Warning message

  • Cisco Support Forums is in Read Only mode while the site is being migrated.
  • Cisco Support Forums is in Read Only mode while the site is being migrated.

Intercluster Trunk between CCM7.1 and CCM3.3

Unanswered Question
Oct 20th, 2010
User Badges:

HI all,

  I was wondering if anyone has had any success with doing ICTs between these two call manager versions?

I have a customer that is looking to make the big transition and they are looking to have a test group on the new version.

I was looking to use call forward unregistered on the legacy system over an ICT.



  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Jaime Valencia Wed, 10/20/2010 - 18:14
User Badges:
  • Cisco Employee,
  • Hall of Fame,


You shouldn't have any problem doing that, the ICT protocol uses H323 and it's backward compatible so you don't need anything special for this.



If this helps, please rate


James Hawkins Thu, 10/21/2010 - 01:03
User Badges:
  • Blue, 1500 points or more


I did exactly this for a customer last year. I used non-gatekeeper controlled trunks and it worked without any problems.

CCM3.3 does not support Call Forward Unregistered though so you willhave to rethink that part (Forward All, Forward Busy and Forward No Answer are supported)


What I did was:

  1. Create a route pattern of 2XXX (DN's were in the range 2000 to 2999) on CM3.3 pointing to the trunk to CUCM7.1
  2. Create an isolation partition on CCM3.3 which was not in any CSS's
  3. To migrate a CCM3.3 phone I would move its DN from Internal_PT to Isolation_PT which causes the dialled digits to match the route pattern created in step 1.

The migration went smoothly - it was interesting to be reminded how simple CCM3.3 was compared to recent versions of CUCM.

srsivara Thu, 10/21/2010 - 16:26
User Badges:
  • Cisco Employee,

Another thing that I always suggest to customers is to ensure that the 'incoming CSS' of the ICT on each cluster doesn't have access to the partition of the Route Pattern to the ICT. This way, there is no chance of a call loop across the ICT between the clusters, preventing code yellow situations on the CCM servers.

- Sriram

clark.adam.p Thu, 10/21/2010 - 16:42
User Badges:

Great ideas.

Thanks for that.  Will have to investigate further


clark.adam.p Thu, 10/21/2010 - 16:43
User Badges:

That is good news.  I remember having an issue with an ICT between 3.3 and an early version of 5.

Lets hope that was a bug just in that code.


This Discussion