Hello,

We have Exchange 2013 mailboxes are placed in Europe, Skype for Business Servers in Europe and Asia. Users in Asia shall utilize Exchange 2013 UMS Features. User's mailboxes shall remain in Europe. There is a Long distance between Lync and Exchange and want to avoid latancy problems.

What is the best practice to implement an Exchange Voice mail solution with a "long" distance between Lync and Exchange?

Thanks for your help.

Hi Silke,

The network requirements or recommendations for UM servers are as follows:

• UM servers using gigabit (1,000 megabits per second (Mbps)) or 1 gigabit per second (Gbps) Ethernet adapters.

• UM servers connected to multiple-switched, fast Ethernet networks of gigabit Ethernet connections.

• A round trip time from the IP gateway or IP PBX of less than 300 milliseconds.

In branch office scenarios or over WAN connections, use the G.723.1 codec instead of the G.711u or G.711A codec to minimize the network traffic that's passed between your IP gateways and your UM servers.

So if you have the required QoS all the time dedicated for Exchange UM - Lync then you should have no issues.

References:

Understanding System Requirements for Unified Messaging

https://technet.microsoft.com/en-us/library/ff629380%28v=exchg.141%29.aspx?f=255&MSPPError=-2147217396

The calls will be answered by the system where the mailbox is, so I'd suggest there's not much you can do about latency issues other than get the mailboxes closer to the users.  That said, voicemail latency isn't as big of a deal typically as regular voice latency because the two parties are unlikely to talk over each other much.  It may go unnoticed unless it's extremely bad.  I'd test it before I make any big decisions.