Ultimate SQM settings: Layer_cake + DSCP marks

Since there are no hard standards each app or provider uses their own system, it's a bit of a mess. But af41 is reasonable as a tag for low latency data. It won't go into voice WMM queue though

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I saw there's something wrong, can you catch it?! @dlakelan Screenshot%20(2)
There's an interested things here

Hi again guys! Perhaps you can help me extend this setup. (if any1 has any other tips to optimize tcp over openvpn be my guest)

I'm trying to add OpenVPN to this for my game and im planning to route the traffic from my windows through the OpenVPN client on OpenWRT by destination IP, or policy based routing)

I tried Windows VPN clients with split-tunneling to try and only route specific apps through VPN but it seem mostly dirty fixes with firewall rules i believe, and just feels dirty.

Currently the OpenVPN works (tun0) and connection established, turned off nagling with tcp-nodelay.

The default routes work to the clients depending whether i use 'route-nopull' or not, obviously use it as i want to do some manual route.

But first I gotta get the Tun0 to work with the veth setup so also ingress from tun0 goes through veth!

Thank you!

with a vpn you'll have two kinds of ingress and two kinds of egress, one "into / out of the tunnel" and one the actual encrypted packet sent out or in on ethernet. If you prioritize the unencrypted (pre/post tunnel) packet, but the encrypted packet waits... you won't get the prioritization you want. It's a bit tricky because you can't look at the encrypted packet at all so likely you want to restrict the tunnel to just gaming, and prioritize all the encrypted packets.

also, if you can use a VPN provider who uses wireguard, it is a better choice due to lower CPU requirements for the router.

Yep, that will be hard to prioritize inside tunnel too, but... the VPN is intended for solely one game! I know the IP destination range, but im having trouble setting it up in the same veth setup as @hisham2630

So at least the tunnel should not be hard to prioritize now and I can just prioritize the whole port of my choosing, i think? (Currently just port 443, but I can change to a different one later)

If I can just have both Eth1.2 (WAN) and Tun0 both let egress go over Veth0/1, and the tunnel sends egress back the regular route to Eth1.2 (WAN)

Or is this too simple thinking?

Edit: I think I already managed it working, but not sure if OK. When I do speedtest (Download) i can see equal Tun0 and Veth data flow!

What i did:

ip route add default dev veth0 table 100
ip rule add iif eth1.2 table 100 priority 100
ip rule add iif tun0 table 100 priority 100

Just added the last line. I use this package to specify route atm the easy way:

I think you want your new rule to have different priority, otherwise you might be overwriting your other rule, not sure. Try:

ip route add default dev veth0 table 100
ip rule add iif eth1.2 table 100 priority 100
ip rule add iif tun0 table 100 priority 101
ipt="iptables -t mangle"
$ipt -A mark_DSCP_ul \
		-p udp \
		-m multiport --dports 1024:65535 \
		-m connmark ! --mark 0x30/0xf0 \
		-m connbytes \
			--connbytes :128 \
			--connbytes-dir original \
			--connbytes-mode avgpkt \
		-m connbytes \
			--connbytes :512 \
			--connbytes-dir reply \
			--connbytes-mode avgpkt \
		-m hashlimit \
			--hashlimit-above 15 \
			--hashlimit-mode srcip,srcport \
			--hashlimit-srcmask 32 \
			--hashlimit-name "mark_game_above" \
		-m hashlimit \
			--hashlimit-upto 128 \
			--hashlimit-mode srcip,srcport \
			--hashlimit-srcmask 32 \
			--hashlimit-name "mark_game_upto" \
		-j CONNMARK --set-xmark 0x50/0xf0 \
		-m comment --comment "Realtime Interactive: Games, match upload traffic, tickrate 15(PUBG)-128(CSGO)"

$ipt -A PREROUTING -m conntrack --ctstate RELATED,ESTABLISHED -m connmark ! --mark 0xf0/0xf0 -m connmark ! --mark 0x60/0xf0 -m connmark ! --mark 0x70/0xf0 -m statistic --mode random --probability 0.005 -j CONNMARK --and-mark 0xff0f
$ipt -A PREROUTING -i br-lan -m connmark --mark 0x0/0xf0 -j mark_DSCP_ul

$ipt -A PREROUTING -m connmark --mark 0x50/0xf0 -j DSCP --set-dscp-class CS4

My iptables rule to match the game traffic. Connmark, connbytes and hashlimit are used. LOL tested.

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It would be nice if you can get it to work.you can use conntrack to auto tag packets on both ways /in/out.

Nice to see something new, it's look complicated, but interested :upside_down_face:

i just use those two rules to catch voip/games, it's working good, many thanks -j @dlakelan

$IPT -t mangle -A PREROUTING -p udp -m hashlimit --hashlimit-name udp_high_prio --hashlimit-above 120/sec --hashlimit-burst 50 --hashlimit-mode srcip,srcport,dstip,dstport -j CONNMARK --set-mark 0x55 -m comment --comment "connmark for udp"
$IPT -t mangle -A PREROUTING -p udp -m connmark ! --mark 0x55 -m conntrack --ctorigsrc -m multiport ! --ports 53,5353,80,443,8080,60887 -m connbytes --connbytes 0:700 --connbytes-dir both --connbytes-mode avgpkt -j DSCP --set-dscp-class CS6 -m comment --comment "small udp connection"

It's tag packets on both in/out bound.
Also which rules do you use to catch bulk traffic, and which rules to speedup web browsing!

This is interesting stuff, I wonder though how accurate is this? I mean is it possible not always game packets are intercepted and tagged?

I theory you could just prioritize traffic on how it behaves / footprint etc, but doesnt piece_of_cake pretty much do this already sufficiently?

Usually games and VOIP doesn't max out packets size, it's use a small packet size to handle important sync
data or voice data, we do exclude port 80,443 http/https, conntrack will catch dest port and ip.

piece_of_cake will place the whole traffic inside one tin, also tagging packets will be useless in this case.
layer_cake will honor your dscp tags and will place the in appropriate tin, you can use 3 or 4 or even 8 tins.
they called diffserv3,diffserv4 and diffserv8.

Yea true, gaming packets and voip usually dont max out the payload. Perhaps just tag packets based on its payload size would actually work well with QoS cake? Dunno, just thinking out loud here :stuck_out_tongue:

I'm just wondering how you could make general rules and optimize it all for general use without having to resort to specifically aiming at applications/games separately.

This will make rules more effective also you will end have a few rules to maintain and understand.more rules
will use more cpu and maybe will make it useless.
it's just the knowledge and testing (try/error), i do packet capturing to see how it's work!

Hello everyone! I came across this post not too long ago and read a couple of the posts in the thread and I have became very interested in setting up dscp markings for my network. But I have no idea whatsoever on how to begin, like which packages to download and how to start marking the packets. Please if you guys can help me out on setting up dscp marking I would really appreciate it. And thanks @dlakelan and @hisham2630 for helping everyone out and contributing to help people achieve the best latency in their networks! Keep up the awesome work!

Hi @Ernieelias welcome to the party :slightly_smiling_face: first thing you should do is install SQM and tune it to your connection speed. Already this will go a long way toward making games and VOIP work better. Everything else here is second order improvement.

Start by running a speed test on dslreports and post the link to the results page here. Then using the Luci app for sqm enable an sqm on your wan interface with about 90% of measured download speed and 95% of measured upload. Redo the test and post that. Once you are at that point we can discuss next steps.

Thanks! Ah yes sorry, I have forgot to mention that I do have sqm installed on Wrt3200acm and I have a wrt1900acv2 setup as a dumb ap. Did you still want me to post the settings of sqm?

Ok, post a speed test result with your current SQM.

If you do not mind also post the output of:

  1. cat /etc/config/sqm

  2. tc -s qdisc #(directly before a speedtest)

  3. tc -s qdisc #(directly after the same speedtest)

Reading @easyteacher's rule it seems to be connmarking connections based on them having a rate between 15 and 128 packets per second. I'm not quite clear on how it prevents connections from bouncing back and forth if they're near to the edge of those ranges, but maybe it doesn't matter. Doesn't seem to take packet size into account at all which could be fine too as long as you're in that range of packets per second the max bandwidth is 1500 bytes * 128 packets/s = 1.5 Mbps. So if you have at least 15Mbps then you're probably fine ignoring packet size. Only issue is if you get a LAN party going with 20 people all wanting to play CS:GO and wind up clogging your entire pipe :slight_smile:

Here is without sqm on

Here is my result for the speed test with sqm on

Now I'm not sure what's going on with the fluctuations in the speed but typically without sqm on I would hit around 800 mbps for download and around higher 800 mbps for upload. I'm not sure if its the ethernet cable is to blame or not. and unfortunately I don't have another pc or laptop to test it on...