Hey everybody!
Today I'm going to share with you a technical case for CloudUSM.
ISSUE DESCRIPTION
The Long Number is not shown correctly to the called party when making a call from a third party to PSTN via CloudUSM. Then, through U1960, the E1 Pilot (unified) number is always shown instead of the user's long number.
VERSION INFORMATION DETAILS
CloudUSM V600R019C00SPC126;
U1960 V200R003C50SPC500.
Network topology
OPERATION SCENARIO
The customer had Huawei extensions with the PRI lines connected to Huawei IPT for the DID.
He has Microsoft Teams with extensions range 88xxxx (where xxxx is the same extension number as Huawei).
Both systems are linked via SIP trunk and internal calls work normally.
When the extensions configured with a long number on CloudUSM make outgoing calls the long number, caller ID is shown correctly.
In the case of extensions on Microsoft Teams making outgoing calls, it goes through the SIP trunk with Huawei and then via PRI lines. It's working fine, except the caller ID shows the Pilot number of the PRI.
The customer needs the long number caller ID to be the same as the corresponding of the Huawei extensions and not the pilot number.
ISSUE ANALYSIS
Confirmed that it is a new installation and has not worked before.
The customer reported that he configured the Long number on CloudUSM only and added the same extension numbers on Microsoft Teams.
Asked the customer to configure a long number on the Microsoft Teams, because for numbers registered on USM, USM can recognize them and change their configurations. However, when it receives calls from other third-party SIP servers, USM is unable to do the change; it will just forward the call according to the prefix policy of the number.
After configuring the long number on Microsoft Teams and having tested the caller ID, it is still shown as E1 pilot number and not as the extension long number configured.
Collected USM SIP traces and found that Microsoft Teams sends the long number to CloudUSM and CloudUSM forwards the message to U1960 with the same long number.
We suspected a configuration issue with U1960, so we asked the customer to collect the U1960 data.bin file. We found there was a Calling number change '300', which changed the calling number to be the unified number of the E1 Trunk.
ROOT CAUSE
Calling Number Change '300' is configured for the national prefix of 90 to change the calling number to the E1 Pilot number.
SOLUTION
Disable the calling number change '300' for the prefix 90.
SUGGESTIONS
When experiencing such problems, always check the configurations first, because the majority of all issues are due to wrong or missing configurations. After that, focus on the signaling or the responses that should exist, as well as the messages that should be captured in each scenario.
Thanks for reading and hope you've learned something from this case!
