Interoffice Trunk Setup with 3 PBX's

[andrewgroup]

Building SIP trunks between 3 offices allowing direct dialing extension

Office 1 uses extension 100 to 200 same for the 2nd and 3rd office..

would creating interoffice SIP trunks to allow direct dialing VIA sip using 5 digit dial with the 1st 2 digits being the office code be the most affective way to accomplish this?

 

assuming the 2 digit offce codes are 50, 51, and 52 what would the dial plan look like to route the call and to recieve a call?

[jag]

Building SIP trunks between 3 offices allowing direct dialing extension

Office 1 uses extension 100 to 200 same for the 2nd and 3rd office..

would creating interoffice SIP trunks to allow direct dialing VIA sip using 5 digit dial with the 1st 2 digits being the office code be the most affective way to accomplish this?

 

assuming the 2 digit offce codes are 50, 51, and 52 what would the dial plan look like to route the call and to recieve a call?

 

 

This can be quite complex, so lets just look at connecting up 1 site for the moment.

 

1. Create a trunk between site A and B and between B and A

 

2. In the dial plan on Site A, create a pattern match to grab all calls starting with 50 and 5 digits long, if found route them to the Site B trunk.

 

3. On Site B, use the pattern matching in the 'extension' field of the trunk to send the call to the specific extension.

 

For pattern matching look at the Wiki for a full explanation of how to do this http://wiki.pbxnsip.com/index.php/Inbound_Calls_on_Trunk

 

Repeat the process for all other sites.

 

NOTE: Inbound calls on trunk is dependant on how you set-up your PBX. If you use multiple domains you should use the tel:alias feature, if they are in one domain, then you can simply use the vanilla extension number to route the call directly to the extension.

You could also do this with DNS and not bother with a registered trunk.

There are many different ways to do this, it all depends on how you want configure the PBX

[andrewgroup]

With lot's of ways to accomplish this, leaves a large margin for error and the likelyhood that those with little practical experience setting up a configuration as described, what's the likelyhood we or others will accidently choose the most affective way to accomplish this goal. The Best Practices forums would be a wonderful place to have an open discussion and real examples of how best, (based on real experience) to create inter-office trunks.

[andrewgroup]

You could also do this with DNS and not bother with a registered trunk.

There are many different ways to do this, it all depends on how you want configure the PBX

 

could you clarify what this means in a practical example, on the surface this seems to be the solution but don't understand it perfectly"

 

using the following example

Hqrtrs has PBXnSIP on 2.2.2.2 with FQDN of pbx.newco.com extensions 100 thru 150

remote1 office on IP 3.3.3.3 with FQDN of oh.newco.com extensions 40 thru 49

remote2 office on IP 5.5.5.5 with FQDN of ky.newco.com extensions 40 thru 49

 

would be best served to make trunks to each other.....or can each office simple make speeddials for ext@IPaddress?

 

If you create Speed dials to an extension VIA the IP or FQDN it appears as if you conserve accounts and accomplish the same thing.

 

Hqrtrs can have phones register on remote PBX to monitor or help answer calls..

 

Then what are the benefits of trunks in this scenario?