Showing results for 
Search instead for 
Did you mean: 

Fast busy on SIP trunks to CMS


Hello all,

A bit of background:

  • A single CUCM cluster of 3 nodes in an isolated, gov't environment running 11.5.1
  • 3 CMS servers

I have created SIP trunks to all 3 CMS servers. Certificates were created and uploaded fine, the SIP trunks indicate "Full Service." All 3 trunks are "running on all Active Nodes."

  • I have created a Route Group, a Route List and a Route Pattern. All three trunks are associated with the Route Group
  • The Route List is a member of the Route Group
  • The Calling Search Space has been set on Rerouting, Incoming and Outbound call settings.

When dialing the IVR number for the CMS, we get a fast busy. 

Where should I be looking?

3 Replies 3

Rising star
Rising star

Is this a new setup? Have you tried resetting the CMS SIP Trunk in the CUCM?

Can you look at the real time data of a call in RTMT and see where it fails? Please share screenshots of the ladder diagram, and the error messages if possible. 

If you need help with the RTMT call analysis procedure, please refer to link below.


Jaime Valencia
Hall of Fame Cisco Employee Hall of Fame Cisco Employee
Hall of Fame Cisco Employee

You don't mention anything about the inbound call routing in CMS, has that been configured?



if this helps, please rate


Good morning gents,

Yes, this is a new setup. We're upgrading from old VCS/MCU stuff to CMS. I am working the Call Manager end of this while a co-worker is configuring the CMS end of things.

First, I discovered that my conference bridges weren't registered. I have corrected that. Then, I verified that everything is in the proper media resource groups and lists and that the route pattern is established.

My co-worker did not have the API account configured for CUCM so I directed him to do that. Now I have asked him to configure the inbound routing as Jamie has asked about.  I apologize for jumping the gun on asking for assistance with this. I'll post the results as soon as we test after the inbound call routing is configured.

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Recognize Your Peers