Re: [rtcweb] Data channel comments and questions

<Markus.Isomaki@nokia.com> Thu, 29 March 2012 21:04 UTC

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From: <Markus.Isomaki@nokia.com>
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Thread-Topic: [rtcweb] Data channel comments and questions
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Date: Thu, 29 Mar 2012 21:04:34 +0000
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Subject: Re: [rtcweb] Data channel comments and questions
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>
>Ah, sorry for not being clear. I mean a situation where we can't setup the UDP
>channel, if one endpoint is for instance in a corporate network from where
>only HTTP or HTTPS is allowed. So presumably we'd have to support some kind
>of HTTP or TLS encapsulation/tunneling for the data channel as well, from the
>endpoint to some kind of relay. But how would the end-to-end data channel
>look like then? I.e. what would be sent over the tunnel?
>

There's by the way at least one other use case where UDP-based data channel sucks. If you want to keep it up for a long time for some infrequent messaging, keeping the NAT state up by a keepalive every ~30s. would drain the battery on a mobile device. To solve that case some kind of TCP-based variant would be needed, at least between the mobile endpoint and a relay. TURN-TCP, I guess. If the other end was still using UDP and doing frequent keepalives, I suppose the relay would unfortunately forward them as well causing the same ill effect. 

I'm not sure if there are apps that would need to keep the data channel up infrequently used, though. Or should they just use the "signaling" path (HTTP, websockets) for that type of purposes. 

Markus