Ibrahim,
Depending on where you are located you can take a global knowledge class such as this one:
Yes you can cluster Connection over the WAN. Below are the requirements in order to do so:
Connection Cluster Requirements When the Servers Are in Separate Buildings or Sites
•
Both servers must meet specifications according to the Cisco Unity Connection 8.x Supported Platforms List at http://www.cisco.com/en/US/docs/voice_ip_comm/connection/8x/supported_platforms/8xcucspl.html.
•For a cluster with two physical servers, both must have the same platform overlay.
•For a cluster with two virtual machines, both must have the same virtual platform overlay.
•For a cluster with one physical and one virtual machine:
–The specifications for the physical server and the virtual machine should match as closely as possible for available hard-disk space/vDisk space and for RAM/vRAM.
–When the hard disks in the physical server and the virtual hard disks in the virtual machine are not the same size, the smaller disks determine the amount of disk space available for voice messages.
–When the number of users supported for the physical server and the virtual machine do not match, only the smaller number of users is supported for the cluster.
–With Platform Overlay 1 servers, you must add 2 GB of RAM to the physical server so the amount of RAM in the physical server matches the 4 GB of vRAM configured for Connection on the virtual machine.
•Depending on the number of voice messaging ports on each Connection server, the path of connectivity must have the following guaranteed bandwidth with no steady-state congestion:
–For 50 voice messaging ports on each server—7 Mbps
–For 100 voice messaging ports on each server—14 Mbps
–For 150 voice messaging ports on each server—21 Mbps
–For 200 voice messaging ports on each server—28 Mbps
–For 250 voice messaging ports on each server—35 Mbps
Note The bandwidth numbers above are intended as guidelines to ensure proper operation of an active-active cluster with respect to synchronization traffic between the two servers. Additional conditions such as network congestion, CPU utilization, and message size may contribute to lower throughput than expected. Call-control and call-quality requirements are in addition to the guidelines above and should be calculated by using the bandwidth recommendations in the applicable Cisco Unified Communications SRND at http://www.cisco.com/en/US/solutions/ns340/ns414/ns742/ns818/landing_uc_mgr.html.
•The maximum round-trip latency must be no more than 150 ms.
•The network must use the following load-balancing techniques for connections to the Connection servers:
–The Connection servers are assigned a common DNS name with the Connection publisher server first.
–All user client and administrator sessions connect to the Connection publisher server. If the Connection publisher server stops functioning, the user client and administrator sessions must connect to the Connection subscriber server.
–Phone systems must attempt to route incoming calls to the Connection subscriber server. If no voice messaging ports are available to answer calls on the Connection subscriber server, the phone systems must route calls to the Connection publisher server.
•The TCP and UDP ports of the firewall must be open as listed in the "IP Communications Required by Cisco Unity Connection 8.x" chapter of the Security Guide for Cisco Unity Connection at http://www.cisco.com/en/US/docs/voice_ip_comm/connection/8x/security/guide/8xcucsecx.html.
•Both Connection servers must have the same software and engineering-special versions installed.
•Both Connection servers must have the same enabled features and configurations.
•Both Connection servers must be configured to be in the same time zone.
•Both Connection servers must connect to the same phone system(s).
•If the Connection servers contain dual NICs, the two NICs on each Connection server must be configured for fault tolerance using a single IP address, or one of the NICs must be disabled. Configuring the two NICs with distinct IP addresses for network load balancing is not supported.
•For selected servers supported for earlier versions of Connection, a memory upgrade. To determine whether your server requires a memory upgrade, see the applicable server-specific table in the Cisco Unity Connection 8.x Supported Platforms List.
•For selected servers supported for earlier versions of Connection, replacement hard disks. To determine whether your server requires hard-disk replacement, see the applicable server-specific table in the Cisco Unity Connection 8.x Supported Platforms List.
Thanks,
Don
