signalling gateway (NGN) (SGW)
The Signaling Gateway(SGW) is a network node in a multiservice network or a Next Generation Network( NGN) that transports the signaling information across the network boundaries and converts it to the various signaling standards.
Functionally, an SGW gateway corresponds to a switching network in classic long-distance telephone networks( PSTN). For example, signaling gateways are used between circuit-switched PSTNs and packet-switched IP networks to transfer signaling information from Signalling System no 7( SS7), Dual Tone Multi Frequency(DTMF), Q-Interface Signalling Protocol( QSIG) or ISDN User Part( ISUP).