Billion Softswitch. Enterprise Edition - Version 2.4 Billion Softswitch main features: * SIP/H323 signalling conversion, * maintenance of connection between two diversegateways or gateways placed in various subnets, * centralized connection with billing system, * querying routing servers for terminating gateways, * gateways set control, * working with devices behind NAT, * protection from unathorized access, * web-access to all configuration parameters.