Showing posts with label Tech. Show all posts
Showing posts with label Tech. Show all posts

Thursday, November 12, 2009

Why You Need to Be Wired Part 2


This is the conclusion of yesterday's "Why You Need to Be Wired Part 1". Read that first for context.

These posts relate to all of the current generation consoles, PS3, Wii and XBox360.

So now that we've talked about interference, we need to talk about overhead and latency. Latency or "ping" refers to the amount of time it takes to get from your computer or console to another computer or console. Overhead and latency go hand in hand, and the biggest portion is encryption. Encryption is very useful to keep people from spoofing your bank's web site as well as protecting your own passwords. That said this protection comes at a cost. First let's look at a low bandwidth ping test.

Using wired Ethernet:


Using wireless:


Looks almost the same, and some may say, wireless is faster, which is true in this case. My wired connection uses Computer -> USB -> Ethernet -> Switch -> Router -> The Internet, where as my wireless connection is Computer -> Wireless -> Router -> The Internet. Yes the extra switch is introducing a 1 ms delay. But remember this is a low bandwidth test, where the router has to do very little to decode the packets and the computer has to do very little to encode them.

A speed test tells the real story.
Using wired Ethernet:


Using wireless:


You'll notice that when I went to a wireless connection, my ping doubled and my bandwidth dropped. This mostly due to the encryption. Additionally, there's what's called overhead with wireless. Overhead is extra control signals from your device to the router (and back again) which is not part of the data you intended to send/receive. It is meant to manage the data being sent and to check for data errors. This overhead reduces your overall bandwidth and processing it introduces some more delay. When the overall bandwidth usage is low, this delay is insignificant, but up the amount of data to transfer and look out.

You'll note in all 4 cases I used exactly the same server, and in all 4 cases I used the same computer and internet connection. I also ran each test more than once to obtain consistent results, and while Comcast may have shaped the packet, they would have done the same in all the tests, thus giving us reliable results regardless.

After seeing all this, some may say "Well, I'm going to turn encryption off!" Please, for the love of all that's holy in this world, do not open up your personal wireless router to everyone. First, this really doesn't solve all your issues, remember the other wireless overhead? Second, removing encryption not only opens up your traffic to everyone else around you but it makes it easy for someone else to connect to your router. Even if you have MAC address filtering, that won't stop someone from connecting to your network and potentially doing malicious things such as downloading child pornography. Guess who the feds blame when they trace the download to your IP? Encryption gives you some protection against this, and in most cases the malicious person will continue on down the street looking for another sucker rather than attempting to crack your connection.

WPA/WPA2 with a pre-shared key is enough for most people.

A final note, yes I live on the west coast, and that does seem to help. I tend to get very good pings on my PS3, typically sub 65 ms when playing in the US official Warhawk servers. And for those who are not math inclined, 1000 ms = 1 second, so 65 ms = .065 s.

Using the numbers from the speed test as an example, a ping of 126 means that I would get 7.9 updates per second. Heck if I removed the extra switch and got that 1 ms back, I'd get 8. Compare that with a ping of 249 (wireless speed test) where I'd be getting 4 updates a second and you can see why this is important.

Effectively, with a ping of sub 65 I'm getting an update from the server 15 times per second or more. Not only does this improve my game play it means the server has better data for the other players to use as well improving their game play. If someone joins with a ping of 333 or more they are getting less than 3 updates a second, 1/5th of my speed and incremental updates are 5 times bigger. And anyone who's crazy enough to join with over 1000 ms ping, they end up bogging a server down (lots more data to send at a time.)

So now that you know why it is important to use your Ethernet connection get a cable. If it is from Dollar Tree or MonoPrice makes no difference, just get one and use it. Your fellow games will thank you (or at least not curse your name due to your horrible ping, no promises on other cursing).

Wednesday, November 11, 2009

Why You Need to Be Wired Part 1


This post goes into all the gory details why using wi-fi to play games online is a bad idea. If you don't care so much as to the why, just find yourself an Ethernet cable and use that.

So wi-fi is great for a lot of things. For downloading items on your laptop or browsing the interwebs it is great. Even for flash games, which download and run on your local machine it works wonderfully.

It is no wonder next generation console makers would include it. In fact the Wii doesn't even have an Ethernet port. It's cheap to add and has wide spread appeal. That said, I've hit the single biggest disservice to gamers I've ever seen.

So, for those who don't know, 802.11a started at 5 Ghz. It was faster, less prone to interference but the signal only went ~50' and the components were expensive. Thus entered 802.11b/g. These two standards used the 2.4 Ghz range to get 3 times the range. 802.11b had a much reduced data rate, but 802.11g finally brought back 802.11a speeds with the extra distance. All is golden right?

Wrong.

As you may or may not be aware, 2.4 Ghz was open as that's the frequency microwaves used. Additionally some portable phones used this frequency as well. Now some are saying how bad could it be?

Imagine a still lake. Now imagine a throwing a rock that water and creating a wave. Also imagine a guy on the other side who measures the time between waves. You can "send" him information and he can receive it. That's your normal wi-fi signal. Nice, clean waves without a lot of interference. Then someone gets the idea to microwave nachos. It's like throwing an injured baby seal into the lake. All the thrashing and such interferes with your nice clean waves. The listener (router) cannot tell what to listen to easily, so it spends extra time filtering out the noise and only looking at the biggest waves, thus degrading the speed. The same thing happens with those 2.4 Ghz phones.

So here's the second and more important piece, do you know why microwaves operate at 2.4 Ghz? It's because that's the wave length which water absorbs. And we have these annoying bags which are filled 2/3 with water walking around all the time. Most people call them family and/or friends.

Furthermore, with the PS3 and Wii, the controllers are Bluetooth based. Again, wireless and you guessed it, at 2.4 Ghz. Add in neighbors and other interference, you're lucky to ever get a signal.

Now I know some of you are saying, but what about 802.11n. Doesn't that run at 5 Ghz? Yes and no. 802.11n uses both 2.4 Ghz and 5 Ghz to increase bandwidth and maintain backwards compatibility. This means your bandwidth can change drastically at a moment's notice. Plus as more and more devices move to 802.11n, we are going to have the same crowding problem we have with 802.11g.

Okay, so we've talked about why you're signal will degrade and cause problems, but so what? Even at the most degraded levels you still get 11Mb/s which far exceeds your cable modem so who cares.

Well there's a second piece we've glossed over. That's protocol overhead and latency added. I'll add that in part 2 of this series.
 
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