help me design a wireless network

Networking/Security Forums -> Networking

Author: moondoggie PostPosted: Wed May 11, 2011 11:12 pm    Post subject: help me design a wireless network
i have a client who has two large rooms currently serviced by four WAPs, two upstairs and two downstairs. they have many problems associated with hosting events in their rooms, namely that people have dropped connections or some can't connect at all. right now they have a combination of four total HP ProCurve and 3Com PoE access points but they continue to have issues. at any given time they may have from 40-150 people trying to use wireless throughout the facility and they are asking me to redesign their network so that they do not continue to have problems.

my thought was to put a separate router on the upstairs and downstairs networks, but i would also like to replace their current WAPs with something extremely reliable that can also handle the bandwidth requirements. can anyone recommend a WAP that has PoE which can handle the kind of situation i've described? or make a recommendation that i am or am not heading the right direction with what i have planned. any useful input is greatly appreciated. Smile

Author: moondoggie PostPosted: Thu May 12, 2011 5:56 pm    Post subject:
that doesn't actually help my situation. this is basically a guest wireless network for events and needs to be able to handle the equivalent of a small convention every week. a leased line is not going to solve anything we're having problems with.

Author: krugger PostPosted: Thu May 12, 2011 6:13 pm    Post subject:
Do you have a WLAN controller?

Each WAP should take about 30 people, so a floor with 140 people should be ok with 4 WAPs. Altough you should check how many people can connect at the same time. The problem might be all WAP operating on the same channel.

Author: moondoggie PostPosted: Fri May 13, 2011 10:03 am    Post subject:
the current network is configured as:

router -> managed PoE switch -> 4 WAPs

what i would like to do is:

router#1 -> managed PoE switch -> upstairs WAPs
router#2 -> managed PoE switch -> downstairs WAPs

also, the current configuration is two upstairs and two downstairs WAPs. each floor is a different group of people, each with 40-150 at any given time. if 30 per WAP is the de facto standard, we are seriously overtaxing the system Shocked

Author: krugger PostPosted: Fri May 13, 2011 3:11 pm    Post subject:
I was asking about a WLAN controller because that should help the AP cooperate and give you some more information on the problema and statistics. But from Cisco Aironet 1200 deployment FAQ:

Q. How many clients can associate to the AP?
A. The AP has the physical capacity to handle 2048 MAC addresses, but, because the AP is a shared medium and acts as a wireless hub, the performance of each user decreases as the number of users increases on an individual AP. Ideally, not more than 24 clients can associate with the AP because the throughput of the AP is reduced with each client that associates to the AP.

So you need more Acces Points if they are like these ones, but your hardware manual should have something about the number of clients per WAP. Some highend Procurve WAP say they support 250 clients, although it might just be marketing. Razz

Author: WeaverLocation: WI, USA PostPosted: Fri May 20, 2011 4:36 am    Post subject:
When sizing for wireless users it is important to distinguish between capacity planning at various layers. OSI aside, there are several layers to consider:

As far as recommendations are concerned --

I'll stop now as I feel like this is turning into an advertisement for Cisco wireless products. I have not used HP or Juniper wireless solutions. 3Com (prior to HP buyout) was fine for small environments on a budget but would not use in high-density cells. I have heard good things from fellow engineers using Aruba gear but can't speak firsthand.


Author: moondoggie PostPosted: Fri May 20, 2011 6:42 am    Post subject:
I appreciate the insight, but the client is not going to approve all new cisco equipment just yet Smile i will keep it in mind, but i'm pretty sure they're not going to go for it. they would prefer to keep their existing equipment if possible.

Author: WeaverLocation: WI, USA PostPosted: Fri May 20, 2011 4:54 pm    Post subject:
As the consultant, MSP, or friend it is your professional obligation to determine the "correct" solution and work with the client to have it implemented.

Whether that solution is making better use of existing hardware, software, and licensing or involves the purchase of one or many additional pieces of hardware, software, and licensing is up to you. As a consultant this is precisely for what you are paid -- your expertise in solving problems.

The problem your client is facing *may* be solvable with existing infrastructure. However, with what information I have read it appears as if the wireless infrastructure is an "autonomous" wireless infrastructure.

The problems you describe and the solutions to the problem you describe have been developed -- in the form of "centralized/controller/unified" wireless infrastructure which includes such vendor agnostic concepts as centralized management and configuration, radio resource/spectrum management and others.

Whether your wireless vendor is HP, Juniper, Aruba, or Cisco -- these vendors have solutions for your problem -- called by different marketing and product names.

The concept is the same -- move from an autonomous to centralized model and benefit with reduced management, increased capacity, and increased reliability.


Author: Sheena PostPosted: Fri Jun 24, 2011 10:33 am    Post subject:
hey buddy i am new to this field so dont know so much about the wireless network ... i am here to learn more from you people .. hope that you all will help me out . Smile

Author: AdamVLocation: Leeds, UK PostPosted: Fri Jun 24, 2011 10:46 am    Post subject:
Weaver wrote:
In very high-density station areas, consider reducing your cell size by intelligently placing more access points and reducing your transmit power on the access points.

This is particularly important - you need to figure out what the coverage area is for each of the four APs at the moment, and if it is overlapping too much.

Four APs says to me that at least two of those must be on the same channel, so you want to make sure they are as far apart as possible. Neighbouring (or overlapping) APs need to be using channels as far apart as possible, so 1, 6, 11 or 1, 7, 13 (depending on your country's regulations).
Some "high bandwidth" APs will be using more than one channel at once which can make this situation even more important to check out.

As number of connections to an AP increases, everyone gets a smaller and smaller slice of the cake (only one station can actually communicate at a time, in tiny time slices). Only way to really increase throughput is to use more APs, which means more care taken over placement and transmit power.

Bear in mind that even if you tune the transmit power of your APs so they don't interfere with each other, the clients may still be turned up to the max and interfering with each other when they are connected to different APs on the same channel.

Networking/Security Forums -> Networking

output generated using printer-friendly topic mod, All times are GMT + 2 Hours

Page 1 of 1

Powered by phpBB 2.0.x © 2001 phpBB Group