Apr 08

Access points having a hard time downloading code

Cisco recently released Software version for their Wireless LAN Controllers (WLC). This version of code is a bug fix version. Over the past couple of weeks I have had the opportunity to upgrade some 2106 and 4404 WLCs to version

Upgrading a Cisco 2106 to

I have a large number of Cisco 2106 WLCs. If you are not familiar with the 2106, it is a small controller that can only handle a hand full of access points. It has a switch on the back with two of the ports providing PoE. Most of my controller have three access points directly connected to the controller.

Most of the upgrades that I have performed to have gone very well. I have had a few of them where the APs (1131) do not come back online. Some of these are due to the AP failing and they need replaced. Others I have found them in the downloading state, then never getting out of that state.

To fix this, I have reverted back to the old version. Once the controller is back on the old version, the APs have always come back online for me. I then shut down the ports going to the APs, then download again and perform the upgrade a 2nd time. After the 2106 is on, then I enable the ports to the APs. The APs have been able to come up, download the new software and register. I have noticed this takes longer then normal. Normally all of the APs are up after 11 minutes, these seemed to take about 15-20 minutes for some reason.

Upgrading a Cisco 4404 to

I have had the opportunity to upgrade some 4404 controllers from an earlier version of 7.0.x.x to I used TFTP from my laptop on the same LAN as the 4404 to get the file there. In the past, I have had the WLC crash and reload when transferring the image via FTP or TFTP over the WAN. It may be painful, but I suggest you always transfer the image from the LAN instead of the WAN for 4404s.

I did a predownload of the image to the access points (AP). The 4404 will only transfer the image to 10 APs at a time. In the morning, I transferred the image to the controller, then issued the predownload command. By the time I did the upgrade in the evening, the predownload was done. I did have about 10% of the APs that didn’t take the predownload and had the image transferred after the WLC rebooted.

Overall, the upgrade went very smooth!! So far, this upgrade is on par with all of the other upgrades that I have done with Cisco’s WLCs.

How has your WLC upgrades gone?
Did everything work well afterwards?

Mar 18

What you really need to take advantage of Cisco’s CleanAir technology

For the past few years Cisco has been talking about their CleanAir technology. If you are not familiar with CleanAir, the CleanAir technology will detect wireless interference and some access points (AP) will change channels to get away from the interference. To read more about Cisco’s CleanAir technology click here.

I feel like the ability to view interferes is highly valuable, especially when the site you are supporting is somewhere else. I have sites that are many hours away and with the non-CleanAir APs, I simply guess at interference problems. In these sites, I randomly change the channels when I feel like the problem may be interference. For me, it was very exciting to receive some CleanAir APs and put them into my network.

After digging into the output that I can receive, I wasn’t very impressed, but I didn’t know what to expect either. On the controller, you are able to find the AP that you want, then look at the CleanAir information. It does give you a list of interferes in real time. It gives you a code of what the device is and gives you a few graphs. In the graphs, it will show you the Air Quality, Channel Utilization and Interference Power. All of this is very good information. As you can see in the image below, it also gives you some information on the interferes.

Cisco WLC 5508 CleanAir

Cisco WLC 5508 CleanAir

(Click on the image to view a larger image)

The controller will give you the real time information, but what about historical information? Prime Infrastructure should solve that problem. Prime Infrastructure (PI), used to be WCS, is the management system that manages the wireless controllers and access points. You are able to manage many controllers and access points from PI. PI is Cisco’s preferred way of managing your wireless infrastructure. PI has a section of canned reports ready to be run for CleanAir information. When I ran these reports, I never got any information, nothing was ever found. I figured this was due to a bug in PI, but never had the urgency to open a case on it.

The lack of CleanAir information in PI has nothing to do with a Bug in the software. PI is not the location to store the historical CleanAir information. This explains why PI would never have anything in the CleanAir reports. All of the historical information is stored in the Mobility Services Engine (MSE). Only after purchasing and connecting my MSE to PI, PI was able to provide information in these reports that I tried to run in the past.

If you want your network to automatically change channels to avoid wireless interference, you need an AP that fully supports CleanAir. Some APs like the 1600 series only report the clean air information, they don’t take any action. The 3600 series APs are supposed to automatically change channels to move away from the interference. You need to identify your needs and your budget to figure out what you should get.

If you want historical information, you need to purchase PI and the MSE. It was very disappointing for me to find out that PI is THE MANAGEMENT SYSTEM, but it doesn’t store historical CleanAir information. It runs on a server, can have plenty of disk space, is advertised as the way you should manage your wireless system, but it doesn’t display any useful CleanAir information by itself.

I do have to say that with the MSE connected to PI, there is some really good CleanAir information that can be gathered through PI. In this regard, Cisco did a good job.

Has anybody else run into this same disappointment as I have?
Any thoughts?

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