RADIUS Attribute - Calling Station ID

As Per RFC 2865

This Attribute allows the NAS to send in the Access-Request packet the phone number that the call came from, using Automatic Number Identification (ANI) or similar technology.  It is only used in Access-Request packets.

A summary of the Calling-Station-Id Attribute format is shown below. The fields are transmitted from left to right.

Open

Type = 31 for Calling-Station-Id.

Length = (>= 3)

String = The String field is one or more octets, containing the phone number that the user placed the call from. The actual format of the information is site or application specific.  UTF\-8 encoded 10646 \[7] characters are recommended, but a robust implementation SHOULD support the field as undistinguished octets.