Storage area network port based data transfer acceleration

• US 7,890,655 B2
• Filed: 02/16/2006
• Issued: 02/15/2011
• Est. Priority Date: 02/16/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Chandrasekaran, Varagur
• Primary Examiner(s): BATES, KEVIN T
• Application Number:
  US11/356,881
• Publication Number:
  US 20070192433A1
• Time in Patent Office: 1,825 Days
• Field of Search: 709/238, 709/242, 709/237, 711/155, 711/156
• US Class Current: 709/238
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

According to the present invention, methods and apparatus are provided for improving data transfers between hosts and targets connected through fiber channel switches. A host connected intelligent port and a target connected intelligent port associated with fiber channel edge switches are configured to snoop frames from the host and target and establish flows for acceleration. The host connected intelligent port and the target connect intelligent port preemptively respond to host and target transmissions to reduce data transfer latency.

Claims

1. A storage area network device, comprising:

a host intelligent port connected to a host configured to snoop a command frame from the host, the host intelligent port configured to determine flow information and support data transfer acceleration; and

one or more processors configured to identify a flow between the host and a target based on the snooped command frame and determine that the target is associated with a target intelligent port that supports data transfer acceleration and has acceleration enabled, the target intelligent port associated with another storage area network device and the target intelligent port connected to the target;

wherein the storage area network device is configured to enable acceleration between the host and the target by preemptively responding to the host with a transfer ready message when the host sends a data transfer request to the target.

2. The storage area network device of claim 1, wherein the host intelligent port responds to the host as a proxy for the target.

3. The storage area network device of claim 1, wherein the target is associated with the target intelligent port.

4. The storage area network device of claim 3, wherein the target intelligent port responds to the target as a proxy for the host.

5. The storage area network device of claim 1, wherein the host intelligent port forwards the data transfer request to the target intelligent port upon preemptively responding to the host.

6. The storage area network device of claim 5, wherein the host intelligent port preemptively responds to the host if the host intelligent port locates sufficient buffer space to receive data frames associated with the data transfer request.

7. The storage area network device of claim 6, wherein the host intelligent port and the target intelligent port manage buffer space for data transfers.

8. The storage area network device of claim 1, wherein acceleration is enabled by entering the host and target pair into a forwarding lookup table.

9. The storage area network device of claim 8, wherein the forwarding lookup table is a ternary content addressable memory (TCAM) table.

10. The storage area network device of claim 9, wherein the TCAM table includes multiple fields with wildcard entries to trap frames going through the intelligent port.

11. A method for accelerating storage area network data transfers, the method comprising:

at a host intelligent port associated with a storage area network edge switch, the host intelligent port connected to a host, snooping a command frame from the host, wherein the host intelligent port is configured to determine flow information and support data transfer acceleration;

identifying a flow between the host and a target based on the snooped command frame;

determining at the storage area network edge switch that the target is associated with a target intelligent port that supports data transfer acceleration and has acceleration enabled, the target intelligent port associated with another storage area network edge switch and the target intelligent port connected to the target; and

enabling at the storage area network edge switch accelerated data transfer between the host and the target by preemptively responding to the host with a transfer ready message when the host sends a data transfer request to the target.

12. The method of claim 11, wherein the host intelligent port responds to the host as a proxy for the target.

13. The method of claim 11, wherein the target is associated with the target intelligent port and wherein after the target intelligent port detects the command frame coming from the host, the target intelligent port determines the location and type of the host intelligent port and determines whether the host intelligent port is configured to determine flow information and support accelerated data transfer.

14. The method of claim 13, wherein the target intelligent port responds to the target as a proxy for the host and wherein if the target intelligent port does not have acceleration enabled, the host intelligent port attempts to enable acceleration at the target intelligent port.

15. The method of claim 11, wherein the host intelligent port forwards the data transfer request to the target intelligent port upon preemptively responding to the host.

16. The method of claim 15, wherein the host intelligent port preemptively responds to the host if the host intelligent port locates sufficient buffer space to receive data frames associated with the data transfer request.

17. The method of claim 16, wherein the host intelligent port and the target intelligent port manage buffer space for data transfers.

18. The method of claim 11, wherein acceleration is enabled by entering the host and target pair into a forwarding lookup table.

19. The method of claim 18, wherein the forwarding lookup table is a ternary content addressable memory (TCAM) table.

20. The method of claim 19, wherein the TCAM table includes multiple fields with wildcard entries to trap frames going through the intelligent port.

21. A system for accelerating storage area network data transfers, the system comprising:

means for snooping a command frame from a host at a host intelligent port associated with a storage area network edge switch, the host intelligent port connected to the host, and the host intelligent port configured to determine flow information and support data transfer acceleration;

means for identifying a flow between the host and a target based on the snooped command frame;

means for determining at the storage area network edge switch that the target is associated with a target intelligent port that supports data transfer acceleration and has acceleration enabled, the target intelligent port associated with another storage area network edge switch and the target intelligent port connected to the target; and

means for enabling at the storage area network edge switch accelerated data transfer between the host and the target by preemptively responding to the host with a transfer ready message when the host sends a data transfer request to the target.