We currently have Lync Enterprise set up in one data center that does not have direct Internet connectivity.  We are planning on setting up an Edge and Director server, where the Edge server is in our DMZ in another data center.  The RTT between these two networks is about 80ms.  Is there any documentation regarding RTT requirements (e.g. for SharePoint, RTT must be <1ms between each server in the farm)?  Is there any documentation about the placement of the Director?

The Lync server planning guide gives the following advice "Provision your network to ensure a maximum end-to-end delay (latency) of 150 milliseconds (ms) under peak load. Latency is the one network impairment that Lync Server media components cannot reduce, and it is important to find and eliminate the weak points." The guide is available for download here and the quote comes from Chapter 2, which deals with infrastructure requirements.

You should allow for the latency introduced by the firewall.

The Director should be on the internal network. Since the Director is used to authenticate user, it would be best to locate it wherever most of the users are located. The Director drops out of the path once it forwards internal users to their home pool. For external users, the Director stays in the communications path, so keep this in mind when deciding on location.

Finally, you might not be aware that the Director is an optional role.

Hope that helps.

Hi,Trevor,

For the latency you can check the network infrastructure requirements on the Technet Document for more details,in your case 80ms should be ok but be aware of the performance.Microsoft has state in another document about Round-trip latency  between the two sites in a Metropolitan Site must not be greater than 20 ms for best practise,and also said  the perimeter network need not be stretched between sites.More details you can check http://technet.microsoft.com/en-us/library/gg679096.aspx. 

Director is an internal server and should be placed inside the internal firewall,you can check the director topology reference with the following link:

http://technet.microsoft.com/en-us/library/gg398228.aspx

Regards,

Sharon

• Proposed as answer by Sharon.ShenMicrosoft contingent staff, Moderator Tuesday, September 06, 2011 6:55 AM
• Marked as answer by Sharon.ShenMicrosoft contingent staff, Moderator Friday, September 09, 2011 1:36 AM

Hi,Trevor,

For the latency you can check the network infrastructure requirements on the Technet Document for more details,in your case 80ms should be ok but be aware of the performance.Microsoft has state in another document about Round-trip latency  between the two sites in a Metropolitan Site must not be greater than 20 ms for best practise,and also said  the perimeter network need not be stretched between sites.More details you can check http://technet.microsoft.com/en-us/library/gg679096.aspx. 

Director is an internal server and should be placed inside the internal firewall,you can check the director topology reference with the following link:

http://technet.microsoft.com/en-us/library/gg398228.aspx

Regards,

Sharon

• Proposed as answer by Sharon.ShenMicrosoft contingent staff, Moderator Tuesday, September 06, 2011 6:55 AM
• Marked as answer by Sharon.ShenMicrosoft contingent staff, Moderator Friday, September 09, 2011 1:36 AM

We do not plan to have the pool stretched between sites, but the Director and Edge server would be sitting at a different site.  I assume by stating that the Edge cannot be stretched between sites, they mean that you cannot have multiple Edge servers on the same VLAN in different sites?

I'm really only looking at putting a distance between the roles.  So the Enterprise and SQL Server sit in the remote location, while Director, Edge, perhaps Media sit in a location at the user's site.  We have such a small userbase (about 1000 - 2000) that I don't need to add more than one server to the Enterprise pool.

yes,what you understand"Edge cannot be stretched between sites" is right,if you just deploy one edge server that should be ok.Putting server roles in different locations is working,just be aware that you should have a stable WAN connection.

Regards,

Sharon

150ms is one-way latency or round trip latencythanks