A gateway in the WebRTC context is a server that bridges WebRTC communication with other protocols and networks, typically the PSTN or SIP-based VoIP systems.
What a WebRTC gateway does
A WebRTC gateway performs several translation functions:
- Signaling translation: Converts between WebRTC signaling (typically WebSocket/JSON) and SIP or other protocols
- Media transcoding: Converts between codecs used on the WebRTC side and the codecs used on the other end, be it audio or video codecs
- Security translation: Terminates DTLS/SRTP from WebRTC and connects to the PSTN/SIP side. Gateways always break E2EE
Gateway vs SBC
A WebRTC gateway and an SBC (Session Border Controller) serve overlapping roles. In practice, many SBC vendors have added WebRTC gateway functionality to their products. CPaaS vendors typically include gateway capability in their platforms, abstracting the complexity from developers.
