Transmission of data packets of different priority levels using pre-emption

A packet transport layer adapted for transmitting Ethernet frames of at least two different priority levels via one or more bearer channels, comprising:

• a fragmentation unit adapted for fragmenting an Ethernet frame into a plurality of corresponding code words prior to transmission, each of the code words in the plurality of corresponding code words comprising a sync code adapted for indicating a priority level of the corresponding Ethernet frame;
• a state machine configured to map priority bits of an Ethernet frame's virtual local area network tag to at least one of the sync code and a start of frame code of the corresponding code words;
• an interface;
• and
• a transmission unit adapted for
• interrupting transmission of low priority code words corresponding to a low priority Ethernet frame in case high priority code words corresponding to a high priority Ethernet frame arrive during transmission of the low priority code words,
• transmitting the high priority code words via the interface, and
• resuming the transmission of the low priority code words corresponding to the low priority Ethernet frame after the high priority code words have been transmitted.

A packet transport layer adapted for receiving code words corresponding to Ethernet frames via one or more bearer channels, each of the code words comprising a sync code, with the sync code indicating a respective priority level, comprising:

• an interface;
• a defragmentation unit adapted for reassembling, for each priority level, code words of a respective priority level that are fragments of corresponding Ethernet frames fragmented prior to transmission via the interface, in order to regenerate the corresponding Ethernet frames of the respective priority level, wherein at least one of the sync code and a start of frame code of the corresponding code words comprises priority bits of an Ethernet frame's virtual local area network tag;
• a plurality of service queues, each service queue being adapted for buffering the Ethernet frames of a respective priority level;
• and
• routing means adapted for routing regenerated Ethernet frames to a respective service queue according to the respective priority level.