[Cake] [rtcweb] Catching up on diffserv markings

Pal Martinsen (palmarti) palmarti at cisco.com
Thu Oct 22 03:48:56 EDT 2015

On 21 Oct 2015, at 18:10, Harald Alvestrand <harald at alvestrand.no<mailto:harald at alvestrand.no>> wrote:

Den 21. okt. 2015 17:51, skrev Dave Taht:
I unsubscribed from rmcat and rtcweb groups a while back after I got
overloaded, and appear.in 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.

That sounds like the world I am living in as well.

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!)

So how would ECN work on UDP? I do not think the necessary bits from the IP header are available for the application to do anything. I do think Linux supports this, have not tested.

And what about the network, would it support UDP when setting the ECN bits? Probably a configuration related problem if not supported.

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

There is a new ICE wg. It was created so “network people” could participate without the overhead of listening to the SDP related discussions. (https://datatracker.ietf.org/wg/ice/charter/)


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 :-)


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.

rtcweb mailing list
rtcweb at ietf.org

rtcweb mailing list
rtcweb at ietf.org<mailto:rtcweb at ietf.org>

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