Alcatel-Lucent 6850-48 Hardware Manual

Page of 188
Hot-Swapping Modules In a Stack
Managing OmniSwitch 6850 Series Stacks
page 4-24
OmniSwitch 6850 Series Hardware Users Guide
September 2009
Hot-Swapping Modules In a Stack
As with chassis-based switches, such as the OmniSwitch 9700/9800, NI modules within an OmniSwitch 
6850 Series virtual chassis are hot-swappable. NI modules are essentially those modules operating in the 
stack in idle mode. These modules can be removed from, or added to, an existing stack without disrupting 
other modules in the stack.
Removing Switches from an Existing Stack
When removing switches from an existing stack, observe the following important guidelines:
• Do not attempt to hot-swap modules operating in primary or secondary management roles
• Be sure the stacking cables and stacking cable redundancy are not disrupted
Hot-swapping is intended for switches in idle and, if applicable, pass-through status only. Removing 
primary or secondary management modules from a stack will trigger a failover sequence, i.e., one or more 
additional modules within the stack must reload in order to reassign the management roles. Whenever 
possible, avoid removing a switch that is operating as a primary or secondary management module.
Also, removing a switch from a stacked configuration can disrupt stack cabling at the rear of the stack. 
When removing a module, be sure that stacking link integrity, including important stacking cable redun-
dancy, is maintained between all remaining modules. For more information on stacking cable connec-
tions, refer to 
Inserting Switches Into an Existing Stack
When inserting switches into an existing stack, observe the following important guidelines:
• Avoid duplicate saved slot numbers
• Never attempt to operate more than eight switches in a single stack
• Make sure all switches are running the same software version.
Note. Other stackable Alcatel-Lucent products, such as the OmniSwitch 6600 Family switch, cannot be 
added to an OmniSwitch 6850 Series virtual chassis.
To avoid duplicate slot numbers, simply make sure that any modules being added to an existing stack have 
been cleared of preassigned slot information. In other words, verify that there is no boot.slot.cfg file 
present in the /flash directory of any switch being added. When the switch is connected to the existing 
stack and booted, the system software automatically assigns it a unique slot number. No duplicate slot 
errors occur. 
Note. If it is preferable to add a switch with an existing boot.slot.cfg file to a stack, be sure that the saved 
slot number of the incoming switch is not already assigned to a switch operating in the stack.