Wireless Network Lag

July 18, 2009 11:18 AM

What are some ways I can improve latency over a wireless network?

When i do the ping test on google i get an average of 90ms, which is not good enough for online games. Are there any ways you can improve latency over a network? I have a Wireless G adapter with 3 computers connected to it. Switching from wireless is not an option for me. Please ask me as many questions as you have to about my network and I'll be happy to answer.

PS - I switched over to OpenDNS. Is that bad news for my network latency?

posted by bobertdude to computers & internet (12 comments total)

I had a heap of trouble gaming over my LinkSys WRT54g. Crippling packet loss that resulted in bad pings. I tried installing some 3rd party firmware, and it was fixed in one fell swoop. DD-WRT was the name of the firmware.

What router are you using?
posted by dualityofmind at 11:47 AM on July 18

I'm using a LinkSys WRT54G just like you. Would I be able to reinstall the LinkSys firmware if any problems arise from using DD-WRT?
posted by bobertdude at 11:51 AM on July 18

Where do I download it? Is it free?
posted by bobertdude at 12:03 PM on July 18

I checked it out and decided that I'm not willing to flash my router. Can anyone suggest a different way?
posted by bobertdude at 12:18 PM on July 18

I'd suggest reconsidering the no-flash policy (though I'd recomment Tomato firmware over DD-WRT), since the remote chance of bricking your router is more than offset by the increased value of having a sweet, fully-functional router.

If you're worried, just flash it while temorarily using a wired connection -- the only way you'll mess that up (providing you read the instructions) is if the power goes out.
posted by astrochimp at 12:38 PM on July 18

Nthing a flash. The stock firmware in the WRT54G sucks; both DD-WRT and Tomato are the ways to resolve this. Nothing else will work, and there's no reason to not flash it.
posted by ellF at 12:57 PM on July 18

You latency over the network probably isn't local to the wireless segment, to test the wireless segment you need to picg from the computer to it's default gateway.

OpenDNS has very little to do with latency except in instances for domain name resolution, typically there isn't much latency here and it won't impact online game play at any rate.

Most of the latency is from your modem or router to the next hop. The last mile of a residential connection typically has the lowest bandwidth and the oldest technology deployed and there really isn't much you can do about that.

So, please don't fuck around with your wireless router until you've determined whether it's contributing in a meaningful way to the latency you describe, it's likely a giant waste of time and effort.

Run a couple of traceroutes, ping each address in that path and you'll figure out where the problem is, THEN and only then consider what the problem you are trying to solve is and what the best answer is to that problem.
posted by iamabot at 1:15 PM on July 18 [1 favorite]

I agree with iamabot, you need to investigate each hop. For troubleshooting purposes, you should also try some pings when wired to the router so you can separate any latency caused by the router itself from that caused by the wireless.

Its quite possible though that the wireless segment is the source of severe latency, at least intermittently. My local pings are typically about 1.5ms over WiFi, but sometimes they jump up 100x and may stay up that high for multiple seconds. I think this is a result of retransmissions and other techniques for dealing with temporary interference. If your signal is marginal, that could be the cause of more enduring latency issues.

Still, its quite possible that most of the issues are out of your hands, short of switching ISPs, and there is no guarantee that will help either. What kind of internet connection do you have? In some technologies, they may accept more latency in order to offer higher speeds more reliably. If you have a cable modem, going to a lower speed grade probably wouldn't help, since the network segment is still operating at full speed. With DSL it might make a difference, though it really depends on how the provider has engineered their network.
posted by Good Brain at 2:08 PM on July 18

One of the things that increases wireless "latency" at regular intervals, is when the router and clients are re-negotiating WEP or WPA/WPA2 encryption keys. Wireless encryption, for several simultaneous wireless clients, also vastly increases the CPU load on the router, because it is doing much more encryption work than any client. Also, if you are asking the router to create individual and individual VLAN for each client (Wireless -> Advanced Wireless Settings -> AP Isolation "On" in the router management interface), you are increasing the router's CPU load significantly. So, if you can risk your wireless network being insecure, kill WiFi security encryption. Next, if your game supports UDP, and you are willing to accept UDP security issues, open up your router for UDP. UDP doesn't require the send/acknowledge handshakes of TCP, and while lossy, is therefore much lower average latency than TCP connections.

I don't recommend running a wireless network this way as a regular thing, as it is an open invitation for abuse. But you can make such settings a "profile" in the standard Cisco firmware interface, and only use it for network game play, and then return to secure wireless operation for normal Web browsing. You may need to suitably configure all your clients for this insecure mode, too, when you switch to it.
posted by paulsc at 2:27 PM on July 18

i get an average of 90ms, which is not good enough for online games.

What makes you think this?
posted by bitdamaged at 3:18 PM on July 18

You've got a couple of mistaken assumptions. First, "pinging google" doesn't tell you much about your network speed since Google has servers all over the world and there's no easy way to know which one you're talking to at any given time. Second, you don't care about your latency to Google, you care about your latency to whatever game server you're playing on. Third, "ping" measures ICMP round trip time, which has very little to do with game performance. Finally, OpenDNS won't affect your network latency meaningfully, especially for games. For other reasons OpenDNS is a bad idea, but if you like what they do it's probably harmless.

To answer your specific question, your wireless network router can cause latency two ways. One, there's a certain amount of latency inherent in WiFi, and there's really not much you can do about it. Two, your router itself could cause extra latency in your network connections. In general both sources of latency should be very low, a couple of milliseconds, even for a crappy router.

There's one important exception though, which is if your router is busy all the time. Ie: you're constantly streaming Youtube videos while gaming, or (worse) downloading files via BitTorrent. In that case your other network activity will bog your network connection down, and your games will feel laggy. In this specific case flashing better router firmware like DD-WRT or Tomato will help performance a little bit; third party firmware often has better Quality of Service scheduling and better NAT routing management.

What games are you playing? Do those games feel slow to you? If it's a game like Team Fortress 2 with a builtin ping monitor, are you unable to find a server with low ping?
posted by Nelson at 5:53 PM on July 18

It doesn't appear that anybody has mentioned sussing out the quality of the wireless signal itself should you find a difference between a wired connection and a wireless connection to the same gateway.

You may, for example, be running other wireless systems (e.g. a wireless phone) that's creating interference and slowing performance... you might try powering down other wireless devices in your environment and see if performance improves.
posted by deCadmus at 9:19 PM on July 18