Method and system for fibre channel arbitrated loop acceleration

• US 7,463,646 B2
• Filed: 07/12/2004
• Issued: 12/09/2008
• Est. Priority Date: 07/16/2003
• Status: Expired due to Fees

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: QLogic Corporation (Marvell Technology Group Limited)
• Inventors: Hareski, Patricia E, Fike, John M
• Primary Examiner(s): Nguyen; Brian D
• Application Number:
  US10/889,267
• Publication Number:
  US 20050013318A1
• Time in Patent Office: 1,611 Days
• Field of Search: 370/462, 370/252, 370/248, 370/241, 370/217, 370/218, 370/227, 370/461, 370/405, 370/406
• US Class Current: 370/462
• CPC Class Codes: H04L 49/602 Multilayer or multiprotocol switching, e.g. IP switching

Abstract

A fibre channel switch element with an acceleration device that connects plural fibre channel devices in an arbitrated loop and monitors frames sent during a loop initialization process is provided. The acceleration device creates an AL_PA table selected by each fibre channel device, wherein the AL_PA table is used for port selection; and during an arbitration process sends a benign primitive to non-arbitrating devices. The acceleration device includes, a global arbitration module, a state machine module, and a matrix for connecting plural fibre channel devices.

Claims

1. A fibre channel switch element, comprising:

an acceleration device that (a) connects a plurality of fibre channel devices in an arbitrated loop;

(b) monitors frames sent by of the plurality of fibre channel devices during a loop initialization process to determine an arbitrated loop physical address (AL_PA) value selected by each of the plurality of fibre channel devices;

(c) creates an AL_PA table based on the AL_PA values selected by each of the plurality of fibre channel devices, wherein the AL_PA table is stored in the acceleration device and the AL_PA table is used for port selection; and

(d) during an arbitration process only an arbitrating fibre channel device and a host port for the acceleration device are connected to the arbitrated loop and the acceleration device sends a benign primitive to non-arbitrating devices so that the non-arbitrating devices start the arbitration process when ports of the non-arbitrating devices are ready for arbitration;

a global arbitration module that validates arbitration requests received from the plurality of fibre channel devices by using the AL_PA table;

a controller module that operates in (i) a loop mode during which an isolated port receives data from an un-isolated port but data from the isolated port is not sent to the arbitrated loop;

(ii) a spray mode when there is no active traffic for the arbitrated loop and data is sent from the host port to other ports; and

(iii) a connection mode when there is traffic for the arbitrated loop and an isolated port receives a primitive but is unable to send frames to the arbitrated loop; and

a state machine that uses a state of the arbitrated loop for changing fibre channel switch element states, instead of using individual port states of the plurality of fibre channel device ports.

2. The switch element of claim 1, wherein during an open process, the acceleration device connects a source fibre channel device that wins arbitration to a destination device via the host port and an open primitive is sent directly from the source fibre channel device to the destination device and in response the destination device directly sends a response primitive (R_RDY) to the source fibre channel device.

3. The switch element of claim 2, wherein non-destination devices receive a benign primitive during the open process to maintain proper loop state machine state instead of receiving an open primitive from the source fibre channel device.

4. The switch element of claim 1, wherein during an open replicate process the acceleration device receives an open replicate primitive from a source fibre channel device and creates a spray pattern to send the open replicate primitive at the same time directly to all ports with which the source fibre channel device intends to communicate.

5. The switch element of claim 1, wherein the acceleration device after the loop initialization process and during data transfer mode reconfigures a data path to directly connect active ports.

6. The switch element of claim 1, wherein during a data transfer mode after the loop initialization primitive process the acceleration device monitors arbitration requests, open requests and close primitives to determine which ports have traffic for creating connection points for a data path.

7. An acceleration device of a fibre channel switch element for connecting a plurality of fibre channel devices in an arbitrated loop via a host port, comprising:

a global arbitration module that validates arbitration requests received from the plurality of fibre channel devices by using an arbitrated loop physical address (AL_PA) table populated with AL_PA values selected by the plurality of fibre channel devices and the AL_PA values are determined by the acceleration device during a loop initialization process when the acceleration device monitors frames that are sent by the plurality of fibre channel devices;

a state machine module that uses a state of the arbitrated loop for changing fibre channel switch element states, instead of using individual port states of the plurality of fibre channel device ports;

a switch matrix for connecting the plurality of fibre channel devices; and

a controller module that operates in (i) a loop mode during which an isolated port receives data from an un-isolated port but data from the isolated port is not sent to the arbitrated loop;

(ii) a spray mode when there is no active traffic for the arbitrated loop and data is sent from the host port to other ports; and

(iii) a connection mode when there is traffic for the arbitrated loop and an isolated port receives a primitive but is unable to send flames to the arbitrated loop;

wherein the AL_PA table is used for port selection; and

during an arbitration process only an arbitrating fibre channel device and the host port for the acceleration device are connected to the arbitrated loop and the acceleration device sends a benign primitive to non-arbitrating devices so that the non-arbitrating devices start the arbitration process when ports of the non-arbitrating devices are ready for arbitration.

8. The acceleration device of claim 7, wherein during an open process, the acceleration device connects a source fibre channel device that wins arbitration to a destination device via the host port and an open primitive is sent directly from the source fibre channel device to the destination device and in response, the destination device directly sends a response primitive (R_RDY) to the source fibre channel device.

9. The acceleration device of claim 8, wherein non-destination devices receive a benign primitive during the open process to maintain proper loop state machine state instead of receiving an open primitive from the source fibre channel device.

10. The acceleration device of claim 7, wherein during an open replicate process the acceleration device receives an open replicate primitive from a source fibre channel device and creates a spray pattern to send the open replicate primitive at the same time directly to all ports with which the source fibre channel device intends to communicate.

11. The acceleration device of claim 7, wherein during a data transfer mode after the loop initialization process the acceleration device monitors arbitration requests, open requests and close primitives to determine which ports have traffic for creating connection points for a data path.

12. A method for accelerating traffic in a fibre channel arbitrated loop topology where a fibre channel switch element with an acceleration device couples a plurality of fibre channel devices to the arbitrated loop via a host port, comprising:

monitoring fibre channel frames during a loop initialization process;

creating an arbitrated loop physical address (AL_PA) table based on AL_PA values selected by the plurality of fibre channel devices;

wherein the AL_PA table values are used by a global arbitration module for validating arbitration requests during an arbitration process when only an arbitrating fibre channel device and the host port for the acceleration device are connected to the arbitrated loop and the acceleration device sends a benign primitive to non-arbitration devices so that the non-arbitrating devices start the arbitration process when ports of the non-arbitrating devices are ready for arbitration;

using the AL_PA table for identifying ports;

connecting a source fibre channel device that sends an OPEN primitive to a destination port;

sending a benign primitive to a non-destination device connected to the arbitrated loop so that the non-destination device maintains a proper loop state machine state;

creating a spray pattern after receiving an open replicate primitive from a fibre channel device; and

sending frames directly to a plurality of destination ports at the same time.

13. The method of claim 12, wherein the acceleration device includes a state machine that uses a state of the arbitrated loop for changing fibre channel switch element states, instead of using individual port states of the plurality of fibre channel device ports.