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Comments on possible data center offsite

We are contemplating moving our existing data center located within our building to an offsite data center within the Dallas metro area. I have never done such a thing in the past and would like some input on the whole idea.

I have a certain comfort level in believing our Windows Servers and production systems will work without issue, however, the Cisco phone system causes me great concern. Basically we are looking at moving EVERYTHING off to the data center - servers, switches, routers, PRI's etc. The only equipment that would remain in the Dallas office would be the switches that the end devices connect to as well as a router to connect back to the off-site data center.

Here's a run down of the existing phone system....

Dallas Office


CallManager Cluster - version 4.0(2a)

212 IP phones (7960/7940)

45 Fax Lines via VG248

Phones connect at 100MB to 4006 switches with Dual GB Uplinks back to 6509 in data center.

CCM Cluster, Conference Connection, Unity connected to 6500 at 100MB.

NYC office


41 Phones (7960/7940) homed back to CCM cluster in Dallas via T1 point to point connection.

100MB Backbone with phones connecting to 3745 switch at 100MB.

Local gateway connections on site so local calls come in and go out locally.

Gateways and all phones are registered with the CCM cluster in Dallas.

No local Unity server. Exchange server local.

To connect everything we are looking at establishing a 10MB link from both the Dallas and NYC offices back to the data center. This link would be an MPLS private line connection via a DS3 circuit.

Any one have any comments on whether this would work? Things I may have not thought of....etc.

Thanks - Chris

Hall of Fame Super Silver

Re: Comments on possible data center offsite

You should not be concerned, what's going to happen is your Dallas and NY sites will basically become remote sites to the Data Center Site. What you need to evaluate is how many phones you have at each location and how much bandwidth is requeired, possibly forcing you to consider using g729 codec to voicemail region if VM servers will be at the HQ as well. 10MB is a lot of bendiwdth and you should be fine with g711. Make sure however that your QoS configuration is in place end to end on the network.


New Member

Re: Comments on possible data center offsite

Thanks for the input. We already use 729 so that should not be an issue. QoS is set up and working great. I figure there shoudn't be a problem with the NY site as we currently run that site across a T1. My main concern is the Dallas location (where I'm at). We are so used to connecting at 100MB (I know we aren't using full bandwidth but haven't done testing to see actual usage), I don't want to move forward and have issues with user experience.....

Re: Comments on possible data center offsite

only other thought here is that if you move CallManager to Dallas, which is fine.. make sure you have SRST configured for the site you are pulling the CCM from... If the link between Dallas and the Dallas datacenter go down, you will need to have SRST working to make 911 calls, etc. I assume NYC already has this configured.


New Member

Re: Comments on possible data center offsite

Good point....need to take this into account. I currently have a 3640 in place with POTs lines for 911 backup, etc. Would you suggest leaving it in the Dallas office and just set up SRST on it?

Re: Comments on possible data center offsite

I would just leave all your PRI's and POTs line you have configured in your Dallas Office, just setup SRST in case you lose a WAN connection from the new data center. If do not have SRST configured on that router in Dallas Office, and you lose your connection to the CCM Cluster, there is no way for a phone to make a call out....

I would just verify with TAC, but if you think about it, all you are doing is changing the Dallas Office from a central office to a remote office (when you look at it from Callmanager) If you were to add a new office to your current topology, you would buy a router with SRST, create you WAN link to the the corporate office. Supply a local PRI or PSTN services at that office, then plug in your phones.

So just keep in mind frame of the Dallas Office, will now be a remote office to CallManager. Set it up like a remote office in the routers for SRST and you should be set.

Hall of Fame Super Silver

Re: Comments on possible data center offsite

Keep in mind that the internal calls wihin Dallas site will not go through the data center. Only the SCCP signaling will go to the data center, RTP stays on local switches. 10 Mb will be sufficient. When you make a call from dallas to NY, if you allow WAN calls it might now go via the data center based on the routing protocol metric.

Another thing to look is how you do conferencing. If you were using CCM to provide conference sessions, now the conferences within Dallas will also go through the data center. You migh want to think about configuring DSP farm on the Dallas site.


New Member

Re: Comments on possible data center offsite

Hello CHRIS ,

Since you are moving to a Data Center , I assume that this Data Center is protected strictly with Cisco ( or any other Brand ) Firewalls. Make sure that the Firewalls will permit all the needed IP Addresses and Ports to flow smoothly from both Remote Offices to your CCM Servers behind the assumed Firwalls.

1 - The needed TFTP Ports for Phone Registrations.

2 - The Needed Ports for Cisco Auto-Attendant if your are using it.

3 - Unity Ports , to be able to receive Voicemails.

Any other Service / Application that will need to access ur CCM Servers inside the Data Center.



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