Alcatel-Lucent OmniSwitch 6450 - Page 91

Managing OmniSwitch 6450 Stacks Roles Within the Stack
OmniSwitch 6450 Hardware Users Guide July 2012 page 6-9
Using Switch Uptime
A user can override both the MAC address and saved slot methods for determining a stack’s primary
management module. This is done by controlling the uptime of switches in the stack. If all elements of a
stack are powered off, the user can force a particular switch to become primary by powering on that
switch and waiting a minimum of 15 seconds before powering on any other switches. This can be useful if
the user wants a switch placed in a specific location, e.g., the top-most switch in a stack, to become the
primary.
As with the lowest MAC address method, the primary management module is dynamically assigned slot
number 1 when the stack is booted.
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 Switch Uptime
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Four OmniSwitch 6450 switches are stacked and connected
via stacking cables. All switches are currently powered off.
The user powers on a single switch in the stack. In this case,
the bottom-most switch is powered on.
The user now powers on the remaining switches in the stack
in short succession.
In this example, when the remaining switches come online,
each has a lower saved slot value than the switch powered on
at step 1. However, the switch powered on at step 1—with its
slot value of 8—retains its
primary management role. The joining switches are essen-
tially ineligible for primary status because they are consid-
ered “late arrivals.”
For the primary switch to forfeit its role to the switch
1
2
3
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Primary
(Saved Slot 8)
Primary
(Saved Slot 8)
Saved Slot 3
Saved Slot 1
Saved Slot 2
Primary
(Saved Slot 8)
The user allows a minimum of 15 seconds to pass.
Because no other switches have joined the stack, the
switch that was powered on considers itself a stand-
alone. The switch assumes a primary role by default—
even if there is a high saved slot number in its
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