FIOS and tcp_vegas support w /qos

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robnitro
Posts: 84
Joined: Sat Feb 26, 2011 4:50 pm

FIOS and tcp_vegas support w /qos

Post by robnitro »

Hi,
I have fios internet that runs 30 mbit down normally, but when streaming video on demand (VOD), it can go up to 50 mbit total. The qos variable system doesn't seem to work too well with that much of a jump, setting max to 50, ends up not always throttling the connection down to 30 when vod is not in use. I can't set max to 30, because then it will choke my connection when vod is used.

I remember tomato had tcp_vegas congestion control and it is also recommended in DD-WRT forum for fios video on demand. However gargoyle/openwrt only have reno and westwood. Is it possible to get tcp_vegas support in gargoyle sometime?

robnitro
Posts: 84
Joined: Sat Feb 26, 2011 4:50 pm

Re: FIOS and tcp_vegas support w /qos

Post by robnitro »

Also found a bug or limit with download max. I was originally having problems with the congestion control showing "disabled*" even though I had it checked. After trying to restart the qos_gargoyle service in /etc/init.d manually, it said, 51200 invalid value. After changing to 50000 downlink speed it worked fine. If i hadn't ran the service on SSH, I probably would have thought that congestion control is broken.

Anyway, would like to know if tcp_vegas might be possible someday... congestion control works but is kind of slow due to the big gap 50mbit to normal 30mbit. Works though, but with tcp_vegas it would be the best setup!

mix
Posts: 292
Joined: Sun Feb 27, 2011 11:18 am

Re: FIOS and tcp_vegas support w /qos

Post by mix »

What Fios speed tier do you actually use? It is pretty common knowledge that you have to set the qos upload and download speed to the minimum speed you normally attain. I don't know where you are getting 30 Mbps with up to 50 Mbps from? Are you talking about bursting or something? I didn't think Fios did that?
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pbix
Developer
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Joined: Fri Aug 21, 2009 5:09 pm

Re: FIOS and tcp_vegas support w /qos

Post by pbix »

I have already corrected the issue with qosmon that causes it to reject links with speeds higher than 50Mbps. It will accept higher limits in the next release but it sounds like you are fine for the moment.

The idea that TCP_VEGAS will help with QoS is not correct but since the source code for Gargoyle/OpenWRT is available you can do as you like in this regard.

I am very interested to hear from you how the Active Congestion Controller works for you at such high speed. What are you QoS goals? Also, what router are you using?
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mix
Posts: 292
Joined: Sun Feb 27, 2011 11:18 am

Re: FIOS and tcp_vegas support w /qos

Post by mix »

It appears that Gargoyle 1.3.10 is using westwood (in actuality it's probably westwood+) as the default tcp congestion control algorithm. This doesn't change whether I select wired or wireless as the wan connection, it is always westwood. You can view it by:

cat /proc/sys/net/ipv4/tcp_congestion_control

I would have expected that reno would have been the default for wired and westwood the default for wireless. Better yet, I would have expected cubic (the default congestion control algorithm for linux since 2.6.18) to be the default for wired, and westwood to be the default for wireless. Of course, I am not exactly sure what role the tcp congestion control plays on the lan vs the wan.

At the very least westwood (again probably actually westwood+) is probably a better choice than reno for most people, so it's nice it's the default.

So the poster is asking where is vegas support... I say where is cubic support? :) Vegas, besides being in dd-wrt, is probably not in any other linux distro. Cubic is pretty much everywhere with a modern kernel.
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robnitro
Posts: 84
Joined: Sat Feb 26, 2011 4:50 pm

Re: FIOS and tcp_vegas support w /qos

Post by robnitro »

Speed tier is 25/25 but I get 30 down/26 up on most tests.
The 50 speed I get is while testing VOD HD streams, which each take 15 mbits. I ran 2 VOD HD streams and was getting 20 down on the PC, which adds up to 50 total. The int eth1 graph in X-Wrt showed a total of around 50 down. Supposedly that is the max of their packages here, but I was never offered it. My friend in another neighborhood has 30/30, benches 32/30. I ran 2 VOD HD streams + PC download and it maxed out at 50 there too.

I use a Buffalo WZR-G300NH. CPU usage was insane until I disabled and chmod -x /etc/init.d/bwmon_gargoyle . I couldn't find where to disable it on the web interface. Now if I max it out, CPU is around 70%. Flat out download and upload at same time is 100% but I still get the maxed out speeds, hmm. With openwrt CPU usage was below 20% but I didn't use the QOS because of the speed change.

The congestion control works, but it is a bit slow to adapt down or up. It is pretty cool though to see it go upwards. If I am using 30 down and start a VOD stream, it starts upping the fair link until the PC download is back to 30. If you have a script or way for me to log the qosmon data, I can run both tests for you.

robnitro
Posts: 84
Joined: Sat Feb 26, 2011 4:50 pm

Re: FIOS and tcp_vegas support w /qos

Post by robnitro »

Oh and my QOS goals are to not have to throttle torrents. I have a synology ds211j running transmission and when it maxes out download, due to it using many connections, ping goes up horribly for gaming or web surfing. A single stream maxed out download barely affects ping.

As for recompiling the kernel with vegas or cubic, I am good as a user/tweaker of linux, but am clueless about programming or scripting. I guess you could say I am more like a networking guy than a programming guy.

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