Vlan groups on WLC 9800-L-F

[ibrahimbadr4669]

Dears,

we configure different vlans and put them under the Vlan group and associate the SSID with the Vlan group. When user associate with the SSID, he get an IP however, it appears on the WLC on vlan different than expected (not matched with its IP) and not working. How I can fix the vlan of the users ? we tried to make the WLC L3 on the user subnets but it's not working

N.B we have old WLC and have L3 interface in the user subnet and working fine

Thanks

[marce1000]

 - Start with a checkup of your current WLC 9800-L-F configuration with the CLI command : show tech wireless , have the output processed with (or by) : https://cway.cisco.com/wireless-config-analyzer , 

 M.

[ibrahimbadr4669]

i tried but there is no error related to this behavior 

[ibrahimbadr4669]

our case no related to roaming, I have one WLC and the external dhcp assign the IP based on the mac address (static assignment ), and the user get the right IP however not get the right vlan corresponding to the his IP. Is there method to adjust the vlan for the users according to its IP. As i read about it that vlan group its dynamic as mentioned below 

"When a wireless client associates to the WLAN, the VLAN is derived by an algorithm based on the MAC address of the wireless client. A VLAN is assigned to the client and the client gets the IP address from the assigned VLAN."

I think that the issue is that more than one vlan associated to same SSID and controller do random selection for vlan which not matched with IP. I wonder how i can fix it and how the old WLC (AirOS) works 

Thanks

[Scott Fella]

Static assignments when using vlan group is not supported.  That is why you are seeing what you are seeing.  Since the controller places the device on vlan B and you have a static on vlan A, your best bet is to have a static on vlan A since the algorithm places the device on vlan A.  Now this will not be 100%, if the vlan DHCP is exhausted or if a vlan is added or the vlan/vlan group changes.  

If you remove the static ip address, I bet the device will get an ip address and the device will have connectivity.

[ibrahimbadr4669]

Thanks alot for kind answer, we don't use static IPs, we use DHCP however DHCP is designed as each time the user login get the same IP (one to one relation between the mac and IP)

[Scott Fella]

Static, Mac reservations, it's in the same family.  You want device A to get ip address A and device B to get ip address B.  Doesn't work when using interface groups, vlan groups, etc.  Re-look at what you are doing and come up with a solution that does work, don't try to make something that is not supported work, that will cause issue and your users will not enjoy the experience.

[ibrahimbadr4669]

Thanks fro reply, However I had AirOS WLC and working fine using Interface group

[Flavio Miranda]

Hi

  The behavior you described is not uncommon. Users on wireless network can be in a vlan with a different IP address due the L3 roaming. In order to not kill user´s connections like NAT, the WLC is able to allow users to move around keeping the same IP address

Take a look here

https://study-ccnp.com/wlan-intercontroller-layer-2-layer-3-roaming/ 

But, it works. So, on your case, something else might be wrong. I´d recommend you to check the client when connected and make sure it is getting all the information it needs like default gateway and DNS server. Make sure it can ping its gateway.

[ibrahimbadr4669]

our case no related to roaming, I have one WLC and the external dhcp assign the IP based on the mac address (static assignment ), and the user get the right IP however not get the right vlan corresponding to the his IP. Is there method to adjust the vlan for the users according to its IP. As i read about it that vlan group its dynamic as mentioned below 

"When a wireless client associates to the WLAN, the VLAN is derived by an algorithm based on the MAC address of the wireless client. A VLAN is assigned to the client and the client gets the IP address from the assigned VLAN."

I think that the issue is that more than one vlan associated to same SSID and controller do random selection for vlan which not matched with IP. I wonder how i can fix it and how the old WLC (AirOS) works 

Thanks

[Prince.O]

On the DHCP server are you using a Superscope ? If so , this can cause an IP/VLAN mismatch as the WLC may be requesting an IP on one VLAN but server is responding with next available IP which may be in a different vlan. 

- If this is the case, i'd suggest breaking the superscope and this should resolve it 

[ibrahimbadr4669]

No SuperScope is used