[SWLUG] SIP questions

Dave Cridland dave at cridland.net
Thu Aug 20 19:10:44 UTC 2009

On Thu Aug 20 19:44:34 2009, Steve Hill wrote:
> On Thu, 20 Aug 2009, Dick Bain wrote:
> > I sort of heard some discussion of SIP at the lug meeting but old  
> age
> > makes ones hearing feeble, could some of those questions be  
> answered
> > on this list?
> There weren't many specific questions that I can remember, just very
> general stuff.  I'll try to summarise off the top of my head:
> SIP is one of a small number of standard IP telephony protocols (by  
> far
> the most commonly used - H.323 has more or less disappeared these  
> days in
> favour of SIP).  It is used by pretty much everything that isn't  
> Skype -
> Skype use their own proprietary protocol which they guard very  
> closely and
> ensure it doesn't interoperate with anything.
And of course there's Jingle, the XMPP stuff that was bootstrapped by  
Google Talk. This, too, uses SDP, ICE, RTP, and many of the same  
codecs as SIP, so you can argue it as being very closely related.

> There are many more SIP<->PSTN gateways, so it is very much a case  
> of
> shopping around and seeing who does the best deal for you.

There are also Google Talk <-> PSTN gateways, too.

Asterisk can, I believe, route calls about through all the various  
flavours of open-standard VOIP, too, so you can terminate your calls  
onto SIP around your home LAN, but route out to the internet via  
Jingle as well.

Dave Cridland - mailto:dave at cridland.net - xmpp:dwd at dave.cridland.net
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