ALLEVIATING BLOCKING CASES IN A SAS SWITCH

• US 20100241779A1
• Filed: 06/01/2010
• Published: 09/23/2010
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: McCarty, Christopher, Johnson, Stephen B.
• Granted Patent: US 8,244,948 B2
• Time in Patent Office: Days
• US Class Current: 710/300
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence

Abstract

A first SAS expander including at least two phys is operably coupled to a first and a second SAS wide port. A second SAS expander including at least two phys is operably coupled to the first and the second SAS wide port. The first and the second SAS wide port each include at least two lanes, one of each at least two lanes designateable as a connection request lane. The connection request lane of each SAS wide port is operably coupled to a different SAS expander.

Claims

1. A Serial Attached Small Computer System Interface (SAS) switch including at least two SAS expanders, comprising:

a first SAS expander including at least two phys;

a second SAS expander including at least two phys;

a first SAS wide port including at least two lanes, one of the at least two lanes of the first SAS wide port designateable as a connection request lane; and

a second SAS wide port including at least two lanes, one of the at least two lanes of the second SAS wide port designateable as a connection request lane,

wherein the connection request lane of each SAS wide port is operably coupled to a different SAS expander of the at least two SAS expanders.

2. The SAS switch of claim 1, wherein each SAS wide port is operably coupled to each SAS expander of the at least two SAS expanders via at least one lane of the each SAS wide port.

3. The SAS switch of claim 1, wherein each lane of each SAS wide port is operably coupled to a phy of a SAS expander of the at least two SAS expanders.

4. The SAS switch of claim 1, wherein the connection request lane of each SAS wide port is designateable as a connection request lane via accepting a SAS connection request initiated external to the SAS switch.

5. The SAS switch of claim 1, wherein the connection request lane of each SAS wide port is designateable as a connection request lane via the SAS switch.

6. The SAS switch of claim 1, further comprising:

a third SAS expander including at least three phys; and

a third SAS wide port including at least three lanes, one of the at least two lanes of the third SAS wide port designated as a connection request lane,

wherein the first SAS expander further includes at least three phys,

wherein the second SAS expander further includes at least three phys,

wherein the first SAS wide port further includes at least three lanes, one of the at least three lanes of the first SAS wide port designateable as a connection request lane,

wherein the second SAS wide port further includes at least three lanes, one of the at least three lanes of the second SAS wide port designateable as a connection request lane,

wherein the connection request lane of each SAS wide port further includes being operably coupled to a different SAS expander of the at least three SAS expanders.

7. The SAS switch of claim 1, wherein the first SAS expander and the second SAS expander each run firmware to coordinate SAS switch operations.

8. The SAS switch of claim 1, wherein the first SAS expander is operably coupled to the second SAS expander for inter-expander communications.

9. A method for combining multiple Serial Attached Small Computer System Interface (SAS) expanders into a SAS switch, comprising:

grouping a first SAS expander including at least two phys with at least a second SAS expander including at least two phys into at least a first common wide port, wherein the first common wide port includes at least two lanes;

grouping the first SAS expander with at least the second SAS expander into at least a second common SAS wide port, wherein the second common wide port includes at least two lanes,

wherein one of the at least two lanes of the first SAS wide port is designateable as a connection request lane,

wherein one of the at least two lanes of the second SAS wide port is designateable as a connection request lane; and

operably coupling the connection request lane of each SAS wide port to a different expander.

10. The method of claim 9, further comprising:

operably coupling each SAS wide port to each SAS expander via at least one lane of the each SAS wide port.

11. The method of claim 9, wherein one of the at least two lanes of the first SAS wide port is designateable as a connection request lane via accepting a SAS connection request initiated external to the SAS switch;

and

wherein one of the at least two lanes of the second SAS wide port is designateable as a connection request lane via accepting a SAS connection request initiated external to the SAS switch.

12. The method of claim 9, wherein one of the at least two lanes of the first SAS wide port is designateable as a connection request lane via the SAS switch;

and

wherein one of the at least two lanes of the second SAS wide port is designateable as a connection request lane via the SAS switch.

13. The method of claim 9, further comprising:

wherein the grouping a first SAS expander including at least two phys with at least a second SAS expander including at least two phys into at least a first common wide port, wherein the first common wide port includes at least two lanes further includes

grouping a first SAS expander including at least three phys with at least a second SAS expander including at least three phys and with at least a third SAS expander including at least three phys into at least a first common wide port, wherein the first common wide port includes at least three lanes;

wherein the grouping the first SAS expander with at least the second SAS expander into at least a second common SAS wide port, wherein the second common wide port includes at least two lanes further includes

grouping the first SAS expander with at least the second SAS expander and with at least the third SAS expander into at least a second common SAS wide port, wherein the second common SAS wide port includes at least three lanes;

grouping the first SAS expander with at least the second SAS expander and with at least the third SAS expander into at least a third common SAS wide port, wherein the third common SAS wide port includes at least three lanes;

wherein one of the at least three lanes of the first SAS wide port is designateable as a connection request lane,

wherein one of the at least three lanes of the second SAS wide port is designateable as a connection request lane, and

wherein one of the at least three lanes of the third SAS wide port is designateable as a connection request lane.

14. The method of claim 9, wherein the first SAS expander and the second SAS expander each run firmware to coordinate SAS switch operations.

15. The method of claim 9, wherein the first SAS expander is operably coupled to the second SAS expander for inter-expander communications.

19. The method of claim 9, wherein one of the at least two lanes of the first SAS wide port is designateable as a connection request lane via the SAS switch;

and

wherein one of the at least two lanes of the second SAS wide port is designateable as a connection request lane via the SAS switch.

16. A system, comprising:

means for grouping a first SAS expander including at least two phys with at least a second SAS expander including at least two phys into at least a first common wide port, wherein the first common wide port includes at least two lanes;

means for grouping the first SAS expander with at least the second SAS expander into at least a second common SAS wide port,

wherein the second common wide port includes at least two lanes,

wherein one of the at least two lanes of the first SAS wide port is designateable as a connection request lane,

wherein one of the at least two lanes of the second SAS wide port is designateable as a connection request lane; and

means for operably coupling the connection request lane of each SAS wide port to a different expander.

17. The system of claim 16, further comprising:

means for operably coupling each SAS wide port to each SAS expander via at least one lane of the each SAS wide port.

18. The system of claim 16, wherein one of the at least two lanes of the first SAS wide port is designateable as a connection request lane via accepting a SAS connection request initiated external to the SAS switch;

and

wherein one of the at least two lanes of the second SAS wide port is designateable as a connection request lane via accepting a SAS connection request initiated external to the SAS switch.