Registering CUCME with more than one ITSP accounts

[telecastle]

Hi,

I have been using a CUCME system in my house for almost 5 years now. I am using it with a ITSP's SIP trunk. One thing that I have not been able to do is to route inbound calls based on the DID to which they are placed. My account has several DIDs that the ITSP forward to the same SIP trunk. The problem is that the ITSP includes the same DID in the TO header of INVITE message sent to me. That DID is the private E.164 number starting with 1777 that the ITSP uses as my SIP account's username. So, there are several questions I would like to ask.

1. I was not able to create a voice translation rule to translate the actual DID (to which the original inbound call is placed) into a local extension. Therefore, I cannot route the inbound calls based on the DNIS. Has anyone had any similar experience?

2. The second option I have is to create several SIP accounts with my ITSP and assign one actual DID to each account. Because each account would have a different private E.164 number (starting with 1777), I would be able to create inbound voice translation rules that would translate each private E.164 number into the local DN at which I want the call to ring. However, I have not been able to successfully register more than one SIP account from the CUCME. The latest version of CUCME (8.5) has a feature to create up to 6 registrar servers with distinct auth-realm arguments in the sip-ua configuration mode. Additionally, the authentication username <username> password <password> realm <auth-realm> command allows one to create more than one set of authentication credentials (this command is also available in the sip-ua configuration mode). However, my ITSP rejects the registration when I specify the auth-realm parameter in either of these two commands. So, is there a way to register more than one SIP account with the same ITSP without using the auth-realm parameter?

3. Finally, my IP phones are still running SCCP. The way that I was able to register the private E.164 (1777 number) is by creating a dummy ephone-dn and assigning that private E.164 to it. Because CUCME by default tries to register all SCCP DNs with the SIP registrar server, I am able to register my account with the ITSP that way. This, of course, requires that I also configure the registrar command and the authentication command in the sip-ua configuration mode.  (I also specify under all other SCCP DNs the optional command that prevents them from being registered with the SIP registrar.)

However, the description of the registrar command specifically says that this command is used only to register non-SIP DNs, from which I deduce that if I wanted to register a SIP DN, I would not have to use the registrar command at all. So, if I were to create a dummy SIP DN (to which I would assign the same private E.164 number), how would I go about registering it with my ITSP? Can I do this without using the registrar command in the sip-ua configuration mode? If so, what command do I need to use to indicate to the CUCME the SIP registrar's hostname? And would this help me register more than one account with the same ITSP?

Thanks for reading this lengthy post!

[telecastle]

I love the self-help nature of this forum!

The feature that allows CUCME to register more than one accounts appeared in IOS 15.0(1)XA, using the following command:

credentials number username password [0| 7] realm

The number keyword did not exist in this command prior to IOS 15.0(1)XA. Along with this feature, IOS 15.0(1)XA introduced CUCME 8.0. The argument  specifies the E.164 number that the ITSP uses to register the SIP account. The arguments and are the authentication credentials issued by the ITSP. In my case, the and the are the same 11-digit number starting with 1777 (This is the way Callcentric does it).

Therefore, by configuring the E.164 number to be registered in a ephone-dn assigned to a line button on a SCCP phone, or configuring this number in a dummy ephone-dn (not assigned to any ephone), then, by specifying this E.164 number in the credentials command listed above, and finally configuring the registrar dns:callcentric.com:5060 expire 60 command, I was able to register more than one E.164 numbers with each being assigned to a different Callcentric account.

In order to be able to make and receive calls, you must assign this ephone-dn as a primary DN to a line button on an ephone from which the call will be made and at which it will be received for each ITSP account, or alternatively, if you assign the E.164 numbers to be registered with the ITSP to a dummy ephone-dn or as a secondary number to an ephone-dn configured as a line button under an ephone, you should create an outgoing voice translation rule that translates the internal DNs from which the call is placed to the appropriate E.164 numbers.

If multiple ITSP accounts are registered by using a dummy ephone-dn, in order for the CUCME to propery route the incoming calls received from from different ITSP accounts, you have to create an incoming voice translation rule that translates the E.164 numbes specified by the ITSP in the address field of the INVITE message of each account (in the Callcentric case it's the same 1777 number that is used for the registration of each account) to the ephone-dn at which you want to be able to receive this call.

Finally, IOS 15.0(1)XA (CUCME 8.0) does not allow you to send registration requests specific to each ITSP if your goal is to register multiple accounts with different ITSPs from the same CUCME. You may still be able to register with different ITSPs, using IOS 15.0(1)XA, but the CUCME will send registration requests about all of your accounts to all of your ITSPs, and naturally, ITSPs will be rejecting the registration requests on the accounts that do not belong to them. In order to send registration requests about specific SIP accounts only to the ITSP who provides those accounts, you must use IOS 15.1(2)T (CUCME 8.5), which introduced the auth-realm keyword in the following command:

registrar  {<1-6>} {dns:[:ipv4:[:ipv6:[:expires ] [random-contact] [refresh-ratio {<1-100>] [scheme {sip | sips} [tcp] [auth-realm ]

The presence of the auth-realm keyword and its value in this command can create a match with the credentials command's realm keyword's value, and therefore, registration requests about a particular account could be sent specifically to the ITSP who provides this account.

P.S. I would refrain from using IOS 15.1(2)T and wait until a later iteration of this T-train is released - e.g. IOS 15.1(2)T2, 15.1(2)T3, 15.1(2)T4, etc. During testing with IOS 15.1(2)T, incoming voice translation rules were not properly translating the E.164 number specified in the address field of the incoming SIP INVITE message, and therefore, the SIP 407 Forbidden was generated by the CUCME back to the ITSP. This was traced to the malfunctioning voice translation rule that failed to translate the E.164 number contained in the address field of the incoming SIP INVITE; therefore, CUCME tried to ring a dummy ephone-dn, which was not assigned to any registered ephone. Once the downgrade back to 15.0(1)XA (CUCME 8.0) was done, the same configuration worked fine, and the incoming voice translation rule configured in a voice translation-profile applied under a matching inbound VoIP dial peer was performing a translation from the E.164 number contained in the address field of the incoming SIP INVITE message to an ephone-dn assigned to a line button on a registered ephone, subsequently directing inbound calls to that ephone's line button.