A session board controller is a device typically installed between the borders of one network to solve the problems faced by calls received through firewalls and traveling across different networks and devices in IP communications. Read on to find out how important it is to your SIP termination business.To put it in simple words, a Session Border Controller, or SBC in short, is a device that is used in VoIP networks to maintain control on signaling and also usually the media streams that are involved in setting up, conducting, and tearing down calls. The term could also be broken down into three words that make it up – session, border and controller. Here, a session stands for communication between any two parties via their devices which are connected over the Internet. Border refers to a point of separation between one network and another while controller means the device’s (SBC) authority and control over the data streams that forms a session.SBCs were first developed to tackle the trouble faced by calls received through firewalls and traveling across different networks and devices. It is (originally) installed between the borders of one network and another. An SBC imposes multiple functions including security, Quality of Service (QoS) and also admission control mechanism over VoIP sessions. Before choosing a session board controller, it is obviously important that you know the overall functions provided by the device.SecurityProtection is one of the basic functions that your SBC provides your network and other devices used in your SIP termination business. It shields you (your network and devices) from harmful attacks, for instance, a denial-of-service attack (DoS) or a distributed DoS. There are counterfeit media streams that are designed to cheat you through fraudulent bill, your SBC protects you from such threats. Other areas where your SBC protects you includes damaged packets, encryption of signaling and media, topology hiding and so on.Quality of serviceYour SBC enforces the QoS (Quality of Service) policy of your network and organizes its flow. These includes traffic policing, rate limiting, resource allocating, call admission control etc.Connectivity/InteroperabilityThis is another important service that your SBC should provide. It should enable various parts of the network to communicate seamlessly. To do this your SBC could use various techniques such as translations between SIP, SIP-I, H.323, VPN (Virtual Private Network) connectivity, NAT (Network Address Translation) traversal, SIP normalization etc.Media related servicesDepending on the type of your SBC, you could receive various media control and services (border-based). Some of these services include voice and video calls support, data and fax inter-working, DTMF relay and inter-working, media transcoding and more. Your SBC is where statistics and billing information are collected as all the sessions that takes place between two parties pass through the device.Given the functions it provides, there is no doubt that session border controllers are crucial as long as VoIP exists. The better and up-to-date your SBC, the more advantage you have in your role as a VoIP/SIP termination service provider. To survive in ever evolving VoIP scene, your SBC should provide the best possible performance, scalability and reliability. While choosing an SBC for your wholesale VoIP termination service, make sure that it is fully integrated into market leading access and interconnect solutions. It should also provide real-time visibility to your network and scale to address the statistic growth of your SIP business and so on.