First of all, I know that I said that the next post would have more information about disaster recovery scenarios. However, this topic is hot on my mind and I'm in a location with very limited internet access this week so I'm going to defer the additional disaster recovery information for something that is more interesting to me at the moment...
I'd like to talk a little bit about wireless networks. For those of you that have been using wireless networks for a few years, you'll agree that they've come a long, long ways. I'm sure that someone will argue with me here, but nowadays I have a hard time justifying cabling a new office vs. using a next-gen wireless infrastructure. The new wireless network equipment from Aruba, Cisco, Proxim, and others is very reliable, easy to deploy and manage, and offers more bandwidth to the desktop than the typical user will need for years to come. It's easy to deploy, inexpensive, and in the cube-land that most of us live in it works very reliably.
<warning - vicious rant follows>This week I'm staying at a hotel out in Tinton Falls, New Jersey. It's an area frequented by technical people as AT&T, the US Army, and others have tech centers here. So why is it that the hotels here have such horribly slow internet access? And more directly, why is it that in today's day and age so many of the hotels that we frequent still don't have wireless networks available? This is, in my opinion, pretty freaking ridiculous. As a technical person (and especially as a network engineer) I guess I just expect better than this. I mean, come on. How many of us have high-speed wireless networks at home? My son setup the last wireless system that we bought for my house and he was 12 at the time - there really are no excuses here... I mean, given a choice of sitting at a desk and using the free wired access or being able to sit comfortably in bed, watching TV and working via a wireless connection - who wouldn't pay an extra $10 for the convenience of wireless? I sure as heck would... These guys are missing both an opportunity to enhance customer service and an opportunity to increase revenues... What gives?<end rant>
With regards to wireless infrastructure, there are three primary categories of wireless equipment. First, there are small, inexpensive wireless devices intended for homes and small businesses. These are the devices made by Linksys (Cisco), Netgear, Belkin, D-Link, and the like. These devices are very affordable and easy to configure but don't offer the manageability or performance that you need in the enterprise environment.
Next, with regards to enterprise class wireless infrastructure, there are two primary classes - systems using fat WAPs and systems using thin WAPs. There are many different terms for these technologies and some people don't consider the fat/thin phrasing to be PC but this is how I learned it when the technology was just emerging and the terms stuck with me.
Fat WAP infrastructure is the traditional 802.11x systems where each WAP operates and is managed individually. This technology is very mature - it's been around several years - and it doesn't require very much expertise to set it up.
Thin WAP infrastructure is a bit different. Within this environment you have a central WAP switch that acts as the brain of the operation. Then, you have dumb WAPs that basically act as antennas - bridging the wireless networks from the switch out into the areas where wireless access is desired. While this architecture is a bit more complicated and harder to setup it can offer huge advantages in terms of advanced features and manageability. I have a good friend who is one of the old timers over at Aruba and some of that they and Cisco can offer through their next-gen wireless technology is really amazing. Imagine being able to walk anywhere in your company carrying your laptop, without ever losing wireless access, changing IP addresses, VLAN, or etc... I'll see if I can get my buddy to post some information about some of the more cool features they offer today.
Now to pay the bills...As you know, I try to add a little something to every post to help keep the lights on around here. For those of you that have deployed wireless networks or are planning to, Orion does a great job of managing this type of infrastructure. For fat WAP environments, we offer an add-on to Orion called the Wireless Network Module. This is an inexpensive way to enhance Orion so that you can track more information on your wireless network like signal quality, errors, and traffic on a per WAP and per wireless user basis. For those of you that are deploying thin WAP systems, you can use the Custom MIB Poller in Orion to track statistics within the wireless switch for both the thin WAPs and the users connected to the wireless network (the specific statistics will vary a bit based upon the hardware vendor and the information that they make available via their MIBs, but more are very good). If you want to learn more about how Orion can help you manage your wireless infrastructure contact your SolarWinds sales dude and he or she will be more than happy to assist.
That's it for tonight.
Flame on...
Josh
One problem we currently see is that a lot of users ask us why we still put wired sockets into locations and not put wireless everywhere and our response is untill 802.11n and beyond are available then to put multiple desktop PCs on a wireless network is a disaster waiting to happen unless you put so many APs in that you only have 4 - 5 users per AP.
So our current policy is to only enable laptops that require mobile access and mobile trolleys.
I would be interested in your response as you say above that you find it hard to justify wired over wireless?
Thanks
Jon
Jon,
Thanks for the comment. I was figuring to receive a lot of heat on this post as when I wrote it I'd been stuck in airports/planes for about 12 hours and having just gotten to my room I was really hoping to just lay in bed doing e-mails and watching TV but was limited by the length of the patch cable...
I've had different experiences with wireless than you report here so I checked with a couple of people that I know that do large scale wireless deployments . I've personally seen many networks operate with 25-35 wireless users per WAP without issue. However, checking with my buddies, their answer was that for typical office users you can do 15-20 users per WAP very safely - meaning that they won't see any performance degradation at all.
They did say that for power users you should still run cables but they're seeing that on average 75% of the users can go wireless.
HTH,
First off, full discloure: I work for Aruba Wireless Networks.
One thing you do have to keep in mind is that wireless is a shared medium (think hub and repeater) where when one device talks, all others on the same AP must listen. So the question you need to answer when you think about users/AP is the amount of bandwidth each client will need. Although it says 54Mbps on the box, you will never see that speed in the real world. Instead you should plan for 19-20 Mbps of throughput at Layer 3 (half duplex remember) per radio.
We have seen that for standard office workers, you can easily place 15-20 users/AP and the users will not experience any noticeable difference in performance. Of course there will always be devices that should be wired in but most workers can be easily moved to wireless.
Also, as a side benefit, most of our customers find their wireless network becomes much more secure tha their wired network. In most networks today, if you can gain physical access to a wall jack, you're free to roam anywhere in the network without authentication or encryption. The new wireless authentication and encryption standards combined with our ability to offer differentiated access (with out built-in per-user stateful firewall) allows you to have a lot more control over who can gain access to the wireless network then you can on your wired network.
I would be leery of .11n at this point. Although you do get much more throughput, you also get a much larger coverage area so in effect you're simply having more users sharing more bandwidth. Also, you need to run Gig to these APs which means a potential closet switch upgrade, they require more power than regular APs (different POE spec), and they use twice the spectrum width as a regular 802.11a or g devices. What this means is that if you run .11n in the 2.4GHz (g) band, you can only have one AP (in the US tehre are only 3 non-overlapping 20MHz channels so since .11n takes 40MHz, you only really have one channel to play with). In the 5GHz (a) band you can have 6 .11n radios or 12 a radios. So if you are going to do .11n in the enterprise, make sure you do it in the 5GHz band.
So to conclude, if you use one of the enterprise-class vendors like Aruba, Cisco, or Trapeze which are capable of dynamically calibrating their channel and power settings as the RF environment changes, you can safely get 15-20 users/AP unless they have very high bandwidth requirements in which case keep that 19-20Mbps number in mind.
Contrary to your statements above, the Custom MIB Poller is hardly a functional equivalent to the Wireless Monitor. There are many Solarwinds customers, and those whom hope to be customers in the future that are eagerly awaiting the release or a Wireless Monitor that supports central WAP switches such as Cisco's Wireless LAN Controllers.