4+ Bridges

[TSlocum]

My company has 9 locations and we'd like to be able to call/transfer between all of them. We have 3CX at two locations so far with the bridge between working swimmingly.

I know how to set up bridges between 3+ locations, but I was just wondering what kind of impact having 8 bridges on each 3CX server would have on the system. Would it work fine, or are there implications in doing so? Network usage, server resource usage, etc?

 

[leejor]

Other than having to work out dialling plan logistics, adding additional Bridges shouldn't have much more impact than adding additional VoIP providers.

There are , no doubt, some large 3CX installs, with multiple bridges, in operation. Hopefully, a forum member, with experience with one of these, can comment on any issues that they had, and suggestions.

 

[TSlocum]

Thank you for the response. I have one other question. Is it possible to bridge three locations, A B and C, and have calls route from A through B to C? Without connecting A and C directly?

 

[leejor]

By using outbound rules, in PBX "B", you should be able to route though to "C" in the same way a caller in "A" could place an outgoing call from a trunk connected to "B". You will be using a call licence in "B", so depending on your situation it may not be the most efficient way to go.

 

[TSlocum]

So if User 1 at Location A makes a call to User 2 at Location C, how would I set that up at Location B? Would just an outbound rule to Location C suffice?

 

[leejor]

I'm sure that other forum member have put this to practice, I haven't, but in theory it should work like this...

If you were using four digit extensions at all locations (just to keep this simple), you would assign a prefix for each of the PBXs.
So...if a caller at PBX A wished to call an extension at PBX B, it's prefix might be 3, so they dial 32012 to reach extension 2012. Outbound rules strip the 3 and send four digits on the bridge trunk, that matches an extension at B and the call is connected.

If the prefix at PBX C is 4, the user at A dials 43102. Outbound rules leave the 4 on and send all 5 digits. At PBX B there is an outbound rule for 4XXXX to strip the 4 and send the remaining digits over the bridge to C. At C it connects to extension 3102.

The more possible routes you have, the more prefixes you will need and you will have to avoid conflicts with existing extension numbers in the tandem PBX. If you were going to set-up something like this , it would be a good idea to do so before all of the interconnected PBXs have had their extension numbers decided upon. Doing so with a large number of existing PBXs will take some planning. A web pattern of trunking is usually more efficient than a star configuration, where all bridge calls tandem through one PBX. It could all be made a bit simpler if, say, all extensions at one PBX were the 2XXX range, another were 3XXX, etc.

This for simple calls from one to another. doing call transfers may introduce other factors. There may also be issues with caller ID displaying something that makes sense to the called party.

Hopefully someone else can offer up some advice, saving you from "re-inventing the wheel"

 

[TSlocum]

A web pattern of trunking is usually more efficient than a star configuration, where all bridge calls tandem through one PBX.

This for simple calls from one to another. doing call transfers may introduce other factors. There may also be issues with caller ID displaying something that makes sense to the called party.

It seems that a direct bridge to and from each PBX will be the best way to go. I guess it won't be too difficult or tedious because we're installing 3CX at each location one at a time. I can just set up all the bridges as I go along.

 

[leejor]

If this is all still in the planning stage, I would suggest that you strongly consider using 4 digit extension numbers at each location and make each a unique range. Not only would it simplify outbound rules, and avoid number conflicts, it would allow users to know where a person was located given an extension number.

Keep in mind that just because you have trunks between each of the PBXs, doesn't mean you can't have a second,backup route, that tandems through another PBX if you limit the number of calls on the first route and they end up being busy.

 

[TSlocum]

We are using 4 digit extensions with each location having a unique range.

Thank you for all the help and info, it helped me plan better.

 

[netswork]

Also if you setup each system so system extensions dont overlapp, you dont have to use prefix codes.
For example

Site 1:
extensions 11XX
Conference Ext 7110
Ring Groups 8110
IVR 8120

Site 2:
Extension 12XX
Conference Ext 7210
Ring Groups 8210
IVR 8220

Or something similar you can direct dial each location without having to add prefixes, which I have found are annoying for users. A little planning will make it clean. The largest install I have is about 7 systems bridged. The only reason they went with bridging is for redundancy. If your sites are linked via a WAN or VPN and branch level redundancy is not needed you dont have to have a PBX at each site.