does somebody have a deeper insight why cisco put the recommendation into the deployment guide that the round trip delay between the unity server and the exchange partner server should be below 40ms ?
i have not a lot experience with unity but was asked why the unity server is recommended to be in the same datacenter as the exchange.
From personal experience, I would recommend that both servers be in the same subnet. I once had a Unity server less than two feet from its partner Exchange, but in a different subnet. We experienced intermittent errors where Unity thought Exchange was offline or not responsive and it would go into UMR mode; also MWI would get out of synch. Moving it to the same subnet as its partner server corrected this problem. Obviously you have the deployment guide, otherwise I would have recommended its design as a best practice - I'm sure others could comment on this as well.
placing unity servers next to the exchange server makes sense. in our case we have the problem, that all our mailboxes are going to be hosted at 3 !! data centers globally. this means, that not all sites are within <200ms network delay.
I think you can see where I am pointing to. is there any solution to place a "remote" unity server somewhere which does not need to be at the same site as exchange mailboxes are?
thank you for your help in advance!
The limitation is due to the fact that Unity uses the Exchange servers as store for the messages and to access it uses MAPI. I already talked to some of the Cisco BUs for a solution but up to 5.x of unity there is none. the MAPI connection is *very* sensitive to timinig and therefore the unity has to life near the Exchange otherwise it gets into trouble. I hope that with unity7 that gets better.
to put it easily,
all the voicemail is stored in your mailstore (in this case Exchange). Unity is constanty talking to partner server via the avnotifier to find changes to the inbox. Then notifying the phone system accordingly. (maybe light the phone if there is a new message)
makes sense - the avnotifier is quite time and resource sensitve then
is this connection a MAPI connection ? or a special API ? I ask because i am searching for a way to split the deployment even it is not recommended - and thought if a WAN optimization product like Ciscos WAAS product line could help
are you talking about this?
Cisco Wide Area Application Services (WAAS) Version 4.0
I am not sure but I think this is more for email. I did some searching and did not find much for vm.
Unity will still have have its reccomendations. There are other issues at hand also like indexing of inbox that might cause delays, and of course the items that Ginger mentioned.
yes wide are application services - WAAS has a MAPI connector to optimize MAPI conversation to exchange servers via the WAN network.
it is only an idea if that could be used to get around or extend that 40ms RTT / same LAN deployment limitation
in our project the exchange server are located in europe and the unity users are in the US and canada - and i am the WAN guy who has to implement the voice RT class to support the unity - which by deployment guide are in europe :-(
therefor it makes sense for us to at least look at possible ways to have another solution - putting exchange servers into the remote locations is no option - costs would be the same as for the RT class - the unity servers is needed anyway
depends on a lot of issues. unified messaging vs. voicemail only, number of mailboxes, sizes of servers, networking, locations, version of Unity and exchange and OS.
we would need more information to be able to help with this issue.