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Bandwidth capacity question (CUCM & UCCX)

We're planning on spliting our UC environment (CUCM, UCXN, UCCX) across a WAN.  By looking at the SRND's for each, I estimate that we'll need 3.7Mbit bandwidth on the WAN just for intercluster communication for all the servers.  We have a 6Mbit connection, so that leaves us 2.3Mbit for actual voice traffic if we were to terminate calls on the other side of the WAN from the users.

The region settings between the WAN-connected sites are set to use G.729 for all calls, except for UCCX (this requires G.711, so it has it's own region).  My question is, when the call is sent from UCCX to the Agent, will this downgrade the call quality to G.729?  Meaning, the only time the calls will be using higher bandwidth is when they are in queue with UCCX (G.711), and once the agent takes them, they will reduce bandwidth to G.729.

Does this sound correct?

Everyone's tags (2)
Hall of Fame Super Silver

Bandwidth capacity question (CUCM & UCCX)

How many servers do you have on each side?

6 Mbps does not seem like sufficient bandwidth to split your cluster, as you will need 1.5 Mbps for each rote CUCM, 1.5 for ICCS traffic.

About 2-3 Mbps for UCCX depending on BHCA and

How many UCON ports are you configuring as this is the biggest one you  need to look at, i.e. you need 7 Mbps for every 50 ports?

For your second question the answer is yes codec will change to G729 when call is extneded to agent. The rest sounds correct.




Bandwidth capacity question (CUCM & UCCX)

Hi Chris,

We have 2-node clusters of CUCM, UCXN, and UCCX.  1 node of each cluster will be in each physical site, separated by 6Mbit WAN (MPLS).

Are you saying we need 1.5Mbit for each node (total of 3Mbit), or between the nodes (1.5Mbit total) for the CUCM and another 1.5Mbit for ICCS?  This was a little hard to grasp in the SRND as well, which is why I came here.

So basically we have:




UCCX Master





UCCX Secondary

Unity currently has 32 ports configured.  UCCX typically has 5-20 calls on hold during peak, and agents toping out at about 75 peak concurrently logged in.

I'm getting the sinking feeling that 6Mbit isn't going to cut it, but I don't have a solid tool (or understanding of how to) profile the current ICCS traffic footprint.  I can easily calculate bandwidth needed for voice traffic, but the ICCS stuff isn't very deeply described in the document.

Hall of Fame Super Silver

Bandwidth capacity question (CUCM & UCCX)

You have to separate these into applications:

CUCM split cluster bandwidth requirements:

ICCS real-time bandwidth - 1.5 Mbps

Database/firewall synchronization bandwidth - 1.5 Mpbs for each remote SUB in your case just one so 1.5 it is

Total CUCM requirements = 3 Mbps

This is all defined in CUCM SRND


32 --> 32/50*7 Mbps = 4.5 Mbps

This is decribed in UCON design guide


based on 10K BHCA

UCCX to UCCX server synchronization - 1.2 Mbps

UCCX to UC Manager JTAPI - 0.8 Mbps

Total = 2 Mbps

Source - CCX SRND

So, 3 +4.5+2 = 9.5 Mbps required to split the cluster

In reality you will not need this much bandwidth, but these are Cisco guidelines and requirements and in order to have TAC supported system you must obey them.

HTH, please rate all useful posts!



Bandwidth capacity question (CUCM & UCCX)

This does indeed help, and thank you.  We like to stay on TAC's good side...:)

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