Troubleshooting the stack – Allied Telesis AT-SBx81CFC960 User Manual
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Chapter 15: Building a Stack
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Section III: Building a Stack with VCStack Plus
Troubleshooting the Stack
The best way to determine if the switches are operating as a stack is with
the SHOW STACK command, as explained in “Verifying the Stack” on
page 307. If the command indicates that the switches are not operating as
a stack, you may be able to identify and resolve the problem with the
suggestions in this section.
The first thing to check is the stacking trunk that links the switches
together. Here are some things to check:
Verify that the SFP+ slots on the controller cards contain only
stacking transceivers. You may not use standard SFP+
transceivers to build the trunk.
Verify that the stacking transceivers are firmly inserted into the
SFP+ slots and that the fiber optic cables are properly secured to
the transceivers.
Inspect the L/A LEDS for the slots. They should be solid or flashing
green.
Verify that there are no network devices, such as media converters
or other switches, between the stacking transceivers in the
switches.
Verify that you are using the correct type of fiber optic cable and
are not exceeding the maximum operating distance of the
transceivers. For more information, refer to “Stack Trunk and
Stacking Transceivers” on page 271 and “Fiber Optic
Specifications of the AT-StackOP/0.3 and AT-StackOP/9.0
Transceivers” on page 321.
Refer to “Fiber Optic or Twisted Pair Transceivers” on page 223 for
additional troubleshooting suggestions for the stacking transceivers.
If the trunk is operating correctly, the switches may have a configuration
problem that is preventing them from forming the stack. You may be able
to identify the problem with the following suggestions. It is important to
remember that at this point the switches, having been unsuccessful at
forming the stack, are operating as stand-alone units, which means that
you have to manage them with separate local management sessions.
Use the SHOW SYSTEM command in the Privileged Exec mode of
the command line interface to confirm that the switches have the
same version of the AlliedWare Plus management software. If they
have different versions, refer to the Software Reference for
SwitchBlade x8100 Series Switches for instructions on how to
upgrade the software.
Use the SHOW LICENSE BRIEF command in the Privileged Exec
mode to confirm that you installed the VCStack Plus licenses and