7.1.1 Overview

The stack logically operates as a single unit by connecting multiple units. A function that manages multiple units as a single logical unit is called a stack function. The stack has the following features:

• Centralized management

  Multiple devices can operate as a single device.

• Redundancy

  Because it consists of multiple devices, it is possible to continue communication even with some failures.

• Extensibility

  You can increase the number of available ports by adding devices.

A stack is configured when a device running the stack function is connected via an Ethernet interface. The following figure shows a stack configuration example.

Figure 7-1: Example of stack configuration

Each unit in the stack is called a member switch, and the number used to identify the member switch is called the switch number. In addition, one of the member switches that comprise the stack is called the master switch and one is called the backup switch. The port that connects the member switches is called the stack port, and the line that connects two member switches with the stack port is called the stack link.

A stack can consist of up to two member switches. A maximum of two stacking ports can be configured for a member switch.

The master switch controls the member switches that make up the stack. The backup switch operates as a new master switch if the master switch fails.