{"json_modified": "2016-10-25T11:11:35.767437", "uuid": "f270143a-2ce5-4304-88b0-30ae12a8eb90", "title": "Signaling and video calling", "url": "/en-US/docs/Web/API/WebRTC_API/Signaling_and_video_calling", "tags": ["API", "WebRTC", "Guide", "Signaling", "Audio", "Video", "Example", "Tutorial", "video", "Media", "audio"], "translations": [], "modified": "2016-10-25T11:11:35", "label": "Signaling and video calling", "localization_tags": [], "locale": "en-US", "id": 166637, "last_edit": "2016-10-25T11:11:13", "summary": "Although <a href=\"/en-US/docs/Web/API/WebRTC_API\">WebRTC</a> is billed as a fully peer-to-peer technology for the real-time exchange of audio, video, and data, there is one caveat. <a href=\"/en-US/docs/Web/API/WebRTC_API/Session_lifetime#Establishing_a_connection\">As discussed elsewhere</a>, in order for two devices on different networks to locate one another, some form of discovery and media format negotiation must take place. This process, called <strong>signaling</strong>, involves both devices connecting to a third, mutually agreed-upon server through which the two devices can locate one another and exchange the needed negotiation messages.", "sections": [{"id": "Quick_Links", "title": null}, {"id": "The_signaling_server", "title": "The signaling server"}, {"id": "Readying_the_chat_server_for_signaling", "title": "Readying the chat server for signaling"}, {"id": "Designing_the_signaling_protocol", "title": "Designing the signaling protocol"}, {"id": "Exchanging_session_descriptions", "title": "Exchanging session descriptions"}, {"id": "Exchanging_ICE_candidates", "title": "Exchanging ICE candidates"}, {"id": "Signaling_transaction_flow", "title": "Signaling transaction flow"}, {"id": "ICE_candidate_exchange_process", "title": "ICE candidate exchange process"}, {"id": "The_client_application", "title": "The client application"}, {"id": "Updating_the_HTML", "title": "Updating the HTML"}, {"id": "The_JavaScript_code", "title": "The JavaScript code"}, {"id": "Sending_messages_to_the_signaling_server", "title": "Sending messages to the signaling server"}, {"id": "UI_to_start_a_call", "title": "UI to start a call"}, {"id": "Starting_a_call", "title": "Starting a call"}, {"id": "Handling_getUserMedia()_errors", "title": "Handling getUserMedia() errors"}, {"id": "Creating_the_peer_connection", "title": "Creating the peer connection"}, {"id": "Set_up_event_handlers", "title": "Set up event handlers"}, {"id": "Starting_negotiation", "title": "Starting negotiation"}, {"id": "Session_negotiation", "title": "Session negotiation"}, {"id": "Handling_the_invitation", "title": "Handling the invitation"}, {"id": "Sending_ICE_candidates", "title": "Sending ICE candidates"}, {"id": "Receiving_ICE_candidates", "title": "Receiving ICE candidates"}, {"id": "Receiving_new_streams", "title": "Receiving new streams"}, {"id": "Handling_the_removal_of_streams", "title": "Handling the removal of streams"}, {"id": "Ending_the_call", "title": "Ending the call"}, {"id": "Hanging_up", "title": "Hanging up"}, {"id": "Ending_the_call_2", "title": "Ending the call"}, {"id": "Dealing_with_state_changes", "title": "Dealing with state changes"}, {"id": "ICE_connection_state", "title": "ICE connection state"}, {"id": "ICE_signaling_state", "title": "ICE signaling state"}, {"id": "ICE_gathering_state", "title": "ICE gathering state"}, {"id": "Next_steps", "title": "Next steps"}], "slug": "Web/API/WebRTC_API/Signaling_and_video_calling", "review_tags": ["editorial"]}