A class 4 softswitch features an intelligent call routing component that helps to minimize latency, congestion and cost. The component also has several elements, including VoIP call quality. Another component that a class 4 softswitch may include is a billing feature. VoIP providers use class 4 softswitches to generate reports of incoming and outgoing calls.
A class 5 softswitch (also called an IP switch) routes calls between end users over relatively small areas. This switch routes calls to a specified IP address, Session Initiation Protocol (SIP) address or Direct Inward Dialing (DID) number.