Closed-loop clock synchronization

• US 8,605,757 B2
• Filed: 07/23/2010
• Issued: 12/10/2013
• 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
• Primary Examiner(s): Nguyen, Steven H
• Assistant Examiner(s): NGUYEN, PHUONGCHAU BA
• Application Number:
  US12/842,794
• Publication Number:
  US 20100284421A1
• Time in Patent Office: 1,236 Days
• US Class Current: 370/535
• 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:

a processor configured to;

determine aperiodic transmission window to transmit data;

partition the periodic transmission window into a plurality of low-priority time-bands and a plurality of high-priority time-bands;

receive a plurality of high-priority packets and a plurality low-priority packets;

truncate at least one of the high-priority packets and one of the low-priority packets;

encapsulate the high-priority packets and the low-priority packets; and

an output device coupled to the processor, wherein the output device is configured to;

transmit a remainder of the truncated high-priority packet in a subsequent high-priority time-bands;

transmit a remainder of the truncated low-priority packet in a subsequent low-priority time-bands;

transmit the encapsulated high-priority packets during the high-priority time-bands; and

transmit the encapsulated low-priority packets during the low-priority time-bands,

wherein the high-priority time bands represent assigned time intervals within the periodic transmission window designated for the transmission of the encapsulated high-priority packets,

wherein at least some of the low-priority packets and some of the high-priority packets are received simultaneously, and

wherein the transmission for the encapsulated low-priority packets and the encapsulated high-priority packets do not overlap.

2. The network component of claim 1, wherein some of the high-priority packets and some of the low-priority packets are not truncated, and wherein the low-priority time bands represent assigned time intervals within the periodic transmission window designated for the transmission of the low-priority packets.

3. 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.

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

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

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

5. The network component of claim 1, 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.

6. The network component of claim 1, wherein the output device is further configured to transmit part of the truncated high-priority packet within a first high-priority time-band.

7. The network component of claim 6, wherein the remainder of the truncated high-priority packet is not transmitted within the first high-priority time-band.

8. The network component of claim 1, wherein an offset is used to align the high-priority time-bands with a second set of high-priority time-bands.

9. The network component of claim 8, wherein the second set of high-priority time-bands are used by a different source node to transmit a second set of high-priority packets, and wherein the high-priority time-bands and the second set of high-priority time-bands do not overlap within the periodic transmission window.

10. The network component of claim 1, wherein a first high-priority packet is assigned to a first high-priority time-band, wherein some of the first high-priority packet is transmitted within the first high-priority time-band, and wherein some of the first high-priority packet is transmitted within a first low-priority time-band immediately following the first high-priority time-band.

11. The network component of claim 1, wherein a first encapsulated low-priority packet is transmitted within a first high-priority time-band during encapsulation of a first high-priority packet that is assigned to the first high-priority time-band.

12. A method for coordinating the dispatch of data from one or more source nodes to a common destination node, wherein the method comprises:

establishing a periodic time window; and

receiving a first data stream that comprises a plurality of first high-priority packets and a plurality of first low-priority packets within the periodic time window,

wherein the first high-priority packets are received within a plurality of first high-priority time-bands for the first data stream,

wherein the first low-priority packets are received within a plurality of first low-priority time-bands for the first data stream,

wherein the first high-priority time-bands represent assigned time intervals within the periodic time window designated for the transmission of the first high-priority packets,

wherein the first low-priority time-bands represent assigned time intervals within the periodic time window designated for the transmission of the first low-priority packets,

wherein at least one of the high-priority packets and one of the low-priority packets are truncated within the data stream,

wherein a remainder of the truncated high-priority packet is placed in a subsequent first high-priority time-bands,

wherein a remainder of the truncated low-priority packet is placed in a subsequent first low-priority time-bands,

wherein the first high-priority packets and the first low-priority packets are encapsulated within the data stream,

wherein some of the first low-priority packets and some of the first high-priority packets are received simultaneously by one of the source nodes, and

wherein the first low-priority packets and the first high-priority packets do not overlap within the data stream.

13. The method of claim 12 further comprising receiving a second data stream that comprises a plurality of second high-priority packets and a plurality of second low-priority packets, wherein the second high-priority packets are received within a plurality of second high-priority time-bands for the second data stream, wherein the second high-priority time-bands represent assigned time intervals within the periodic time window designated for the transmission of the second high-priority packets, and wherein the first high-priority time-bands and the second high-priority time-bands do not overlap.

14. The method of claim 13 further comprising receiving a second data stream that comprises a plurality of second high-priority packets and a plurality of second low-priority packets, wherein the second low-priority packets are received within a plurality of second low-priority time-bands for the second data stream, wherein the second low-priority time-bands represent assigned time intervals within the periodic time window designated for the transmission of the second low-priority packets, and wherein the first low-priority time-bands and the second low-priority time-bands overlap.

15. The method of claim 14, wherein the first low-priority packets and first high priority packets are encapsulated using an Open Systems Interconnection (OSI) layer 2 header, wherein a first encapsulated low-priority packet comprises a portion of the truncated low-priority packet, and wherein a second encapsulated low-priority packet comprises a remaining portion of the truncated low-priority packet.

16. The method of claim 12 further comprising:

delineating the start of the first high-priority packet with a start special character; and

delineating the start of the first low-priority packet with a second start special character.