|  | U-Boot has networking support for VLANs (802.1q), and CDP (Cisco | 
|  | Discovery Protocol). | 
|  |  | 
|  | You control the sending/receiving of VLAN tagged packets with the | 
|  | "vlan" environmental variable. When not present no tagging is | 
|  | performed. | 
|  |  | 
|  | CDP is used mainly to discover your device VLAN(s) when connected to | 
|  | a Cisco switch. | 
|  |  | 
|  | Note: In order to enable CDP support a small change is needed in the | 
|  | networking driver. You have to enable reception of the | 
|  | 01:00:0c:cc:cc:cc MAC address which is a multicast address. | 
|  |  | 
|  | Various defines control CDP; see the README section. |