A network unit for use in a switching fabric includes multiple units collectively constituting a single network entity, each having ports for the reception and forwarding of data packets. The network unit has at least one fabric port for connection to a partner port on another one of the units by at least one link. The network unit is organized to send and receive via the at least one fabric port protocol packets which contain information on the path costs between said units in the fabric and to perform an algorithm to determine, on the basis of said information, routes for data packets within the fabric to other units of the fabric.