What are the rules for an S series switches to select and refresh router IDs

On an S series switches, the rules for selecting and refreshing router IDs are as follows:

If the router id command is executed, the configured router ID is used.
If the router id command is not executed and the loopback interfaces with IP addresses configured already exist, the switch selects the largest IP address from the loopback interface addresses as the router ID.
If the router id command is not executed and the loopback interfaces with IP addresses configured do not exist, the switch selects the largest IP address from the IP addresses of other interfaces as the router ID. In this case, the Up or Down state of interfaces is not considered.
The router ID is reelected only when the interface IP address that is elected as the router ID is deleted or modified.
Interface status changes do not result in reelection of the router ID.
If the IP address of a non-loopback interface is originally selected as the router ID and currently the IP address of a loopback interface is configured, the router ID will not be reelected.
If a larger interface IP address is set, the router ID will not reelected.
If the master and slave MPUs are installed on the switch, the system backs up the configured router ID and the router ID selected among interface IP addresses.
During system startup, when the protocol attempts to obtain the router ID, the RM may not obtain the information about all interface IP addresses. In this case, a smaller interface IP address may be selected as the router ID to return to the protocol. This is not considered as a problem.
When the router ID is changed, you need to manually reset the protocol to obtain a new router ID.
The router ID cannot be 0.0.0.0 or 255.255.255.255.

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