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Managing anything in a K-12 environment can be a very strenuous activity. Imagine all those different school buildings, thousands of students, parents, and teachers and then multiply that by government regulation and bureaucracy. In this episode of AirWaves we speak with Michael Cooper of Oak Hills Local School District who has been managing a Cisco autonomous AP based network for several years. Michael shares his thoughts on WLAN network management and how he transitioned from an, “I’ll just console in,” management style to valuing the benefits of an enterprise grade network management tool. Please take a listen and provide your feedback in our forums.

 

 AirWave Podcast with Denver International Airport: Play Now | Play in Popup | Download

There has been a lot of press recently around Denver International Airport moving from a “paid” wifi service to a “free” service. I had the opportunity to speak with Mikael Rasmussen who is the WiFi Manager for Qwest Government Services and has the actual responsibility for running and maintaining all of the wireless LAN services at DIA. The free network is getting most of the publicity today but Mikael also has the responsibility for other wireless LAN services that the airlines and the airport use for things like baggage handling and security. Mikael inherited the AirWave Wireless Management Suite when Qwest took over responsibility for the network but has quickly become a convert as he’s had to deal with legacy networks and multiple vendors. Take a listen and feel free to post questions on our forum.

Recently, while doing some wireless training, I’ve had a lot of questions about the importance of keeping historical data and how to use that for troubleshooting. When we get right down to it, troubleshooting any system that is already in production is all about the ‘delta’.

In math, a delta is the difference between two items. When troubleshooting network issues, the delta is the difference between when the network was working properly and when it’s not. In most organizations, it’s the networks fault until proven otherwise!

So, what are the items that we need to track effectively to determine what is different, when things aren’t going the way we expect? Well, it varies on the hardware and the type of network you have deployed, but some of the basic items revolve around user counts, bandwidth, client signal strength, and 802.11 radio counters. For effective troubleshooting using these values, we need more than just a day or even a week of data. In some cases, we need months or even a years worth of data to identify trends.

Let me give you some real world examples where these values are important. First, we have user counts and bandwidth. These two values tell us about the utilization of the network. Most AP vendors will have a recommended maximum number of users per AP. When looking at this trending data, are we passing this number when users start complaining? Bandwidth is a little easier to trend since we know we only have so much bandwidth available, depending on the radio mode we’re using.

Client signal strength and 802.11 counters are a bit more ambiguous. These are the values that without historical information have almost no context. Often the ‘slow’ network issue from users is really a lack of good wireless signal. This can be caused by the user being in an area where there is a known lack of coverage, or it can be because something changed in the environment that is causing an issue. I’ve seen things like new construction (unknown to the IT staff of course) or, my favorite is the twenty pallets of canned beans that get delivered to the warehouse that drastically change the RF coverage.

Looking at the 802.11 radio counters can be an eye opening experience. These values usually relate to reception (i.e. interference issues) and transmissions errors. Things like transmission errors can be caused by stolen antennas (mostly in high schools!) or if you’re using outside antennas and the errors peak when it’s raining, you are getting water down into the coax. Reception errors are more varied, but generally point to some sort of interference. This can be caused by things like microwaves (the graphs will jump up during the lunch hour) or cordless phones. I had one situation where all the clients at a facility dropped off the wireless network every Tuesday at 1pm. I verified the wireless disconnect by looking at the roaming history for the clients. When I looked at the 802.11 counters, I saw a spike in the receptions errors every week at the same time over the last couple of months. After further investigation, it turned out to be the backup generator on the roof doing its weekly self test!

So, the rule of thumb when troubleshooting an already deployed system is to find out what the network looked like when it was working properly and what’s different now, when the network is misbehaving.

 

 Ivy Plus League WiFi Panel: Play Now | Play in Popup | Download

This week we recorded a podcast with the main wireless LAN guys from MIT, Brown and Princeton…hence the Ivy+ League moniker. Chris, Don, and Daniel offer candid insights into how they are managing their campus wide WLAN deployments, where their networks are headed and how they are dealing with new technologies like 802.11 and the iPhone. These guys have been cumulatively running wireless networks for over 10 years and they have all seen the impact of different radio technologies, wireless LAN architectures, and physical deployment scenarios. If you are managing your own wireless LAN or would like to learn from people who are managing hundreds of wireless nodes and supporting thousands of wireless clients, please take a listen.

We recently hosted a webinar (click to view) with Craig Mathias on wireless trends for the upcoming year. Craig, as always, did a very interesting job of talking about both WWAN and WLAN technologies as well as the impact on devices and users. By far the topic that is generating the most interest is 802.11n. Most questions centered around the additional speed and coverage that “n” brings but also a lot of questions about how “n” will co-exist with existing a/b/g networks. One of Craig’s main points was the “n” shouldn’t be considered a replacement for “g” and should be used to augment existing networks. He also stressed using “n” in the 5GHz range (same as 802.11a) to avoid interference with existing “g” networks.

Craig was able to answer quite a few questions and if you have some of your own feel free to post them on our forum.

 

 AirWave & Intel Podcast [20:18m]: Play Now | Play in Popup | Download

I had the pleasure to record a podcast with Ray Sliteris of Intel to discuss how they manage their internal wireless LAN on a global basis. Managing over 6,000 access points and controllers is a pretty huge task for any corporation; these guys have the added benefit of working for a company that is a main driver behind the entire WiFi industry.

A few interesting items that particularly caught my attention:

1. Last year they were almost 100% autonomous access points and now they are about 25% converted to a controller based approach. This migration will take them several years to move entirely to a thin AP model. My guess is most organizations are like this, they would very much like to take advantage of the “latest and greatest” but due to organizational inertia and network size it takes a while to make any radical changes.

2. The biggest challenges they faced in deploying a network of this size were creating consistent configurations and having a global network view.

3. 802.11n is not a big push for them. They are testing this new technology out in a few areas but they see this as a 2009 production deployment type of technology. The big business drivier for Intel will not necessarily be the additional throughput but rather the improved connection reliability inherent with MIMO.

Please take a listen to the podcast and let me know what you think!