An SBC is a session border controller, a network device used to protect SIP-based* VoIP networks. The SBC provides call control, interoperability, voice optimization, and security. The device, known as a “Back-to-Back User Agent,” is capable of supporting businesses, regardless of their size, and adding protection to build a safe and valuable VoIP communication solution. Even though it uses the IP for convenience, the IP telephony network is still very susceptible to security breaches and call theft. With advanced methods of examining and managing network traffic available, an SBC network device helps protect against attacks. Finally, session border controllers use sophisticated call-processing algorithms to improve voice quality.