QoS - does it really help you improve your ping during gaming?

[Ozpa]

Hi guys!

I'm in a pickle - I'm trying to run uTorrent and play TERA (MMORPG) at the same time but I get lots of delay if my download bandwidth go up over 35% of my total connection speed or if my upload goes over 40%. Is this normal? It's strange that even if you leave, for example, 20% of your download/upload speed free the ping rises so much. I was looking into QOS to solve that but I'm really puzzled how to set it up on my DD-WRT Linksys router. I understand the priority levels but everything else is a blur (like port numbers and protocol).
Also, I was wondering does QOS work for gaming at all (while using something like utorrent)? I mean is it possible to use, for example, 80% of your download and upload speeds while gaming and having decent pings? (well up to 40% increased in in-game ping is still tolerable for me)

 

[Steevo]

That router is OK, but it lacks the processing power to inspect enough packets and prioritize, buffer, and repackage data.

Try lowering your MTU.

 

[Ozpa]

Oops sorry I forgot to mention it's a Linksys WRT54G v7.2 (DD-WRT build 14929). It's an old router of about 3 years but it's supposed to be good for the day.

Can you elaborate a bit more on why I should lower the MTU? Is that so the router can cope easier? What are the drawbacks of lowering MTU? Thanks.

 

[Steevo]

Lower MTU means it will send more, and smaller packets, thus trying to move smaller traffic along more easily, but you give up some throughput, not that any internet connection will suffer until you reach saturation, and that will only rarely happen.


It is on the rest of the WWW that the lower packet size will help.

ping www.google.com -f -l 1468

the number 1468 in the example is the packet size of empty data, and needs 32 added to it for addressing, so a 1500 MTU in your router is 1468

Now lets say your network can handle Jumbo packets, your router can also, but your ISP won't, that means your packets over 1500 get split, and that adds latency, while not an issue if you are downloading, it IS an issue on time dependent packets.

If you get the error message.
"Packet needs to be fragmented, but DF bit set."

Lower your payload 32 bits at a time until you no longer get it, add 32 back and that is your new MTU.

 

[Suhidu]

Is DHT enabled in Preferences->BitTorrent? That feature opens up many connections, too many for some routers to handle. It gave me internet connectivity issues even when I should have had plenty of bandwidth left over. Most torrents continue to work fine without DHT.

 

[Jetster]

Not if your running torrents and gaming on the same rig. QoS will not help. If you have separate PCs then maybe. But running torrents and gaming on the same network is never pretty

 

[Ozpa]

DHT is off.

What a shame Jetster

Is there any other way to prioritize the game's traffic so you'd get lower ping in games? Maybe some special software.

 

[3870x2]

I am interested in this also, not sure how using only a small amount of bandwidth for a download makes everything else have high latency.

BTW steevo what is your avatar?