VM with remote off-box storage

[jcarr]

If I configure voice (or unified) messaging to use an off-box Exch 2k message store, with the exchange server across a WAN link from the Unity, what are the considerations? Do I need QoS over the WAN to handle streaming when playing back to a subscriber over the phone? Or does a telephone caller subscriber retrieving messages have to wait for the message to download (possibly a long time over a busy slow link)?

[kechambe]

This type of design is not something that should be taken lightly. Thanks for asking first.

Unity streams the messages over RPC from Exchange. Unity accesses Exchange real time during several points in the TUI conversation. If access to Exchange is delayed during these interactions, there will be gaps of silence while Unity waits. Depending on delay, these can be very significant.

Some others and I just wrapped up testing for this type of configuration. Our results and requirements for support will be documented in the Unity 4.0 Design Guide. These are most likely what the results/requirements will look like.

-The Unity partner server must be on the same LAN as Unity (Server with the Unity_ mailbox)

-Unity can not have Exchange installed on box

-Unity can service only 1 Exchange server connected over a WAN link (This server can not be the DC/DG which Unity is synchronizing with)

-40 ms of one-way delay is that maximum

-All traffic between Unity and the remove Exchange server must be prioritized

These are the bandwidth requirements. (I hope this comes out good once I post it)

WAN Speed Codec LLQ Priority Queue (Voice) in Kbps Number of Calls Call to Subscriber Ratio Maximum # of Users Maximum One-way WAN Delay

256K G711 109 1 1:25 25 40 ms

512K G711 219 2 1:25 50 40 ms

256K G729 109 4 1:25 100 40 ms

512K G729 219 8 1:25 200 40 ms

T1/1536K G711 657 8 1:25 200 40 ms

T1/1536K G729 657 25 1:25 625 40 ms

Hope that helps...

Keith

[kechambe]

(WAN Speed) (Codec) (LLQ Priority Queue (Voice) in Kbps) (Number of Calls) (Call to Subscriber Ratio) (Maximum # of Users) (Maximum One-way WAN Delay)

[jcarr]

very helpful. I was hoping that for some of my smaller sites, that I could have a local Unity server but a common Exchange store across the WAN. As our WAN is, uh, sometimes challenging to deal with, it sounds like it would be preferable to have a small local Exchange server. The users will probably welcome this anyway as they complain now that their email access is too slow.

[kechambe]

Yeah, sounds like your making the right decision in not trying to deploy in this manor.

Keith