SBC

A Session Border Controller (SBC) is a network element deployed at the edge of a VoIP network to control and secure real-time communication sessions. It manages SIP signaling and RTP media between different network domains.

Key functions include NAT traversal, topology hiding, call admission control, codec transcoding, TLS/SRTP termination, DoS protection, and regulatory compliance (e.g., lawful intercept). SBCs are essential for VoIP service providers interconnecting with carriers and enterprise customers.