SBCs connect IP networks (enterprise to service provider) and introduce new edge requirements in three major areas: security, service assurance and law enforcement. SBCs sit at the edge of the service provider’s network and complement established routers with their ability to perform required control functions by integrating session signaling and media control. SBCs operate as SIP back-to-back user agents, MGCP proxy/network-address translations (NATs) and/or H.323 back-to-back gateways. They are both the source and the destination of all signaling messages and media streams entering and leaving the provider’s network.

The SBC space has been largely cornered by startup vendors, but other equipment vendors have taken two approaches: they have partnered with the SBC vendors or embedded SBC functionality into some of their existing solutions, such as routers. Gartner recognizes that there are some embedded solutions with SBC function, but counts only those that are stand-alone. Vendors such as Cisco and Sonus Networks have integrated SBCs into their routing and switching platforms.