For the purposes of the present document, the following terms and definitions apply.
3GPP Access Operator:
an operator offering access network over 3GPP specified radio access form (e.g. GERAN/UTRAN).
3GPP Access Domain:
Domain administrated by 3GPP Access Operator.
the ability for the subscribers to access their IP Multimedia services over any access network capable of providing IP-connectivity, e.g. via:
3GPP (UTRAN, GERAN)
Non 3GPP accesses with specified interworking (e.g. WLAN with 3GPP interworking)
Other non 3GPP accesses (e.g. xDSL, PSTN, satellite, WLAN without 3GPP interworking)
a relation between two or more parties, it may include one or more of the following elements: roaming agreement, charging agreement, authentication agreement and settlement agreement.
Unless specifically stated otherwise, the word "domain" is used to denote an administrative domain. An administrative domain is under the control of an actor (e.g. company). Some domains used in the present document may (roughly) correspond to technical domains specified by 3GPP. The technical details regarding such relationships are not covered by the document.
The operator of 3GPP compliant IP multimedia CN subsystem (IMS). IMS operator provides the users of its IMS domain with identity/identities by which the users are known.
Domain administrated by IMS operator
IMS roaming refers to the possibility for subscribers of one IMS to obtain IMS services from an IMS the users have not subscribed to, due to a business agreement between the two IMS service providers.
Non-3GPP Access Operator:
an operator offering IP-connectivity over an access form not being conformant to 3GPP specifications (e.g. WLAN, xDSL).
PS roaming refers to the possibility for subscribers of one 3GPP operator to obtain GPRS service from an other 3GPP operators that users have not subscribed to, due to a business agreement between the operators.
Further definitions are given in 3G TR 21.905
For the purposes of the present document, the following abbreviations apply:
Personal Digital Assistant
Universal Integrated Circuit Card
x Digital Subscriber Line
Further abbreviations are given in 3G TR 21.905