A BGP capable packet network device is located at the boundary of an autonomous network and in communication with a peer BGP capable packet network device in a neighboring autonomous network. The BGP capable packet network device is comprised of one or more line cards for receiving and, processing and sending packets of information, and for receiving and forwarding routing update information to a route processor comprising the packet network device. The route processor runs a border gateway protocol which is configured with one or more policies that operate to filter the routing update information received from the line card. The routing update information filter is comprised of at least one variable length path attribute and the filter operates such that it only applies the variable length path attribute one time to the routing update information.