Re: [rtcweb] Catching up on diffserv markings

Harald Alvestrand <> Wed, 21 October 2015 16:11 UTC

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To: Dave Taht <>, "" <>, "" <>, "" <>,
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Subject: Re: [rtcweb] Catching up on diffserv markings
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Den 21. okt. 2015 17:51, skrev Dave Taht:
> I unsubscribed from rmcat and rtcweb groups a while back after I got
> overloaded, and started working so well, (for both ipv6 and
> ipv4! I use it all day long now!), to focus on finishing up the new
> "cake" qdisc/shaper/aqm/QoS system, among other things.
> Cake is now entering the testlab, and among other things, it has
> support for the diffserv markings discussed in the related, now
> concluded dart wg, but in ways somewhat different from that imagined
> there. We have not got any good code in our testbeds yet to test
> videoconferencing behavior, and we could use some, although it does
> look like we can drive firefox with some remote control stuff with a
> fixed video playback now....
> Five questions:
> 1) Has anyone implemented or tested putting voice and video on two
> different 5-tuples in any running code out there?

All VC systems I know of except WebRTC-based ones do it, AFAIK.
It's putting them on the same that's unusual.

> 2) How about diffserv markings in general? Do any browsers or webrtc
> capable software support what was discussed way back when?

I know Hangouts did something like that internally, on the controlled
network. But not according to spec.

> 3) Were diffserv marking changes eventually allowed on the same 5-tuple?

Yes, with caveats. draft-ietf-tsvwg-rtcweb-qos has the table.

> 4) Did the ECN support that was originally in one draft or another
> ever make it into any running code?

I don't know. I think we lost it from the docs.

> (yea, apple plans to turn on ecn universally in their next OS!)
> 5)  What else did I miss in the past year I should know about?

For TCP and SCTP congestion controllers, we're back to one DSCP marking
per flow, and resetting the congestion control state if DSCP marking

> Feel free to contact me off list if these have already been discussed.
> I have totally lost track of the relevant drafts.

They're not finished still :-)

> Sincerely,
> Dave Täht
> I just lost five years of my life to making the edge
> of the internet, and, wifi better.
> And, now... the FCC wants to make my work illegal
> for ordinary people to install.
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