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Wireless Networks Thread, WAPs supporting upto 25 concurrent users in Technical; We're using Cisco aironet 1100 wireless access points. These have proved to be very reliable. The problem we're having is ...
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    WAPs supporting upto 25 concurrent users

    We're using Cisco aironet 1100 wireless access points. These have proved to be very reliable.

    The problem we're having is supporting 20+ users on a single access point. After about 15 have logged on, the other 5-10 cannot gain access to the network.

    The client laptops are using Intel pro/wireless 2200BG wireless modules.

    I've tried putting 2 access points on either side of the same room, and setting the channels on each to be very different, but no luck.

    I think the issue is an RF one - I'm pretty sure there's no maximum client restrictions in the Cisco operating system. The Intel wireless modules are also (relatively) pretty old now..

    Just curious if anyone else has achieved 20+ concurrent connections in a classroom with any other access point ?

    Rauf

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    localzuk's Avatar
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    The practical maximum for a single access point is about 15 - after that number, things become stupidly slow, rather than just rather slow. The optimal maximum is usually stated as being around 8 users per AP, but as a school regularly would have a class of 30 people using wireless, 10 would be normal, with 3 AP's serving them.

    This isn't necessarily down to the access point itself, but think about what is being used here. Most AP's connect to the network via a 100Mbps connection - sharing that between 25 users would be ridiculous and only provide 4Mbps per user. That is very, very slow.

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    SYSMAN_MK's Avatar
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    Most AP's connect to the network via a 100Mbps connection - sharing that between 25 users would be ridiculous and only provide 4Mbps per user. That is very, very slow.
    Even worse when you consider the the 25 users are sharing the bandwith of a 54Mps AP!

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    Not forgetting the IP throughput being about 20Mbit/sec on a 54 access point!

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    You could opt for an 802.11n AP which is supposed to support up to 50 connections at a time with a 1Gb connection to the network?

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    Just spoken to one of the technicians here.

    With the two laptop trolleys we have here, each has a Devolo Plug-In Access point that is plugged into each room as each trolley is put out.

    Now, amazingly, even though these bits of kit of 'domestic' they have been able to support both trolleys out in one room (ie. 32 Laptops in total).

    I was somewhat amazed by this, but they really are impressive bits of kit. They also have an additional Data over Power module as well (included in the starter kit) which is used from time to time, but generally they are plugged into the a power socket with a Ethernet cable plugged into what is sometimes the only network port in the room and away they go!

    The Model is the Devolo dLAN Wireless Extender .

    HTH

    Pete

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    ricki's Avatar
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    I would not believe any claims of manufactures of being about to hold this many reliable connections. The most I have managed is 25 to a router and once I get above 15 the connection speed and reliability become that bad its not worth doing. Please note if you are running sophos and wsus performance and speed reduce even quicker.

    Richard

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    I have 15 macbooks and an airport extreme 11n router which is set up in bridge mode. I have not received any complaints of login failure from either both OS X or XP. They have even used iMovie across the connection although it failed poorly i think. I have had users using garageband across the wifi network though with no issues.

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    Quote Originally Posted by raufdean View Post
    I think the issue is an RF one - I'm pretty sure there's no maximum client restrictions in the Cisco operating system. The Intel wireless modules are also (relatively) pretty old now..
    We have exactly the same AP's as you and there is actually a setting for that, but its fairly useless because while it stops any more connections, the PC will just keep trying to connect to it rather than looking for another AP

    And if we have 16 (one trolley) on one its very slow...any more than that and its just ridiculous. As we have no managed system we've just had to say maximum of 15/16 per room and even then they have to stagger logons
    Thankfully this has got teaching staff finally realising that wireless really isnt that great when you want a whole class on computers

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    Thanks for all the replies.

    From an ethernet point of view ~1Mb / user should not be that bad. After all I can VPN into the school's network over my home contended ADSL connection and achieve perfectly acceptable results.

    Sidewinder - your experiences sound very familiar!

    FragglePete - Thanks for the link. I'll take a look.

    Rauf

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    Quote Originally Posted by HodgeHi View Post
    You could opt for an 802.11n AP which is supposed to support up to 50 connections at a time with a 1Gb connection to the network?

    Nice idea, but I'm stuck with 25 intel 2200bg wireless laptops for the time being

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    torledo's Avatar
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    Quote Originally Posted by HodgeHi View Post
    I have 15 macbooks and an airport extreme 11n router which is set up in bridge mode. I have not received any complaints of login failure from either both OS X or XP. They have even used iMovie across the connection although it failed poorly i think. I have had users using garageband across the wifi network though with no issues.
    imovie failing miserably over a wifi connection.....no kidding

    The only way we can use imovie over the network for a group of 10+ machines is at full gigabit speeds on the client, plus link aggregated ports on the server, plus a striped raid array for storing the imovie projects....anything else would fail horribly, especially over wifi which shouldn't even be attempted even for a couple of clients.

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    localzuk's Avatar
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    The other option is something like the Extricom stuff, which can have 4 radio's per access point (so, it could be seen as 4 access points per unit). It also allows you to have overlapping AP's.

    http://www.extricom.com/

    A base unit (8 port) is about £3500 and a 4 radio AP is about £370.

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    Quote Originally Posted by torledo View Post
    imovie failing miserably over a wifi connection.....no kidding

    The only way we can use imovie over the network for a group of 10+ machines is at full gigabit speeds on the client, plus link aggregated ports on the server, plus a striped raid array for storing the imovie projects....anything else would fail horribly, especially over wifi which shouldn't even be attempted even for a couple of clients.
    You gotta try though aint ya?

    We managed to have a few on running iMovie. Its just some failed. The projects aren't huge anyway and the data was already captured. The users were just editing the footage.

    The Users home dirs are stored on our XRAID which is connected to the Xserve via a 4Gb connection. The server is then connected to the network via a 1Gb connection. The classrooms connect using 10/100Mb/1000Mb and the AP connects to this in bridged mode which gives a 11n wifi connection to the Macbooks. It all works most of the time.

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    torledo's Avatar
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    Quote Originally Posted by HodgeHi View Post
    You gotta try though aint ya?

    We managed to have a few on running iMovie. Its just some failed. The projects aren't huge anyway and the data was already captured. The users were just editing the footage.

    The Users home dirs are stored on our XRAID which is connected to the Xserve via a 4Gb connection. The server is then connected to the network via a 1Gb connection. The classrooms connect using 10/100Mb/1000Mb and the AP connects to this in bridged mode which gives a 11n wifi connection to the Macbooks. It all works most of the time.
    Our xraid is only 2gbs FC .... or should i say our xserve G5 fc card is 1/2gbps capable.

    similar setup to yours, except our imacs connect to a gigabit switch in our core (cisco 3750), the xserve is two 802.3ad gigabit connections connected to the same core, used to be five copper gigabit connections, but we realised the performance bottleneck was the speed and setup of the RAID and not the network connection to the server, so we stuck with two gigabit connections. Our imovie projects are anywhere between 5 and 10 gig in size each, so we require a lot of storage space and good performance. footage is captured from the cameras onto network home dirs on the Xraid, and edited from there....works well so long as you've got everything setup correctly - a lot of trial and error and head scratching when stuff starts crashing.



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