Best way of spreading wireless load without managed system?

[sidewinder]

I know the only real way of not having AP's overloaded is with a managed solution, and I think we are looking towards that next year, but for the time being we are stuck with unmanaged Cisco Aironet 1100's

 

A department was complaining that after the first 8 or so laptops log on, it becomes almost impossible to get any more on, which makes sense if they are all trying to connect to the same AP

 

There are multiple ones, one in each room, and from a quick roam around that room when you get to the outer edges, it does what you expect and connects to the next room

 

However the tables arnt like that, all the kids sit fairly central so it makes sense as to why they are all hitting the same AP.

 

I cant put a connection limit on them, because while it works a treat and doesnt let anyone else connect, there is no intelligence to pass the connection request onto another WAP, the laptop just sits there trying to connect and constantly getting rufused

 

So my question is, is there any simple way to improve this a bit?

My idea, which may be awful, is that if I put 2 WAP's in the same room, at an equal distance apart, with the same SSID and on the same channel, would both be available or would it just cause havoc?

 

I cant really have multiple ones on different channels in the same room, because it would interfere with surrounding rooms.

 

Is my idea ridiculous or not? It was suggested to me a while ago by someone doing a quick network audit, when we said about all the problems we have with wireless

 

Or is there any way of decreasing the amount of data transfer that happens during logon? I already use a tiny mandatory profile, I try and keep starup scripts etc to a minimum on laptops, but still it takes ages

[Quackers]

 

A department was complaining that after the first 8 or so laptops log on, it becomes almost impossible to get any more on, which makes sense if they are all trying to connect to the same AP

 

 

We somtimes have over 50 clients connected to 1 AP at one time, when say 2 rooms next to each other both book a 30 machine laptop trolly. We get no complaints of speed issues, and i was in the rooms the first time i knew that many laptops would be in 1 area to see how it handled it. You either have way to much being redirected on the laptops to network resources so traffic per client is way to large, or your getting interference.

[Vegas]

 

A department was complaining that after the first 8 or so laptops log on, it becomes almost impossible to get any more on, which makes sense if they are all trying to connect to the same AP

 

 

We somtimes have over 50 clients connected to 1 AP at one time, when say 2 rooms next to each other both book a 30 machine laptop trolly. We get no complaints of speed issues, and i was in the rooms the first time i knew that many laptops would be in 1 area to see how it handled it. You either have way to much being redirected on the laptops to network resources so traffic per client is way to large, or your getting interference.

What AP's are you using?

[plexer]

You cannot put 2 waps on the same channel within hearing distance of each other it will cause havoc.

 

The only option is to put them on seperate channels and then you could use mac filtering on them to decide which laptops connect to which wap.

 

Ben

[Quackers]

 

A department was complaining that after the first 8 or so laptops log on, it becomes almost impossible to get any more on, which makes sense if they are all trying to connect to the same AP

 

 

We somtimes have over 50 clients connected to 1 AP at one time, when say 2 rooms next to each other both book a 30 machine laptop trolly. We get no complaints of speed issues, and i was in the rooms the first time i knew that many laptops would be in 1 area to see how it handled it. You either have way to much being redirected on the laptops to network resources so traffic per client is way to large, or your getting interference.

What AP's are you using?

 

D-Link 2100 AP Got 20 of them round the school, all alternating between channel 1,6 and 11 making sure non of them overlap in channel number. Runs all staff laptops with sims and pars etc , and all 120 student use laptops fine.

[PEO]

I have setup 3 areas for our laptop trolley which holds 30 laptops. each area has 3 3com APs. each AP allows only a maximum of 10 laptops. works really well.

[ChrisH]

Hope that firmwares upto date there is a very easy exploit you can do on those APs

[PEO]

ChrisH are you refering to the 3com APs? if so what is the exploit and how. Yes firmware is upto date and monitored :-)

[Quackers]

Think he means

 

http://www.securitytracker.com/alerts/2006/Jun/1016234.html

 

Mr happy

[PEO]

God I almost had kittens for a sec

[sidewinder]

You cannot put 2 waps on the same channel within hearing distance of each other it will cause havoc.

 

The only option is to put them on seperate channels and then you could use mac filtering on them to decide which laptops connect to which wap.

 

Ben

 

Thought so, thanks, just needed it confirmed

 

Might try with the MAC filtering

[sahmeepee]

I found this page on cisco's site about avoiding wireless interference quite useful when I was planning our setup:

 

http://www.cisco.com/en/US/docs/wireless/technology/channel/deployment/guide/Channel.html

 

If you want multiple APs in one room on different channels, you may be able to turn the power of the signal down on the APs - unfortunately I'm not familiar with your model so I can't say. It's definitely possible on Linksys APs running DD-WRT firmware. Unfortunately, as the article explains, the laptops may still be transmitting at full blast so they will cause interference between rooms.

[steve]

If the laptops have abg cards how about putting a couple of 802.11a APs?

 

We have 3 802.11a APs each with a different SSID and 10 laptops setup for each AP.

[Alis_Klar]

If the laptops have abg cards how about putting a couple of 802.11a APs?

 

We have 3 802.11a APs each with a different SSID and 10 laptops setup for each AP.

 

We have 4x Cisco Aironet 1200 Series AP 2 in science dept and 2 in Technology dept. Each pair support 20 laptops between them. Both pairs of AP's have the same SSID with automatic channel selection turned on.

 

No problems with speed BUT awful problems with dropped connections. We have 11b/g and 11a bands enabled with the same SSID.

 

Do you think spliting the AP's into 2 different SSID's with 10 laptops associated with each would solve my problems. Or has it to do with having the same SSID for both 11a and 11g bands. I have WPA-PSK encryption enable and are using windows zero config to configure Intel 3945ABG wireless card in laptop.

 

The other weird thing is we have much more problems in science than in technology. In science the AP's are nearer.

 

We also have an old lucent 2 card AP which is 11b with a different SSID. But this shouldn't be a problem as the Cisco's are dynamically choosing the optimum channel to use to avoid interference. Called "least congested frequency" by cisco

 

Cheers

[Alis_Klar]

Yes you would want different AP's in order to load balance. Sorry forgot what the original question was. Can anyone give me advise pls?

[Alis_Klar]

• Disable the 802.11g radio just leaving 802.11a
   
  
• Turn off one of the pair of AP leaving just one in a location
  
• turn off the old 11b AP
  
• assign different SSID's to each AP
  
• assign different SSID's to each Radio/Band
   
  
• Update the firmware in the Intel 3945ABG
   
  
• Update the IOS in the AP's I have IOS Release 12.3(08)JA. How do I do this? (sorry)
  

[Ric_]

If you assign different SSIDs to the APs and then set up half the clients to use one and the others to use the other. This will give you some crude load balancing.

 

I will also point out that you must make sure that you have no overlapping channels.

[SimpleSi]

I'm a great believer in different SSIDs for different APs in different rooms but the only problem is that laptops can start up and latch onto a unwanted weaker signal from another AP.

 

The work-around is to get all pupils to check which AP they are connected to (and change if needed) before starting the lesson.

 

This might not be feasible if using 30 laptops (we use 15 with pupils working in pairs) or unreasonable pupils!

 

regards

 

Simon

[Alis_Klar]

Sorry if I hijacked this thread!

 

I have solved my problem (which was not load balancing but dropped wireless connections)

 

I was using 11g and 11a in rooms with an existing 11b access point on another SSID. 11a/g were on the same SSID. And the clients were configured to connect to both SSID's. I turned off the 11b AP and disabled 11g on the Cisco. Just leaving 11a. Was assuming the Cisco 1200 had internal 11a antenna. NO THEY DO NOT!!!!! I only had a single 2.4GHz (11bg) Antenna and no 5GHz (11a) antenna. I have simply screwed the 2.4GHz antenna (part AIR-ANT4941) to the bottom RP-TNC connector (5GHz port). This works but I have to order the correct 5GHz antenna on order (part AIR-ANT5135D-R).

 

So I need to narrow it down to what action fixed it

 

• Eliminated Possible interference (+clients switching to as it was in WZC network list) from 11b Access Point
  
• Eliminated two bands working on same AP in same SSID (these ap's support multiple SSID's and VLANS)
  
• Altered Antenna Configuration