SBCs or session border controllers manipulate IP communications’ signaling as well as media streams. Additionally, they provide various functions:
Multivendor interoperability – The job of the SBC is normalizing Session Initiation Protocol or SIP signalling messages and stream headers for mitigating multivendor incompatibilities.
Safety – Session border controllers shield against DoS (Denial of Service) and DDoS (Distributed DoS) attacks. Again, they also safeguard against service theft and toll fraud. Thus, it provides media and signal encryption to ensure confidentiality. Additionally, they shield against masquerade or impersonation.
Quality of Service – The job of the SBCs also involves enforcing CAC (call admission control) policies, ToS (Type of Service) marking, or rank limiting for service QA.
Protocol interworking – Session border controllers enable interworking between different protocols like SIP-to-H.323. Again, it also enables interworking between diverse codecs like g.711 to g.729.
Session routing – Session border controllers route sessions across different network interfaces for ensuring high availability or enabling LCR (least cost routing).
Types of session border controller
Both enterprises and communications service providers utilize AudioCodes session border controllers. If you see service providers, you will find them deploying SBCs at core, access, and interconnect network borders. Again, enterprises, too, deploy session border controllers at the edge of an enterprise network, for instance, in the form of a termination point where a SIP trunking service can work. Due to the diverse scalability and functional needs, numerous manufacturers propose enterprise SBC products and distinct service provider SBC families. Commonly, enterprise SBCs are known as eSBCs or E-SBCs. A few manufacturers of SBC offer software-based session border controllers that run on a virtualized industry-standard server to enable the virtualization of NFV or network functions.
The applications of SBC
A few applications of SBC are:
IP contact centers – Most often, E-SBCs are deployed at different corporate IP network borders for routing calls across a distributed IP contact center environment. Several organizations have decided to migrate legacy a TDM-based contact center network to every IP network for cutting down costly PSTN fees.
SIP trunking – E-SBCs or enterprise session border controllers are commonly installed at the corner of the enterprise networks and towards the demarcation point. A few SIP trunking service providers also bundle customer premises-based enterprise session border controllers with the service. A few session border controller trunking service providers combine the service with the customer premises-based E-SBCs. This way, they maintain the management and ownership of a device. A few providers implement the enterprise session border controller in the form of a virtual appliance. Many other SIP trunking service providers suggest customers’ purpose.
Cloud-based IP communications services – Enterprise SBCs help protect and control access to even the remoted hosted communications services including video or audio conferencing services.
Unifying disparate communications environments – Enterprise SBCs get installed at various internet orders for extending corporate IP communications services to teleworkers, mobile workers, and small offices.
Service provider border security – You will habitually see service providers to be using SBCs for protecting and controlling essential network borders. They also access network borders, and interconnect borders. It means they establish connections to different legacy networks and service provider networks.
