Metaswitch’s Emergency Standalone (ESA) Proxy preserves voice calling capability and emergency service access in heterogeneous access networks connected to a SIP core.
Adding ESA functionality into an operator’s network architecture is easy.
The ESA function acts as a SIP proxy Registrar, monitoring registrations and building a dynamic database of endpoints, while passing the registrations into the core network Registrar as usual.
From mobile clients to BLCs, registered endpoints can include any device that presents an upstream SIP interface to the core network.
If the access network loses connectivity with the core network, the ESA Proxy uses its learned registration information to maintain service continuity and call capabilities within its service area.