AB291A Fabric Clustering System Support Guide (12-port Switch), April 2004

Chapter 6
Monitoring and Troubleshooting
Monitoring and Troubleshooting the HP-UX Host
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Linkloop Command
Checking Connectivity Between Two Interfaces
Description: This command is used to check the connectivity from one IPoIB interface to another IPoIB
interface. Use the destination IPoIB interface’s MAC address when using this command.
Syntax: linkloop -i [ipoib_ppa][destination ipoib_MAC address]
Syntax Example: linkloop -i 9000 0x0000040cfe800000000000000002c90200001001
NOTE The following output is an example of a successful connection between two interfaces.
Output Example:
Link connectivity to LAN station: 0x0000040cfe800000000000000002c90200001001
-- OK
NOTE The following output is an example of an unsuccessful connection attempt between two
interfaces.
Output Example:
linkloop -i 9000 0x0000040cfe800000000000000002c90200012345
Link connectivity to LAN station: 0x0000040cfe800000000000000002c90200012345
error: get_msg2 getmsg failed, errno = 4
-- FAILED
frames sent : 1
frames received correctly : 0
reads that timed out : 1
Known Problems
This section describes known problems with IPoIB, including corresponding symptoms and workarounds.
NetTL
• Description: IPoIB PPA instance numbers start at 9000, but the current NetTL tool does not support
interfaces whose PPA instance numbers are greater than 255.
When running a trace on the system, the correct PPA number is provided, but when formatting trace
packets for a specific PPA (known as filtering), you need to make an adjustment in the request to obtain
the proper information.
Symptoms: Unless a specific PPA instance number is adjusted by subtracting 9000, the trace request
will not work as expected.
Workaround: When filtering on a particular IPoIB instance, like 9005, specify the instance number“5”
instead of the actual interface number.
Filter Example: In the example below, the filter configuration file may contain the following line to view
trace packet information only for IPoIB PPA 9005.
formatter filter device_id 5 IPOIB