Method and apparatus for egress jitter pacer

• US 9,013,999 B1
• Filed: 12/05/2008
• Issued: 04/21/2015
• Est. Priority Date: 01/02/2008
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Kondapalli, Raghu
• Primary Examiner(s): Banks Harold, Marsha D
• Assistant Examiner(s): HOUSHMAND, HOOMAN
• Application Number:
  US12/329,088
• Time in Patent Office: 2,328 Days
• Field of Search: None
• US Class Current: 370/235.1
• CPC Class Codes: H04L 47/215 using token-bucket
• CPC Class Codes: H04L 47/22 Traffic shaping
• CPC Class Codes: H04L 47/245 using preemption
• CPC Class Codes: H04L 47/522 Dynamic queue service slot or variable bandwidth allocation
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority

Abstract

Aspects of the disclosure provide a device transmitting a sequence of packets. The device may include a first queue configured to queue the sequence of packets for transmission by an egress port to a receiving device, and a queue control module configured to transmit the sequence of packets in time slots of the egress port. The sequence of packets can be uniformly distributed across the time slots to satisfy an agreed data rate between the device and the receiving device.

Claims

1. A device, comprising:

a first queue configured to queue a sequence of packets for transmission from an egress port to a receiving device; and

a queue control module configured to schedule the sequence of packets in time slots of the egress port, the packets being included in the time slots of the egress port, such that the packets are uniformly distributed across the time slots and transmission of the sequence of packets satisfies an agreed data rate between the device and the receiving device, the queue control module further configured to transmit a packet from the sequence of packets of the first queue by delaying transmission of a packet from a second queue configured to queue a sequence of packets having different priority than the packets queued in the first queue for transmission from the egress port to the receiving device when the transmission of the packet from the second queue, in absence of delay, hinders the uniform distribution of packet transmission from the first queue, the queue control module further configured to transmit the packet from the first queue even when the transmitting the packet causes the first queue to exceed a token limit of a token bucket of the first queue only when outputting a packet from the second queue affects the uniform distribution of packet transmission from the first queue.

2. The device according to claim 1, further comprising:

the second queue configured to queue at least one packet, wherein the queue control module is further configured to schedule a packet from the first queue before a packet from the second queue for transmission in a time slot of the egress port in order to ensure the packet from the first queue is transmitted in the time slot.

3. The device according to claim 1, wherein the queue control module is further configured to shape transmission rate from the first queue based on an agreed transmission profile.

4. The device according to claim 1, wherein the queue control module further comprises:

a token bucket configured to store a number of tokens, and the queue control module is further configured to update the number of tokens in the token bucket based on the agreed data rate.

5. The device according to claim 4, wherein the queue control module is further configured to determine a packet transmission from the first queue based on comparing the number of tokens in the token bucket to a token limit.

6. The device according to claim 4, wherein the queue control module is configured to increase the number of tokens by a token rate.

7. The device according to claim 6, wherein a number of tokens corresponding to a size of a packet is subtracted from the token bucket when the packet is transmitted.

8. The device according to claim 1, wherein the sequence of packets corresponds to a media stream.

9. The device according to claim 1, wherein the device is used for providing media data as a part of a network media system, the network media system comprising:

the receiving device for playing the media data; and

a network communication channel configured to provide a channel to transmit the media data from the device to the receiving device.

10. The device according to claim 1, wherein the uniform distribution of packet transmission from the first queue ensures transmission of one packet from the first queue per each of first time slots allocated for the first queue.

11. A method for outputting a sequence of packets, comprising:

queuing a sequence of packets into a first queue for transmission from an egress port to a receiving device;

scheduling the sequence of packets in time slots of the egress port, such that the packets are uniformly distributed across the time slots, and transmission of the sequence of packets satisfies an agreed data rate between a media source and the receiving device;

delaying transmission of a packet from a second queue configured to queue a sequence of packets having different priority than the packets queued in the first queue for transmission from the egress port to the receiving device in order to transmit a packet from the sequence of packets of the first queue when the transmission of the packet from the second queue, in absence of delay, hinders the uniform distribution of packet transmission from the first queue; and

transmitting the packet from the first queue even when the transmitting the packet causes the first queue to exceed a token limit of a token bucket of the first queue only when outputting a packet from the second queue affects the uniform distribution of packet transmission from the first queue.

12. The method according to claim 11, further comprising:

queuing at least one packet in the second queue for transmission from the egress port; and

scheduling a packet from the first queue before a packet from the second queue for transmission in a time slot of the egress port in order to ensure the packet from the first queue is transmitted in the time slot.

13. The method according to claim 11, further comprising

determining a transmission time in a time slot for the egress port to transmit a packet of the sequence of packets.

14. The method according to claim 13, wherein determining the transmission time further comprises:

updating a number of tokens in a token bucket with a token rate based on the agreed data rate; and

determining the transmission time based on the number of tokens in the token bucket.

15. The method according to claim 14, wherein determining the transmission time further comprises:

comparing the number of tokens in the token bucket to a token limit.

16. The method according to claim 14, further comprising:

determining the transmission time based on the number of tokens in the token bucket and a potential pace interfering packet, which belongs to a lower class of service than the sequence of packets, and is queued for transmission from the egress port.

17. A device, comprising:

a first queue with a first transmission profile;

a second queue with a second transmission profile;

a queue control module configured to schedule respective packets from the first queue and the second queue for transmission from an egress port, and check the first transmission profile of the first queue before transmitting a packet from the second queue, the queue control module further configured to transmit a packet from the first queue by delaying transmission of a packet from the second queue configured to queue a sequence of packets having different priority than the packets queued in the first queue for transmission from the egress port to a receiving device when the transmission of the packet from the second queue, in absence of delay, hinders the uniform distribution of packet transmission from the first queue, the queue control module further configured to transmit the packet from the first queue even when the transmitting the packet causes the first queue to exceed a token limit of a token bucket of the first queue only when outputting a packet from the second queue affects the uniform distribution of packet transmission from the first queue.

18. The device according to claim 17, wherein the first and the second transmission profiles include at least one of a bandwidth and a priority.

19. The device according to claim 17, wherein packets are queued into the first queue and the second queue based on one or more of a plurality of criteria.

20. The device according to claim 19, wherein the plurality of criteria include at least one of class, flow and stream.

21. The device according to claim 17, wherein at least one of the first and the second transmission profiles are adjustable.

22. The device according to claim 17, wherein in response to checking the first transmission profile of the first queue, the packet from the second queue is not scheduled for transmission if such scheduling has an adverse impact on the first queue.

23. A method for outputting a sequence of packets, comprising:

queuing packets into a first queue with a first transmission profile;

queuing at least one packet into a second queue with a second transmission profile;

scheduling packet transmissions from the first queue and the second queue based on the first and the second transmission profiles;

checking the first transmission profile of the first queue before transmitting a packet from the second queue;

delaying transmission of a packet from the second queue in order to transmit a packet from the first queue when the transmission of the packet from the second queue configured to queue a sequence of packets having different priority than the packets queued in the first queue for transmission from an egress port to a receiving device, in absence of delay, hinders the uniform distribution of packet transmission from the first queue; and

transmitting the packet from the first queue even when the transmitting the packet causes the first queue to exceed a token limit of a token bucket of the first queue only when outputting a packet from the second queue affects the uniform distribution of packet transmission from the first queue.

24. The method according to claim 23, wherein the first and the second transmission profiles include at least one of a bandwidth and a priority.

25. The method according to claim 23, wherein queuing packets into the first queue and the second queue is based on one or more of a plurality of criteria.

26. The method according to claim 25, wherein the plurality of criteria include at least one of class, flow and stream.

27. The method according to claim 23, wherein at least one of the transmission profiles are adjustable.