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New Member

Intercluster trunk creation - CUCM 6.1

Hi all,

I will be creating an ICT between CCM 6.1 and a remote 4.3 site.

It will be Non-GK controlled.

I believe i will need to:

1 - create the SAME ICT setup on both my Subs, pointing them to the same pair of remote IP addresses of the remote Subs.

2 - on the remote Subs, create ICT setup on each Sub pinting to my two Subs.

3 - (this is the bit i am unsure about) on the local cluster, what partition and CSS settings should i use?

4 - link the ICT to the relevant Route Pattern for non-local tie-line calls from my local cluster.

5 - repeat step 4 for the remote end too (remote side Route Pattrns to point to my local end)

I'm a little unclear about whether a new partition and CSS would be needed for the ICT? At present each phone (logged out - ext mob) has internal calling capabilities only. I would want to be able to allow both "logged out" and also "logged in" Ext Mob IP phones to be able to use the ICT if they needed to.

Any thoughts around how/what to use for the partiton and CSS appreciated. If i create a new partitoon and CSS for the ICT, how can i easily relate that to ALL my IP phones to allow *anyone* to establish an ICT call to the remote site? (We have several CSS's to allow very restricted internal calls only, thru to unrestricted calls to anywhere in the world. Different users have different CSS's.

I have one other CSS setup for *all* internal devices that each phone emplate uses, should i use such a CSS?

I have IP reachability and no firewalls blocking RTP or other IP packets.


Cisco Employee

Re: Intercluster trunk creation - CUCM 6.1

an ICT is an emulation of an H323 GW.

simply use the same logic you would use for a GW when it comes to CSS and partitions.

if you want all users to call being logged in/out include the partition from the route pattern in their CSS. if not, do not add it. there is no special consideration for ICTs.



if this helps, please rate



if this helps, please rate
New Member

Re: Intercluster trunk creation - CUCM 6.1

You set the ICT up the same as you would any gateway.

I would warn you that if you have overlapping dial plans between the two clusters you will run into problems with loops.

You'll need to put any Route Patterns that point to your ICT into a Partition that the phones can access but NOT the ICT itself. The ICT needs a Calling Search Space that can access the phones and gateways etc but be unable to route calls back down itself. If it does then you'll see the error "High Traffic, try again later" on your phones. This is the CallManager throttling call processing down the ICT.

New Member

Re: Intercluster trunk creation - CUCM 6.1

Hi guys - thanks for the updates !

We use a "CSS_Gateway" Calling Search Space on all our gateways that is linked to partitions for ALL our phones on this site. I assume i would re-use this CSS for the ICT so the ICT can be used by all phones?

I was going to create a RG and RL for the new ICT and then stick the Route Pattern (4XX.XXXX)into those. Is that sufficient? These will then be linked to a new Patition.

The ICT gateway has access to the phones via CSS_Gateway.

The Route Pattern will have access to the ICT via the RL, RG and Partition i guess...?

Will that work and prevent loops?

Oh - we use unique seven digit extensions on this site and the remote sites, so hopefully no dial-plan issues. (ie unique 3 digit tie codes for each site such as "456", with 4 digit extensions beyond them)


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