5760 wireless LAN controller - AP groups

[SHABEEB KUNHIPOCKER]

Hello All,

I have implemented a stack ( one active and one standby controller) of 5760 controllers at a customer site. There are several floors in the building and I assigned an AP group and VLAN per floor.  I am broadcasting single SSID in all the floors. Now when I test I  see that I am getting same  IP address in two different floors even though the vlans assigned in two floors are different. Please help me to resolve this issue ASAP .

Thanks in advance

[Leo Laohoo]

Now when I test I  see that I am getting same  IP address in two different floors even thou
gh the vlans assigned in two floors are different.

So let's say you are in a three story building and you are currently in the second floor.  Are you saying that your have joined to an AP located either in Level 3 or Level 1? 

If this is the case, then what's the issue?  This is very common.  At the end of the day, the decision to join which AP falls on the wireless client's NIC card.  It is very common to see a wireless client join the furthest AP in the planet.   

Look, just because you are on Level 2 doesn't mean the signal of the nearest AP is better than an AP located either above or below.   This information you haven't provided.  

What you can do is help "influence" the situation by adjusting the data rates.  If you'd like you could try disabling data rates from 1 Mbps up to 11 Mbps.  Make 18 Mbps as Mandatory and the rest as Supported.

[SHABEEB KUNHIPOCKER]

Hi Leo, 

I guess u understood it wrong. Let me explain it more.

1-  I went to the first floor , connected to the first floor AP and got an IP address designated for the first floor. This is working as expected

2- After that I went to the third floor and connected to the third floor access point. But still the client gets the same IP address from the first floor. 

The first floor and third floor access points are in two different access point groups. My requirement is that the client should get  ip addresses from different subnets when it connects to different floors.

Thanks in advance

[Leo Laohoo · Accepted solution]

The first floor and third floor access points are in two different access point groups. My requirement is that the client should get  ip addresses from different subnets wh
en it connects to different floors.

The APs are on different floors and the APs themselves are on different subnets.  Ok, this make sense, HOWEVER, you are connected to the same SSID?   

So the SSID is connected to ONE specific Dynamic Interface, isn't this correct?  This specific Dynamic Interface dictates what IP address the wireless clients will have and NOT the APs management IP address. 

So you going to any other floor will get one specific IP address based on the IP address of the Dynamic Interface.

[SHABEEB KUNHIPOCKER]

Hi Leo,

My scenario is as follows.

1-  I have a building with 44 floors.

2 - Each floor has 6 APs. Per floor I have created AP groups.

3 - In all the floors I am broadcasting the same SSID, say " Test"

4- I need clients in each floor to get IP address from a different subnet.

Now my issue is that if I connect my laptop to an AP in floor 1 , am getting an IP address 192.168.1.1. Now I go to the 44th floor and connect to an AP there still am getting the same IP for my laptop ( 192.168.1.1),. Actually i should get an IP address from the 192.168.44.0/24 subnet. Is there any way that I can stop this behavior from the controller. Now I hope its clear for you.

Thanks 

[Leo Laohoo]

Now my issue is that if I connect my laptop to an AP in floor 1 , am getting an IP address 192.168.1.1. Now I go to the 44th floor and connect to an AP there still am getting the same IP for my laptop ( 192.168.1.1),. Actually i should get an IP address from the 192.168.44.0/24 subnet. Is there any way that I can stop this behavior from the controller. Now I hope its clear for you.

I understand what you are trying to do but unless you create a distinct SSID with an equally distinct Dynamic Interface, it can't be done.  

Let me explain what you have:  Ok, you have a "TEST" SSID.   This SSID is tied to a Dynamic Interface.  Let's say the Dynamic Interface has an IP address of 192.168.1.0/24.  

So this means that whatever floor you are in, if you are connected to this SSID, you will always get 192.168.1.0/24 IP address.  

Now, I'm going to give you something to chew on ... Let's say you create a unique SSID per floor and, subsequently, each floor has a Dynamic Interface on it's own subnet.  

In theory, if you go to Level 44, you'll join the SSID found in Level 44 and you'll "land" on an IP address for Level 44.  Right?  Well, not all the time.  

The final decision to join which AP, whether it's an AP on this floor, floor above, floor below, or three floors either way, falls directly upon the wireless NIC card.  So there's no guarantee that if you are on the Level 23 the wireless client will join an SSID found in Level 23.  It is very common to see a wireless NIC card join an SSID found in Level 20, 21, 22, 23, 24, 25, etc.  

It is honourable thing what you are envisioning.  Will it work?  It might, it might not.  

[SHABEEB KUNHIPOCKER]

Hi Leo,

I found out the issue. The flow is as follows.

I got connected to an AP in the first floor. I got IP address assigned to that floor.The controller will have entry for my client in its client database.Now I disconnect from the first floor AP and go to 44th floor , if the controller still has the old entry for the client in its database it will retain the old IP address if am connecting to the same SSID. The controller sees my client as a roaming client and in order for better roaming it is doing so it seems. The user idle time out is 5 minutes by default and if I reach the 44th floor within 5 minutes I will get the old IP from first floor and if that 5 minutes timeout has passed before reaching the 44th floor then the client entry is deleted and the client will be assigned an address from the pool assigned for 44th floor. Thanks a lot for your help on the issue.

Shabeeb