Cut-through forwarding module and a method of receiving and transmitting data frames in a cut-through forwarding mode
The disclosure relates to cut-through forwarding module, an integrated circuit, a semiconductor device and a method of receiving and transmitting data frames in a cut-through forwarding mode. The cut-through forwarding module processes received data frames in data blocks. The module comprises a pre-loading unit for storing a first data block of a received data frame. The stored first data block may be pre-loaded by the pre-loading unit in a transmitter unit before a receiver unit receives a subsequent data frame. The processing unit controls the transfer of a first data block to the pre-loading unit and controls the use of a pre-loaded data block as a first data block of a data frame to be transmitted.
1. A cut-through forwarding module comprising:
a receiver unit being configured to receive data frames and to partition data packets of the data frames into data blocks,
a transmitter unit being configured to transmit data frames based on received data packets,
a pre-loading unit being configured to store a first data block of a first received data frame and to pre-load the stored first data block into the transmitter unit before a subsequent data frame is being received by the receiver unit,
a processing unit being configured to control a transfer of the first data block of the first received data frame to the pre-loading unit and to control use of the pre-loaded first data block as a first data block of subsequent data frame to be transmitted by the transmitter unit, the subsequent data frame is to be transmitted after a transmission of a first transmitted data frame being based on the first received data frame.
2. A cut-through forwarding module according to claim 1 , wherein the processing unit is configured to control the transfer of the first data block of the first received data frame to the pre-loading unit when a content of the first data block of the first received data frame does not match a content of the first data block stored in the pre-loading unit.
3. A cut-through forwarding module according to claim 1 , wherein the processing unit is configured to control the use of the pre-loaded data block as a first data block of the subsequent data frame to be transmitted if the subsequent data frame to be transmitted is based on a subsequent received data frame of which a content of the first data block matches the content of the first data block stored in the pre-loading unit.
4. A cut-through forwarding module according to claim 1 , wherein the processing unit is further configured to process the data blocks and to control transfer of data blocks to the transmitter unit for transmission.
5. A cut-through forwarding module according to claim 1 , wherein the pre-loading unit is configured to transfer the stored first data block to the transmitter unit when the receiver unit receives a preamble of a subsequent data frame.
6. A cut-through forwarding module according to claim 1 , wherein the pre-loading unit comprises a data block storage register for storing the first data block.
7. A cut-through forwarding module according to claim 1 , wherein the pre-loading unit comprises a comparing unit for comparing a content of a first data block of a received data frame with the content of the first data block stored in the pre-loading unit.
8. A cut-through forwarding module according to claim 7 , wherein the comparing unit is configured to provide an interrupt to the processing unit when the content of the first block of the received data frame differs from the content of the first data block stored in the pre-loading unit.
9. A cut-through forwarding module according to claim 6 , wherein the comparing unit is configured to apply an XOR function to the content of a first block of the received data frame and the content of the first data block stored in the pre-loading unit.
10. A cut-through forwarding module according to claim 1 , wherein the pre-loading unit comprises a transmission attributes register comprising transmission attributes used by the transmitter unit for transmitting the data of the first data block being stored in the pre-loading unit, the pre-loading unit being configured to provide the transmission attributes to the transmitter unit while pre-loading the stored first data block into the transmitter unit.
11. A cut-through forwarding module according to claim 1 , wherein the pre-loading unit comprises a status and control attributes register which comprises status and control attributes related to a status of the pre-loading unit, the status and control attributes register is configured to be read by the processing unit and the processing unit being configured to write status information in the status and control attributes register.
12. A cut-through forwarding module according to claim 11 , wherein the status and control attributes of the pre-loading unit comprise at least one of the following attributes:
reset attribute for indicating a required reset of the pre-loading unit,
locked attributed for indicating whether a data block is stored in the pre-loading unit and whether the data block may be overwritten,
mismatch expected attribute for indicating whether it is expected that first data blocks of received data packets may be different from the first data block stored in the pre-loading unit,
mismatch attribute for indicating whether the first data block of the last received data frame did not match with the first data block stored in the pre-loading unit,
change attribute for indicating whether the data block stored in the pre-loading unit must be overwritten by the first data block of the next received data frame or by the first data block of the data frame currently being received,
size attribute for indicating a size of the data blocks.
13. A cut-through forwarding module according to claim 1 , wherein the data blocks are of equal length.
14. An integrated circuit comprising at least one cut-through forwarding module according to claim 1 .
15. A semiconductor device comprising at least a cut-through forwarding module according to claim 1 .
16. A method of receiving and transmitting data frames in a cut-through forwarding mode, the method comprises:
receiving a first data frame by a receiver unit,
partitioning the first data frame into data blocks,
controlling, under control of a processing unit, the transfer of the first data block of the first data frame to a pre-loading unit and controlling the storage of the transferred first data block in the pre-loading unit, and
pre-loading the data block stored in the pre-loading unit into the transmitter unit if no data is being received by the receiver unit.
17. A method of receiving and transmitting data frames in a cut-through forwarding mode according to claim 16 , the method further comprises:
controlling, under control of a processing unit, the transfer of the data blocks to a transmitter unit, and
transmitting a second data frame by the transmitter unit, the second data frame comprises the transferred data blocks.
18. A method of receiving and transmitting data frames in a cut-through forwarding mode according to claim 16 the method further comprises:
receiving a third data frame by the receiver unit,
partitioning the third data frame into data blocks,
controlling the use of the data block which is pre-loaded into the transmitter unit as a first data block of a fourth data frame to be transmitted, the fourth data frame is to be based of the received third data frame,
transferring a second and further data block of the third data frame to the transmitter unit,
transmitting the fourth data frame by the transmitter unit, the fourth data frame comprises the pre-loaded first data block and the second and further transferred data blocks.
19. A method of receiving and transmitting data frames in a cut-through forwarding mode according to claim 16 , the method further comprises:
comparing a first data block of the first data frame with the data block stored in the pre-loading unit,
and wherein the stage of controlling the transfer of the first data block of the first data frame to the pre-loading unit results in the transfer and storage of the first data block into the pre-loading unit when the compared first data block is different from the data block stored in the pre-loading unit.
20. A method of receiving and transmitting data frames in a cut-through forwarding mode according to claim 18 further comprising:
comparing a first data block of the third data frame with the data block stored in the pre-loading unit,
and wherein the stage of controlling the use of the data block which is pre-loaded into the transmitter results in the use of the pre-loaded data block for the fourth data frame when the compared first data block is equal to the data block stored in the pre-loading unit.