webRTC

Question 1

Pros

Answer 1

No need to download plug-ins

Peer to peer connection reduces load on server and reduces chance of man in the middle attack

Encryption improves privacy

Question 2

Which browsers does not support webRTC?

Answer 2

Safari
Internet Explorere
IOS browsers

Question 3

Cons

Answer 3

Doesn’t work on every browser

Scaling can be hard

Question 4

Getting your own media

Answer 4

const startStream = ()=>{
            //getUserMedia API setup
            navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia;

            //Constraints
            const constraints = {
                audio:false,
                video: {
                    mandatory:{
                        minWidth:640,
                        maxWidth:640,
                        minHeight:360,
                        maxHeight:480,
                    }
                }
            };

            //GetUser
            navigator.mediaDevices.getUserMedia(constraints).then((stream)=>{
                $videoArea.srcObject = stream
                $videoArea.className = 'grayscale_filter';
                $videoArea.play()
            }).catch((error)=>{
                console.log("Error with getting user media: " + error)
            });

    }

    startStream()

    $videoSelect.onchange = startstream()

Question 5

3 Ways to establish a connection via signalling?

Answer 5

Public IP’s

STUN server

TURN server

Question 6

What is signaling?

Answer 6

Signallng is the process of sharing ICE candidates, and SDP or session description protocol offers and answers between 2 or more participants in a webRTC session

Before a peer to peer connection can be established, a signal server is required to establish the connection before a call

Signalling is the process of coordinating communication through an exchange of messages.

SDP (session description protocol) is used to send offers and answers as well as ICE candidates

Question 7

ICE Framework

Answer 7

Interactive connectivity Establishment Framework

The ICE framework finds the best path to connect peers. It tries all possibilities in parallel and chooses the most efficient option that works.

first ICE tries to a direct connection using the host address abtained from a diveice’s operating system

if that fails, A stun server is used to get an external (public) network address

if that fails, a TURN server is used to relay traffic.

For this to happen the applicaiton must pass ICE server URL’s to RTCPeerConnection

Question 8

Controlling peer

Answer 8

The peer that is controlling the session. Decided by ICE

Question 9

STO

Answer 9

Signaling Transport Options

HTTP
WebSockets
MQTT
Carrier Pigeons

Question 10

What is webRTC?

Answer 10

Framework that enables realtime communication in the browser.

Question 11

3 major api’s

Answer 11

getUserMedia()
RTCPeerConnection()
Data channel
.

Question 12

Typical architecture topologies

Answer 12

peer to peer

Mesh

Mixer(MCU) -uses a media server

Routing(SFU) - uses a server