[asterisk-dev] Asterisk as voice gw to the IMS world

[John Todd]

>Hi all,
>
>I am involved in an EU project that aims to integrate the SIP 
>signalling of Asterisk with the IMS from 3GPP. Asterisk is going to 
>operate as a voice gw between ISDN-BRI and IMS-SIP. This is the 
>first step to integrate the PSTN world with the IMS world, using 
>Asterisk.
>
>Asterisk will be registered to the IMS (P-CSCF) and operate as a 
>voice gw between ISBN-BRI and IMS/SIP, transforming fixed telephony 
>calls to the IMS environment.
>
>SIP signalling from IMS is a little bit different from the Asterisk 
>SIP stack. 3GPP has defined some extentions to the protocol.
>
>Did anybody work on this in the past? Any help is welcome.
>
>Thanks!
>
>- George


I have not performed any specific work to this goal, but I have a few 
comments that perhaps are worth noting:

  - as far as I know, IMS requires TLS.  More appropriately, RFC3261 
requires IMS.  Asterisk does not support TCP, therefore cannot 
support TLS.  Is the IPSec tunnel method a way around this problem? 
(I don't know...)

  - does your network vendor require certification before integration?


For those programmers who want to know more about IMS and who don't 
mind being overwhelmed with an enormous amount of acronyms and 
confusing examples created by telephony (not IP) people, this seems 
to be a good resource for the mostly-savvy investigator:

  http://www.tech-invite.com/

JT