Unity 7.x MAPI connection to Exchange 2007 partner server

Unanswered Question
Nov 27th, 2009

I was wondering if you could advise me.  I am doing a migration from Cisco Unity 4.0.4 to 7.0.2.


We are currently running Unity 4.0.4 in a unified messaging scenario.  Unity 4 is based in a datacentre in Angel, London , which is where the current email servers are (Exchange 2003 servers). 


My new Unity 7.0.2 server will be sitting in a resource domain called ERME, geographically based in our local datacentre in Canary Wharf ,  London .  Our Exchange 2007 servers with the mailboxes will sit in the ERRF domain (within the same forest, two-way trusts setup already), but based over the WAN in two separate datacentres( East London & West London).


According to the Cisco Unity 5.x design guide it states, The Unity server needs to be on the same network as the “partner” Exchange server, and uses MAPI over RPC to connect to Exchange.  The network response time for MAPI calls from Unity to Exchange partner server should be less than 10ms.


My question is as follows.  My Exchange 2007 servers are based in two datacentres, East London,  West London .  If I install just a partner Exchange 2007 server with the mailbox server role (but hosting no actual user mailboxes) in Canary Wharf datacentre which is part of the same Exchange Server’s group (E.London & W.London), will the 10ms rule be adhered to?  Would the local Unity 7.x box talk directly to only the local Exchange Server which is its partner, or would it require a 10ms response to the rest of the Exchange servers in the E & W London datacentre?


Sorry to bother you, but I could not find any definitive documentation on this.


Kindest Regards


Emran  Bangladesh

I have this problem too.
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Ginger Dillon Mon, 11/30/2009 - 12:59

Hi -

From the same design guide, there is a statement in the "Physical Placement and Network Consideration" section, "Every Exchange server on which mailboxes for that Cisco Unity server are homed. If Cisco Unity is separated by a WAN from an Exchange server on which subscriber mailboxes are homed, a second Cisco Unity server must be co-located with the remote Exchange server."  Here are a couple of tests you could perform:

- From your Canary Wharf datacenter, at a PC, go into Outlook and access an Exchange inbox on an Exchange server in one of the other data centers.  What is your Outlook performance?  How long does it take to open the remote mailbox?  The unitymsgstoresvc account for the Unity 7.0 server will need to make the same trip any time a subscriber wants to check voice messages.

- From the Canary Wharf datacenter, ping the Exchange servers at the other data centers.  Is the response time to the ping < 10 - 20 ms?

If you use a new Exchange 2007 server as the Unity 7.0 server's partner, a mailbox called Unity_servername will be created on the partner server.  So the mailstore will at least host this mailbox.  This mailbox is used to receive incoming voice messages from external callers.  Note that if Unity's partner server is down, all subscribers are put into UMR mode - meaning voice messages can only be retrieved from the phone.  Only when Unity's partner server comes back online are the voice messages moved to the respective Exchange servers.  If the partner server is available, but Unity thinks a remote Exchange server is down, subscribers with mailboxes on that server will go into UMR mode.  I have found that if Unity is not in the same subnet as its partner or the other Exchange servers, Unity can "perceive" Exchange to be unavailable and go into UMR mode.  You will have to do some availability tests between Unity 7.0 server and the remote Exchange servers.  If the response time is not as stated or you see delays, you may have to install a second Unity server as mentioned in the design guide.

Sincerely, Ginger

bangladeshs Tue, 12/01/2009 - 02:39

Thanks Ginger for the reply, it has been very helpful.


Emran Bangladesh

bangladeshs Wed, 12/02/2009 - 03:31

I have an answer from Cisco TAC as follows.

"Looking at the notes, I can see the lst question you asked is "does
Unity only communicate with the Exchange partner server?"
The answer here is yes. Once the message arrives on Exchange, it is down
to Exchange routing to ensure that the message is sent to the correct
mailbox on the correct server within the Exchange cluster."

So I have two trains of thought here, one from Ginger saying the Unity 7.x Server needs to be in the same location as the Exchange 2007 partner and mailbox servers.  The 10ms MAPI response time will be upheld then.

The second from Cisco TAC being, that only the Exchange 2007 partner server communicates with Cisco Unity, and once a voicemail retrieval request is recieved by the Exchange 2007 partner server, it is up to the Exchange routing to do the rest.  This is suggesting that only the Exchange 2007 partner server needs a 10ms MAPI response time with Unity, and needs to be located together on the same LAN (Exchange mailbox servers can exist elsewhere on the WAN).

I am seeking confirmation of the Cisco TAC answer and will update this post as soon as I have a response.


Emran Bangladesh

bangladeshs Wed, 12/02/2009 - 03:48

Confirmation from Cisco TAC as follows.

"Unity is only concerned with the partner server. Once the message reaches
there it is down to Exchange to do the rest. Design guides for Unity will
not touch on recommendations for your entire Exchange setup, but will focus
only on the requirements for the partner server. As long as you adhere to
the requirements for the partner server then things should be ok, but
obviously if there are major delays on the Exchange side, this will have a
knock on effect."

Anyone has anything furthur to add?



MichaelRyker Thu, 12/03/2009 - 06:02


In my environment I am running Unity 7.0.2 and Exchange 2003.  My experience has been message delivery works as TAC describes, the message goes to the partner server for routing.  Message delivery is generally not a time-sensitive affair and users will not be aware of the time it takes for a message to be delivered to their mailbox.

Message access via the TUI is however a real-time process as Unity streams the WAV file directly from the mailbox while the user is on the phone.  I'm in agreement with Ginger, the TUI access is where Unity connects directly to the Exchange server hosting a particular mailbox and where latency will become a problem.

Good Luck,



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