Devices, Systems and Methods for Run-Time Reassignment of a PHY to MAC Devices Interconnect

• US 20120328289A1
• Filed: 06/22/2011
• Published: 12/27/2012
• Est. Priority Date: 06/22/2011
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Julien, Martin, Brunner, Robert, Lessard, Stephane
• Granted Patent: US 8,509,616 B2
• Time in Patent Office: Days
• US Class Current: 398/45
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance

Abstract

Devices, systems and methods for run-time reassignment of the interconnection between devices pertaining to a Physical (PHY) layer and devices pertaining to a Media Access Control (MAC) layer, with no packet loss or with at most one packet lost are provided. The strategies employed by these devices, systems and methods used REMOTE FAULT, PAUSE and IDLE PATTERN messages. The devices may be interconnected via a reconfigurable optical crossbar.

Claims

1. A method (700) for switching a physical (PHY) device of a system linked via a communication media to a remote system, from being connected to a first processing (MAC) device to being connected to a second processing (MAC) device, the method comprising:

receiving (S710) an indication of an upcoming change of connection by the first MAC device and the second MAC device;

after the receiving of the indication, buffering (S720) egress traffic in the second MAC device;

transmitting (S730) egress traffic buffered in the first MAC device prior to the receiving of the indication, via the PHY device and the communication media to the remote system;

interrupting (S740) transmission from the first MAC device to the first PHY device, while continuing reception of ingress traffic or of an empty-traffic indication by the first MAC device from the remote system via the PHY device;

upon receiving (S750) a no-remote-traffic indication from the remote system, interrupting, in the first MAC device, reception of ingress traffic or indications from the remote system via the PHY device;

providing (S760) a physical connection between the second MAC device and the PHY device;

transmitting and receiving (S770), in the second MAC device, no-remote-traffic indications towards and from the remote system via the PHY device, after the physical connection is provided;

validating (S780) a connection between the second MAC device and the PHY device, by transmitting and receiving empty-traffic indications towards and from the remote system via the PHY device, for at least a predetermined time interval; and

transmitting (S790) the buffered egress traffic from the second MAC device via the PHY device and the communication media, to the remote system after the validating.

2. The method of claim 1, wherein the PHY device, the first MAC device, and the second MAC device are connected to a reconfigurable crossbar.

3. The method of claim 2, wherein the reconfigurable crossbar is an optical crossbar, and the method further includes converting electrical signals corresponding to ingress or egress traffic and indications into and from optical signals before being communicated between the PHY device and the first MAC device or the second MAC device via the optical crossbar.

4. The method of claim 1, wherein the PHY device has a transmission line and a reception line initially connected to a first transmission line and a first reception line of the first MAC device, respectively, and then connected to a second transmission line and a second reception line of the second MAC device, respectively.

5. The method of claim 4, wherein the transmission line and the reception line of the PHY device, the first transmission line and the first reception line of the first MAC device, and the second transmission line and the second reception line of the second MAC device are connected to a reconfigurable crossbar.

6. The method of claim 5, wherein the reconfigurable crossbar is an optical crossbar, and the method further includes converting electrical signals corresponding to traffic and indications to and from optical signals before being communicated between the PHY device, the first MAC device or the second MAC device via respective transmission and reception lines connected to the optical crossbar.

7. The method of claim 4, wherein the first MAC device interrupts the first transmission line upon emptying buffers storing the egress traffic buffered prior to the receiving of the indication of the upcoming change of connection.

8. The method of claim 4, wherein the first MAC device and the second MAC device send “

Remote Fault”

(RF) indications via the first transmission line or the second transmission line, respectively, if no traffic or indications are received on the first reception line or the second reception line, respectively.

9. The method of claim 8, wherein the no-remote-traffic indication received from the remote system is an RF indication.

10. A system (800) connected to a remote system (801) via a communication media (810), comprising:

a physical (PHY) device (820) connected to the communication media (801) and configured (1) to forward egress traffic and indications received from a first MAC device (830) or from a second MAC device (840), towards the remote system (801), via the communication media (810), and (2) to forward ingress traffic and indications received from the remote system (801), via the communication media (810), towards the first MAC device (830) or the second MAC device (840);

the first MAC device (830) initially connected to the PHY device (820) and configured to buffer and forward egress traffic and indications to be transmitted to the remote system (801), via the PHY device (820), and to receive ingress traffic and indications from the remote system (801) via the PHY device (820);

the second MAC device (840) configured to be connected to the PHY device (820), to buffer and forward egress traffic and indications to be transmitted to the remote system (801) via the PHY device (820), and to receive ingress traffic and indications from the remote system (801) via the PHY device (820); and

a controller (850) connected at least temporarily to the first MAC device (830) and to the second MAC device (840), and configured to control the first MAC device (830) and the second MAC device (840) while the system (800) switches from having the PHY device (820) connected to the first MAC device (830), to having the PHY device (820) connected to the second MAC device (840), by

(1) sending an indication of an upcoming change of connection to the first MAC device (830) and the second MAC device (840),

(2) redirecting egress traffic of the system (800) from the first MAC device (830) to the second MAC device (840) after sending the indication,

(3) controlling the first MAC device (830)

a. to transmit egress traffic buffered in the first MAC device (830) prior to receiving the indication of the upcoming change of connection, via the PHY device (820) and the communication media (810), to the remote system (801), after the receiving of the indication,

b. to stop transmitting any traffic or indications towards the first PHY device (820), while continuing to receive ingress traffic or empty-traffic indications from the remote system (801) via the PHY device (820) and the communication media (810), until a no-remote-traffic indication is received from the remote system (801), and

c. to interrupt a connection with the PHY device (820) upon receiving the no-remote-traffic indication from the remote system (801) via the PHY device (820) and the communication media (810), and

(4) controlling the second MAC device (840)

a. to buffer the egress traffic therein, after receiving the indication of the upcoming change of connection,

b. to transmit no-remote-traffic indications until receiving a no-remote-traffic indication from the remote system (801),

c. to validate communication with the remote system (801) via the PHY device (820) by transmitting and receiving empty-traffic indications for at least a predetermined time interval, after receiving the no-remote-traffic indication from the remote system (801) via the PHY device (820), and

d. to transmit the buffered traffic via the PHY device (820) and the communication media (810) to the remote system (801), after the communication has been validated.

11. The system of claim 10, further comprising:

a switch connected to the PHY device, the first MAC device, and the second MAC device and configured to initially provide a first physical connection between the PHY device and the first MAC device, and then to provide a second physical connection between the PHY device and the second MAC device.

12. The system of claim 11, wherein the switch is a reconfigurable crossbar.

13. The system of claim 12, wherein the reconfigurable crossbar is an optical crossbar.

14. The system of claim 13, further comprising:

a first optical engine device connected between the first MAC device and the optical crossbar and configured to convert electrical signals corresponding to traffic and indications to and from the first MAC device, into optical signals;

a second optical engine device connected between the second MAC device and the optical crossbar and configured to convert electrical signals corresponding to traffic and indications to and from the second MAC device, into optical signals; and

a PHY optical engine device connected between the PHY device and the optical crossbar and configured to convert electrical signals corresponding to traffic and indications to and from the PHY device, into optical signals.

15. The system of claim 10, wherein the PHY device is configured to be connected to the remote system via the communication media according to an Ethernet communication protocol.

16. The system of claim 15, wherein the Ethernet communication protocol enables one of a 10 Gbps, 40 Gbps and 100 GBps speed.

17. The system of claim 10, wherein the first MAC device and the second MAC device are located on different blades of a processing blade block, and the PHY device is located on an I/O blade of a media bridge block.

18. The system of claim 17, wherein the system further comprises a crossbar switch connected between the processing blade block and the media bridge.

19. The system of claim 18, wherein the crossbar switch is an optical crossbar and the system further comprises optical engines located on the blades on which the first MAC device, the second MAC device and the PHY device are respectively located, the optical engines being connected between a respective device and the optical crossbar and being configured to convert electrical signals corresponding to traffic and indications to and from the respective device, into or from optical signals.

20. A MAC device (900) useable in a system communicating with a remote system, comprising:

a processor (910) configured

(1) to receive an indication of an upcoming change of connection related to an existing connection with a PHY device of the system,

(2) to transmit egress traffic buffered prior to receiving the indication of the upcoming change, via the PHY device to the remote system,

(3) to interrupt transmission towards the first PHY device, while continuing reception of ingress traffic or of an empty-traffic indication after finishing transmitting the egress traffic buffered prior to receiving the indication of the upcoming change,

(4) to interrupt reception from the PHY device upon receiving an indication that the remote system no longer receives any traffic or indications after interrupting the transmission,

(5) to buffer egress traffic received after receiving an indication of an upcoming new connection with a PHY device,

(6) to transmit indications that no traffic or indications are received after receiving the indication of the upcoming new connection with a PHY device and no traffic or indications has been received, and

(7) to transmit empty-traffic indications for a predetermined time interval before starting to transmit the buffered traffic towards the remote system, after receiving traffic or indications following receiving the indication of the upcoming new connection with a PHY device; and

a plurality of communication ports (920) configured to enable communication with the PHY device.

21. A method (1100) for switching a physical (PHY) device of a system linked via a communication media to a remote system, from being connected to a first processing (MAC) device to being connected to a second processing (MAC) device, the method comprising:

receiving (S1110) an indication of an upcoming change of connection by the first MAC device and the second MAC device;

after the receiving of the indication, buffering (S1120) egress traffic in the second MAC device;

transmitting (S1130) egress traffic buffered in the first MAC device prior to the receiving of the indication, via the PHY device and the communication media, to the remote system;

sending (S1140) a pause message requesting no ingress traffic to be sent from the remote system (801) for a first predetermined amount of time, from the first MAC device, to the remote system via the first PHY device, while continuing to receive ingress traffic or of empty-traffic indications by the first MAC device from the remote system via the PHY device;

transmitting (S1150) empty-traffic indications for a second predetermined amount of time after sending the pause message, from the first MAC device, towards the remote system via the first PHY device, while the remote system finishes sending an in-flight packet and then starts sending empty-traffic indications for the first predetermined amount of time towards the system, via the communication media and the PHY device;

after the second predetermined amount of time, interrupting (S1160) a transmission line from the first MAC device to the PHY device and connecting a transmission line of the second MAC device to the PHY device, while a reception line of the first MAC device remains connected to receive empty-traffic or no-remote-traffic indications from the remote system via the PHY device;

upon receiving (S1170) a no-remote-traffic indication from the remote system, interrupting, in the first MAC device, a reception line to the PHY device, and connecting a reception line of the second MAC device to the PHY device enabling the second MAC device to receive traffic and indications from the remote system;

upon receiving a no-remote-traffic indication from the remote system, sending (S1180) empty-traffic indications towards the remote device from the second MAC device, via the PHY device;

validating (S1190) a connection between the second MAC device and the PHY device, by transmitting and receiving empty-traffic indications towards and from the remote system via the PHY device, for at least a third predetermined time interval; and

transmitting (S1200) the buffered egress traffic from the second MAC device via the PHY device and the communication media, to the remote system after the validating.

22. The method of claim 21, wherein the PHY device, the first MAC device, and the second MAC device are connected to a reconfigurable crossbar.

23. The method of claim 22, wherein the reconfigurable crossbar is an optical crossbar, and the method further includes converting electrical signals corresponding to ingress or egress traffic and indications into and from optical signals before being communicated between the PHY device and the first MAC device or the second MAC device via the optical crossbar.

24. The method of claim 21, wherein the first predetermined amount of time exceeds a maximum transmission unit used during communication between the system and the remote system.

25. The method of claim 21, wherein the second predetermined amount of time is larger than a maximum transmission unit used during communication between the system and the remote system but smaller than the first predetermined amount of time.

26. The method of claim 21, wherein the no-remote traffic indication is a “

Remote Fault”

(RF) message issued by one of the first MAC device, the second MAC device or received from the remote system when no traffic or indication is received for a receipt-error time interval.

27. A system (800) connected to a remote system (801) via a communication media (810), comprising:

a physical (PHY) device (820) connected to the communication media (801) and configured (1) to forward egress traffic and indications received from a first MAC device (830) or from a second MAC device (840), towards the remote system (801), via the communication media (810), and (2) to forward ingress traffic and indications received from the remote system (801), via the communication media (810), towards the first MAC device (830) or the second MAC device (840);

the first MAC device (830) initially connected to the PHY device (820) and configured to buffer and forward egress traffic and indications to be transmitted to the remote system (801), via the PHY device (820), and to receive ingress traffic and indications from the remote system (801) via the PHY device (820);

the second MAC device (840) to be connected to the PHY device (820), and configured to buffer and forward egress traffic and indications to be transmitted to the remote system (801) via the PHY device (820), and to receive ingress traffic and indications from the remote system (801) via the PHY device (820);

a switch (825) connected to the PHY device (820), the first MAC device (830), and the second MAC device (840) and configured to initially provide a first physical connection between the PHY device and the first MAC device, and then to provide a second physical connection between the PHY device and the second MAC device; and

a controller (850) connected at least temporarily to the first MAC device (830), to the second MAC device (840), and to the switch (825) and configured to control the first MAC device (830), the second MAC device (840) and the switch (825) while the system (800) switches from having the PHY device (820) connected to the first MAC device (830), to having the PHY device (820) connected to the second MAC device (840), by

(1) sending an indication of an upcoming change of connection to the first MAC device (830) and the second MAC device (840),

(2) redirecting egress traffic of the system (800) from the first MAC device (830) to the second MAC device (840) after sending the indication,

(3) controlling the first MAC device (830)

a. to transmit egress traffic buffered in the first MAC device (830) prior to receiving the indication of the upcoming change of connection, via the PHY device (820) and the communication media (810), to the remote system (801), after receiving the indication,

b. to send a pause message requesting no ingress traffic for a first predetermined amount of time to the remote system (801), while continuing to receive ingress traffic or empty-traffic indications from the remote system (801) via the PHY device (820), and

c. to transmit empty-traffic indications for a second predetermined amount of time after sending the pause message towards the remote system (801) via the first PHY device (820),

(4) controlling the second MAC device (840)

a. to buffer the egress traffic therein, after receiving the indication of the upcoming change of connection,

b. to transmit no-remote-traffic indications until receiving a no-remote-traffic indication from the remote system (801),

c. to validate communication with the remote system (801) via the PHY device (820) by transmitting and receiving empty-traffic indications for at least a predetermined time interval, after receiving the no-remote-traffic indication from the remote system (801) via the PHY device (820), and

d. to transmit the buffered traffic via the PHY device (820) and the communication media (810) to the remote system (801), after the communication has been validated, and

(5) controlling a switch (825)

a. to interrupt a transmission line between the first MAC device (830) and the PHY device (820) and to connect a new transmission line between the second MAC device (840) and the PHY device (820) after the second predetermined has elapsed, and

b. to interrupt a reception line between the first MAC device (830) and the PHY device (820) and to connect a new reception line between the second MAC device (840) and the PHY device (820) when a no-remote-traffic indication is received from the remote system (801).

28. The system of claim 27, wherein the switch is a reconfigurable crossbar.

29. The system of claim 28, wherein the reconfigurable crossbar is an optical crossbar.

30. The system of claim 29, further comprising:

a first optical engine device connected between the first MAC device and the optical crossbar and configured to convert electrical signals corresponding to traffic and indications to and from the first MAC device, into and from optical signals;

a second optical engine device connected between the second MAC device and the optical crossbar and configured to convert electrical signals corresponding to traffic and indications to and from the second MAC device, into and from optical signals; and

a PHY optical engine device connected between the PHY device and the optical crossbar and configured to convert electrical signals corresponding to traffic and indications to and from the PHY device, into and from optical signals.

31. The system of claim 27, wherein the PHY device is configured to be connected to the remote system via the communication media according to an Ethernet communication protocol.

32. The system of claim 31, wherein the Ethernet communication protocol enables one of a 10 Gbps, 40 Gbps and 100 GBps speed.

33. The system of claim 27, wherein the first MAC device and the second MAC device are located on different blades of a processing blade block, and the PHY device is located on an I/O blade of a media bridge block.

34. The system of claim 33, wherein the system further comprises a crossbar switch connected between the processing blade block and the media bridge.

35. The system of claim 34, wherein the crossbar switch is an optical crossbar and the system further comprises optical engines located on the blades on which the first MAC device, the second MAC device and the PHY device are respectively located, the optical engines being connected between a respective device and the optical crossbar and being configured to convert electrical signals corresponding to traffic and indications to and from the respective device, into or from optical signals.

36. A MAC device (900) useable in a system (800) communicating with a remote system (801), comprising:

a processor (910) configured

(1) to receive an indication of an upcoming change of connection related to an existing connection of the MAC device with a PHY device of the system,

(2) to transmit egress traffic buffered prior to receiving the indication of the upcoming change, via the PHY device to the remote system,

(3) to send a pause message requesting no ingress traffic to be sent from the remote system (801) for a first predetermined amount of time while continuing to receive ingress traffic or of empty-traffic indications from the remote system via the PHY device,

(4) to transmit empty-traffic indications for a second predetermined amount of time after sending the pause message, towards the remote system via the first PHY device,

(5) to interrupt transmission towards the first PHY device, while continuing reception of ingress traffic or of an empty-traffic indication after the second predetermined amount of time,

(6) to interrupt reception from the PHY device upon receiving no-remote-traffic indication from the remote system,

(7) to buffer egress traffic received after receiving an indication of an upcoming new connection with a PHY device,

(8) to transmit no-remote-traffic indications after receiving the indication of the upcoming new connection with a PHY device and until traffic or indications are received, and

(9) after receiving traffic or indications from the remote system via the PHY device following the indication of the upcoming new connection with the PHY device, to validate the new connection by transmitting empty-traffic indications for a third predetermined time interval, before starting to transmit the buffered traffic towards the remote system; and

a plurality of communication ports (920) configured to enable communication with the PHY device.