A SIP User Equipment (UE) is registered with an Application Server (AS).
- The UE may belong to a public or a private network and AS belongs to a core network.
- TheSBC is intermediary between the UE and the AS in the core network.
- The UE is pre configured with one or more SBC addresses.
- The SBC protects core network from harmful attacks and high traffic levels.
- The SBC authenticates and ensures only registered subscribers or UE's access the service.
- The SBC provides facilities for protocol repair and verification.
- The SBC routes the UE registration request to an appropriate AS.
- When the UE contacts the SBC and the UE is unable to authenticate with the AS, the SBC rejects the UEs request for service.
- If the UE is able to authenticate with the AS, the SBC recognizes the UE and allocates the resources for that UE.
Figure : SIP UE Registration with AS