Improve and Reduce Latency in DD-WRT with QoS

Question

I was tasked with making a home network today and after installing DD-WRT in one of the routers, I ran some diagnosis and the games became a problem.

There is usually one or two people using Internet heavely, that means, seeing Netflix, YouTube, or just downloading something. That hurt the latency of online games (Dota 2, CSGO, alikes) when the young ones try to play, and so Google Hangouts/Skype calls.

I tried to set up a QoS rule in DD-WRT, making Skype and those games as "Premium" and "Maximum", but the problem persist when the Internet is being used heavily - it seems the router doesn't "prioritize" these packets.

What I'm doing wrong?

Solution

After some doing some research, DD-WRT didn't assign a priority over a saturated network. The only way I could make something advanced regarding diagnosing the problem was installing a very handy "page" in DD-WRT from Crazy Software Developments, called QoS IP Connection Tracking / Bandwidth Monitor version 0.13e.

Update Jun-2016:

I decided to go for OpenWRT and use SQM instead of QoS, mainly because is not longer maintained actively but still works for traffic shaping a peer. SQM does wonders.

Update: I'm using ddwrt_conntrack, a more stable and updated version of the CSD script.

This particular "plugin" allowed me to know in real time what bandwidth the peers, connected to the router, were using; connections and QoS rules applied to the incoming traffic.

While the QoS was in effect, a saturated bandwidth broke the QoS, so the only way to allow some sort of effective bandwidth management was to track down who used too much of it.

With this data I tracked down two devices - particularly, two tablets, that were using too much upstream and downstream. With QoS, I just add their MAC Address to the list and limited the kbits available for them.

After some minutes, the WAN started to behave normally and clients didn't fight for the total bandwidth anymore. This made games like LoL (a kitty dies every time somebody plays that) and some XB1 games more responsive online (latency) due to the saved bandwidth directive.

If you have some latency problems, lag spikes, or similar with real-time applications, like multiplayer games and the like, you should try to track and limit your peer's uploading bandwidth.

Comments

[Daniel B]

You can’t QoS downstream traffic.