centralised vs distributed deployment

[Peter Coggle]

Hi,

We are planning to have a remote site with around 30 users.

The one way latency from our datacentre (where our CUCM servers are located) and the remote site is around 160ms.

What would you suggest for our remote site -? centralized deployment or a distributed set-up with a CME at the remote site?

When I check the cisco SRND, I dont see any hardcore latency limit suggestions for remote site deployments.

I find the following lines "The influence of latency on design varies, based on the type of Unified Communications service considered for remote deployment. If a voice service is hosted across a WAN where the one-way latency is 200 ms, for example, users might experience issues such as delay-to-dialtone or increased media cut-through delays" from   http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/8x/uc8x/models.html"

What criteria should I have for deciding the deployment model?

Experts, please share your experience.

Many thanks,

Pete

[Dennis Mink]

Dont put a CUCM on a site with 30 users and a rtt of 160, if you distribute your cluster, the 80 ms RTT requirement for cluster replication will not hold.

add users to the centralised cluster and if you want you can use CME on the remote site for fallback (SRST reference)

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/8x/uc8x/models.html

and search this document for 80msec (wan considerations)

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[Peter Coggle]

thanks a lot for the reply, Mink.

I was just confused if we should add those remote users to our CCM in a datacentre and have the site as a SRST site or have a CME for the remote office.

Regards

Pete

[Nishant Savalia]

Hi Peter,

First of all would like to suggest to reduce your one-way latency of 200 ms. Because,The telephone industry standard specified in ITU-T G.114 recommends the maximum desired one-way delay be no more than 150 milliseconds. With a round-trip delay of 300 milliseconds or more, users may experience annoying talk-over effects.

Keeping in mind the above point, will recommend you to have Distributed deployment with call processing server as CME as you have only 30 users now unless and until you reduce your one-way latency.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/8x/uc8x/models.html#wp1044021

Regards,
Nishant Savalia

[Peter Coggle]

Thanks a lot for the reply, Nishant.