Industry analysts tend to focus on the trunking gateway use cases when measuring activity in the Carrier VoIP marketplace.   However, the imperative for operators today is to generate more revenues per subscriber and this drives the need to create additional enhanced services and then convince subscribers to sign up. 

What is the impact of this trend on gateways?   First, connecting directly to SIP is important, because whether the service is IP Centrex, conferencing, call centers or multimedia downloads, SIP is the protocol that glues it together.   Second, most of the subscriber infrastructure for both the wireline and wireless infrastructure uses SS7 signaling, so the need to interwork between SS7 and SIP is critical.  Hence, enhanced services are driving the need for SIP to SS7 gateways, particularly when compared to the more expensive and complex option of using a multiple box solution such as a softswitch plus a media gateway.   

SS7 is typically part of the connection requirements, but other protocols such as ISDN, CAS, SIP-I, H.323 and ISUP over SIGTRAN M3UA may also come into play, driving the need for Any-to-Any features in the SIP-enabled gateway.   

In summary, the growing use of SIP for enhanced services is changing the way that carriers use media gateways, driving the need for SS7-SIP gateways and Any-to-Any feature sets.   At Dialogic, we serve these market requirements with products such as the Dialogic® IMG Integrated Media Gateways.