Ask the Wi-Fi Guru, Episode IV

By Aaron Weiss

June 12, 2008

In this month's installment, the Guru addresses questions about packet loss and gaming, properly assigning IP addresses, and combination wired/wireless networking.

Sometimes when the Guru is driving his car, he thinks, “This piece of machinery is really complicated. There are so many parts, each with its own complexities, and all the parts have to work together in just the right way. He thinks about how many discs and bolts and belts and chips could break at any given moment, and he marvels that the thing even works at all, and finally he concludes, "Watch out for that truck!"

Your wireless network is not nearly as dangerous, but, like your car, it does rely on a lot of links in the chain to keep on truckin’. From signal reception to network settings to firewalls, there is a lot that can go awry, leaving you stranded offline. Hopefully, yours is running smoothly, but if it isn’t, think of the Guru as your friendly auto club (only without any tow trucks and somewhat slower to respond). The Guru gets your e-mails, so keep 'em coming.

Q: I’m using a Linksys WRT54G and DD-WRTv24 to create a bridge to my D-Link WBR-1310. I flashed the 54G without any major stress and disabled the security settings on both the 1310 and the 54G. The issue is that while I can see the home network and it appears to have set the bridge, once I reset the computer’s NIC to automatically obtain an IP, it fails. The WBR-1310 is 192.168.0.1 and the 54G is 192.168.1.1 is this a problem? -- NoOne


A: Yes.

Everything was going well here until your last sentence. In a bridged network, all of the clients share the same subnet. Think of a subnet as being in the same virtual room, or virtual bus, or virtual political party. Networks can be a complicated subject. As you already know, an IP address is made up of four "parts" or, technically, "octets," in the form A.B.C.D. Your best bet to create a simple shared subnet is to assign IP addresses using the formula A.B.C.x, where only x changes. Each device should have a unique x octet, from 1-254 (in this case, 1 is already taken by your WBR-1310).

In your case, you should assign your 54G to the subnet that the WBR-1310 is on—in other words, 192.168.0.2 might be good.

Q: I enjoyed reading your articles on the DDWRT and setting up WDS, wireless bridge, etc. All these articles seem to use the wireless connection from router to router. Is there a way to use a wired connection between routers and set up WDS or a bridge.

I would like to set up a second router in my garage workshop (I already have a cat5 from a router there) and want to have both wired and wireless clients connect to it. -- Jonathan

A: You ask a great question, because sometimes we can get so caught up in doing things wirelessly, we may overlook a good old fashioned wired network solution—just like grandpa used to do.

This might be a heretical thing to say in a publication devoted to Wi-Fi, but wired connections are pretty great, too. They are fast, free from interference, and do not need security like WPA. Of course, they are not invisible, and running them across floors and through walls is grunt work.

You can absolutely do what you are describing. In fact, it will be easier than setting up WDS (which is only needed for wireless-to-wireless bridges). It will also be faster, because wireless bridges cut in half the bandwidth at the extension router. A wired extension like you describe should not cost you any speed.

Just about any wireless router will work in this scenario. You have two basic configuration options:

1. Create a bridged connection to router #1. In this configuration, any devices connected to router #2 (by wire or wireless) will share the same subnet as router #1 (also see question above). As part of the shared subnet, all your devices will occupy the same "virtual room" and see each other, allowing them to share files, for example.To do this, you will connect the cable from one of router #1's LAN jacks to one of the LAN jacks in router #2. Most wireless routers include one "WAN" (sometimes labeled "Internet") jack and anywhere from 1-4 LAN jacks. Do not use the WAN jack on router #2.To configure router #2 you will also connect a cable from another of its LAN jacks to your PC. Follow the manufacturer's instructions for accessing your router's administration page using a Web browser. From there, you will want to disable this router's DHCP server and also disable its firewall. These services are being provided by router #1. You will also want to assign this router a static IP address compatible with your subnet (definitely see question above).You can configure router #2's wireless SSID and security any way you wish for the environment, independent of however the wireless settings of router #1 are set.

2. Create a new subnet in your garage, separate from (but piggybacked on) router #1. In this configuration, PCs connected to router #2 would make up a separate "virtual room" from machines connected to router #1. You might wish to do this, for example, if router #1 is connected to your home office PCs, and router #2 is going to be used by your kids to do whatever they do, and you'd rather keep the two networks separate.To do this, you will connect the cable from one of router #1's LAN jacks to the WAN (or "Internet") jack on router #2. In this configuration, router #2 will "think" of router #1 as your ISP. Or, to put it another way, router #1 is playing the role as ISP, just like your "real" ISP is playing that role to router #1.What this means is that router #2 will isolate its clients from router #1 using its own firewall and network addressing scheme. You do need to configure router #2 so that it assigns addresses using a different subnet block than router #1. For example, many routers come out of the box set to assign addresses in the 192.168.1.x range. You do not want both routers using this range. If router #1 is assigning 192.168.1.x addresses, then configure the DHCP settings on router #2 to assign addresses in 192.168.0.x.

In case the distinction between scenarios #1 and #2 is confusing, you are most likely to want scenario #1. This way, your garage is basically just an extension to your house. In fact, you could daisy chain many routers using wired connections as per scenario #1, to extend your network—both wired and wireless—over a large area. Doing so may be more reliable than bootstrapping a series of wireless repeaters, but of course involves a lot of cable pulling.

Q: I love my 802.11g network, but I have not been able to overcome one major obstacle: packet loss in gaming. Even with my gaming-oriented D-Link DGL-4300, I experience heavy packet loss in online games, regardless of signal strength, proximity, firmware version, or port forwarding. Is there any hope for me with settings like RTS/Fragmentation threshold, or is this a shortcoming of wireless networking?

A: The Guru admits up front that he does not do much gaming. Somehow, video games became too complicated when they changed from one-button joysticks to gamepads. Do you remember Pac-Man? That was awesome! (Even I will admit that Pong was a little primitive. But only a little.)  From what I understand, though, modern Internet games require two important criteria: you need very low network latency and also, you need to kill everything you see.

Latency is a measurement of how long it takes for one of your data packets to reach the gaming server. In the context of gameplay, this might mean the time it takes for your bullet to pierce your enemy's face. So the stakes are understandably pretty high. Your packet loss—or data, which is being lost on the way from your PC to the server—is effectively increasing your latency, since it takes that much longer for your data to get to the server, perhaps so long that your head is blown off before you even get a round off.

Why are you losing packets? One common problem with gaming is congestion at your router. If you have several applications using the network at one time—whether your own PC or other PCs sharing the connection—they might be competing with each other. Many of the "better" routers today include a feature known as "QoS" or Quality-of-Service, which is basically a form of packet discrimination. A QoS system gives higher priority to certain kinds of packets, thus allowing real-time activities like games and VoIP to get through before passive activities like file downloads.

The DGL-4300 is marketed as a "gaming" router, which basically means it offers QoS tuned for games. D-Link calls this "GameFuel" and it has to be enabled. In addition, you may need to create a gaming rule specific for your games, which can involve parameters like the network ports that the game uses. This is not quite the same thing as port forwarding, as described in your message, which allows specified network applications to pass through your firewall, but does not give them priority. So, check your "GameFuel" settings. (Other router models may use a different name for gaming QoS.)

Next, troubleshoot whether the packet loss is a result of the wireless link to your router. Disable the wireless adapter on your PC and connect a wired cable to the router. Do your games still experience significant packet loss?

If the problem persists, and the wireless link is not to blame, is your gaming PC running a software firewall? In some cases these have been known to adversely affect gaming performance.

If all that fails, I would borrow or trial another wireless router—just in case your broadband connection itself is the problem.

These troubleshooting steps may be more likely to yield results than fiddling with RTS and Fragmentation settings. Wireless networking itself should not be an impediment to online killing—err, gaming. I said gaming.

[Editor’s note: If it turns out your broadband connection is the problem, try replacing your modem. Gamers we know have had great success with this.]

Aaron Weiss is a freelance writer, editor, and Wi-Fi enthusiast based in upstate New York. To submit your questions to the Wi-Fi Guru, simply click on his byline and put "Wi-Fi Guru" in the subject line.



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