SMC Networks SMC8848M manual Stacking Topologies

CONNECTING SWITCHES IN A STACK

Stacking Topologies

All units in the stack must be connected via stacking cable. You can connect units in a simple cascade configuration, connecting Down ports to Up ports, from the top unit to the bottom unit. Using this “line” topology, if any link or unit in the stack fails, the stack is split and two separate segments are formed. The Stack Link LEDs on the units that are disconnected flash to indicate that the stack link between them is not functioning. (See Table 1-2 “System Status LEDs” on page 1-6.)

When using line topology and a stack link failure occurs, the stack reboots and a Master unit is selected within each of the two stack segments. The Master unit will be either the unit with the Master button depressed or the unit with the lowest MAC address if the Master button is not depressed on any unit. When the stack reboots and resumes operations, note that the IP address will be the same for both of the stack segments. To resolve the conflicting IP addresses, you should manually replace the failed link or unit as soon as possible. If you are using a wrap-around stack topology, a single point of failure in the stack will not cause the stack to fail. It would take two or more points of failure to break the stack apart.

If the Master unit fails or is powered off, the backup unit will take control of the stack without any loss of configuration settings. The Slave unit with the lowest MAC address is selected as the backup unit.

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