Communications system with first and second scan tables

• US 20060133406A1
• Filed: 12/22/2004
• Published: 06/22/2006
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Exar Corporation (Maxlinear Incorporated)
• Original Assignee: Exar Corporation (Maxlinear Incorporated)
• Inventors: Homer, Russell, Duong, Khai Hoan
• Granted Patent: US 7,590,130 B2
• Time in Patent Office: Days
• US Class Current: 370/442
• CPC Class Codes: H04J 3/08 Intermediate station arrangements, e.g. for branching, for tapping-off
• CPC Class Codes: H04L 12/433 with asynchronous transmission, e.g. token ring, register insertion
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/525 by redistribution of residual bandwidth

Abstract

A communications system comprising a first stage including a first scan table and a second stage including a second scan table. The first stage is configured to select a first channel identification from the first scan table and provide data from a channel identified by the first channel identification. The second stage is configured to receive the data and select a second channel identification from the second scan table to provide the received data at essentially a data rate of the channel on a synchronous network.

Claims

1. A communications system, comprising:

a first stage including a first scan table; and

a second stage including a second scan table, wherein the first stage is configured to select a first channel identification from the first scan table and provide data from a channel identified by the first channel identification, and the second stage is configured to receive the data and select a second channel identification from the second scan table to provide the received data at essentially a data rate of the channel on a synchronous network.

2. The communications system of claim 1, wherein the second stage includes a timer associated with the second scan table and configured to periodically initiate a channel identification selection from the second scan table in response to the expiration of a timed period.

3. The communications system of claim 1, wherein the second stage includes a scheduler configured to maintain a credit count that indicates available transmission time.

4. The communications system of claim 3, wherein the scheduler includes a service queue that indicates channels to be serviced and the scheduler is configured to service the channels to be serviced based on the available transmission time.

5. The communications system of claim 1, wherein the first stage is configured to select channel identifications that identify the channel to transmit the data from the channel at approximately the data rate of the channel on the synchronous network.

6. The communications system of claim 1, wherein the first stage includes a timer associated with the first scan table and configured to periodically initiate a channel identification selection from the first scan table in response to the expiration of a timed period.

7. The communications system of claim 1, wherein the second stage includes a third scan table, and the first stage and the second stage are configured to maintain synchronized channel selection between the first scan table and the third scan table.

8. The communications system of claim 1, wherein the second stage includes a third scan table and the second stage is configured to select a scan table entry that identifies the channel from the third scan table.

9. The communications system of claim 1, wherein the second stage includes a first-in-first-out memory configured to store data of the channel and the second stage is configured to store the received data into the first-in-first-out memory.

10. The communications system of claim 1, wherein the second stage is configured to transmit the data through a system packet interface to the synchronous network at essentially the data rate of the channel on the synchronous network.

11. The communications system of claim 1, wherein the synchronous network comprises:

a SONET/SDH ring network.

12. A communications system, comprising:

a first system including first scan tables that include first channel entries; and

a second system including second scan tables that include second channel entries, wherein the first system is configured to select the first channel entries from the first scan tables to provide channel data based on each of the selected first channel entries to the second system that is configured to receive the channel data and select the second channel entries from the second scan tables to provide the channel data on a synchronous network based on each of the selected second channel entries.

13. The communications system of claim 12, wherein the first channel entries identify channels and each of the identified channels has a corresponding channel data rate on a synchronous network and the first system is configured to provide channel data from each of the identified channels at the corresponding channel data rate.

14. The communications system of claim 12, wherein the second channel entries identify channels and each of the identified channels has a corresponding channel data rate on a synchronous network and the second system is configured to provide channel data from each of the identified channels at the corresponding channel data rate.

15. The communications system of claim 12, wherein the first system comprises timers and each of the timers is associated with one of the first scan tables and configured to periodically initiate a channel entry selection from the associated one of the first scan tables in response to the expiration of a timed period.

16. The communications system of claim 15, wherein each of the timers is configured to have a different timed period and to initiate the channel entry selection from the associated one of the first scan tables independently of the other timers.

17. The communications system of claim 12, wherein the second system comprises timers and each of the timers is associated with one of the second scan tables and configured to periodically initiate a channel entry selection from the associated one of the second scan tables in response to the expiration of a timed period.

18. The communications system of claim 17, wherein each of the timers is configured to have a different timed period and to initiate the channel entry selection from the associated one of the second scan tables independently of the other timers.

19. The communications system of claim 12, wherein the first channel entries in one of the first scan tables identify one channel multiple times.

20. The communications system of claim 12, wherein one of the first scan tables is configured to identify one channel and another one of the first scan tables is configured to identify the one channel.

21. The communications system of claim 12, wherein the second channel entries in one of the second scan tables identify one channel multiple times.

22. The communications system of claim 12, wherein one of the second scan tables is configured to identify one channel and another one of the second scan tables is configured to identify the one channel.

23. The communications system of claim 12, wherein the second system includes a scheduler configured to maintain a credit count that indicates available transmission time on the synchronous network.

24. The communications system of claim 23, wherein the scheduler includes a service queue that indicates channels to be serviced and the scheduler is configured to service the channels to be serviced based on the available transmission time.

25. A communications system, comprising:

means for scheduling a first channel selection from a first scan table;

means for providing data from a selected channel;

means for receiving the data;

means for scheduling a second channel selection from a second scan table; and

means for providing the received data at a data rate of the selected channel on a synchronous network based on the second channel selection.

26. The communications system of claim 25, wherein the means for scheduling a second channel selection comprises:

means for timing a timed period;

means for periodically initiating the second channel selection from the second scan table based on the periodic expiration of the timed period;

means for maintaining a credit count that indicates available transmission time; and

means for servicing channels that need to be serviced based on the available transmission time.

27. The communications system of claim 25, wherein the means for scheduling a first channel selection comprises:

means for scheduling the first channel selection to provide the data from the selected channel at the data rate of the selected channel on the synchronous network.

28. The communications system of claim 25, wherein the means for scheduling a first channel selection comprises:

means for timing a timed period; and

means for periodically initiating the first channel selection from the first scan table based on the periodic expiration of the timed period.

29. A method for maintaining bandwidth in a communications system, comprising:

scheduling a first channel selection from a first scan table;

providing data from a selected channel;

receiving the data;

scheduling a second channel selection from a second scan table; and

providing the received data at a data rate of the selected channel on a synchronous network based on the second channel selection.

30. The method of claim 29, wherein scheduling a second channel selection comprises:

timing a timed period; and

initiating the second channel selection from the second scan table based on the periodic expiration of the timed period.

31. The method of claim 29, wherein scheduling a second channel selection comprises:

maintaining a credit count that indicates available transmission time; and

servicing channels that need to be serviced based on the available transmission time.

32. The method of claim 29, wherein scheduling a first channel selection comprises:

scheduling the first channel selection to provide the data at the data rate of the selected channel on the synchronous network.

33. The method of claim 29, wherein scheduling a first channel selection comprises:

timing a timed period; and

initiating the first channel selection from the first scan table based on the periodic expiration of the timed period.