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Travis Russell

"The IP Multimedia Subsystem (IMS): Session Control and Other Network Operations"

This is exactly what
happens in the wireless world, but not yet in the Internet.
In a wireless network, there are several addresses that are assigned to the device
and the subscription that are communicated to the wireless network. The phone is
identified in the CDMA network via the Equipment Serial Number (ESN), which is
embedded within firmware of the phone itself. This number identifies the type (make
and model) of phone, as well as a unique serial number for the phone. This is used to
verify that the device is not stolen.
The subscription in the CDMA network is identified through a Mobile Identification
Number (MIN); this is usually derived from the phone number, although it does not
have to be. The MIN is used by the network to identify the subscription, but this does
not apply to the IMS. The MIN would only be used to identify the subscription within
the access network and not the IMS.
In the GSM network, a similar mechanism is used. The phone is assigned an
International Mobile Equipment Identity (IMEI) to identify the make and model of
the GSM phone. But its use is much different than the ESN in CDMA networks. In the
GSM network, the IMEI only identifies the phone and is not tied to the subscription.
The subscription is identified through another identity, known as the International
Mobile Subscriber Identity (IMSI).
Addressing in the IMS 91
The IMSI is programmed into the Subscriber Identity Module (SIM), which is found
inside the GSM phone.


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