WLC-MESH-EthernetBridging-DHCP

[justsmaran]

Hi,

We are testing out a scenario, We are using 1532AP as Root and 1600E as Mesh and we have enable Ethernet Bridging on these devices to give network access to a PC or another AP. For the record the customer location has flat network (No VLANS, No DHCP nothing just plain). We have created a DHCP pool in WLC for Wireless and it is working fine and when we are trying Ethernet Bridging the DHCP is dropped by the Client, but if we use a static IP to the client then the client PC will get access to network and again if we use an external DHCP server like in firewall in this case and disabling DHCP in WLC then we are getting IP from the server and able to access network.

To make it simple, Ethernet Bridged client not getting DHCP IP when WLC acts as DHCP server.

I am attaching Topology, Configuration and DHCP client debug Log with this post.

[Scott Fella]

This is why DHCP isn't used much on the WLC. The preference is to use an external DHCP server. The WLC DHCP is and should be used for wireless clients and or access points but again, not preferred. The WLC will not hand out or should not issue DHCP to wired clients on the network. 

-Scott

[justsmaran]

Thank you for the immediate response Scott

I understand what you are trying to say. But if Ethernet Bridging is supported by WLC/Access Points then Internal DHCP must support for the Bridged clients too, I assume.

What could be the reason that Internal DHCP is not supporting the Ethernet Bridged clients. I know Wireless traffic will be in CAPWAP tunnel. But...for Ethernet Bridging it's not the case. Just want to know why?

[Scott Fella]

Take a look at the docs for DHCP on he WLC.  Cisco states that the DHCP is used for wireless clients and access points.  Since the WLC will not respond to wired clients, then it would not respond to wired clients behind and AP also.  I don't make the rules, I just can tell you what works and what doesn't.  There is no workaround to have the WLC issues DHCP to wired clients.  

-Scott