Systems (100) and methods (800) for routing packets within a Multi-Channel Communications Device (“MCCD”). The methods involve receiving a first packet (300) which has a first classification level and a second packet (300) which has a second different classification level. Subsequently, modified first and second packets (400) are generated by inserting routing headers (402) between data link layer protocol headers (308, 308′) and network layer protocol headers (310, 310′) of the first and second packets. Each routing header comprises an error-detecting code (512) and routing information (502) describing a route within the MCCD along which the first or second packet is to travel. The routing headers are then used by a single packet router (160) to simultaneously route the modified first and second packets through the MCCD to at least one port of a plurality of output interface ports (116, 1901, . . . , 190N) of the MCCD.