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ip telephony sol

One of my client is looking for a ip telephony solution for 10000 users which include redundent CUCM  and Unity connection so could any one suggest me the best design.I am planning to to provide this server MCS7845I3-K9-CMD1, MCS7845I3-K9-UCC1 is it a good choice and also what all other ordering configurations for this server to be included in the Bill of Material i am not able to get the details.

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ip telephony solution for 10000 users

HI Raju,

Why dont you go for Cisco UCS box, you can have both the application on same box + future addition of CUPS/UCCX or CUXAC can be done on same hardware. So one hardware will support multiple application.

For sizing you can also use cisco sizing tool vailable.

For BOM, Cisco has free service to get the BOM related query solved. Plese open case at

Ronak Patel

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Regards Ronak Patel Rate all helpful post by clicking stars below the answer.
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ip telephony solution for 10000 users

Last >15.000 cluster I did was on a UCS. I chose the 7500 user per node template because it will only cost you 2 cores compared to the 10.000 user per node which will set you back to 4 cores per VM. The difference is either 2 VMs per B-blade or 4 VMs per B-blade.

Anyway... for 10.000 phones I would use:

1 Publisher (no subscribers)

4 subscribers for a total of 30.000 users. I presume you have 2 datacenters, if one side should fail you still have a 15.000 capacity for your 10.000 phones.

2 dedicated media servers for MOH and a bit of conferencing

2 dedicated TFTP servers.

For this you need at least 4 node licenses which are free depending on your licencing model. You have 5 UCS VMs on one site and 4 on the other. This means at least 3 ESXi VMware licenses (they are not cheap) and 3 blades. I would recommend that you have at least a spare B-series blade on each site with an active VMware ESXi installation because v-motion is really cool and makes your UCS administration a lot easier.

Personally I reserve 2 extra subscribers to terminate trunks, CTI and voice ports. They CAN be used for phones if needed. And because I work with more than 15.000 users per cluster I have a total of 6 subscribers for phones. Which brings my total to 13 servers. 13 servers is also the biggest configuration you can do without mandatory support from Cisco Professional Services so you still operate within the usual product specifications.

As for Unity, 2 servers, one in each site. They work a bit differently compared to the Callmanager. One is active and the other one is standby. I believe the current maximum concurrent port capacity on the Unity connection 8.x is 250. It totally depends on your mailbox usage. I am currently looking at a system with 4500 active mailboxes, with 144 licensed ports. My MRTG stats have shown a maximum of 4 concurrent ports over the last year. So a total overkill.  But I guess this depends on the kind of company your are in, features you use and communication behaviour of your users.


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ip telephony solution for 10000 users

Contact the local cisco sales office they will be glad to provide all needed support.

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