what is the function of "show connectstates stationtype primaryserver" command

Prerequisites

The Redundancy Backup control item in the license is available on the standby node.

 NOTE:

Run the show license command to view license control items. If the Right value for Redundancy Backup is TRUE,the Redundancy Backup control item is available.

Normal Active and Standby Node

When both the primary and standby nodes run properly:

• Users at HQ and branches are registered on the primary node. The primary node synchronizes data to the standby and local nodes in real time.
• The primary node processes all the users' service requests from HQ and branches. The standby and local nodes reject users' service requests.
• The primary node, standby node, and local node send heartbeat messages to each other to ensure normal operation.
• The status of E1/T1 links is IDLE on the primary node and is FAULT on the standby node .

Primary Node Failure

When the primary node is faulty:

• The standby node disconnects from the primary node, processes all the service requests from HQ and branches, and does not synchronize data to the local node in real time.
• The standby and local nodes send heartbeat messages to each other to ensure normal operation.
• The status of E1/T1 links on the standby node is IDLE.

When the primary node is faulty, the standby node will take over the services from the primary node. The default response time for the standby node to take over the services is 120s. The response time can be changed by running the config modify station heart command on the primary node.

 NOTICE:

The two-mode cluster software License is valid for 30 days. If the primary node is faulty, repair or replace the primary node before the expiration date to prevent service interruption.

When the primary node is restored, the following situations may be involved due to the primary and standby node disconnection duration:

Situation 1: The disconnection duration does not exceed the automatic switchover time.

 NOTE:

To configure the automatic switchover time, run the config modify switch wait time <0–255> command on the standby node. The switchover time ranges from 0 to 255 minutes and is 5 minutes by default.

Under this situation, the services are automatically switched from the standby node to the primary node. After the switchover, the primary node starts to synchronize data to the standby and local nodes.

Situation 2: The disconnection duration exceeds the automatic switchover time.

Under this situation, the services can only be manually switched from the standby node to the primary node. After the switchover, the primary node starts to synchronize data to the standby and local nodes.

 NOTICE:

After the switchover, the data on the primary node overwrites the data on the standby node. To prevent loss of data that is newly generated on the standby node during the fault period, record the configuration operations performed on the standby node and perform such operations on the primary node after the primary node recovers.

Local Regeneration

When the primary and standby nodes are faulty or the HQ network is disconnected from the branch network, the local node at the branch processes local user requests to achieve local regeneration.