Support for distinguished minimum latency traffic guard band
View Patent ↗A network device may implement a guard band for reducing latency of transmitting high priority data. The device may identify a scheduled communication time for high priority data, which may include a scheduled reception time of the high priority data by the network device or a scheduled communication time of the high priority data. The network device may initiate a guard band prior to the scheduled communication time, and even before the high priority data is received by the network device. When the guard band is active, the network device may prevent transmission of low priority data, which may include preempting an in-progress low priority packet when initiating the guard band. Upon receiving the high priority data, the network device may immediately transmit the high priority data without incurring additional latency for preempting a low priority packet.
1. A device comprising:
a communication interface configured to transmit a first packet;
a media access client (MAC) client circuitry configured to:
identify, from a predetermined communication schedule, a scheduled future time to send the first packet through the communication interface; and
determine a guard band initiation time to activate a guard band for high priority data, the guard band initiation time being prior to the scheduled future time, wherein the guard band initiation time accounts for a worst-case latency in preempting in-progress transmission of a packet with lower priority than the first packet;
send a guard band initiation notification at the guard band initiation time;
send a guard band release notification a predetermined time after the guard band initiation time; and
MAC merge sublayer circuitry configured to:
receive the guard band initiation notification via a dedicated communication line directly linking the MAC merge sublayer circuitry and the MAC client circuitry, and in response:
initiate the guard band for transmittal of the first packet to ensure that no packet with lower priority than the first packet is being transmitted through the communication interface at the scheduled future time;
receive the guard band release notification, and in response release the guard band,
wherein the MAC client circuitry is configured to determine an amount of time between the guard band initiation time and the scheduled future time by taking into account an inter packet gap time.
2. The device of claim 1 , wherein the MAC client circuitry is configured to identify the scheduled future time to send the first packet prior to the device receiving the first packet.
3. The device of claim 1 , wherein the MAC merge sublayer circuitry is configured to initiate the guard band, after receipt of the guard band initiation notification, by:
determination that a second packet with lower priority than the first packet is being transmitted through the communication interface; and
preemption of transmission of the second packet prior to the scheduled future time.
4. The device of claim 1 , wherein the MAC client circuitry is configured to determine the guard band initiation time to further account for a latency in sending a fragment trailer.
5. The device of claim 1 , wherein the MAC client circuitry is configured to send the guard band release notification even if the first packet is not received by the device.
6. The device of claim 1 , wherein the MAC merge sublayer circuitry is further configured to release the guard band by allowing transmission of a packet with lower priority than the first packet.
7. The device of claim 1 , wherein the first packet comprises distinguished minimum latency traffic (DMLT).
8. A method comprising:
in a network device:
identifying, in a media access client (MAC) client of the network device and prior to receiving a first packet, a scheduled communication time for communication of the first packet by the network device;
communicating a guard band activation message from the MAC client to a MAC merge sublayer of the network device via a dedicated communication line directly linking the MAC client and the MAC merge sublayer;
activating, by the MAC merge sublayer, a guard band at a guard band initiation time, which accounts for worst-case latency in preempting in-progress transmission of a packet with a priority lower than the first packet, prior to the scheduled communication time;
determining, by the MAC client, an amount of time between the guard band initiation time and the scheduled communication time by taking into account an inter packet gap time
when the guard band is active, preventing transmission of data with lower priority than the first packet; and
releasing the guard band a predetermined time after the guard band initiation time.
9. The method of claim 8 , wherein preventing the transmission of the data with lower priority than the first packet comprises:
preempting transmission of an in-progress second packet with lower priority than the first packet prior to receipt of the first packet.
10. The method of claim 8 , further comprising determining the guard band initiation time as an amount of time prior to the scheduling communication time by accounting for a preemption parameter.
11. The method of claim 10 , wherein the preemption parameter comprises a minimum packet fragment size for a preempted lower priority packet.
12. The method of claim 8 , wherein releasing the guard band includes deactivating the guard band to allow transmission of lower priority packets after transmission of the first packet has occurred.
13. The method of claim 12 , wherein releasing comprises releasing the guard band even when the first packet is not received by the network device.
14. The method of claim 8 , wherein the first packet comprises distinguished minimum latency traffic (DMLT).
15. A device comprising:
a communication interface; and
guard band circuitry including at least a media access client (MAC) and a MAC merge sublayer, and being in communication with the communication interface, the guard band circuitry configured to:
identify, in the MAC client and prior to receipt by the communication interface of a first packet, a scheduled communication time for communication of the first packet by the communication interface;
determine, in the MAC client, a guard band initiation time for initiation of a guard band mode, which accounts for worst-case latency in preempting in-progress transmission of a packet with a priority lower than the first packet, prior to the scheduled communication time and prior to receipt of the first packet;
communicate a guard band initiation message from the MAC client to the MAC merge sublayer via a dedicated communication link directly linking the MAC client and the MAC merge sublayer;
determine, in the MAC client, an amount of time between the guard band initiation time and the scheduled communication time by taking into account an inter packet gap time;
at the guard band initiation time and by the MAC merge sublayer, prevent transmission of data with lower priority than the first packet; and
release the guard band a predetermined time after the guard band initiation time.
16. The device of claim 15 , wherein the guard band circuitry is configured to prevent the transmission of the data by preempting in-progress transmission of a second packet with lower priority than the first packet.
17. The device of claim 15 , wherein the guard band circuitry is configured to prevent the transmission of the data with lower priority than the first packet until at least the scheduled communication time.
18. The device of claim 15 , wherein the guard band circuitry is further configured to identify the scheduled communication time from a predetermined communication schedule.
19. The method of claim 8 , wherein identifying, prior to receiving the first packet, the scheduled communication time for communication of the first packet by the network device comprises accessing a predetermined communication schedule to identify the scheduled communication time.
20. The method of claim 8 , wherein activating the guard band at the guard band initiation time prior to the scheduled communication time comprises activating the guard band prior to receipt of the first packet.