Asterisk PBX to/from IMS

Radnik · October 4, 2010, 11:15am

Hi all,
here i have an offer from IMS company to use telephone services within IP technology and bumped into this (translated into English ). Please can someone push me into right direction to figure this one out.

In order to use services it it nessesary to achieve apropriate SIP signaling between PBX an IMS system.

[ul]Your PBX has to forward request for registration, REGISTER message with it’s SIP address with whom you get registred on our IMS system and which represents all PBX local users. REGISTER message must contain:

Request URI header which containts home network domain (REGISTER sip:ims.telco.com SIP/2.0)

From and To headers has to contain Trunk group’s primary SIP URI Public User Identity

PBX has to forward second REGISTER message which containts “nonce” and “response” values as well as username which contains Trunk’s group SIP URI Private User Identity
[/ul]

[ul]
PBX has to use domain name as host part of SIP URI within From, To, P-Asserted-Identity and Request fields for calls from PBX to IMS.
[/ul]

[ul]
For outgoing calls (from PBX to IMS), PBX send INVITE message with P-Asserted Identity (PAI) field which has to contain Trunk group’s SIP URI Public User Identity in order to get identified by Aplication IMS Server as Trunk group (PBX). From field in INVITE message has to contain PBX user’s Calling Line Identity (CLID), it’s a user who have started the call (caller). From filed has to contain TEL URI or SIP URI.
[/ul]

[ul]
For incoming calls (from IMS to PBX), PBX has to identify local user (callee) based on To field in INVITE message from IMS. To field contains primary Trunk user’s SIP URI Identity. Request URI field in INVITE message contains primary SIP URI Public User Identity (PUI) Trunk’s group. Based on Request-URI field IMS Application Server has identifed apropriate Trunk group (PBX) and has forward the call to this Trunk[/ul]

Say i would like 3 lines registered: 55500, 55501 and 55502, with primary 55500. config files would be like?

sip.conf

;
[general]
context=ims-incoming
bindport=5060
bindaddr=192.168.0.1
srvlookup=yes
pedantic=no (nonce=" " and response=" ")
deny=0.0.0.0/0.0.0.0
permit=192.168.0.1/255.255.255.255
registertimeout=10 
registerattempts=10
useragent=Asterisk PBX
;
register=> 55500:55500@ims.telco.com:5060;user=phone
register=> 55501:55501@ims.telco.com:5060;user=phone
register=> 55502:55502@ims.telco.com:5060;user=phone
;
[ims-outgoing]
type=peer
host=ims.telco.com
username=55500
secret=55500
fromdomain=192.168.0.1
insecure=very
qualify=yes
nat=no
disallow=all
allow=ulaw,alaw,gsm,g726,speex,adpcm
outboundproxy=192.168.0.1
;

users.conf

;
[55500]
type=friend
host=dynamic
username=55500
secret=55500
dtmfmode=rfc2833
callerid=55500
disallow=all
allow=ulaw,alaw,gsm,speex,g726,adpcm
context=local
insecure=very
canreinvite=no
qualify=yes
nat=no
outboundproxy=192.168.0.1
;
[55501]
type=friend
host=dynamic
username=55501
secret=55501
dtmfmode=rfc2833
callerid=55501
disallow=all
allow=ulaw,alaw,gsm,speex,g726,adpcm
context=local
insecure=very
canreinvite=no
qualify=yes
nat=no
outboundproxy=192.168.0.1
;
[55502]
type=friend
host=dynamic
username=55502
fromdomain=192.168.0.1
secret=55502
dtmfmode=rfc2833
callerid=55502
disallow=all
allow=ulaw,alaw,gsm,speex,g726,adpcm
context=local
insecure=very
canreinvite=no
qualify=yes
nat=no
outboundproxy=192.168.0.1
;

extensions.conf

;
[ims-incoming]
exten=> 55500,1,Dial(SIP/55500)
exten=> 55501,1,Dial(SIP/55501)
exten=> 55502,1,Dial(SIP/55502)
;
[ims-outgoing]
exten=> _9X.,1,Dial(SIP/${EXTEN:1}@ims-outgoing)
;
[local]
include=> ims-outgoing
exten => _555XX,1,Dial(SIP/${EXTEN})
;

Thank you for your time, for at least reading it.
Ivan.