This figure shows how traffic passes back and forth through the various hardware systems that comprise Service Broker. The SS7 and IMS traffic comes into the Service Broker SSUs servers from the Web through a firewall. Traffic between the Service Broker SSUs and PNs (running SVC and/or VPN) runs through another firewall. The SSUs connect to the web application server serving the SVC/VPN features through a third firewall using HTTPS-enabled traffic. Finally the web application server connects to subscribers through a fourth firewall using HTTPS-enabled traffic.