Managed Wireless Systems

[maniac]

its actually cheaper for us to buy a cisco 4402 controller with 20 aironet thin aps than the extricom system on the basis we have 4 out buildings... And thats before you have to buy their access points. No doubt this system has its merits and does sound good from the demo but in most large secondaries with lous of buildings it seems expensive.

 

I do like the idea of adding more radios to increase the throughput but how do you tell you laptops etc which ap to associate to..

Posted via Mobile Device

 

Yes, it is expensive you can't deny it that.

 

The 'access points' aren't really access points in the extricom system, they are more elaborate 'aerials' for the controller, the controller its self is effectively the access point. To the wireless device it appears as it it's associated with the same access point anywhere you are within the building, and you are, you are associated with the controller, not the individual transmitters. The controller then simply switches transmissions to the transmitter nearest to the device which it knows because it keeps a real time track on devices within the range of each transmitter.

 

If you have two transmitters close to each other, the system will load balance between them by forcing transmissions from different devices to be sent/received by a specific transmitter. The device doesn't need to associate with this transmitter, its association is with the controller so the controller can choose any transmitter it likes to send the data to the device. As long as the device is within range of the transmitter the controller has chosen, then it will receive the packets sucessfully.

 

It completely and totally controls the wireless traffic within your organisation to a very precise level, I've yet to find any other wireless system that can do that to the degree that the extricom system does.

 

@dhicks, yes you're right the available bandwidth will eventually run out, there's only a certain amount you can cram in any single air space, just extricom makes much better use of the available air space than most other systems can, and when you're deal with hundreds of wireless laptops in a building, that can't be a bad thing! So I agree, there is a small flaw in the keep adding Access points arguement.

Mike.

Edited July 27, 2008 by maniac

[Joedetic]

Some copypasta on John's behalf:

 

John MBCS - IT Consultant™ says:

theres a thread made called Manged Wireless Systems so my RSS feed has told me

John MBCS - IT Consultant™ says:

as im not reading the form properly whilst im awy

John MBCS - IT Consultant™ says:

can ou post on there and say that I whole hartidly recomend ruckus

John MBCS - IT Consultant™ says:

got a load of kit on trial at the moment and LOVE it

 

 

[dhicks]

I suspect that since the controller is centralized it is able to share the wireless space more effectively by using highly precise timing... ...delays and uncertainties inherient in IP there would be no way to syncronize the traffic flows without slowing the system to a crawl

 

Hang on, though - what about Network Time Protocol (NTP)? Checks Wikipedia... Would accuracies of 200 microseconds be good enough?

 

--

David Hicks

[stevenlong1985]

How much is it costing you, for how many access points / what size of school?

 

--

David Hicks

 

6k for 10x 7942 and a controller "Zone Director 1000"

which includes all Net-Ctrl support for 3 years and hardware replacement support.

 

I'm spent £800 for other network equipment for 2x 10 port gigabit PoE switchs and other networking stuff (cables, patch panels etc)

 

We are a three form Primary School near the city center of Birmingham with 700 Students and staff, looking to get between 60 to 120 maybe more Mini Laptops. I'm waiting to get a loan kit of the ASUS EEE PC 1000. but so far only 70+ Workstations.

 

Once you have tired the demo Kit you'll be amazed! Its makes your life easy, you wont have anything to worry about, its dead easy. if you can configure it your self which u will do, you wont have to spend like £xxx on getting someone else to configure it for you

 

 

Hope this helps

 

Steven

[SYNACK]

Hang on, though - what about Network Time Protocol (NTP)? Checks Wikipedia... Would accuracies of 200 microseconds be good enough?

 

--

David Hicks

 

Not when you are talking about a synchronized release of packets, the issue becomes your network latency rather than you accuracy unless you are just dividing up the time equally. Your average network latency will change depending on traffic levels and how much hardware is in between the controller and the AP. To schedule it efficiently the transmit/receive allowances should be real time scalable rather than fixed, otherwise you will end up with an AP with one host having the same allocated bandwidth as one with 15 hosts if they are in close proximity. One delayed or lost packet could leave the system ignoring users on one AP. There is also the traffic demands of routing every bit of signal and transmission information from each device to the controller, it would need a larger CPU just to handle all of the continuous real time information about the signals. Just putting most of the APs into full debugging mode makes them slow down to a crawl and there is far less information involved in that than the amount that would be needed to successfully imitate the extricom system.

 

TCP/IP is just to unreliable and inconsistent.

Edited July 28, 2008 by SYNACK

[Haptic]

Our sister company T James Wired And Wireless Communications are a extricom specialist so if you would like some more information or a free demonstration send me a pm with your contact details and I we can help you further,

[Ric_]

In particular, does anyone know if the Sputnik system can handle the "high-volume" traffic that we gets in schools, i.e. 30 odd laptops in a classroom all trying to work at once? How do other systems handle this issue - do they simply reduce the power on each access point, reducing the interference between access points (but requiring more access points around the place, of course)?

 

Have you tried speaking to Ivan Dimitrov who is mentioned at Sputnik Blog Boston University, United Kingdom to see how his implementation of Sputnik works?

 

Most managed systems will cleverly fiddle with the power and channel so that they don't interfere with adjacent APs. If there is an area that you know will not be heavily used by mobile users you would have a low density of APs whilst in areas that have laptop trolleys and people hammering the wireless, you would increase the density of your APs.

[adurrant]

Ruckus will talk straight back to AD no need for a Radius server!

[eean]

If you have two transmitters close to each other, the system will load balance between them by forcing transmissions from different devices to be sent/received by a specific transmitter

 

That's what a 'traditional' (Cisco et. al.) managed wireless system does. It works because the APs within range of each other are on different channels. So if I have 30 laptops and they are in range of 3 APs most of the laptops will connect to the closest AP but some will also connect to the other two APs because even though they are further away and subject to more noise (i.e. lower speed) overall throughput will be higher because they are balanced. The management system figures all this out.

(OP: This is a main advantage of a managed solution. If it's not managed all the clients will connect to the loudest AP even if there are other APs within range that could be used to balance the load.)

 

maniac: What I don't understand is how this can work if all the APs are on the same channel. Remembering that channel is just radio frequency and 2 aerials within range of each other transmitting on the same frequency will cause interference.

If I have 30 laptops in one room within range of 3 AP/transmitters all on the same channel even if the laptops are balanced between the transmitters surely their transmissions are going to interfere?

 

This is a very interesting system Maniac - I'm just trying to get my head round how it works!

[Spitfire]

If all the previous replies have confused you speak to the boys from Cisco, we had them in to explain and demonstrate their wireless gear. It was then installed by a contractor and any problems were overseen by Cisco. we now have a brilliant 802.11n wireless system managing up to 1000 laptops with no problems.

[localzuk]

eean, the way some of these systems work is by the antennae being completely dumb. They just transmit radio waves, like a remote antenna. All the work is on the unit they connect to. So in fact, the 'AP' is actually the management unit, and not the antennae.

[Trojan]

I was also very impressed with the Extricom wireless system when we had a demo here, they also used a couple of VOIP handsets and we could actually see the signal moving between the dumb AP's.

 

The guy even unplugged a couple while we were talking and the signal didn't miss a beat, no drop at all.

 

It was however very expensive (£20k) compared to other systems and we couldn't justify it.

 

We went with a colubris system in the end which is ok, but nowhere near as good as the Extricom would have been.

[adurrant]

If you are worried about signal drop out forget Cisco and go for Ruckus!

 

The signal is so strong and very very reliable, its so strong the system can see 10 rouge AP's which happen to be people living around the school!

 

I saw the guys from Net-Ctrl at BETT and their one Ruckus AP was out performing all the others at the show!

 

It had a constant db of at least 60, the rest were all dropping out!

[moggy]

I saw the guys from Net-Ctrl at BETT and their one Ruckus AP was out performing all the others at the show!

 

Right now I'm only going to be trialling wireless in one room, however I'm sure the powers that be will soon be asking me to extend coverage.

 

In this thread there seems to be a number of offerings recommended, but just as an example, is it feasable for the single room coverage to start off with a single unit from Ruckus and then extend it? What sort of price is a single unit?

[john]

With the Ruckus system you can start small and build up but it does cost you more. You really need to know if they will expand from that one room, if its only ever going to be that 1 room with never any more than I'd got for a couple of APs without posh management stuff, but if its going to expand start as you mean to go on. High initial price for the first few rooms but soon becomes cheaper once you've got going.

[White_Fi]

Hi

 

We would welcome the chance to talk to you about your school, your network and what it is you need to deliver to your users and Governors.

 

Please contact us at Net-Ctrl on 01473 281 211 or [email protected].

 

We have various ways of introducing you to Ruckus Wireless, but why not have a search on this forum under Ruckus or Net-Ctrl.

 

Kind regards

Net-Ctrl

 

 

 

 

 

QUOTE=dhicks;218904]Hello All,

 

Managed wireless systems. I want one. How do they work? How can I make one? Specifically, what is it about a "managed" wireless solution that makes it cost £10,000 upwards, whereas just buying access points enough to cover our school would cost around £2,000? I've had a look at the websites for a couple of systems, which tend to be a little woolly on the detail side of things, but a "managed" wireless system seems to mostly consist of a central combined server/PoE switch and a bunch of access points. The access points don't generally seem to need to be plugged directly in to the server, although it seems that sales types will cheerfully try and flog you extra servers.

 

So, basically, a managed wireless solution is a server that manages a bunch of access points. Is the Sputnik system suitible for use in schools - does anyone else use this system? This system would seem to consist of just access point, managed by a central server that is an application running on top of a CentOS Linux distribution - something I could just plonk on our existing system as a VM, no need to get extra bits of hardware or anything.

 

In particular, does anyone know if the Sputnik system can handle the "high-volume" traffic that we gets in schools, i.e. 30 odd laptops in a classroom all trying to work at once? How do other systems handle this issue - do they simply reduce the power on each access point, reducing the interference between access points (but requiring more access points around the place, of course)?

 

--

David Hicks

[sentinelprime2009]

I have read various threads regarding wireless systems. We are looking to upgrade our site wide netgear wireless solution for a new one. Currently we have been recommended either Extricom or Meru. Can any of the three systems that have been discussed (Extricom, Meru, and Ruckus) support minimum of 250 wireless laptops spread over 13 buildings. We will be having in the future areas of 60-90 laptops in the same location. Ideally, we want the speed to be as close as wired as poss, so we are considering n for the clustered areas. Any thoughts?

[Haptic]

I have read various threads regarding wireless systems. We are looking to upgrade our site wide netgear wireless solution for a new one. Currently we have been recommended either Extricom or Meru. Can any of the three systems that have been discussed (Extricom, Meru, and Ruckus) support minimum of 250 wireless laptops spread over 13 buildings. We will be having in the future areas of 60-90 laptops in the same location. Ideally, we want the speed to be as close as wired as poss, so we are considering n for the clustered areas. Any thoughts?

 

Ruckus ,Meru ,Extricom would have no problem with this at all,

 

If you would like to pm me your details We can provide you info and pricing on all these solutions as we are partnered with them:cool:

 

p.s we have buy one get one free on N at the moment but its ending this month so hurry hurry!

Edited December 8, 2009 by Haptic

[Haptic]

was great speaking with you fella and look forward to working with you;)