I have a 7 server cluster on UCM running version 8.5x with over 3,500 devices. My question is should I have TFTP turned on on all my subscribers and if not where should it be turned on? Maybe just a server and a subscriber?
Thanks in advance for any replies.
I think the SRNDs recommend dedicated TFTP for over 1250 phones.
In real life, it's no big deal. Some deployments we have TFTP/MOH dedicated VMs, but often we don't.
If a phone can't find the TFTP server when it boots, it will use cached data and register anyway, so fault tolerance isn't a major issue.
During upgrades you generally have plenty of time pencilled into a maintenance window so unless minimising endpoint downtime is a big priority there's not much to be gained.
with the deployment size that you have, i think having two tftp servers and possibly running media services ont he TFTP servers would suffice and leave the publisher without call processing, tftp, media and tftp duties leaving you 4 subscriber servers across 3500 phones which is more than sufficient.
hope this helps.