I am needing to upgrade our schools wireless equipment and need some suggestions as to what to get. We currently have Linksys WRT54G AP with two 24dbi external dish antennas to cover the school campus. Linksys wireless routers only provide 30 simultaneous users before the router begins experiencing lock ups. After many posts on Linksys forums this appears to be an issue with the power cycle and user overload.
I have looked at some of the Sonicwall Unlimited user access points (TZ190) however we do not need the added security features of the Sonicwall that appear to make it more pricey. We have a Barracuda Networks web filter in place and that seems to be sufficient for our network filtering needs.
Does anyone know of a wireless AP that will allow more users that doesnt have the added security features similar to the Sonicwall? We would really like a basic access point that we can connect external antennas to.
The 24dbi dish antenna was part of the existing installation before I arrived. It basically serves to put a wireless signal down onto a lower part of campus. It has done an ok job, the width is a little narrow, as you mentioned, but distance is a bigger issue as our campus isn't very wide but longer. I've looked into an Omni directional antenna solution but cant afford to loose distance. The longest distance traveled is about 500 yards (figuring high).
I have looked at adding an amplifier to help with a stronger signal. Our biggest issue right now is our Linksys WRT54G. It locks up a few times a week and seems to be an issue with Linksys firmware a well as user limits so we'd like a simple unit that can handle greater than 30 consecutive users, as that seems to be the issue with the Linksys.
You will never get an unlimited number of usable wireless users.
If you are using a "speed" of 54Mbs you are realistically only transferring data at a throughput of 27Mbs and at 500yds you will be lucky if the throughput is 5Mbs. If you had 50 users and the throughput is 27Mbs then they are are probably getting less than 500Kbs if the bandwidth is equally shared out, if anyone is transferring a large file then the rest will get less bandwidth and so on. You need to know how many users there are going to be and what their requirements are, you will also have to factor in any increase in users that may occur. It may mean that you have to consider using several AP's in order to accomplish what your "customers" require.
Last edited by Leaky_coax; 02-28-2008 at 08:18 AM.
I understand the lack of speeds for the distance traveled is a concern, however as far as speed goes, our current setup is working fine for the needs of our staff (basic email and IM). Right now or primary concern is finding a wireless AP that will provide more users. This is the issue with our Linksys WRT54G as we've determined user overload causes it to lock up. The network can still be seen and connected to yet use of the network shuts down.Un-plugging the unit for about 30 seconds and plugging it back in effectively resets it and internet comes back up. This is more of an annoyance than anything.
A SonicWall TZ190 with unlimited nodes was suggested as a solution.
A Cisco Aironet was also suggested with a user limit of over 2,000.
However, these units also come with many subscription and security features that we do not need, along with a heftier price tag. Perhaps this is a problem that could be solved with simply switching from Linksys to a different company with a better model. Such as D-Link DWL-8200AP??
I should also say that we are not located within the continental US. We are setting this up on a US territory in Micronesia. Our staff consists primarily of
volunteer teachers. This means that our internet is primarily used for basic email communication without any large file transfers. We are really looking more to the stability of the network rather than significant network usages.
Q. How many clients can associate to the AP?
A. The AP has the physical capacity to handle 2048 MAC addresses. However, 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 should associate with the AP because the throughput of the AP is reduced with each client that associates to the AP.
The school has one location for a hardwired AP. Would placing wireless repeaters help in this situation? We do not have the option to hardwire multiple AP's around campus. We have anywhere from 60-70 wireless users on campus.
We have alot of things here that are not "ideal" for our wireless internet. Internet speeds on island are very slow and expensive compared to that of the states. We are really just trying to find a solution to our Linksys lock up issues.
I have a preference for wired solutions. I have no practical experience in using multiple repeaters. Single radio repeaters store and forward the data on a single channel which means the data throughput is cut in half for each "hop". They also operate on the same channel as the originating AP which means you could have 2 or more repeaters in close proximity trying to transmit on the same frequency at the same time and this could cause interference and loss of data. I presume the software used in " mesh" networks reduces the possibility in their networks.
You didn't say how many people actually try to access the network at the same time, if only a max of 50 do have you considered just adding another WRT54G with external antennas and connect both WRT54G'S to a wired router for your Internet access? You could run one on channel 2 and one on channel 10 and split the traffic that way.
Which version of WRT54G are you using? Have you considered using 3rd party firmware on it as it can improve a number of options including QoS? What is DD-WRT? - DD-WRT Wiki
The total number of users connecting at any given time fluctuates so I really am not sure on a specific number of users. I would say at any time there is no more than 50. I had not considered running a second AP next to our existing one. Would this solution operate seamlessly or would users have to switch manually to AP1 or AP2? Would adding one or two repeaters operating at over 100ft from the main AP still cause interference?
The firmware version is: 4.21.1 although on Linksys forums lock up issues seemed to be prevalent through out all the firmware updates.
I had not considered 3rd party firmware as I am unfamiliar with the reliability.
If there is one that has been reported to be very stable I would consider using it.
I would suggest you split your users in 2 and have 2 different networks and not consider seamlessly moving from from one AP to the other. You can also split your "High usage" staff in half for each AP and reduce the possibility of overloading one AP.
My one experience with a "Range Extender" is that I did not not get the increase in range I expected. It came with a fixed antenna and since it was on loan I couldn't dismantle it and replace it with a higher gain one. There are a number of AP's on the market which will work in WDS mode:- Wireless Distribution System - Wikipedia, the free encyclopedia
Some of these have a WDS+AP option which is very similar to a repeater. I will add one disadvantage to the list in that for a lot of these AP's I have only been able to get WDS to work properly if all the WDS capable AP's have been from the same manufacturer. I have not tried any wireless routers using 3rd party firmware for this mode.
If you decide to use some form of "Repeater" with a high gain "Omni" antenna then bear in mind that the height of the antenna and the Vertical beamwidth, normally quoted in the antenna spec, could mean that users close to the "Repeater" may not get a good connection. Omnidirectional Antenna Beamwidth Analysis
When I was asking about the version of the router I was not referring to the firmware, the WRT54G has at least 8 versions and then there are GL's,GR's,GS's....
There are different versions of 3rd party firmware and you will need to check your version of WRT54G to see if it will work with one of the versions of firmware. Some versions of WRT54G only had a small amount of RAM and the full version of firmware could not be loaded.
Free firmware:- Tomato Firmware | polarcloud.com Main Page - DD-WRT Wiki
As long as you follow the installation instructions precisely you should be able to try these and if you don't think they are of use you can re-install the Linksys firmware. DD-WRT has been around for quite a while and as long as you use a stable, non-beta, version you should be alright.
Last edited by Leaky_coax; 03-02-2008 at 01:46 PM.
I'm not familiar with the WDS mode. How does it differ from just repeating a signal? Are two AP's both hardwired but interact seamlessly?
If I split the users between two AP's how far apart would I need to put the two antennas to avoid interference? Or will setting them at different channels be sufficient?
I think running a small router and connecting the two AP's to it and splitting our user load is a very workable solution as we can use our existing equipment with minimal extra purchases.
Any experience with the D-Link DWL-8200AP or the DWL-7200AP? I am looking at these as potentially better options than a Linksys model.
The WRT54G model is V2.0
WDS can be used to provide two modes of *wireless* AP-to-AP connectivity:
1. Wireless Bridging in which WDS APs communicate only with each other and don't allow wireless clients or Stations (STA) to access them.
2. Wireless Repeating in which APs communicate with each other and with wireless STAs.
As long as you are using a minimum of 5 channels separation you should be able to mount your Antennas on the mast you are presently using. I have no experience with the D-Link DWL-8200AP or the DWL-7200AP but are you looking to try and future proof your system? Both of these are dual band radio systems and unless any of your users have 802.11a wireless adapters then you would be wasting your money, the same applies for any "extra" speed they may quote you can get. 802.11a does not travel as far as 802.11g so you probably would need a "Repeater" for this mode. Since you have been looking at DLink eqpt did you look at the DWL-2700AP?
I would look at using a Commercial Ap from www.zigwire.net as I know they have a factory direct department for Schools and universitys . The AP units only support 125 clients, You may be better off using a Mesh system from them , Each mesh unit supports 250 clients. and are $1000 each. They will de a complete design at no charge for Schools etc. may be good to look at.
The DWL-2700AP is a nice looking unit although the outdoor features wouldn't be needed. If we went this route we would only be able to purchase one unit as it a little pricier. Would it support our user load as a single AP?
The price on the DWL-7200AP made it attractive as we could purchase two of them and split our users. I am hesitant to purchase another Linksys as we've had so many lock up issues with it and after spending some time on Linksys forums this seems to be a common problem. Although splitting users might solve that issue along with potentially purchasing one with more RAM. This was the biggest reason for looking at D-Link. I was looking at the multiple radios since I dont always know what the staff will have with them as far as wireless cards. The volunteer teachers for the school rotate per school year.
wifimaster, do you mean 125 total clients accessing or 125 clients in simultaneous useage? This would be more than enough for our campus. If its 125 users at the same time that might be an easier solution to our problem. Any idea which models they carry support this?
The problem is trying to find something usable with 2 antennas which is why I suggested another WRT54G and possibly using 3rd party firmware.
I will be interested to see what "zigwire" recommends. They don't seem to have the manuals readily available and the support page requires a logon.
I don't know whether you come under FCC regulations or not but I can't find any zigwire products that have been FCC certified, it is possible they have been done under another name. If "wifimaster" could quote some FCCID's for the items.
Last edited by Leaky_coax; 03-03-2008 at 10:25 AM.
I contacted zigwire and they have recommended the AMU-2405G-SMA unit. AMU-2405G-SMA---Zigwire
The secondary antenna services only one house so I can set up a single unit that can handle a large user load and use our existing Linksys to service the second antenna with a light user load.
A 13dBi antenna was suggested: YG-2413---Zigwire
although i am not sure if this is much better than the dish we currently have.
zigwire has also recommended a specific network switch to connect everything through. NSH-561 Managed Switch NSH-561 Managed Access Switch---Zigwire
They are claiming a consumer unit (such as a 4 port Linksys) has to small of a processor and could get overloaded.
I will look into FCC and local regulations. Although I am relatively certain there is nothing.
Any suggestions on the equipment they've recommended?
With the possibility of using a higher capacity unit for one dish do you know any AP's that would work for a higher user load and only a single dish connection? This might be an easier solution and allow the existing WRT54G to handle the lighter load. The two dishes point in opposite directions. One goes to one side of campus with the high user loads and 99% of traffic and the other to the opposite side of campus with very little user load.
It does not say it will act as a router so what would you intend to use?
Since there are no readily available manuals and I can't find it on the FCC web site I can't really check any specs. It would be nice if Zigwire could produce an FCCID No for the item so it could be checked in their database. If you come under the FCC reg's then zigwire will have to provide s/ware to ensure you can only use Ch's 1->11 and not to Ch13(minor point) and it should really be FCC certified(not just conforming to the FCC reg's).
I don't know why they recommended a switch as a router would be required if you are not going to use the WRT54G for that function.
edit: Does your modem have NAT and DHCP capability? A switch should work in that case.
Did they quote any prices for their eqpt?
Last edited by Leaky_coax; 03-04-2008 at 08:22 AM.
Yes all the units have certification, Some countrys have different allowable limits for point and multi point applications, from 200mWatt to 5000mwatt.
Certificate
ISO 9001 ( 776KB )
ALINK-5801a (CE,FCC)
( 159KB )
ALINK-5801a (NCC) ( 151KB )
AAP-2401 (CE,FCC)
( 216KB )
AMU-2405G (CE,FCC)
AAP-2405 (CE,FCC) ( 229KB )
AAP-24005 (CE,FCC) ( 229KB )
ASU-24005g (CE,FCC) ( 242KB )
AAP-2410 (NCC)
The AP units support 125 clients at one time, you can use a management system of your choosing, or select a security feature, or , most small schools choose to use Mac Addressing , This unit has the ability to handel 1000 Mac addresses , but only 125 should be on at one time. Remember the weakest part is the Router, Can the small processor handel 125 clients IP at once ?That will be your weakest link. For any questions just email them directly from the web site, www.zigwire.net
I was thinking I could connect it directly to a simple non-managed Linksys 8 port router. They said it was POE and just to connect the network cable to a router. Maybe I didnt fully understand their configurations. It appears the only connection would be through the network cable. Would the WRT54G we currently have be much different from a regular router for the signal? If possible I would like to take it out of the equation for this set up.
The modem does not have NAT or DHCP support.
They have quoted 325$ for the AMU-2405G-SMA. And 95$ for the Yagie antenna. Shipping is yet to be determined. The equipment comes with a one year warranty.
Yes all the units have certification, Some countrys have different allowable limits for point and multi point applications, from 200mWatt to 5000mwatt.
Certificate
ISO 9001 ( 776KB )
ALINK-5801a (CE,FCC)
( 159KB )
ALINK-5801a (NCC) ( 151KB )
AAP-2401 (CE,FCC)
( 216KB )
AMU-2405G (CE,FCC)
AAP-2405 (CE,FCC) ( 229KB )
AAP-24005 (CE,FCC) ( 229KB )
ASU-24005g (CE,FCC) ( 242KB )
AAP-2410 (NCC)
wifimaster,
You seem to be very familiar with this company. Do you know if there are any reviews or case studies from other implementations of these products? You've mentioned their use with other schools or universities. Do you know any names of such facilities that we might be able to contact directly?
. I am hesitant though as to the reputation of the company. I know nothing about them and they appear to not market anything to the U.S.
It seems to be a great idea but I dont want to end up with junk equipment either. Know any companies offering similar equipment that I might be able to compare things with?
After a search they appear to be re-badged Alcon Telecommunications products. ALCON Telecommunications Co., Ltd
The site also has user manuals available. They have an office in Miami. About US
The AMU-2405 which also has a label with ASU-24005G on it would correspond to the Alcon item which has an FCCID No S7X24005G02. There is also no panel antenna in the Zigwire one but the radios will be identical so that they can use the same FCC certification.
Test Report:- https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
Last edited by Leaky_coax; 03-04-2008 at 12:54 PM.
"re-badged" normally refers to items which have been made by one company and then sold under a different name, normally with the agreement of the originating company.
You can purchase this at a Distributor such as http://www.cellamericas.com/ in Florida. or many other Distributors.Some of the same items are there but many of these are unique to their ISP system offering.
Hope this helps, Alcon and Hotware have been in business 18 years and are from Taiwan mainly. I just like to pass this along as I have used many manufactures devices, Mostly Motorola Canopy but there have been many advancements in the last 2 years and some companys never change their offerings. WWW.Zigwire.net is also only selling through Distributors or Dealers.
Need help with wireless upgrade for small school? 
Linear Mode
