same SIP Trunk with another 3cx server

[Yellow_Flash]

Hi,

We have a 3cx server(say, xxx.companyname.uk) in our office and it has 3 SIP trunks.
I would like to know whether it is possible for us to use these same 3 SIP trunks with another 3cx server (say, yyy.companyname.uk, remote server) when there is an issue with Primary server.
Thank you.

 

[AWS2P]

Hi,
best is to do test, i've done a try and even if trunk register with no problems on 2nd PBX it never receive incoming calls.
Have after deactivated trunk on first pbx, but no more incoming calls, so surely there's a provider security restricting this to be done to prevent hacking.

 

[i3]

I don't think you can keep the trunks registered on both systems at the same time. It would be a manual process of when the first pbx has issues, to register the trunks on the second pbx. Now you should be able to keep the trunks configured on the 2nd pbx just have them disabled so that all you need to do is activate them in the time of pbx1 issues. With all that in mind, you will need to ensure that you have firewall rules and everything work and are pre-configured on the 2nd pbx.
Secondly, depends on the configuration of your trunks and provider.

Are you using IP based auth for the trunks or digest?
Do you have to update public ip of pbx at the provider?
Check with the provider, mine here in US (siptrunk.com) allows for a "backup trunk" for all our trunks.
So I keep primary trunk registered on pbx1 and backup trunk registered on pbx2. Provider allows to failover from primary trunk to backup in the event of unreachable pbx1.

 

[leejor]

If the provider allows SIP Forking (ask them), then it's possible, but not advised. Many providers will forward calls to another number if the primary route is un-registered.

 

[AWS2P]

I don't think you can keep the trunks registered on both systems at the same time

my test proved the opposite, the recording of trunk was done on both PBXs (green both), that said, it did not work even after having disabled the trunk of the 1st PBX. incoming calls were forwarded to the degraded mode number used in case trunk failure. So surely my provider makes this impossible for security reasons and considering the trunk unavailable therefore returns the calls to the backup solution.

 

[cobaltit]

So the answer is a very straightforward maybe .

For registration-based trunks, the answer is yes but.... For a 3CX configured failover scenario this works perfectly. You can replicate this by configuring the trunks on both PBXs and then manually disabling the trunks on the second PBX. This is basically what 3CX failover does. If you have 2 or more PBXs with the same registration-based trunk configured, then calls will go to the most recently registered PBX which is a bad thing. If the trunk(s) are disabled on the 2nd PBX then they will only go to the first PBX. Then if the first PBX goes down, you enable the trunks on the 2nd PBX and that should be it.

If you have IP based trunks and can configure failover trunk routing you can accomplish something similar.

Either way you don't want to try and be sneaky about it. Tell your provider what you are trying to accomplish and find out the the supported way of accomplishing your goal is.

 

[Yellow_Flash]

@aws2p @i3 @leejor @cobaltit Thank you for the replies.
I had a check with the Trunk provider, and what they have informed me is,

"You can register up to 5 devices against one sip account, but make sure you keep one device on standby if the devices are PBX systems because we will send the request on all the active devices and there will be a conflict if there are two different PBXs registered on the same account."

So, I think it is clear that I can register the same trunks on another PBX, as long as I don't activate trunks on both PBX at the same time.

 

[leejor]

So, I think it is clear that I can register the same trunks on another PBX, as long as I don't activate trunks on both PBX at the same time.

Depends on what you mean by "activate". It sounds as if your provider will allow more than one device to be concurrently registered, which means, if trunks at both PBXs are registered, then both will ring on an incoming call. Ideally, you want the second PBX powered down, until needed, or in some other way, isolated from the internet.

 

[Yellow_Flash]

Depends on what you mean by "activate". It sounds as if your provider will allow more than one device to be concurrently registered, which means, if trunks at both PBXs are registered, then both will ring on an incoming call. Ideally, you want the second PBX powered down, until needed, or in some other way, isolated from the internet.

Doesn't it also mean that I can keep the trunk active on One PBX and disable the trunk on the Second PBX and it would work fine, instead of powering down a PBX.

 

[leejor]

If you are able to prevent it from registering, then , yes.

 

[Yellow_Flash]

If you are able to prevent it from registering, then , yes.

If we disable the trunk, will it register back on its own?
Also, this scenario is when there is no network connectivity in the office, so I believe trunk will be unregistered.

 

[cobaltit]

Disabling the trunk stops it from trying to register until you enable it. So when you enable it, it will then try to register. Probably better to disable the trunk regardless of internet connectivity so the logs don't spam the failed attempts. It might also set off alerts each time

 

[Yellow_Flash]

Disabling the trunk stops it from trying to register until you enable it. So when you enable it, it will then try to register. Probably better to disable the trunk regardless of internet connectivity so the logs don't spam the failed attempts. It might also set off alerts each time

Disabling the trunk at primary server stops it from registering there, right? If I enable the trunk at secondary server, is there any chance that the trunk will try to register with primary sever too?
I was under the impression it will register only on the sever where we enable it.
Please clarify.

 

[cobaltit]

Well I'm assuming we are talking about 3CX so yes, disabling the 3CX in 3CX only applies to the 3CX instance you disable it at.

 

[Yellow_Flash]

Well I'm assuming we are talking about 3CX so yes, disabling the 3CX in 3CX only applies to the 3CX instance you disable it at.

Yes,3cx only. Disabling the trunk in one particular instance will disable the trunk for that particular instance, and enabling the trunk for another instance will enable the trunk for that particular instance only. That's what I thought.