Allied Telesis AT-8000GS/POE Stacking Members Unit ID Removing Replacing, Stacking Chain Topology

Stacking Chain Topology

Stacking

Members and

Unit ID

Removing and

Replacing

Stacking

Members

AT-8000GS Series Gigabit Ethernet Switch Installation Guide

automatically switches to a Stacking Failover topology without any system downtime. An SNMP message is automatically generated, but no stack management action is required. However, the stacking link or stacking member must be repaired to ensure the stacking integrity.

After the stacking issues are resolved, the device can be reconnected to the stack without interruption, and the Ring topology is restored.

In a chain topology, there are two units that have only one neighbor. Every unit has an uplink neighbor and a downlink neighbor. The chain topology is less robust than the ring topology. A failure in the chain results in a topology change to the stack. The location of the failure determines the severity of this topology change. The chain topology also acts as a fail- safe for the ring topology. When the ring topology fails, the stack automatically reverts to the chain topology.

Stacking Unit IDs are essential to the stacking configuration. The stacking operation is determined during the boot process. The Operation Mode is determined by the Unit ID selected during the initialization process. For example, if the user selected stand-alone mode, the device boots as a stand-alone device.

The device units are shipped with the default Unit ID of the stand-alone unit. If the device is operating as a stand-alone unit, all stacking LEDs are off. Once the user selects a different Unit ID, the default Unit ID is not erased, and remains valid, even if the unit is reset.

Unit ID 1 and Unit ID 2 are reserved for Master-enabled units. Unit IDs 3 to 6 can be defined for stack members.

When the Stacking Master unit boots, or when inserting or removing a stack member, the Stacking Master initiates a stacking discovering process.

If two members are discovered with the same Unit ID, the stack continues to function, however only the unit with the older join time joins the stack. A message is sent to the user, notifying that a unit failed to join the stack.

For first time Unit ID assignment, see the Installation Guide.

Stacking member 1 and stacking member 2 are Master-enabled units. Unit 1 and Unit 2 are either designated as Stacking Master or Secondary Master. The Stacking Master assignment is performed during the configuration process. One Master-enabled stack member is elected Stacking Master, and the other Master-enabled stack member is elected Secondary Master, according to the following decision process:

If only one Master-enabled unit is present, it is elected Stacking Master.

If two Master-enabled stacking members are present, and one has been

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