Master switch
The master switch manages the stack. A stack has only one master switch.
Standby switch
The standby switch is the backup of the master switch. A stack has only one standby switch. If the master switch becomes unavailable, the standby switch assumes the master role, and continues to the keep the stack operational.
Slave switch
A slave switch forwards service traffic. A stack may have multiple slave switches. A high number of slave switches can increase forwarding bandwidth in a stack.
Apart from the master and standby switches, all the other member switches are slave switches. If the standby switch becomes unavailable, a slave switch assumes the standby role.
The master switch, standby switch, and slave switches are responsible for forwarding service traffic.
Adding, removing, or replacing a stack member may change the stack member roles. For details about add and remove a stack member, see Adding and Removing a Stack Member. For details about replace a stack member, see Replacing a Stack Member.
A standalone device is a device stack with one stack member that also operates as the master switch. You can connect one standalone device to another to create a device stack containing two stack members, with one of them as the master switch. You can connect standalone devices to an existing device stack to increase the stack membership.