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Community Member

Wireless solution(s) for existing network

Hello all,

Hoping you can help me with the following issue. I have no experience setting up a wireless network, so bear with me.

We have a network where 9 office floors are connected by access switches [Catalyst 3560] to 2 core switches in the server room [Catalyst 4500] providing network connectivity to approx. 50 users per floor. Each floor has it's own dedicated VLAN.

Management has asked me to install a wireless connection to the existing network on one floor but with more floors very likely to follow in the future.

Please guide me to the likely hardware solutions for our situation as I'm finding it difficult to make a good choice.

Also, if you good people could make any suggestions as to the steps I should follow setting up such a wireless solution, they are very welcome. I'm already reading up on encryption and authentication solutions and any help (or real-life experience) would be greatly appreciated.

Should you need more information, please ask.




Re: Wireless solution(s) for existing network

Whats up?

First order of business is to determine what you are planning to do with your wireless network? Throw voice over it? General email/web? Your own corporate apps?

You need to find out how much bandwidth your going to need as it will define the data rates you need to serve up.

Next order of business is to review your floor plan and mark where you want coverage and making notes of high density areas. (large gathering of user's cubes, conference rooms etc).

Take your map of requested coverage and walk through your area looking for troublespots.. Essentially large metal objects, and the building material used. Concrete walls result in a ~10-15db loss ( every 3db is = to half the signal ), where drywall is about 4db.

Obtain something in the effect of Kismet(linux) or Netstumbler(windows) and review your area and see how many APs are in your near (neighbors). This is not the best guage of your spectrum but will give you an idea, obtain a spectrum analyzer (such as the cognio spectrum expert). With this info you will likly gauge if you need to go to the 5ghz band due to interference.

Now you will want to do a site survey, you may desire to do this yourself or hire the task out. If you do it yourself, you will have some reading to do however i believe in the end it will make you much better at administrating your WLAN.

Once the site survey is done you will know how many APs you will need. This is when you will decide how you will manage these guys. If you only have a handfull you can manage them individually.. However if you end up getting a decent number of APs you may want to look into the Wireless Lan Solution Engine. Speaking of this, if your looking for layer 3 roaming yuo will want to take a glance at the LAN controllers.

For ease of management i would advise you to talk with your techsupport people and plan out how to roll out firmware and driver upgrades for the wireless cards. I would also try and butter them up to the goal of having a single brand/model of wireless nic.

Please rate posts you find helpful.

Community Member

Re: Wireless solution(s) for existing network


Thanks for your suggestions!

The wireless access will not support voice traffic but it will have to support the day to day work of my users including web and e-mail support and accessing applications from the network. These users are normally hardwired to the network but want to have a wireless solution for in meetings as such but it is my experience that it won't take long before they expect the full connected experience from a wireless access point.

We're doing an implementation of one of the floors in our building first as kind of a test run and hopefully learn from this experience as we go.

Your site survey suggestions have been duly noted and were very helpful as I start planning this implementation. Because of the severe time constraints (management wants it sooner rather than later) I've ordered a Cisco Aironet 1130 AccesPoint to do some preliminary testing with on the office floor, It looks like a good candidate based on the specifications.

If any of you have any more considerations for me to research, please let me know.



Re: Wireless solution(s) for existing network

Being multi-floor you will want to keep in mind when your doing your channel selection ( remember only 1,6, and 11 are non overlapping) that you have to consider the floors above and below.

Take a look at this book, its available on safari as well.

802.11 Wireless Network Site Surveying and Installation

ISBN: 1587051648

Dont forget to get smartnet on your APs! When the bigwigs are coming down hard when theres an issue, it can come in handy. Not to mention the almost required image upgrades.

Community Member

Re: Wireless solution(s) for existing network


First consider

1) Architecture of the building

2) Total covered area of the floor

3) what type of traffic will run such as Internet,database etc etc

4) Now how much assess points will cover all the floor with full strength

5) all the accees points will connect to each other by using WDS link

6) Only 1 access point will connect through cable with your switch or any equipment that will give services to all users...

Try to use high gain antenna so that they won't interrupt signals and your network will work smoothly

Any more help needed ????

Community Member

Re: Wireless solution(s) for existing network

Thank you all,

Could you elaborate more about the WDS link and the hardwired connection to the switch ? Any configuration settings I need to take into account ? A first google search on WDS links brought up some security issues. Are there any ?

Thanks all, you've been a great help!

Community Member

Re: Wireless solution(s) for existing network


WDS stands for Wireless Distribution Link which means wireless connectivity between multiple APs

while WEP/WPA defines security between APS

mean whenever they connect to each other they will have to give password to each other ( u can call it PKE (Publick key encryption))

I never use Cisco APs but i used other companies APs so i m used to this scenario

Any more help needed tell me

Just connect 1 of your AP to switch and then make WDS link between all of them by point to point connectivity then your all network will convert into WLAN

Hall of Fame Super Red

Re: Wireless solution(s) for existing network

Hi GB,

Here is some info on the role of WDS to add to the great tips you have received from Robert and others so far.

Configuring WDS, Fast Secure Roaming, and Radio Management

Understanding WDS

When you configure Wireless Domain Services on your network, access points on your wireless LAN use the WDS device (either an access point or a switch configured as the WDS device) to provide fast, secure roaming for client devices and to participate in radio management. If you use a switch as the WDS device, the switch must be equipped with a Wireless LAN Services Module (WLSM). An access point configured as the WDS device supports up to 60 participating access points. A WLSM-equipped switch supports up to 300 participating access points.

Fast, secure roaming provides rapid reauthentication when a client device roams from one access point to another, preventing delays in voice and other time-sensitive applications.

Access points participating in radio management forward information about the radio environment (such as possible rogue access points and client associations and disassociations) to the WDS device. The WDS device aggregates the information and forwards it to a wireless LAN solution engine (WLSE) device on your network.

Role of the WDS Device

The WDS device performs several tasks on your wireless LAN:

Advertises its WDS capability and participates in electing the best WDS device for your wireless LAN. When you configure your wireless LAN for WDS, you set up one device as the main WDS candidate and one or more additional devices as backup WDS candidates. If the main WDS device goes off line, one of the backup WDS devices takes its place.

Authenticates all access points in the subnet and establishes a secure communication channel with each of them.

Collects radio data from access points in the subnet, aggregates the data, and forwards it to the WLSE device on your network.

Registers all client devices in the subnet, establishes session keys for them, and caches their security credentials. When a client roams to another access point, the WDS device forwards the client's security credentials to the new access point.

Participating Access Points Supported by WDS Devices

Access point that also serves client devices


Access point with radio interfaces disabled


WLSM-equipped switch


Role of Access Points Using the WDS Device

The access points on your wireless LAN interact with the WDS device in these activities:

Discover and track the current WDS device and relay WDS advertisements to the wireless LAN.

Authenticate with the WDS device and establish a secure communication channel to the WDS device.

Register associated client devices with the WDS device.

Report radio data to the WDS device.

From this good doc;

Wireless Domain Services Configuration

Wireless Domain Services FAQ

What is WDS and Why Do I Need It?

The WDS is used with Autonomous AP's, you may also want to look into using a "Lightweight" architecture (LWAPP) that does simplify rollouts and ongoing support.

Understanding the Lightweight Access Point Protocol (LWAPP)

Hope this helps!


Re: Wireless solution(s) for existing network

5 for rob, =) Great info

Community Member

Re: Wireless solution(s) for existing network

Yes. Great info all around :-)

I've gotten a lot of helpful information from you fine people and I can't wait to get started. Thanks for all the kind help!

All the best,


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