Publisher - Subscriber = 40ms should be the RTD. Are there any value of RTD between the IP Phone and the CCM Server. Also would like to know how about if I put the IP Phones over WAN. How much BW would be required for the phones to connect with the centralized server.
RTT of 800+ ms are common for sites via VSAT. WAN codec will be g729 rather g711. The most important requirement is that the round-trip delay from one server to any other server needs to be less than 40 milliseconds. It's also good to allocate about 1.5Mbps bandwidth for intra-cluster communication. A good practice is to change your QOS policies so that intra-cluster communication gets better than best-effort service. The easiest way to do that is to use ACL's and match based on source and destination IP address, making sure that any traffic from any CCM server to any other CCM server will be matched. The BW problems may have been due to interrupted intra-cluster communication.
that number has changed with the 6.1 release, it's 40 ms one way or 80 round trip, not 40 round trip as in previous releases.
The maximum one-way delay between any two Unified CM 6.0 servers should not exceed 20 msec, or 40 msec round-trip time (RTT). Beginning with Cisco Unified CM Release 6.1, the maximum one-way delay between two Unified CM servers can be up to 40 msec, or 80 msec round-trip time. Measuring the delay is covered in Delay Testing. Propagation delay between two sites introduces 6 microseconds per kilometer without any other network delays being considered. This equates to a theoretical maximum distance of approximately 3000 km for 20 ms delay or approximately 1860 miles. These distances are provided only as relative guidelines and in reality will be shorter due to other delay incurred within the network.
To add to these great points, the RTT for clustering accross the WAN were adjuested as pointed out to 80ms, however you need more bandwidth as the delay increments (check out SRND for more details). As far as the phones delay I would suggest staying below 200 ms as you may notice delay issue when you go over that number, i.e. delay dial tone, etc (slightly). 800 ms will surly create noticable delay, i.e. you press speaker button you'll wait 2 or so seonds before it engages, etc.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.