Managing OmniSwitch 6855 Series Stacks
Slot Numbering
OmniSwitch 6855 Series Hardware Users Guide
September 2011
page 7-21
Dynamic Slot Number Assignment
Dynamic slot number assignment occurs when there are no
boot.slot.cfg
files present in the switches’
/flash directories. This is the case for new, “out of the box,” switches that have not been previously
booted.
When a brand new stack (or stack with no
boot.slot.cfg
files) is booted, the system software automati-
cally detects the module with the lowest MAC address. This module is assigned the primary management
role (see
page 7-4
) and, by default, is given the slot number 1. The module connected to the primary’s
stacking port A is automatically assigned the secondary management role and given the slot number 2.
As the other modules in the stack become operational, they are assigned idle roles and are automatically
assigned unique slot numbers depending on the number of switches in the stack. The slot numbering for
idle modules is determined by each module’s physical location in the stack. Refer to the diagrams below
for more information on dynamic slot numbering.
Note.
As the slot numbers are dynamically assigned,
boot.slot.cfg
files are auto-generated in the /flash
directory of each switch. When modules are subsequently booted, each switch reads its slot number
assignment from this file and comes up accordingly. The diagram below is for example purposes only,
currently only four OS6855-U24X switches can be stacked at a time
Dynamic Slot Numbering Example 1
Slot 1 - Primary
Slot 2 - Secondary
Slot 3 - Idle
In this example, the fourth switch from the top is
elected the primary management module for the
stack. (It can be assumed that this switch has the
lowest MAC address in the stack.) This switch is
automatically assigned slot number 1.
The switch immediately below is connected to the
primary switch’s stacking port A and, as a result, is
assigned the secondary management role and given
slot number 2.
The system software allows the switch immediately
below slot 2 to have the next slot number preference.
It is assigned an idle role and given the slot number 3.
The switch immediately below slot 3 is given the slot
number 4, and so on. When the bottom of the stack is
reached, the slot numbering sequence resumes at the
top of the stack, as shown. This helps ensure a more
ordered and manageable stack topology.
Slot 4 - Idle
Slot 5 - Idle
Slot 6 - Idle
Slot 7 - Idle
Slot 8 - Idle
