Systems and methods for performing a soft-block of a queue based on a size of a remaining period of a guard band

• US 9,960,872 B2
• Filed: 06/08/2015
• Issued: 05/01/2018
• Est. Priority Date: 03/08/2012
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Pannell, Donald
• Primary Examiner(s): Mesfin, Yemane
• Assistant Examiner(s): Davenport, Mon Cheri
• Application Number:
  US14/733,296
• Publication Number:
  US 20150365337A1
• Time in Patent Office: 1,058 Days
• 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: H04J 3/0697 Synchronisation in a packet node

Abstract

A network device including first and second queues, a determination module, a counter module, a comparison module and a blocking shaper. The determination module determines a size of the second frame. The counter module determines an amount of time remaining in a guard band and converts the amount of time to a size representative of the time remaining in the guard band. The guard band refers to a period of time leading up to a window. The first frame is scheduled to be forwarded from the first queue during the window. The comparison module compares the size of the second frame to the size representative of the time remaining in the guard band and generates a result based on the comparison. The blocking shaper, based on the result, determines whether to permit or block transmission of the second frame from the second queue during the guard band.

Claims

1. A network device comprising

a first queue configured to store a first frame;

a second queue configured to store a second frame;

a determination module configured to determine a size of the second frame;

a counter module configured to (i) determine an amount of time remaining in a guard band, and (ii) convert the amount of time to a size representative of the time remaining in the guard band, wherein the guard band refers to a period of time leading up to a window, and wherein the first frame is scheduled to be forwarded from the first queue during the window;

a comparison module configured to (i) compare the size of the second frame to the size representative of the time remaining in the guard band, and (ii) generate a result based on the comparison;

a first blocking shaper configured to, based on the result, determine whether to permit or block transmission of the second frame during the guard band;

a queue gating module configured to generate a first bit, wherein the first bit indicates a permitted transmission state of the second queue;

a first logic module configured to (i) compare the first bit to a second bit, and (ii) generate an output signal, wherein the second bit indicates that the frame is in the second queue; and

a second logic module configured to generate a pass signal based on (i) the output signal, and (ii) the result of the comparison, wherein the pass signal indicates whether transmission of the second frame is permitted during the guard band.

2. The network device of claim 1, wherein the first blocking shaper is configured to operate in a soft-block mode, which allows the second frame to egress the second queue as long as transmission of the second frame can finish prior to an end of the guard band.

3. The network device of claim 1, wherein the first blocking shaper permits transmission of the second frame during the guard band if the size of the second frame is less than or equal to the size representative of the time remaining in the guard band.

4. The network device of claim 1, further comprising a data pass module configured to (i) receive a descriptor, and (ii) generate a frame signal, wherein:

the second frame includes a header;

the descriptor is generated based on the header;

the descriptor indicates the size of the second frame;

the frame signal indicates presence of the second frame in the second queue; and

the second logic module is configured to generate the pass signal based on the frame signal.

5. The network device of claim 1, further comprising:

a selector module configured to generate a selection signal based on the pass signal; and

a multiplexer configured to select the frame based on the selection signal.

6. The network device of claim 1, further comprising a second blocking shaper, wherein:

the queue gating module is configured to (i) generate a first queue gating signal for the first queue, and (ii) a second queue gating signal for the second queue;

the second blocking shaper is configured to permit transmission of the first frame based on the first queue gating signal,

the second blocking shaper is configured to permit transmission of the second frame based on the second queue gating signal.

7. The network device of claim 6, wherein:

the first queue gating signal includes a third bit;

the third bit indicates during the window that transmission of the first frame is permitted;

the second queue gating signal includes a fourth bit; and

the fourth bit indicates (i) during the guard band, transmission of the second frame is permitted, and (ii) during the window, transmission of the second frame is not permitted.

8. The network device of claim 1, wherein an end time of the guard band is a same time as a start time of the window.

9. The network device of claim 1, wherein:

the size of the second frame is in bits or bytes; and

the size representative of the time remaining in the guard band is in bits or bytes.

10. The network device of claim 1, further comprising a timing module configured to generate a local clock signal based on a global clock signal,

wherein the counter module is configured to determine the amount of time remaining in the guard band based on the local clock signal.

11. The network device of claim 1, further comprising a third queue configured to store a third frame, wherein:

the determination module is configured to determine a size of the third frame;

the comparison module is configured to (i) compare the size of the third frame to the size representative of the time remaining in the guard band, and (ii) generate a result based on the comparison; and

the first blocking shaper is configured to, based on the result, determine whether to permit or block transmission of the third frame during the guard band.

12. The network device of claim 1, further comprising:

a third queue configured to store a third frame; and

a second blocking shaper,

wherein

the determination module is configured to determine a size of the third frame;

the comparison module is configured to (i) compare the size of the third frame to the size representative of the time remaining in the guard band, and (ii) generate a result based on the comparison; and

the second blocking shaper is configured to, based on the result, determine whether to permit or block transmission of the third frame during the guard band.

13. A method of operating a network device, wherein the network device comprises a first queue and a second queue, the method comprising:

storing a first frame in the first queue;

storing a second frame in the second queue;

determining a size of the second frame;

determining an amount of time remaining in a guard band;

converting the amount of time to a size representative of the time remaining in the guard band, wherein the guard band refers to a period of time leading up to a window, and wherein the first frame is scheduled to be forwarded from the first queue during the window;

comparing the size of the second frame to the size representative of the time remaining in the guard band;

generating a result based on the comparison;

based on the result, determining whether to permit or block transmission of the second frame during the guard band;

generating a first bit and a second bit, wherein the first bit indicates a permitted transmission state of the second queue, and wherein the second bit indicates that the frame is in the second queue;

comparing the first bit to the second bit;

generating an output signal; and

generating a pass signal based on (i) the output signal, and (ii) the result of the comparison, wherein the pass signal indicates whether transmission of the second frame is permitted during the guard band.

14. The method of claim 13, further comprising operating in a soft-block mode including allowing the second frame to egress the second queue as long as transmission of the second frame can finish prior to an end of the guard band.

15. The method of claim 13, further comprising permitting transmission of the second frame during the guard band if the size of the second frame is less than or equal to the size representative of the time remaining in the guard band.

16. The method of claim 13, further comprising:

generating a descriptor based on a header, wherein the second frame includes the header, and wherein the descriptor indicates the size of the second frame;

generating a frame signal, wherein the frame signal indicates presence of the second frame in the second queue; and

generating the pass signal based on the frame signal.

17. The method of claim 16, further comprising:

generating a selection signal based on the pass signal; and

selecting the frame based on the selection signal.

18. The method of claim 13, further comprising:

generating (i) a first queue gating signal for the first queue, and (ii) a second queue gating signal for the second queue;

permitting transmission of the first frame based on the first queue gating signal; and

permitting transmission of the second frame based on the second queue gating signal.

19. The method of claim 18, wherein:

the first queue gating signal includes a third bit;

the third bit indicates during the window that transmission of the first frame is permitted;

the second queue gating signal includes a fourth bit; and

the fourth bit indicates (i) during the guard band, transmission of the second frame is permitted, and (ii) during the window, transmission of the second frame is not permitted.

20. The method of claim 13, wherein an end time of the guard band is a same time as a start time of the window.

21. The method of claim 13, wherein:

the size of the second frame is in bits or bytes; and

the size representative of the time remaining in the guard band is in bits or bytes.

22. The method of claim 13, further comprising:

generating a local clock signal based on a global clock signal; and

determining the amount of time remaining in the guard band based on the local clock signal.