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