Can two sites with different voice subnets share same device pool, gateway and phone settings?

[rahul14]

Good day, I am seeking some assistance with a scenario. There is a main site that has a subscriber CUCM and some phones. There is also a remote site not too far away that has phones that connect to the same subscriber CUCM via an extended fiber LAN (layer2) -  they have the same voice subnet, device pool and utilize the same voice gateway for PSTN calls as the main site.

We are looking to change the remote site to layer 3(new voice subnet) and connect in an MPLS network however we want the remote site to remain using the same voice gateway and phone settings as the main site. Also note that the majority of phones  (approx 150) are at the remote site and approx 10 at the main site. The main site is primarily a host for the CUCM/gateway. Most of the phone communication is internal at the remote site as well as PSTN.

Can the phones at the remote site continue using the same device pool(regions, location settings, media resources etc) without any issues or additional configurations needed?  

[Jaime Valencia]

The IPs, vlan, site to site technology, etc. have nothing to do with the CUCM configuration when it comes to what you're asking. As long as the devices can reach each other for RTP, and CUCM for signaling / features, what device pool, location, MRG, etc. is up to you and your design.

[rahul14]

Thanks for replying Jamie. I  just wanted confirmation though that the remote site with new subnet over WAN  can continue using the same device pool (media resources, region, location settings) as the main site without configuring new region/location, transcoder, conference bridge settings etc. as it is with the extended lan. I am not sure this will cause any bandwidth issues so just checking.

Note also there is no dsp resources at the remote site.

[Jaime Valencia]

The only one who could tell if there will be BW issues or not would be YOU, based on codecs and number of calls, access to central site resources, etc. and the link BW you will have, if how much will be dedicated to voice, etc.

[Scott Leport]

Hi there,

As I know absolutely nothing about your environment, I will say that the only things I can think of which may have some dependency between CUCM and your IP subnet would be if:

1. Your CUCM is running the DHCP Service

2. Your CUCM has Device Mobility configured.

Point 1, it's best that you don't. I think I've encountered that only in one deployment and it was a long time ago!

Point 2, not a showstopper by any means, but as DMI uses IP subnet info, you might find that some of your call routing isn't quite working as expected, if a person is at a remote site.

If you're running none of these, then as mentioned already, your CUCM configuration doesn't need to change. That being said, I would actually take the approach and configure a whole new set of Device Pools, Regions, MRGL's etc etc. They may all have the same parameters as your central site, but for me it makes a clear distinction about what's site A, site B and so on and imo is more scalable in case of any future changes at the site.

[rahul14]

Thanks Scott!