Netgear M5300-28G-POE+ (GSM7228PSv1h2) - 12-Port Managed Gigabit Switch Softwarehandbuch

The stack master stores and maintains the saved and running configuration files for the 
switch stack. The configuration files include the system-level settings for the switch stack and 
the interface-level settings for all stack members. Each stack member retains a copy of the 
saved file for backup purposes. If the master is removed from the stack or becomes 
unavailable, another member is elected master and then runs from that saved configuration.

The switch master copies its running configuration to the stack member configured as the 
standby

 unit whenever it changes (subject to some restrictions to reduce overhead). This 

enables the standby unit to take over the stack operation with minimal interruption if the stack 
master becomes unavailable. The running-config synchronization also occurs when the 
running configuration is auto-saved on the stack master or when the standby unit changes.

All stack members are eligible stack masters. If the stack master becomes unavailable, the 

remaining stack members participate in electing a new stack master from among themselves. 
The following factors determine which switch is elected the stack master:

The switch that is master always has priority to retain the role of master.

Assigned priority.

MAC address.

When the stack is powered up and completes the boot process or the original stack master 
becomes unavailable, the stack master is determined through an election process. 

The rules for stack master election are as follows:

If a unit was elected stack master previously, then it remains the stack master and other 
units are stack members. 

If no units were stack masters, or more than one unit was a stack master, then the unit 
with the highest management preference is elected stack master. The management 
preference can be assigned by the administrator. However, if all units are assigned the 
same management preference, then the unit with the highest MAC address is assigned 
as the stack master.

If the stack master is reset to the factory default settings (see 

716), the stack master applies the default settings to all the stack 

members and resets the stack, including all participating stack members. When the stack 
boots, the stack master election process begins.

A switch can be described in terms of three semi-independent functions called the forwarding 

plane, the control plane, and the management plane. The forwarding plane forwards data 
packets. The forwarding plane is implemented in hardware. The control plane is the set of 
protocols that determine how the forwarding plane forwards packets, deciding which data 
packets are allowed to be forwarded and where they go. Application software on the