asterisk users - Apr 2003 - Which VoIP, H.323, SIP reference books are recommended?

Looks like it is time for me to get some good reference books
on VoIP, H323, SIP etc.  Which ones are recommended?

Thanks

Gary Mart

I can't speak to H323, but there seem to be quite a few titles out there.

The one SIP book I found was the O'Reilly "Practical VOIP using 
VOCAL" which is fairly specific to using the Vovida (Cisco) VOCAL 
package, but it had a reasonable explanation of SIP.  Personally, I'd 
suggest you start surfing the Cisco website and looking for their 
whitepapers on SIP - they are well-written and illustrated, and are 
more current than most printed material you'll be able to find.

H323 supposedly is the bulk (90% was the quote I heard) of VOIP 
traffic on the big carrier-to-carrier networks, but I'd say that 
almost every vendor is trying to figure out how to convert to SIP. 
I'm trying to avoid learning H323 in detail until it's absolutely 
required, but I have a number of books here that claim to be able to 
tell me what I need to know (though I haven't read them, so can't 
recommend them.)

JT

>Looks like it is time for me to get some good reference books
>on VoIP, H323, SIP etc.  Which ones are recommended?
>
>Thanks
>
>Gary Mart