Roles Within the Stack Managing OmniSwitch 6450 Stacks
page 7-14 OmniSwitch 6450 Hardware Users Guide September 2015
To avoid a pass-through condition following a reboot, make sure that all saved slot values for the stack are 
unique. Use the stack set slot command. For example, change the saved slot value for the idle switch in 
slot 3 from 2 to 3:
-> stack set slot 3 saved-slot 2
Use the show stack topology command to verify the change:
-> show stack topology
      Link A  Link A          Link B  Link B
NI      Role      State   Saved  Link A  Remote  Remote  Link B  Remote  Remote
                          Slot   State   NI      Port    State   NI      Port
----+-----------+--------+------+-------+-------+-------+-------+-------+-------
   1 PRIMARY     RUNNING    1    UP          3   StackA  UP          2   StackA
   2 SECONDARY   RUNNING    2    UP          1   StackB  UP          3   StackB
   3 IDLE  RUNNING    3    UP          1   StackA  UP  2   StackB
Recovering from Pass-Through Mode (Duplicate Slot Numbers) 
The first step in recovering from pass-through is to determine which modules are currently operating in 
pass-through, as well as the reason for the pass-through state. To view this information, use the 
show stack topology command. For example:
-> show stack topology
      Link A  Link A          Link B  Link B
NI      Role      State   Saved  Link A  Remote  Remote  Link B  Remote  Remote
                          Slot   State   NI      Port    State   NI      Port
----+-----------+--------+------+-------+-------+-------+-------+-------+-------
   1 PRIMARY     RUNNING    1    UP       1001   StackA  UP          2   StackA
   2 SECONDARY   RUNNING    2    UP          1   StackB  UP       1001   StackB
1001 PASS-THRU   DUP-SLOT   2    UP          1   StackA  UP          2   StackB
Switches operating in pass-through mode are given distinct slot numbers. These slot numbers are not 
related to their position in the stack. Instead, they are assigned the prefix “100,” followed by the numeri-
cal order in which they were forced into pass-through (1001–1008).
Note. For pass-through elements 1001 through 1008, the slot indicator LED on the chassis front panel 
blinks 1 through 8, respectively. For example, if a module enters pass-through and has the slot number 
1004, the LED for the module blinks the number 4. For more information on the slot indicator LED, refer 
to “OmniSwitch 6450 LED Status” on page 3-32.
In the example above, the switch with the NI (i.e., slot) number 1001 is operating in pass-through. Note 
that the role assignment is PASS-THRU; also, the state displays DUP-SLOT, or duplicate slot number. 
This can be further verified by looking down the saved slot column in the table. Note that slot 2, operating 
in the secondary management role, has a saved slot value of 2. Slot 1001, operating in pass-through, also 
has a saved slot value of 2.