Controller-less WLANs

How does the IAP detects the mismatch vlan between the client and uplink?

Uplink Vlan Monitoring feature 
 
Applies to 6.3.1.1-4.0 and above.


Scenario:
 
When a Client VLAN is configured on the IAP, which is not allowed or configured on the IAP’s uplink device: any client which connects to such an SSID will not be able to obtain an IP address.



Solution: 

This feature triggers the VLAN alert whenever a client connects to a SSID whose VLAN is not in allowed list of upstream device. This upstream device can be a switch directly connected to IAP or behind a tunnel. No CLI or GUI changes with respect to the feature.
 
Usually we see the VLAN alert with DHCP alert when client is unable to obtain the IP address if the connected SSID is configured with the mismatched VLAN.

How it works?
 

VLAN X as Verified,  when an IAP receives any packet with VLAN X tag from the upstream device. This indicates that VLAN X is in allowed VLAN list of upstream device. Hence VLAN Alert is not generated.
 
VLAN Y as not Verified, when an IAP has not received any packet with VLAN Y tag from the upstream device. This indicates that VLAN Y is not in allowed VLAN list of  upstream device. Hence an alert is generated for such a VLAN when a client is trying to connect to the SSID(with VLAN Y configured) and unable to obtain the IP address.
 
VLAN X as Verified,  when an IAP receives any packet with VLAN X tag from the upstream device. This indicates that VLAN X is in allowed VLAN list of upstream device. Hence VLAN Alert is not generated.
 
VLAN Y as not Verified, when an IAP has not received any packet with VLAN Y tag from the upstream device. This indicates that VLAN Y is not in allowed VLAN list of  upstream device. Hence an alert is generated for such a VLAN when a client is trying to connect to the SSID(with VLAN Y configured) and unable to obtain the IP address.
 

Alert can be seen as show below from UI & CLI




The below commands shows the list of verified VLANs on the IAP