select TFTP server

Answered Question
Dec 4th, 2007

i having 2 MCS 7835 server and i am supporting 2500 users. and i am made 1 publiser and 1 is subscriber. here my publiser is tftp server 1 is this selection is right(means may choose subscriber as tftp 1 server) or nor plz segest me..

I have this problem too.
0 votes
Correct Answer by ananddiwakar about 8 years 10 months ago

You can keep either Publisher or subscriber as TFTP server.

If you have configured Publisher as TFTP, it should not be an issue. In this case just make sure that IP phones are having subscriber as primary server and publisher as secondary.

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Overall Rating: 4.5 (5 ratings)
Correct Answer
ananddiwakar Tue, 12/04/2007 - 23:08

You can keep either Publisher or subscriber as TFTP server.

If you have configured Publisher as TFTP, it should not be an issue. In this case just make sure that IP phones are having subscriber as primary server and publisher as secondary.

allan.thomas Wed, 12/05/2007 - 01:36

Jay, I have noticed that you have posted the same question in the Unified Communications Applications 'load balancing across Publisher and Subscriber' which I have posted you a reply.

Further to my previous post, and in light of the fact that the cluster size will be supporting 2500 users, please be aware of the following regarding TFTP.

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 than1250 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 Cisco Unified CallManager 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 Unified CallManager Release 5.0, by default, caches the configuration files in memory and does not store them on the hard drive of the TFTP server. This default setting can be changed to place the configuration files on the hard drive of the TFTP server, but doing so will impact TFTP performance. Therefore, Cisco recommends that you do not change this default setting.

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



UCBNOCWAN Wed, 12/05/2007 - 03:15


I have a silly question here. I have worked on clusters where the TFTP service runs either on the Publisher or the Subscriber. I have never come across an instance where there is a separate TFTP server. If we have a separate TFTP server, do we need CCM to be installed on it or can it be any server?

allan.thomas Wed, 12/05/2007 - 04:19

Generally the actual deployment or cluster ratio 2:1 or 1:1 is dictated by the customers expediture at the day, and although we would like to follow best practice or cisco recommendations it is not always possible.

Cisco recommend that if you use a separate TFTP server then the same platform model should be used as for your subscribers.

In answer to your question, I have only specifically configured TFTP on a CCM platform, having said that you can certainly configure a Master TFTP and alternate TFTP servers for backup purposes, whereby the Master generates the configuration files and replicates them accordingly. For this reason, it would seem possible to configure your alternate TFTP on another platform, not necessarily with CCM, although I have never used this feature.

Take a look at the following document regarding Cisco TFTP, this provides more insight into the TFTP process including Master and Alternate TFTP.

Hope this helps.



UCBNOCWAN Wed, 12/05/2007 - 04:39


Thanks a lot. This certainly enriches my knowledge. Have a nice day.

Thanks & Regards,


allan.thomas Wed, 12/05/2007 - 04:47

You are most welcome, thank you for the ratings and best of luck.

Best Regards


UCBNOCWAN Thu, 12/06/2007 - 02:02

No need to be so formal Allan. It's my duty to rate helpful posts. All the best.



Hello Allen,

Thanks for the education on TFTP services in CCM. I would like to enable a second TFTP server in my cluster for redundancy. Up until now, we have always ran the tftp service on the publisher. I enable the tftp service on the subscriber server. Now what needs to be configured to get the two TFTP repositories in synch? Or does this happen automatically between the TFTP servers in the cluster? When I compare files on both servers they are different. I am on CCM 4.1.3.



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