Support For Two-Unit Stack Linear-Topology Trunks; Building A Two-Unit Linear-Topology Trunk Manually - Arris Ruckus ICX 7850 Series Configuration Manual

Changes to Stacking in FastIron Release 08.0.90

Support for two-unit stack linear-topology trunks

c. To enlarge the connections between two units, configure the multi-stack-trunk command to change both ends of a
live link at the same time. Then connect the new links. The links won't cause loops because they have proper stack-
trunk configuration.
d. To reduce the live connections between two units, physically remove the unwanted cables first. Then configure the
multi-stack-port or multi-stack-trunk command to change both ends of the live link at the same time. For
example, suppose you have an ICX 7750 stack with a live link stack-trunk 1/2/1 to 1/2/3 connected to stack-trunk
2/2/4 to 2/2/6. After removing the unwanted cables between ports 1/2/3 to 2/2/6 and/or between ports 1/2/2 to
2/2/5, you can enter the command multi-stack-port 1/2/1 and 2/2/4 or the command multi-stack-trunk 1/2/1 to
1/2/2 and 2/2/4 to 2/2/5 to reduce the number of ports in the live link.
e. Changing stacking ports to data ports may cause loops. It is better to disconnect the unwanted cables before
reducing live connections as explained in the previous point. The other option is to reduce live connections and then
disable the data ports after reducing live connections using the disable port-number command in interface
configuration mode.
Support for two-unit stack linear-topology
trunks
FastIron 08.0.90 and later releases support a linear-topology trunk in a two-unit stack. A two-unit stack can form a linear-
topology trunk containing all stacking ports, instead of dividing the ports into the two directions of a ring topology. The linear-
topology trunk provides the same redundancy as a two-unit ring because of trunk load balancing. Furthermore, a linear-topology
trunk doubles the bandwidth of the stacking ports between two units.
In a two-unit ring topology, only one direction is used even though there are two paths for a unit to reach the other unit. In
contrast, a linear-topology trunk uses all ports to reach the other unit.
NOTE
In a ring of more than two units, all directions of any unit are fully utilized because each direction is to a different unit.
Therefore, the linear-topology trunk is not supported in a stack of more than two units.
NOTE
A linear-topology trunk cannot co-exist with another stack-port or stack-trunk in the same unit. Therefore, if you
configure a linear-topology trunk, the original stack-port or stack-trunk configuration is removed. If a unit has a linear-
topology trunk and you configure a stack-port or stack-trunk, the linear-topology trunk is removed.

Building a two-unit linear-topology trunk manually

The following procedure uses an ICX 7250 stack as an example. A two-unit ICX 7250 stack has two potential linear-topology
trunks, (x/2/1 to x/2/4) and (x/2/5 to x/2/8). The following figure shows the appropriate cabling for the four-port linear topology
trunk (x/2/1 to x/2/4) on an ICX 7250 two-unit stack configured in the following procedure.
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Ruckus FastIron Stacking Configuration Guide, 08.0.90
Part Number: 53-1005572-01