Session Border Controllers | Functionalities

AC.

Session Border Controllers (SBCs) are specialized network devices that provide several critical functionalities for real-time interactive communications, particularly in Voice over IP (VoIP) and Unified Communications (UC) networks. SBCs typically sit at the edge of an organization's network and are used to control signaling and media traffic that crosses network boundaries, such as between different service providers, enterprise networks, or public internet connections.

The two functionalities provided by Session Border Controllers are:

A. Edge proxy functions: SBCs act as edge proxies between different networks, allowing them to span multiple networks and provide secure and controlled connectivity between them. SBCs are typically used to manage and regulate real-time interactive communication sessions, such as voice and video calls, instant messaging, and presence information, across network borders. By acting as intermediaries between networks, SBCs can provide a range of security and quality-of-service features, such as firewall traversal, network address translation, packet inspection, and encryption.

B. Session-aware control: SBCs are session-aware devices that enable end-to-end control of interactive communications across Public Switched Telephone Network (PSTN) network borders. They can inspect, manipulate, and route Session Initiation Protocol (SIP) messages, which are used to set up, maintain, and tear down communication sessions. SBCs can also manage media flows, such as voice and video streams, by implementing signaling and media control protocols, such as Real-Time Transport Protocol (RTP) and Secure RTP (SRTP). By providing session-aware control, SBCs can help to ensure that communication sessions are reliable, secure, and high-quality, even across different network domains.

Option C is incorrect because SBCs do not complement existing edge routers, but rather, they work alongside them to provide specialized functions for real-time interactive communications. Option D is also incorrect because SBCs typically do not provide routing functions for IP, TCP, or SMTP protocols. Finally, Option E is incorrect because SBCs do not replace typical edge routers and firewalls, but rather, they complement them by providing additional security and control functions for real-time interactive communications.