Replacing Stack Units; Adding New Links Between Existing Stack Units - Arris Ruckus ICX 7850 Series Configuration Manual

Replacing stack units

Consider the following points when replacing stack members.
• To replace a unit with a clean unit containing the same modules, simply disconnect the old unit and replace it with a
clean unit using the same links. The new unit will be discovered in less than two minutes. No command is needed on the
active controller or the clean unit.
• A non-clean unit cannot be discovered by the unit replacement feature. It logs and prints a message when it receives
unit replacement probing packets. To convert a unit to a clean unit so it can be discovered by stack zero-touch
provisioning or stack interactive-setup, enter the erase startup-config command on the unit followed by the reload
command without entering the write memory command.
• Replacing a unit does not cause loops, even when STP is not configured. The reason is that replacing a unit uses the
same links that are already configured as stack-ports or stack-trunks.
• If the stack is a ring topology, replacing a unit does not break the stack. The stack becomes linear until the new unit joins
to form a ring. If the stack is a linear topology, only the edge unit can be replaced. Replacing a non-edge unit in a linear
stack causes other units behind it to become unreachable. The unit replacement could fail because the loss of multiple
units causes ambiguity.
• To replace multiple units at the same time, first replace all units and make all physical connections before entering the
stack interactive-setup command.

Adding new links between existing stack units

Adding new links between existing units causes loops if STP is not configured. Any link, excluding stacking ports, between two
units in the stack causes loops.
Use one of the following methods to add links successfully between existing stack units.
1. Configure STP and run the stack interactive-setup utility.
a. Configure spanning tree protocols (for example, STP, RSTP, MSTP, and PVST) on the active controller before making
connections. You can enable either global STP or STP only on the default VLAN. If there are already loops before STP
is configured and if the looping packets have higher priority than the STP BPDU packets, STP may not converge. In
this case, disable or disconnect the looping links to break loops and allow STP to converge. Then reenable or
reconnect the links. For example, suppose a link from data port 1/2/4 to 2/2/4 creates a loop. You can configure
disable under interface ethernet 1/2/4 to break the loop. Then configure enable after STP converges.
b. Make all new physical connections.
c. Wait for STP to converge before entering the stack interactive-setup command. When STP converges, it places
some looping ports in the BLOCKING state.
d. Run the stack interactive-setup utility. Either option 2 or 3 can discover new links within the stack and configure
proper stack-ports or stack-trunks. A linear stack may become a ring. The utility can discover multiple sets of links
between unit pairs. For example, it can convert a linear stack to a ring and discover the links among units in one
run.
e. Be sure to enter the write memory command if the system prompts you with a "write memory" message.
2. Use stack-port, stack-trunk, multi-stack-port, or multi-stack-trunk commands to create links.
a. This approach does not require configuring STP.
b. Configure the stack-port or stack-trunk command on both edge units to change a linear stack to a ring. Then add
new links to connect both edge units.
Ruckus FastIron Stacking Configuration Guide, 08.0.90
Part Number: 53-1005572-01
Changes to Stacking in FastIron Release 08.0.90
Stacking deployment guidelines
35