Managing OmniSwitch 6850/6850E Series Stacks
Roles Within the Stack
OmniSwitch 6850/6850E Series Hardware Users Guide
June 2011
page 6-9
Using Saved Slot Information
The saved slot number is the slot number the switch will assume following a reboot. This information is
stored in a switch’s
boot.slot.cfg
file; the switch reads its slot number assignment from this file at bootup
and assumes the specified slot number within the stack.
If switches in a stacked configuration have no preconfigured slot assignments, the slot number for each
switch is dynamically assigned by the system software. Slot numbers can also be manually assigned by the
user. For more information on manually assigning slot numbers, refer to
“Manual Slot Number Assign-
ment” on page 6-25
.
When a stack with preconfigured slot information is booted, it is
not
the lowest MAC address that deter-
mines the primary management module. Instead, the slot information stored in each switch’s
boot.slot.cfg
is read by the system software and used in determining the primary. The switch with the lowest saved slot
number becomes the primary management module.
Note.
Although, for ease-of-management purposes, it is recommended that slot numbers are assigned
beginning with slot number 1, it is not a requirement. In other words, a stack of four switches can have
slot assignments 3, 4, 5, and 6. However, it is important that each element in a stack is assigned a
unique
slot number. Do not assign duplicate slot numbers to elements in a stack. Otherwise, one or more switches
will be forced into pass-through mode. For more information on pass-through mode, refer to
page 6-14
.
For more information on using saved slot information to determine the primary switch in a stack, refer to
the diagram below:
Primary Management Module Selection Using Saved Slot Information
Slot 6
Slot 5
Slot 4
Primary: Slot 3
Assumes Slot 6
Assumes Slot 5
Assumes Slot 4
Assumes Slot 3
Saved Slot 6
Four switches are stacked; all switches are connected via stack-
ing cables. The user configures each switch to have a unique
saved slot number. When each saved slot number is configured,
the information is automatically
written to the
boot.slot.cfg
file located in the /flash directory of
each switch.
The user reloads all the elements in the stack either by
issuing the
reload all
command or by physically powering
off and then powering on all switches.
Instead of assigning the primary management module
based on the lowest MAC address, the system software
reads the slot information from each switch’s
boot.slot.cfg
file during the boot process. The switches
in the stack come up using their assigned slot numbers.
The switch with the lowest assigned slot number automatically
assumes the primary management role. In this case, the switch
assigned slot 3 has the lowest slot number in the stack and
becomes the primary management module.
1
2
3
4
Saved Slot 5
Saved Slot 4
Saved Slot 3
Reload
