Roaming
Roaming lets a subscription use visited networks outside its home market under inter-operator agreements, while the home network keeps control.
Definitions only — a term explained here is not a service we sell.
Roaming lets a subscription attach to visited networks outside its home market under inter-operator agreements. The visited network carries the traffic, and the home network keeps authentication and policy control.
Where roaming traffic goes
Home routed
- Handset
- Visited network
- Mobile core
- Home network
- PGW / UPF
- Internet
- Handset
- Visited network
- Mobile core
- Local breakout
- Internet
Text description
In the first state the handset reaches the visited network, then the home network and its gateway. The second state exits through a breakout node in the visited network.
The path the traffic takes
The visited network asks the home network to authenticate the device, then carries the traffic under a roaming agreement. Signaling usually runs over GRX or IPX, and billing records follow.
In home routing, traffic returns to the home network first: control stays central and latency grows. In local breakout, it leaves near the user: latency falls, policy and billing spread. The Home routing vs local breakout explainer sets out the trade-off.