Solved Switching Carriers - Duplicate DID Issue

[kriley87]

Hi there-

I am currently in the process of moving a bunch of DIDs from one carrier to another. Coming from FreePBX, you would just have your inbound routes which were trunk agnostic but in 3CX your inbound routes are tied to the specific SIP trunk where the DID is defined.

Here's my issue.. I have several number ports in place that are going to move a bunch of my DIDs from one carrier to another.. In order to ensure a smooth transition, I have trunks set up for both carriers on several systems, however, 3CX doesn't like duplicate DIDs even if they're assigned to different SIP trunks. Doing this results in inbound calls failing.

Since I am unable to add my DIDs tied to another SIP trunk since they're already defined with the original SIP trunk from the carrier I am moving away from, what are my options to ensure a smooth and seamless transition when my number port actually takes place?

I cannot afford to let my customers go down and have to rush in, delete the old SIP trunk and inbound routes and define the new inbound routes to the new SIP trunk provider.

Hopefully this makes sense.. Thank you!

 

[YiannisH_3CX]

Hi @kriley87

3CX is capable of handling multiple trunks with the same DIDs as long as it is set up correctly and your trunks can be configured to use Call source identification.
Are you using 3CX supported providers? If you do we could assist with the configuration.If not then you will need to figure out what the correct settings are.

The call source identification settings of each trunk consist of 2 parts. You can enable the first part and configure the settings that will allow the PBX to match the call to the correct trunk using the selected SIP field and value and you can also enable the "strict" section which essentially tells the PBX to try to also look at the number as well.



How the PBX does the matching can be found here: https://www.3cx.com/docs/sip-trunk-inbound-calls/

Alternatively what you can try is to disable Call source identification completely from both trunks and create identical inbound rules for both trunks. Then let the PBX try to match the call to a trunk and follow the correct inbound rule.

 

[kriley87]

Hi Yiannis-

Thank you for your reply! I'm using 3CX supported providers. My primary is Bandwidth and my new provider is Skyetel.

I took your suggestion and disabled the Call Source Identification from both trunks and inbound calls from my test DID that is assigned to both trunks are now working..

However, various other DIDs are not working even after this change even though they are assigned to the same two SIP trunks with Call Source Identification disabled. Not sure why if it worked for my test DID but not for other DIDs..

I will put in a support ticket if that makes it easier so someone can look at my configuration since I am using 3CX supported SIP trunks.

 

[YiannisH_3CX]

OK, now that we know the providers, things are a little easier (and more complicated). The reason why you have DIDs that are not working is because the format the numbers are coming in from the providers is the same. Both providers send the number in the E164 format (+1xxxxxxxx) so the solution i suggested above will not work.

Since Skyetel does not have Call source identification you will need to do the following to get this working:
1. Set both trunks to their default configuration
2. Delete all DIDs from the Bandwidth trunk including the main trunk number.
3. Replace the main trunk number with a fake number that does not belong to your DIDs
4.In the Bandwidth trunk, set your real main trunk number as the Caller ID in the Caller ID tab so you can still use the trunk for outbound calls.
5. Add all DIDs in Skyetel trunk in the E164 format.
6. Create your Inbound rules accordingly

This way the PBX will match ALL inbound calls to the Skyetel trunk until the porting is complete and once the porting is complete you can just delete the Bandwidth trunk and the config will remain the same.

Try it and let me know

 

[kriley87]

That did the trick! Thank you Yiannis!

 

[YiannisH_3CX]

Glad i could assist