Understanding The Stack Topology; Stacking Failover Topology; Stacking Members And Unit Id - Alcatel OS-LS-6224 User Manual

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Managing Stacking
Switch software is downloaded separately for each stack members. However, all
units in the stack must be running the same software version.
Switch stacking and configuration is maintained by the Stacking Master. The
Stacking Master detects and configures the ports with minimal operational impact in
the event of:
• Unit Failure
• Inter-unit Stacking Link Failure
• Unit Insertion
• Removal of a Stacking Unit
This section provides an introduction to the user interface, and includes the following
topics:

• Understanding the Stack Topology

• Stacking Failover Topology

• Stacking Members and Unit ID

• Removing and Replacing Stacking Members
• Exchanging Stacking Members
• Switching between the Stacking Master and the Secondary Master
Understanding the Stack Topology
The devices operate in a Ring topology. A stacked Ring topology is where all
devices in the stack are connected to each other forming a circle. Each device in the
stack accepts data and sends it to the device to which it is attached. The packet
continues through the stack until it reaches its destination. The system discovers the
optimal path on which to send traffic.
Most difficulties incurred in Ring topologies occur when a device in the ring becomes
non-functional, or a link is severed. In a stack, the system 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.
Stacking Failover Topology
If a failure occurs in the stacking topology, the stack reverts to Stacking Failover
Topology. In the Stacking Failover topology, devices operate in a chain formation.
The Stacking Master determines where the packets are sent. Each unit is connected
to two neighboring devices, except for the top and bottom units.
Stacking Members and Unit ID
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. Stacking LEDs are dual mode
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