06-17-2004 11:28 PM - edited 07-04-2021 09:43 AM
Design Scenario
I have a project that requires 8 Access Points (AP1200) to be deployed in one single area (a 702sqm. Multi-purpose Training Room) using IEEE 802.11a standard. It requires maximum 300 wireless clients to be deployed during special events. All 8 APs are to be equally connected into two separate switches having the same subnet, and configured as Root. All 8 APs are to be mounted on the ceiling to operate in omni-directional instead of having a patch/directional radiation pattern.
Questions:
1. In configuring the Access Point to address clients seamless mobility, is it appropriate to have the same SSID to all 8 Access points or to assign a unique SSID to each AP? The design configuration calls for setting the Broadcast SSID in Beacon to No so that client devices must match exactly to the Access Points SSID. Should all APs have the same SSID so they could work seamlessly if the client moves (roaming) within a single area? What is the advantage of having a unique SSID assigned to each AP in terms of security and client seamless mobility? Please also note that the company does not want peer-to-peer roaming.
2. How many number of WLAN clients can AP1200 accommodate to maintain transmission bandwidth of 54Mbps?
3. What is the appropriate way to balance the data traffic load between 8 APs against 300 WLAN clients to minimize bottleneck while maintaining 54Mbps throughput over radio transmission?
4. In terms of data access security, is it appropriate to install the Cisco Secure Access Control Server locally, or in the main building where companys Enterprise Server is located? Please note that the Multi-purpose Training Hall is linked to the main building over ATM network using fiber optic cable.
5. Does 60 feet at 54Mbps data rate (indoor range) be attained by setting the antenna module to either Omni-directional or patch/directional?
6. Does Access Point attain the same range of 60 feet at 54Mbps (indoor range) while setting its power output to either 40 mW(16dBm) or 5 mW(7dBm)?
I am looking forward to have your answers soon. Thank you very much for your help.
Sincerely yours,
Sixto A. Mejia
06-18-2004 05:26 AM
These forums are a great place to get a quick tip or a highlevel summary of some part of the technology- they should not be considered a replacement for paying someone who knows what he's doing to come to your location for a survey and design. What you're asking leads me to suspect that what you need is the latter not the former.
With that said, see the following:
"1. In configuring the Access Point to address clients seamless mobility, is it appropriate to have the same SSID to all 8 Access points or to assign a unique SSID to each AP? .... Should all APs have the same SSID so they could work seamlessly if the client moves (roaming) within a single area? What is the advantage of having a unique SSID assigned to each AP in terms of security and client seamless mobility?"
If you want your clients to roam and loadbalance from one AP to another, your APs should be configured with the same SSID. Clients will try to stay with the same SSID if at all possible, but will roam freely between different APs on the same SSID.
"The design configuration calls for setting the Broadcast SSID in Beacon to No so that client devices must match exactly to the Access Points SSID."
This is bad design. Turning SSID broadcast off does nothing to improve security and decreases the efficiency of authorized communications- in much the same manner that taking the building numbers off of your house will not protect you from burglars but will make things more difficult for your guests. If you want to secure the WLAN, use security features like 802.1x. SSID name is not a security feature.
"Please also note that the company does not want peer-to-peer roaming."
If by this you mean that clients on the WLAN should not be able to communicate directly with other clients on the WLAN, you will want to enable PSPF on the access points.
"2. How many number of WLAN clients can AP1200 accommodate to maintain transmission bandwidth of 54Mbps?"
One.
The radio spectrum is shared medium, just like a 10base2 coax cable. Available bandwidth is divided among all clients on that frequency. If you want 54Mbps to a client, that must be the only client on that AP. (And he won't get 54 megs anyway, since some of that is used by overhead.)
"3. What is the appropriate way to balance the data traffic load between 8 APs against 300 WLAN clients to minimize bottleneck while maintaining 54Mbps throughput over radio transmission?"
Loadbalancing is handled internally to the 802.11 protocol suite; you don't need to worry about it. However, your 300 users will not all be getting 54 megs no matter what you do. If you require high guaranteed bandwidth to a dense and numerous user population, run Cat 5 and forget the wireless.
"4. In terms of data access security, is it appropriate to install the Cisco Secure Access Control Server locally, or in the main building where companys Enterprise Server is located? Please note that the Multi-purpose Training Hall is linked to the main building over ATM network using fiber optic cable."
Doesn't really matter. Radius traffic is not bandwidth-intensive; put it where it's most convenient.
"5. Does 60 feet at 54Mbps data rate (indoor range) be attained by setting the antenna module to either Omni-directional or patch/directional?"
No way to know without doing a survey. Every site's radio environment is different.
"6. Does Access Point attain the same range of 60 feet at 54Mbps (indoor range) while setting its power output to either 40 mW(16dBm) or 5 mW(7dBm)?"
As a rule of thumb, you can expect greater range at greater power levels, but see #5.
-Gabriel
06-21-2006 11:28 PM
I was doing a search on the forum and came across your answers here. They were quite insightfull.
Although posted a while ago, i do have an interesting question that I hope can be answered.
Our customer has aprox 15 APs, a WLSE and an ACS, We got WDS deployed and all is working fine with PEAP client authentication.
With the help of the WLSE reports we established that there are a few APs that have up to 10 clients associated at one time. From what I could understand, this means they each client will never get any better bandwidth than 5Mb/s if there are 10 clients connected to one AP. This is leading to some frustration to some of the clients. ( Specially the managers ). Without using WLSE selfhealing functions, how can one guarentee a bandwidth no less than 11Mb/s for all clients at any given time. I think it might be a configuration on the AP itself, but maybe i'm wrong. Maybe one needs to install extra APs. Looking forward to a response.
Pierre
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