Pre-emption in passive optical networks

1. A method comprising:

transmitting a first type of data traffic addressed to a first optical network unit (ONU) to a passive optical network over a common port;

pre-empting transmission of the first type of data traffic addressed to the first ONU over the passive optical network in response to detecting a presence of a second type of data traffic addressed to a second ONU, the second ONU being distinct from the first ONU, or in response to receiving a first request to hold the first type of data traffic;

transmitting the second type of data traffic addressed to the second ONU to the passive optical network over the common port; and

resuming the transmission of the first type of data traffic addressed to the first ONU to the passive optical network over the common port upon completion of transmitting the second type of data traffic addressed to the second ONU, or responsive to receiving a second request to release the hold of the first type of data traffic.

2. The method of claim 1 , wherein the first type of data traffic comprises non-critical data traffic and the second type of data traffic comprises express data traffic.

3. The method of claim 1 , wherein a first portion of a frame of the first type of data traffic is transmitted prior to pre-empting the transmission of the first type of data traffic and a remaining portion of the frame of the first type of data traffic is transmitted upon resuming the transmission of the first type of data traffic.

4. The method of claim 1 , further comprising:

suspending transmission of a frame of the first type of data traffic at an end of a first grant and resuming transmission of the frame of the first type of data traffic at a beginning of a next grant.

5. The method of claim 1 , wherein the passive optical network comprises an Ethernet passive optical network.

6. The method of claim 1 , further comprising:

pre-empting the transmission of the first type of data traffic responsive to receiving the first request to hold the first type of data traffic.

7. The method of claim 6 , further comprising:

resuming the transmission of the first type of data traffic over the passive optical network responsive to receiving the second request to release the hold of the first type of data traffic.

8. The method of claim 1 , wherein the first type of data traffic is associated with a first logical link identifier and the second type of data traffic is associated with a second logical link identifier.

9. The method of claim 1 , further comprising:

sending a report packet after pre-empting the transmission of the first type of data traffic.

10. A device comprising:

a first media access control (MAC) module configured to receive a first type of data traffic and transmit the first type of data traffic to a MAC merge module;

a second MAC module configured to receive a second type of data traffic and transmit the second type of data traffic to the MAC merge module;

a multipoint MAC control module configured to provide an indication to the MAC merge module when transmission of the first type of data traffic should be pre-empted in favor of the second type of data traffic; and

the MAC merge module configured to receive the first and second types of data traffic from the first and second MAC modules, respectively, and provide the first and second types of data traffic for transmission over a port to a passive optical network, wherein the MAC merge module is configured to pre-empt the transmission of the first type of data traffic over the port in response to receiving the indication from the multipoint MAC control module.

11. The device of claim 10 , wherein the multipoint MAC control module is further configured to:

transmit a hold request to the MAC merge module; and

transmit a release request to the MAC merge module.

12. The device of claim 11 , wherein the multipoint MAC control module is further configured to:

transmit the hold request in response to receiving the hold request from a MAC client; and

transmit the release request in response to receiving the release request from the MAC client.

13. The device of claim 11 , wherein the multipoint MAC control module is further configured to:

anticipate the second type of data traffic and a duration of the second type of data traffic;

transmit the hold request to the MAC merge module in response to anticipating the second type of data traffic;

determine when the duration of the second type of data traffic has expired; and

transmit the release request to the MAC merge module in response to determining that the duration has expired.

14. The device of claim 11 , wherein the MAC merge module is configured to:

stop acceptance of the first type of data traffic from the first MAC module upon receiving the hold request from the multipoint MAC control module; and

resume the acceptance of the first type of data traffic from the first MAC module upon receiving the release request from the multipoint MAC control module.

15. The device of claim 14 , wherein the MAC merge module is configured to:

transmit a first portion of a frame of the first type of data traffic over the port prior to stopping the acceptance of the first type of data traffic; and

transmit a remaining portion of the frame of the first type of data traffic over the port after resuming the acceptance of the first type of data traffic.

16. The device of claim 11 , wherein the first and second MAC modules are associated with a first logical link identifier and further comprising:

a third MAC module configured to receive the first type of data traffic and transmit the first type of data traffic to another MAC merge module, wherein the third MAC module is associated with a second logical link identifier; and

the another MAC merge module is configured to receive the hold request from the multipoint MAC control module and stop accepting the first type of data traffic from the third MAC module in response to receiving the hold request.

17. The device of claim 10 , wherein the first type of data traffic comprises non-critical data traffic and the second type of data traffic comprises express data traffic.

18. A computer program product comprising instructions stored in a non-transitory computer-readable storage medium, the instructions being executable by a controller, the instructions comprising:

instructions to cause an optical line terminal (OLT) to transmit a burst comprising a plurality of forward error correction codewords including a portion of a plurality of frames during a first time period;

instructions to cause the OLT to suspend transmission of one of the plurality of frames at an end of the first time period, a beginning portion of the one of the plurality of frames being transmitted in one of the plurality of forward error correction codewords, and

instructions to cause the OLT to resume transmission of the one of the plurality of frames at a beginning of a next burst, the next burst comprising another forward error correction codeword that includes a remaining portion of the one of the plurality of frames.

19. The computer program product of claim 18 , the instructions further comprising:

instructions to cause the OLT to suspend the transmission of the one of the plurality of frames at the end of the first time period in response to detecting express data traffic.

20. The computer program product of claim 19 , wherein detecting the express data traffic comprises receiving an indication of the express data traffic from a multipoint MAC control module.