AGL Resources












Soft Switches (SIP Server)

Although SIP is still an evolving standard, it's gaining wide acceptance across the board. SIP is said to become the most important standard in communications convergence today. True or not, the fact is SIP enables network operators easier integration, more choices and to lower costs. In a multi-vendor, multi-application and widely distributed communication system, SIP provides a reliable way to optimize the network infrastructure. For carriers and enterprises, SIP puts you in control to easily deploy converged and next generation real-time voice, data and video communication services across landline and wireless networks. SIP is attracting a strong interest from Chinese operators, developer and VOIP community. MiPhone is based on SIP.

MiPhone's Soft Switches implemented the RFC 3261. They consist of SIP Registrar Server, SIP Proxy Server, SIP Redirect Server, Media Server, Radius Accounting and Billing server. To guarantee the system's high scalability, high availability and high affordability(not cost too much), Soft Switches Scale-Out are enabled. SIP Servers use high cache to cache users' locations in memory, use replication to synchronize the location information between servers. The load is distributed across any number of load-balanced SIP Servers to increase the capacity of the switches. Additional switch capacity can be added by simply adding more servers. Load Balancers used in SIP traffic are based on round-robin DNS. Soft Switches also provide the best routing for PC2Phone service to different PSTN providers based on destination and cost.