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New Member

Unity connection High availability questions

I am working on getting CUC clusters in different data centers.

I have few questions which I dont have a setup to perform in test lab

1. If we configure 250 ports on each server, CUC SRND says we need 35Mbps of bandwidh..

When this bandwidth is used ???

Is it to sync the Voicemail message???             

2. We configure in Line group to go to Subscriber  VM ports.

If we lose WAN connection between data centers, what happens to the voicemail ports and how is this affected to the users??    

Thanks in advance


Hall of Fame Super Silver

Unity connection High availability questions

1. Correct, that is the guideline, you need 7 Mb for 50 ports -->  50 * 90kbps per call = 4.5 Mbps + some overhead Cisco assumes :-)

2. Ports stay registered to their local UCON, so for users at data center A that UCON is going to be available and for users at data center B the other UCON is available. If there are no users at the unreachable data center then it wont be used for anything.



New Member

Unity connection High availability questions

Thanks for the reply Chris.

For my first question... You are right, we require 7Mbps for 5 ports... but is this bandwidth for between  Unity Connection  servers or between CUCM and CUC??

2. Another question to this

We are going to divide ports

Subscriber   Publisher


  0-50            51-100

101-150        151-200

201-250         251-300

We assign subscriber ports in the top list of the Linegroup.  so if we lose WAN are saying that it is still going to hit the port 0-50 . Correct??

What is going to happen when subscriber is it going to hit port 51 to get into Unity connection??

Hall of Fame Super Silver

Unity connection High availability questions

This is bandwidth between UCON servers, remember as message is being recorded on a port it is being replicated to the other server.

2. There is no reason to split them this way, simply configure 250 ports on SUB and 250 SUB on Pub, if one of the UCON servers is not reachable CUCM will route to the other via line group/hunt list routing when using SCCP.

I would urge you to use SIP instead of SCCP as then you dont have to worry about ports on CUCM and simply create 2 SIP trunks, one pointing to SUB and one to PUB.