Closed-Loop Clock Synchronization

• US 20100284421A1
• Filed: 07/23/2010
• Published: 11/11/2010
• Est. Priority Date: 01/26/2007
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Fourcand, Serge Francois
• Granted Patent: US 8,605,757 B2
• Time in Patent Office: Days
• US Class Current: 370/458
• CPC Class Codes: H04J 3/047 Distributors with transistors or integrated circuits
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2408 for supporting different services, e.g. a differentiated services [DiffServ] type of service
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/564 Attaching a deadline to packets, e.g. earliest due date first
• CPC Class Codes: H04L 47/568 Calendar queues or timing rings

Abstract

A network comprising a destination node, and a plurality of source nodes configured to transmit high-priority data and low-priority data to the destination node, wherein the source nodes correlate the transmission of the high-priority data to the destination node such that the high-priority data from each source node does not substantially contend with the high-priority data from the other source nodes upon arrival at the destination node. Also disclosed is a network component comprising at least one processor configured to implement a method comprising creating a periodic time window, partitioning the time window into low-priority time-bands and high-priority time-bands, placing a plurality of high-priority packets in the high priority time-bands, and placing a plurality of low-priority packets in the low-priority time-bands.

Claims

1. A network component comprising:

at least one processor coupled to a memory and configured to;

create a periodic time window;

partition the time window into low-priority time-bands and high-priority time-bands;

place a plurality of high-priority packets in the high-priority time-bands; and

place a plurality of low-priority packets in the low-priority time-bands.

2. The network component of claim 1, wherein the high-priority packets and the low-priority packets are not truncated.

3. The network component of claim 1, wherein the high-priority packets overrun and/or underrun the high-priority time-bands, and wherein the low-priority packets overrun and/or underrun the low-priority time-bands.

4. The network component of claim 3, wherein the processor is further configured to:

track the overrun, underrun, or both of the high-priority packets, low-priority packets, or both; and

reduce the overrun or underrun by replacing one of the low-priority packets with a high-priority packet.

5. The network component of claim 3, wherein the processor is further configured to:

track the overrun, underrun, or both of the high-priority packets, low-priority packets, or both; and

reduce the overrun or underrun by replacing one of the high-priority packets with a low-priority packet when the overrun or underrun reaches a predetermined threshold.

6. The network component of claim 1, wherein the high-priority packets belong to a plurality of high-priority flows, and wherein there is at least one high-priority time-band for each high-priority flow.

7. The network component of claim 1, wherein the processor is further configured to:

fill some of the high-priority time-bands with low-priority packets when there are not any high-priority packets to place in the high-priority time-bands.

8. The network component of claim 1, wherein the processor is further configured to:

fill some of the high-priority time-bands with low-priority packets when there are not any high-priority packets to place in the high-priority time-bands, and fill some of the low-priority time-bands with high-priority packets when there are not any low-priority packets to place in the low-priority time-bands.

9. The network component of claim 1, wherein the processor is further configured to truncate one of the high-priority packets, one of the low-priority packets, or both.

10. The network component of claim 9, wherein the processor is further configured to delineate the start of the high-priority packets with a control symbol.

11. The network component of claim 9, wherein the processor is further configured to delineate the start of the high-priority packets with a control symbol, and delineate the start of the low-priority packets with another control symbol.

12. The network component of claim 9, wherein the processor is further configured to:

place the remainder of the truncated high-priority packet into a subsequent high-priority time-band.

13. The network component of claim 9, wherein the processor is further configured to:

place the remainder of the truncated high-priority packet into a subsequent high-priority time-band, and place the remainder of the truncated low-priority packet into a subsequent low-priority time-band.

14. The network component of claim 9, wherein the processor is further configured to encapsulate the high-priority packets.

15. The network component of claim 14, wherein the low-priority packets contend with the high-priority packets prior to encapsulation but not after encapsulation.

16. The network component of claim 9, wherein the processor is further configured to encapsulate the high-priority packets and the low-priority packets.

17. The network component of claim 16, wherein the low-priority packets contend with the high-priority packets prior to encapsulation but not after encapsulation.

18. The network component of claim 1, wherein all of the high-priority packets are contained within the high-priority time-bands, and wherein all of the low-priority packets are contained within the low-priority time-bands.

19. A method comprising:

creating a periodic time window;

partitioning the time window into low-priority time-bands and high-priority time-bands;

placing a plurality of high-priority packets in the high-priority time-bands; and

placing a plurality of low-priority packets in the low-priority time-bands.

20. The method claim 19 further comprising:

truncating one of the high-priority packets, one of the low-priority packets, or both;

delineating the start of the high-priority packets with a control symbol, delineating the start of the low-priority packets with another control symbol, or both;

placing the remainder of the truncated high-priority packet into a subsequent high-priority time-band, placing the remainder of the truncated low-priority packet into a subsequent low-priority time-band, or both; and

encapsulating the high-priority packets, the low-priority packets, or both,

wherein the low-priority packets contend with the high-priority packets prior to encapsulation but not after encapsulation.