a servers on the other end. MGCs are the base of support for both existing voice services like class 4/5 features and evolving applications such as integrated access, VPN and unified messaging. The MGC controls the switching and routing of media packets between MGs across the packet network. In addition, other services can be brought into the communication flow that it controls through interconnection with SS7 networks, databases, and logic/feature/media servers. A single MGC can control multiple MGs. Signaling Gateway: In the softswitch architecture, the signaling gateway (SG) integrates the SS7 functionality into the architecture and provides connectivity to traditional AIN services. SGs interface to both SS7 and IP networks, allowing SS7 information to be carried to-and-from IP-based applications such as MGCs and mobile network elements. SGs provide the means to transfer the call control protocol to the MGC over the IP network. Whereas the MG bridges the gap between circuit and packet switched worlds from a call flow perspective, SGs bridge the gap from a call control perspective. Needless to say, the SG is an essential link between the PSTN and packet networks. Through the SG, the packet network services can make use of existing PSTN intelligent network (IN) services, such as toll free and calling-name delivery. Feature and Media Servers: Besides simply emulating Class 4 and Class 5 telephony features, the softswitches will have to support and provide enhanced feature and service creation. In the traditional PSTN network, new The Ultimate Guide to Building and Delivering OSS/BSS service creation was difficult - it had to be introduced either in the switch or from the AIN in a centralized manner. The feature server and the media server provide a much more flexible, scalable and open platform for development of new features and services in the softswitch environment. The feature server (FS) is the place where new services will be introduced, executed and managed. There are two distinct categories of FS - those 