Wireless Troubleshooting

When it comes to technology such as ethernet, it can be a little bit problematic at times. We need to make sure that we run our ethernet cables properly, that we're not getting next to equipment that's letting out a lot of electromagnetic interference, that we don't run those lines too far, and that we are terminating the ends properly. If we don't, it can cause problems on our wired networks.

When it comes to wireless, all of those issues are amplified to such a greater degree. The way we transfer data through the air is just problematic, and so it creates some problems with troubleshooting. We're going to start out by just taking a glance at the troubleshooting steps, then talk about some issues that could come up when it comes to wireless not connecting, and then also talk about when we are connected but just have poor performance, low speeds, low throughput.

The troubleshooting steps

Just a reminder: when it comes to troubleshooting, we're not just going to jump in and start making changes and see what happens. When we approach things that way, we end up with misconfigurations causing more problems and just creating chaos with our networks.

So we need to take an organized approach to troubleshooting. Sit down and actually analyze what the problem is, identify the specific problem that you're having, and then think through what could be causing that. There's a brainstorm session that comes up where we think through what could be causing that problem. We're going to then choose something that we have some sort of theory behind of what could be causing the problem, and then test that theory out: find a way to be able to change the environment to be able to test that specific variable out. Sometimes it is a change in configuration, but there are other ways that we can go about that as well.

Then establish a plan of action, roll out that plan of action, and then verify that you have corrected the problem. And then don't forget the last step, documentation. Chances are you'll probably encounter it in the future, and there are times we forget what we did to actually change the outcome, to improve the situation. So make sure you document at the end.

When a client is not connecting at all

Let's first of all address when a client machine is not making any sort of connection, when you are just not getting a connection. What are some of the possible things you can try, and what are some of the possible problems that you will see?

First of all, you can use ping in this scenario. Ping works just as well on wireless networks as it does on wired networks, with one exception, and that is that wireless networks are layer 1 and layer 2. So if you're not making a connection at layer 1 and layer 2, you're just not going to be able to ping anything that's out there. Ping does give us some feedback though, so still utilize that.

Check the interface for connectivity on your client. Your client will tell you whether it's connected or not connected. You could be connected but still not be able to communicate to anything, and that's going to be a different scenario than if it's not connecting at all. If it's not connecting at all, maybe it's some sort of wireless password that you've got wrong on there. Maybe you need to clear out the configs of it, you need to wipe out that network and then get back onto it and retype the password in. So maybe there's something along those lines. If it's connected, it may tell you that it doesn't have internet connectivity, or it may give you some other feedback with it. So check the client to see what kind of information is on that connectivity.

You can use ipconfig or ifconfig to see if it's getting the proper IP address. If it's not, maybe it's not getting an IP address at all, and maybe it's getting an APIPA address, a 169.254 number, and that will be a sign that it's not getting an IP address. So maybe it has connectivity but you need to research why it's not getting an IP address.

You can check the wireless client settings. Go through there and make sure that maybe there's a statically assigned IP address to that machine and so there's something wrong with that. So check the client machine with it.

And try connecting to another network. You can take that client machine and connect it to another network, and that will let you know if the wireless card is even working. Or maybe it can connect to another network and it's something problematic with the wireless infrastructure that you're trying to connect to, or you have some sort of configuration wrong on it.

One thing you can also try is to update the machine's drivers, update the machine's firmware, update the machine's OS, operating system — do updates on the machine. Something along those lines could also be causing a problem, and that update could fix the problem. So those are some things to try.

Intermittent issues and slowness

Troubleshooting intermittent issues and slowness can be difficult at times. When you're having an issue where something is just flat out down, what you can do is you can sit there and try different commands and try different things until you get it up and running and solve the issue. But when you're talking about something that's intermittent, you have to hit it in the window that is causing a problem, or shuffle through logs to find out answers of why there's some sort of problem during those intermittent issues. Or when it comes to slowness, it's just really difficult to figure out what the core reason is for that slowness. So you'll spend a little more time probably in those scenarios with troubleshooting. Just be patient with it.

One thing that you can do just to eliminate some of these issues is just making sure your software is up to date: making sure that your wireless LAN controller and your access points have up-to-date firmware on them, making sure that the clients have up-to-date operating systems on there. So that's an easy step, just to make sure that that's not part of the issue, that that's not playing into the issue. But there are other things that will slow down your network as well.

Here I've got the headquarters office and I've got some access points, and it's showing you the coverage of these access points. So what are some other things to watch out for?

Watch out for clients that don't have strong signals to these access points. If you've got an access point that's right here, then this access point is going to be connected by multiple clients; it acts as a hub. So if you've got somebody at the far reaches of your network that's out here, it takes them a while to communicate because their speed is slower. The further you go out, the connection gets poorer and so your speeds decline, and that's going to affect everybody that's connecting to that access point. So watch out for those devices that are too far out from your network. In fact, when you have higher-end access points, you can set up your access points to make sure that, number one, you're not broadcasting too much power out in the coverage area that you're trying to reach, but also that devices that are on the far extent can't connect to your access point — it doesn't allow them to access your access point if they have too weak of a signal.

Kind of along similar lines, watch out for the protocols that they're using. There are some older protocols that are not as fast as newer protocols, so if somebody's using the older protocols then that can slow down your other users. So sometimes we want to shut off some of those other protocols to improve the operability for the users that are connecting to the access point.

Watch out for any high-access users who are using a lot of bandwidth. If you have a user that, let's say, is sitting well within this range of this access point and they are downloading lots of information and they have lots of information that's flowing in and out of their computer, that can be problematic for others. Once again, this acts like a hub, so when that device is communicating, other devices can't communicate, causing problems.

Watch out for interferers within your space. Perhaps you have a microwave that's somewhere in your space, or maybe you have some other devices that use that 2.4 GHz or 5 GHz frequency. When you're using the enterprise-level access points, a lot of times these devices will actually point out to see if you have other interferers close on your network, things that are interrupting the signal between the access point and the client. So that can help to troubleshoot some of this as well.

Also, these access points, if you've got nice ones, are capable of quite a few clients to them, but there is a limit on how many access points, or how many users, can access an access point all at once. So if you've got lots of people and you're saturating that link, that access point, that is going to be problematic as well.

And then also look for blind spots in your network. There could be spaces where, let's say this access point right here goes down, and now you have this spot in here that's not really getting great coverage. So that could also happen on your network as well. Make sure you've got really great coverage. Access points have come down a lot in price, so you should be able to do some pretty decent coverage across your network nowadays, so that way you don't have those types of blind spots.

So those are a few things to watch out for when it comes to slowness on your network and intermittent problems. We talked briefly about the troubleshooting steps, we went into some things to look out for and things to try when it comes to wireless devices not connecting, and we also talked about what it would look like with some sort of wireless network slowness or intermittent issues. That's wireless troubleshooting. Once again, it can be a little bit more difficult with wireless, but still doable, and it's something that most networks nowadays need — some sort of wireless connectivity — so you'll probably end up having to do some troubleshooting with it.