phone call from your friend Randy. You answer on your IP phone. Being Randy, he suddenly wants to play a new jingle he created while being in the mood the day before. The phone speaker is not a good device for a cool guitar riff – is it? On the same desk you have your PC with a softphone that supports HD voice and really cool loudspeakers. Why not transfer the audio to the PC while still using the phone’s microphone? After that, you want to play a video for Randy. Now you want to add media from your laptop to the call – while the call is still managed by the IP phone.

This is a true multimedia session, that is not that far away. But it’s too complex to manage in the SIP protocol today. I just found out about the SPLICES working group in the IETF that is working on this issue. I also know that the Asterisk development team is working on a new media architecture - something we’ve needed for many years. My presentation about the new media architecture from Astridevcon 3 years ago talks about being able to add streams, have multiple streams of the same kind and remove streams dynamically during a call. SPLICES, when finished, will help us implement it in a really cool way in SIP.

Another mailing list to follow.

Do you know another thing? Randy and I wouldn’t be able to have this call as easily if we did not use SIP over IPv6. Doing a call like the one above over two NATs would be awfully complex…