Hi all,
I manage a smallish enterprise deployment (about 150 wireless clients). This is part of an ongoing series, "tech enthusiasts are often not IT professionals--confuse the two at your own peril."
just brew it! wrote:So the *internal* walls are 1'+ concrete? That's rough. I can't think of any obvious inexpensive solutions.
Zenlessyank did!
SecretSquirrel wrote:A wifi access point per room, or per pair of rooms if you can locate it in a centralized point and run a couple of coax lines to an antenna mount in each room. It's not cheap, but in the scheme of networking, not terribly expensive unless you go with tier-1 gear. What you would get with a tier-1 solution is the ability to manage it all a bit better. If you are trying to do it on the cheap, you can probably do wifi in each room for about $100 per room plus another $150-200 per 16 rooms, plus the cost of labor. This all assumes you can get cable run too.
No two ways about it, if the signal degradation is as bad as you say, you need antennas in every room.
WiFi doesn't work that way. Beacon frames are single stream, and if a room can't hear that stream, they're out of luck. What about abg modes, you ask? (You won't because a minute of Googling is enough to convince anyone that this stuff is
voodoo.) You then run afoul of
diversity.
notfred wrote:
802.11f never took off (for some strange reason vendors weren't interesting in improving compatibility with other vendors' products). These days, 802.11r fills that role, and has widespread support among enterprise gear and clients designed in 2010 and later.
SecretSquirrel wrote:Because of the way RF and antennas work, no, afraid not. Even if you could, you probably wouldn't like the results. A wireless access point is capable of supporting a certain bandwidth, say 54Mbps. That bandwidth is divided amongst all devices sending or receiving traffic through that access point. So feeding several classrooms with a single AP where that is the sole method of connectivity, especially if the students are using devices too, would lead to pretty crappy network speeds.
Right for the wrong reason.
SecretSquirrel wrote:One thing to note is that you do not need "wireless routers", in fact you don't want any of the functionality they provide. Authentication and DCHP need to be handled by a central system. All the access point needs to do is provide connectivity at the transport layer.
Access points are layer 2 devices, so transport layer is also incorrect.
NovusBogus wrote:Does handoff really matter here? It's a school so I'm assuming he has some teacher PCs that never move and possibly a set of tablets that are occasionally brought to a room and powered up for an hour at a time.
By attempting to determine actual requirements instead of blindly making recommendations, you have demonstrated that you are the smartest person in the thread. Well done--now go forth and frustrate people that want simple answers to complex questions.
To address your question, there could be scenarios where roaming matters. Wireless clients are simple devices--by default, they connect to the AP with the strongest signal. When you have multiple APs in the same coverage area (an auditorium/lecture hall/repurposed briefing room), this often results in an unevenly balanced load. Redistributing this load is 802.11k's job, and 802.11r makes this transition as quick as possible (which yields significant benefits when 802.1x authentication is in use).
Flatland_Spider wrote:You're going to be dealing with APs not routers, and if you have all of them running on the same SSID and security key the hand off won't be a problem. You'll, of course, have to have adequate coverage to avoid dead spots, but this really isn't a problem. This is how wifi access works in deployments that need to cover a wide area. There are a bunch of APs that all broadcaset the same SSID and use security key. There is usually a central controller, so support doesn't have to touch each AP when a change is made. End users just see magic, if they notice at all.
Correct, depending on the implementation. Behind the SSID is a BSSID, and if you have a bunch of APs that aren't tied into a controller, the client will treat each AP's BSSID as a unique network and cling to it as long as possible. Once it finally loses connectivity, it will gravitate towards the strongest signal AP in its list of preferred networks. This results in a far from seamless transition. Controller-based networks tie APs into a single BSS/ESS which, depending on the client, will make client<>AP associations less "sticky."
Flatland_Spider wrote:Depending on the budget, I would either go with cheap consumer routers running DD-WRT in AP mode
I wouldn't wish this on my worst enemy.
drsauced wrote:We're using Ubiquiti Unifi WAPs, which are, in my opinion, the best and cheapest on the market. There's four APs to choose from, the AP Pro and the AP 'ac' being PoE out of the box. The regular and long range units need a 48v to 24v converter to work with PoE switches and adds about $20 per AP. The AP Pros are my choice, the range is very good, comes with 802.11a, and like all the Unifi APs, very easy to mount on a ceiling or wall. The AP 'ac' models don't yet do fast roaming and require the 3.0.something management software which is still in beta.
Well, you did say it was your opinion.
In my opinion, the Cisco 2504 wireless controller is the best because the vent grille design reminds me of the ocean.
OP, femtocells are expensive and likely not suitable for your environment. Landlines are a reasonable alternative. The necessary wiring may already be in place. If it isn't, consider IP phones and a VoIP PBX. Runner up is a two-way intercom system.
As Zenlessyank suggested, wires are the way to go. This will provide basic connectivity to each classroom, and will have to be run anyway with a wireless deployment, as repeaters are a terrible idea. When it comes to pulling cable, there is little difference between pulling one cable and pulling three.
With this silly notion of "wireless everything" out of the way, you can then allocate wireless capability as needed. Room full of laptops? Make it a computer lab--wired. Room full of tablets--get an AP. Teacher with a tablet she bought--USB cable. Two computers and a printer? Switch. If you're looking at more than a handful of APs, go with a controller-based network (and maybe a cheap spare AP to loan out in a pinch). Consumer-grade equipment only leads to heartaches and headaches.