Ask Wireless Case Study

[Rakhmadian Purnama]

Dear All,

Currently, I'm developing Cisco wireless equipments in my customer. The devices is consist of :

Wireless Access Pint --> AIR-LAP1252AG-A-K9

Wireless LAN Controller --> Cisco WLC 5508

Wireless Control System --> Cisco WCS v.7.0.220.0

We put 2 access point in each floors, let say we put 2 access point in 3rd floor and 4th floor.

Those AP connected to the WLC and then WLC connected to the router (gateway). We manage them by WCS.

We have a SSID in each floor which using 802.1x authentication method. We use VLAN technology for segmenting user IP and bind it into dynamic interface at WLC.

For example,

- If 3rd floor user connect to this SSID they will get IP : 192.168.3.X /24 --> Vlan 3 (di03)

- If 4th floor user connect to this SSID they will get IP : 192.168.4.X /24 --> Vlan 4 (di04)

The problem is :

Sometimes, the 3rd user get IP address 192.168.4.X. When I check to WCS, this client connect to AP in the 3rd Floor.

This is weird, I already asssign di04 (dynamic interface for user 4th floor) only to AP in the 4th Floor.

But, why it can still occur ? Can somebody tell me, what's the keyword of this problem when I want to search in Google.

[Leo Laohoo]

Review your Bill of Materials.  You will no longer be able to purchase 1250 as it's end-of-sale.

We put 2 access point in each floors, let say we put 2 access point in 3rd floor and 4th floor.

No way.  No darn way.  WHO made the decision to put X amount of WAPs per floor?  If the answer is "him", "her", or "Management", then my rebuttal is "wrong answer" (push the red button, trap door opens, and ...).

You want to do this right?  Get a wireless site survey done.  Period.

- If 3rd floor user connect to this SSID they will get IP : 192.168.3.X /24 --> Vlan 3 (di03)
- If 4th floor user connect to this SSID they will get IP : 192.168.4.X /24 --> Vlan 4 (di04)

Not possible unless you wrap each floor with Faraday cage.  The SSID, for example, for the 3rd floor will "bleed" up to the 4th floor and vice versa.  This wireless is NOT wired network.

[Rakhmadian Purnama]

Hi leolaohoo,

Thanks before for your response..

We also use WCS map feature to allocate the WAP position in each floor. What do you think, if we try to manipulate the BSS/ESS area range by change some parameters such as : roaming parameters, channel, etc.

Actually, some user in the 3rd floor and 4th floor already get connection normally. But in a particular zone, there is 3rd floor user got wrong IP segment from WAP 3rd Floor. It's seems there is a "leakage".

[Leo Laohoo]

But in a particular zone, there is 3rd floor user got wrong IP segment from WAP 3rd Floor. It's seems there is a "leakage".

That is to be expected.

We also use WCS map feature to allocate the WAP position in each floor.

Wireless site survey is better.  Period.