Describes the type of port. One of the following: cascadeExternal - Port is an uplink with physical connections which are externally visible cascadeInternal - Port is an uplink with physical connections which are not externally visible, such as a connection to an internal backplane in a chassis localExternal - Port is a downlink or local port with externally visible connections localInternal - Port is a downlink or local port with connections which are not externally visible, such as a connection to an internal agent 'internal' is used to identify ports which place traffic into the repeater, but do not have any external connections. Note that both DTE and cascaded repeater downlinks are considered 'local' ports.