Roaming helps ensure that a traveling wireless device (typically a cell phone) is kept connected to a network without breaking the connection. In wireless telecommunications, Traditional Roaming is a general term referring to the ability for a cellular customer to automatically make and receive voice calls, send and receive data, or access other services, including home data services, when travelling outside the geographical coverage area of the home network, by means of using a visited network. For example; should you travel beyond your cell phone company's transmitter range, your cell phone would automatically hop onto another phone company's service, if available.

Using another phone company's service can be done by using the subscriber identity in the visited network. Roaming is technically supported by mobility management, authentication, authorization and accounting billing procedures (known as AAA or 'triple A').

The term "roaming" originates from the GSM (Global System for Mobile Communications) standard[citation needed] used by mobile phones, which is the de facto global standard for mobile communications with over 80% market share. The term "roaming" can also be applied to the CDMA technology, (a channel access method that includes 3G, etc.).

Contents [hide]
1 Roaming in general
2 Home and visited networks
3 Roaming agreements
4 The roaming process
4.1 Location update
4.2 Mobile Terminated Call
5 Tariffs
5.1 Roaming between European countries
5.2 Roaming between other countries
6 Additional notions and types of roaming
7 See also
8 References
9 Standardisation Organizations
10 External links
Roaming in general[edit]

An SMS welcome to Proximus (Belgium) customers who have roamed ontoT-Mobile in the UK
Roaming is divided into "SIM-based roaming" and "Username/password-based roaming", whereby the technical term "roaming" also encompasses roaming between networks of different network standards, e.g. WLAN (Wireless Local Area...