Selected Cases for IMS Troubleshooting: http://support.huawei.com/carrier/docview?nid=SCL1000000486

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Symptom

IMS subscribers fail to make calls and the S-CSCF displays a number analysis error.

Problem Analysis

The phone-context parameter for the called number sent by the terminal is invalid. As a result, the ATS cannot normalize the called number in SIP URI format, which in return causes the S-CSCF to be unable to query the ENUM server.

Handling Procedure

1. Create a message tracing task to check the INVITE message.
2. The called number in the Request-URI of the INVITE message sent by the calling party is a SIP URI.
3. The INVITE message sent by the ATS contains the SIP URI, which is not normalized by the ATS.
4. Analyze the SIP URI sip:018xxxxxxxxx@5.219.2.2 and find that 018xxxxxxxxx is a local number.

   As stipulated in the protocol, a local number cannot be started with the plus sign (+).

5. The ATS converts the SIP URI to the example tel URI: tel:018xxxxxxxxx;phone-context==5.219.2.2. A local number must carry phone-context.
6. As stipulated in RFC 3966, phone-context can only be set to a global number or domain name.
7. The preceding analysis results indicate that the INVITE message carries an invalid number format. As a result, the ATS fails to convert the called number to a SIP URI format.
8. Modify data configurations on the terminal to ensure that the format of the called number in a message sent by the terminal is correct.

Suggestion and Summary

None.

Typcal fault case!

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