Methodology and apparatus for solving lockup conditions while trunking in fibre channel switched arbitrated loop systems

• US 7,403,481 B1
• Filed: 01/30/2004
• Issued: 07/22/2008
• Est. Priority Date: 01/30/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Emulex Design & Manufacturing Corp. (Broadcom, Inc.)
• Inventors: Goodwin, William P.
• Primary Examiner(s): To; Doris
• Assistant Examiner(s): Moore; Ian N
• Application Number:
  US10/769,580
• Time in Patent Office: 1,635 Days
• Field of Search: 370229-236, 370400-406, 370411-420, 370/389, 370/392, 370532-542, 370459-463, 710/200, 710/316, 707/1, 709/201, 709/235, 709/238, 711/152, 711/147, 711/163
• US Class Current: 370/235
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Abstract

Lockup conditions are solved while trunking in Fibre Channel switched arbitrated loop systems. Within a particular switch, a particular combination of pending OPN conditions is detected, indicating a lockup condition. At least one of the detected pending OPN conditions is closed, which alleviates the lockup condition.

Claims

1. In a switched arbitrated loop system with multiple trunks including strings, configured for communication using the Fibre Channel protocol, a method to address lockup conditions, comprising:

a) with respect to a particular switch in the system, detecting a particular combination of a plurality of pending open conditions on the multiple trunks indicating a lockup condition, wherein step a) further comprises;

a1) detecting that, with respect to the particular switch, there is a pending open at a first port on at least one particular one of the strings and a connection on one of a first and second port for at least another of the strings; and

a2) detecting at least one port not detected in a1) having a destination that is a connection on at least one string detected in a1) wherein the pending open on the port detected in a2) has a close counter at maximum value; and

b) based on the detection, closing at least one of the plurality of pending open conditions, thereby alleviating the lockup condition.

2. The method of claim 1, wherein:

step a) further includes detecting, for particular ones of the multiple trunks on which there is a connection, a lack of data communication on those trunks.

3. The method of claim 2, wherein:

detecting a lack of data communication on a particular trunk includes detecting that a particular type of signal has not been detected on that particular trunk for a predetermined period of time.

4. The method of claim 3, wherein:

the particular type of signal includes a Receiver Ready primitive and a Start of Frame delimiter.

5. The method of claim 2, wherein:

with respect to the particular switch, the trunks are configured into groups of multiple trunks; and

the particular condition includes, for each of the groups of multiple trunks, at least one of the trunks being characterized by a pending open condition and at least one other of the trunks being characterized by a lack of data communication thereon.