Patent ID: 7558266

Claim:
A method comprising: receiving a data unit including layer 2 client-identification data; determining whether the data unit includes layer 3 address data; if the data unit does not include any layer 3 address data: determining whether the layer 2 client-identification data has been recorded; if the layer 2 client-identification data has not been recorded: recording the layer 2 client-identification data; enabling a layer 3 address assignment status restriction attribute; if the layer 2 client-identification data has been recorded, unless the address assignment status restriction attribute is enabled, forwarding the data unit; if the data unit includes layer 3 address data, determining whether the layer 3 address data confirms a layer 3 address assignment; if the layer 3 address data confirms a layer 3 address assignment: disabling the layer 3 address assignment status restriction attribute; forwarding the data unit.