2006 Dec 05 - Tue

NTP for Callmanager

Since Cisco generally recommends that the Callmanager server not be a member of an Active Directory domain, is is unable to make use of the time distribution protocols normally available to member servers and computers. As background, I think Cisco's stance is understandable, and reflects the quantity of testing Cisco performs with each upgrade and service pack install. If a server is a member of a domain, it is entirely possible that registry entries, dlls, or applications coulds be modified through Group Policies that may affect the reliable functioning of the phone server.

As an alternative to Microsoft's time distribution protocol, the industry standard NTP (Network Time Protocol) can be used. The Callmanager installation automatically installs an NTP client, but does not turn it on.

To turn it on is quite simple. Obtain an address of an NTP server, either on your network or an external one. Using the one that drives the Active Directory domain controllors would be best. As a last resort, an address from pool.ntp.org could be used.

Edit the file C:\WINNT\system32\drivers\etc\ntp.conf and apply the ip address to the server line. Save the file. Bring up Microsoft's Services management application. Set the Network Time Protocol service to Automatic and start it up.

The Event Log will record startup and synchronization messages for your reference.

Be aware that with each Callmanager upgrade you perform, the service may be turned back to Manual and the ntp.conf file may be overwritten. You may want to make a backup of the configuration file so you can easily re-apply after your next upgrade.