CUCM Cluster with MCS-7845-I4

[mkulovainio]

Hi,

I am doing a CUCM design for a customer with MCS-7845-I4 servers. We are building a Central solution with CUCM,CUPS, UCCX and Unity Connection.

There will be 4 CUCM servers. All gateways (about 40) will be H323, each with 1 E1 for PSTN. All gateways will have DSP for conferencing and Codec. MoH will be enable on CUCM. G.729 cross the WAN. G.711 to access Unity and UCCX from all sites configured with Regions to avoid codec issues.

The solution should support 2500 phones in phase 1.

My plan for Phase 1 is as follows:

1. Publisher/TFTP

2. Sub 1 - Sub 2(Primary and Failover)

3. Sub 3 - Sub 4(Primary and Failover)

4. Sub 2 and Sub 4 will be MoH

5. Sub 2 and Sub 4 will be backup for Media processing such as Conferencing. They will aslo Annuciator etc. This means I wont enable Cisco IP Voice Media Streaming App service on Pub, Sub1 and Sub 2

6. CTI manager will be enable on all subscribers

Question: Should I use backup TFTP on lets say Sub 2, what is your best experience?

The solution should support 8000 phones in phase 2.

My plan for Phase 2 is as follows:

1. Publisher

2. A separate TFTP server

Rest as Phase 1.

Question: Should I use backup TFTP on lets say Sub 2, what is your best experience? Can I manage phase 2 with Phase 1 design?

Any feedback would be much appreciated regards the total design, maybe you have a better design solution, maybe I have missed something here.

Br,

Mattias

[Rob Huffman]

Hi mattias,

It really looks like you've done your homework here

My one comment is on the need for "dedicated" TFTP servers;

TFTP Server

The TFTP server performs two main functions:

•The serving of files for services such as MoH, configuration files for devices such as phones and gateways, binary files for the upgrade of phones as well as some gateways, and various security files.

•Generation of configuration and security files. Most files generated by the Cisco TFTP service are signed and in some cases encrypted before being available for download.

The TFTP service can be enabled on any server in the cluster. However, in a cluster with more than 1250 users, other services might be impacted by configuration changes that can cause the TFTP service to regenerate configuration files. Therefore, Cisco recommends that you dedicate a specific server to the TFTP service in a cluster with more than 1250 users, with Extension Mobility, or with other features that cause configuration changes.

The TFTP server is used by phones and MGCP gateways to obtain configuration information. There is no restriction on the number of servers that can have TFTP service enabled, however Cisco recommends deploying 2 TFTP servers for a large cluster, thus providing redundancy for TFTP service. More than 2 TFTP servers can be deployed in a cluster, but this can result in an extended period for rebuilding of all TFTP files on all TFTP servers. When configuring the TFTP options using DHCP or statically, you can normally define an IP address array (more than one IP address) for a TFTP server. Therefore, you can assign half of the devices to use TFTP server A as the primary and TFTP server B as the backup, and the other half to use TFTP server B as the primary and TFTP server A as the backup. To improve performance on dedicated TFTP servers, you can set service parameters to increase the number of simultaneous TFTP sessions allowed on the server.

When upgrading a Unified CM cluster, Cisco highly recommends that you upgrade the TFTP servers after the publisher and before any other server, also allowing additional time following the upgrade for the TFTP server to rebuild all the configuration files. Either use the typical Cisco TFTP - BuildDuration time or use the real-time monitoring tool to monitor the Cisco TFTP - DeviceBuildCount until it stops incrementing. This upgrade order ensures that any new binaries and configuration changes are available before the upgrade of other services in the cluster. If you are manually adding a specific binary or firmware load for a phone or gateway, be sure to copy the file to each TFTP server in the cluster.

Cisco recommends that you use the same hardware platform for the TFTP servers as used for the call processing subscribers.

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/callpros.html#wp1043790

Cheers!

Rob

[David Hailey]

If you have over 1250 phones (1000 phones is the usual number), you need a dedicated TFTP server.  Now, your TFTP server can provide other services such as MoH but your Publisher should be a DB only server.  Example architecture for 2500 phones:

Pub

TFTP

Sub 1 (Active)

Sub 2 (Backup)

You could also have:

Pub

TFTP / MoH

Sub 1 (Active)

Sub 2 (Backup)

In any case, you need a server to offload TFTP from the Publisher.  This is clear outlined in the SRND.  In terms of support, there isn't much argument against it.

Hailey

Please rate helpful posts!

[mkulovainio]

Hi David,

thanks for your response,

Ok, I will have 5 7845 servers and I dont really want to add another one to the BoM, and I want to have 2 groups of subs with a maximum of 4000 active phones/group. Now it looks like I need to do a design to support 8000 phones with 5 servers, what would be the best design?

how about this,

Pub

Sub 1 (Active)

Sub 2 (Backup, TFTP)------I dont have any experience using TFTP on Sub

Sub 3 (Active)

Sub4 (Backup,MoH)

If I really need to add another 7845 to keep up with the design I would do it like this:

Pub

TFTP

Sub 1 (Active)

Sub 2 (Backup,MoH)

Sub 3 (Active)

Sub4 (Backup,MoH)

What is your opinion?

Mattias

[David Hailey]

Option 2 is a supported option and much better than the first. The first doesn't address SRND design recommendations. You need a dedicated TFTP.

[mkulovainio]

David,

using the MCS-7845 servers, how many phones would you register on the active subscriber. Transcoding and Conferencing would be done on gateway DSP.

7845 supports 7500 phones, I have put the limit to 4000phones/server.

I am thinking to increase this to  5000 phones/server, what do you think about this?

Thanks for support!

Mattias

[David Hailey · Accepted solution]

5000 would be fine.

Hailey

[mkulovainio]

Thanks David,

you answered my question.

Mattias