What are the total roles of the switch after forming a VSU? What are the election rules?

Each device in the VSU is called a member device. Member devices are categorized into three roles according to their functions:

Active
: the main device, responsible for managing the whole VSU.

Standby
: A slave device that operates as a standby device for Active. When Active fails, Standby will automatically upgrade to Active to take over the work of the original Active.

Candidate
: Candidate device, running as a backup device for Standby. When Standby fails, the system will automatically elect a new Standby from Candidate to take over the work of the original Standby. In addition, when Active fails, while Standby is automatically upgraded to Active to take over the work of the original Active, the system will also automatically elect a new Standby from Candidate to take over the work of the original Standby.

The election rules are as followed:

The election rules for the Active role are as follows:-------------Match by serial number

1)The current host takes precedence.

2)Device with large priority takes precedence.

3)Smaller MAC addresses take precedence.

The election rules for the Standby role are as follows:------------Match by serial number

1)Closest to the host takes precedence.

2)The device with the highest priority takes precedence.

3)Smaller MAC addresses take precedence.

In the role election phase, all devices elect Active from the topology according to the election rules for the Active role; the device elected as Active elects Standby from the remaining devices. After the election is completed, the Active's device sends a Convergence message to the entire topology to notify all devices in the topology to work together for topology convergence, and then the VSU enters the management and maintenance phase