I've got a small Call Manager 4.2(3) cluster, that contains 1 Pub and 1 Sub.
Cluster is configured with default device pool, that using manually inserted Date/Time group.
There is one Call Manager group is configured, where Sub is the 1st priority, Pub is the 2nd priority.
As a result, IP Phones, associated with default device pool, are registered with Sub, i.e. as I need.
The problem is in that IP Phones got their time value and format (except separator) from Subscriber,
while they registered to Subcriber. They do not take time from date/time group of their device pool.
It's very, very strange.
I've tried to reconfigure Call Manager Group by assigning the 1st priority (1st place in list)
for Pub, and second one for Sub. After resetting all becomes fine. Again reverted back
(Pub-Sub to Sub-Pub) and the problem returns.
Any advice will be highly appreciated.
Those date time groups are just timezones. It obviously has to compare it to something, and it does that by comparing it to the local time of the boxes. Therefore if you servers are in different regions and are not NTP sync'd, when the phones register to different subscribers you will get different time. How do you think DTG Groups work? Magic? Also if you think it has nothing to do with the local server time why would anyone Cisco releasing DST patches?
Tobvian as I said originally check you correlation of your particular DTG to your subscriber OS, its ALWAYS going to rely somewhat on the subscriber OS!!