The IETF stands for Internet Engineering Task Force.
It is an international organization in charge of many network related specifications, WebRTC among them.
The IETF specifies how WebRTC traffic looks on the network, making interoperability between browsers, devices and backend servers possible.
The IETF collaborates with another organization, the W3C which in turn specifies the WebRTC APIs.
WebRTC Glossary is a collaborative space where users can learn more about WebRTC related terms. Anyone can also modify or add new terms to this glossary, but it requires registration to the site first.