How to configure multiple sip registers ?

Question

I have a CME with several cisco phones and 1 SIP TSP. SIP trunk is registered and calls are coming in and out, but the thing is that only 1 active call can be made. If one is active second call cannot be made. I contacted our TSP, they have asterisk on their side and they said that if I want to use more channels I have make more registers with different usernames.  Router model is 2900 with universal  IOS 15.2. this is the old config of sip-ua :
sip-ua
credentials username xxxxxxxxxxx password 7 0xxxxxxxxxxxxxxxxx realm xxxxxxxxxxxxxxxx
authentication username xxxxxxxxxxxxxxxxx password 7 xxxxxxxxxxxxxxxxxxxxxx
no remote-party-id
max-forwards 15
registrar ipv4:xxxxxxxxxxxxx expires 600
host-registrar
and this is the new one:
sip-ua
credentials username xxxxxxxxxxxx password 7 xxxxxxxxxxxxxxxxx realm xxxxxxxxxxxxx
credentials username xxxxxxxxxxxx password 7 xxxxxxxxxxxxxxxxx realm xxxxxxxxxxxxx
authentication username xxxxxxxxxx password 7 xxxxxxxxxxxxxxxxx
no remote-party-id
max-forwards 15
registrar 1 ipv4:xxxxxxxxxxxxx expires 600
registrar 2 ipv4:xxxxxxxxxxxxx expires 600
host-registrar
actually the realms and registar-s are the same IP addresses, passwords are also the same, only difference is in username. The thing is that I cannot enter new authentiation parameters, when I enter the new one it replaces the old one.
and this is the register status :
show sip-ua register status
--------------------- Registrar-Index  1 ---------------------
Line                             peer       expires(sec) registered P-Associ-URI
================================ ========== ============ ========== ============
9954932203300                    20002      64           yes       
9954932203301                    -1         64           no        
--------------------- Registrar-Index  2 ---------------------
Line                             peer       expires(sec) registered P-Associ-URI
================================ ========== ============ ========== ============
9954932203300                    20002      68           yes       
9954932203301                    -1         68           no 
as you can see second username cannot register.
So I have 2 questions:
1) Does cisco router's SIP trunk support more than one channels ( simultineous calls) or not?
2) If it doesnot support , how can I add second register and what is needed to use it for several calls at a time?

Answer 1

Support for Multiple Registrars on SIP Trunks on a Cisco Unified Border Element, on Cisco IOS SIP TDM Gateways, and on Cisco Unified Communications Manager Expres:
http://www.cisco.com/en/US/docs/ios/voice/cube/configuration/guide/vb_9655.html
Restrictions for Support for Multiple Registrars on SIP Trunks
The Support for Multiple Registrars on SIP trunks feature has the following restrictions:
•Old and new forms of the registrar command are mutually exclusive: the registrar can be configured in  either primary/secondary mode or multiple registrar mode—not both.
•Dynamic  Host Configuration Protocol (DHCP) support is not available with  multiple registrars (available for primary/secondary mode only).
•Only one authentication configuration per username can be configured at any one time.
•A maximum of six registrars can be configured at any given time.
•A maximum of 12 different realms can be configured for each endpoint.
•You  cannot restrict the registration of specific endpoints with specific  registrars—once a new registrar is configured, all endpoints will begin  registering to the new registrar.
•You cannot remove multiple configurations of credentials simultaneously—only one credential can be removed at a time.
HTH
Jorge Armijo
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