Data Channel Error when one of the participant is close.

[SL]

I have a web conference app it will throw Data Channel Error when one of the participant is close. Let said A is host, B & C is participants. When C close the browser, all data channel of the room is lost (So A cannot sent data to B), however the video remain fine.

Data Channel Error also occur In WebRTCAppEE/conference.html

[Enes Kuluk]

Could you provide exact reproduce scenario please? And the version that you use please?

Best Regards,

Enes.

[SL]

I use /WebRTCAppEE/conference.html open 3 browser (let said A,B,C) and all join to the same room. And if one of the participant C close the browser, the host A and the participant B will lost the Data Channel connection and give this error 

Data Channel Error: RTCErrorEvent {isTrusted: true, error: RTCError: Transport channel closed, type: "error", target: RTCDataChannel, currentTarget: RTCDataChannel, …}

 

 

[SL]

I tried it on 2.21 and the snapshot version 2.3.0-SNAPSHOT 20201224_1404, both give this error

 

 

[Enes Kuluk]

It is normal have this error due to closed data channel. But you are not losing data-channel between A and B.

Best Regard,s

Enes.

[SL]

No. It does lost data-channel connection. Using the /WebRTCAppEE/conference.html

If C exit then B try to Unmute local mic the sendNotificationEvent method return error and cannot use the sendData as well

function sendNotificationEvent(eventType) {

if(isDataChannelOpen) {

var notEvent = { streamId: publishStreamId, eventType:eventType };

webRTCAdaptor.sendData(publishStreamId, JSON.stringify(notEvent));

} else {

console.log("Could not send the notification because data channel is not open.");

}

}

 

[SL]

I think is the Call back 'data_channel_opened' did not call again after C leave, so  the variable isDataChannelOpen still have a false value

callback: (info, obj) => {

 if (info === 'data_channel_opened') {

console.log('Data Channel open for stream id', obj)

this.isDataChannelOpen = true

} else if (info === 'data_channel_closed') {

console.log('Data Channel closed for stream id', obj)

this.isDataChannelOpen = false

}

}

[Enes Kuluk]

Thank you for that. This issue is assigned on me this week and i resolve it until next monday.

You can check the status of issue here: https://github.com/ant-media/Ant-Media-Server/issues/2848

Best Regards,

Enes.

[Enes Kuluk]

I tried to reproduce this but i think it comes to point where i mentioned about it doesnt break data channel connection between A and B.

It shows this error because data channel in C is not available anymore. So it shows this error.

But data channel between A and B is not broken because they do not have such relation.

WebRTC does not work as mesh. A is not connected to B and C. There is a publisher and receiver.

So if you are publishing A, then you are playing B and C streams. This means A stream(which is the stream you publish) is not connected to the stream B or C.

You are just playing stream B or C in your client and publishing A.

When you stop playing C, its datachannel brokes and it gives the error you see.

To exemplify it, i modified conferece.html a bit to send datachannel message every 5 second.

I created 3 streams, let's name it A,B,C and i closed the tab C.

And still stream A and B continues to send data channel messages.

This is from A stream, as you can see it receives message from EyaRBi etc.

And this is from B stream, as you can see it receives message from TxKSBP etc.

Hope this clarifies your worries.

Best Regards,

Enes.