That's not true. It is in vsu configuration mode.

Abnormal ports are used together with dual-machine detection.

The exception port is generally the connection port on the switch, which is used to avoid the situation that all interfaces are down during the dual-machine detection, resulting in the unavailability of remote devices.

The following are the contents of the official document:

Why should I configure dual host detection?

1. When all physical links of the VSL are abnormally disconnected, the slave chassis will switch to the master chassis when it is considered that the master chassis is lost, and two master chassis will appear in the network with the same configuration. At the third layer, any virtual interface (VLAN interface and loopback interface, etc.). ) will have the same configuration, and IP address conflicts will occur in the network, resulting in network unavailability.

2. After configuring the dual-host detection mechanism, the BFD dedicated link will detect the existence of dual-host chassis according to the sending and receiving of dual-host messages, and the system will select a chassis (low-priority chassis) to enter the recovery mode according to the dual-host detection rules. All ports will be forcibly closed except the VSL port, MGMT port and the exception port designated by the administrator (Telnet can be used when other ports of the equipment are closed).

Therefore, dual-host detection can prevent the network from still being available when the above abnormal faults occur (provided that other devices are connected to dual cores with redundant link conditions).

VSU configuration:

Ruijie (Configuration) # Interface gi2/4/2

Ruijie (config-if-gigabit Ethernet 2/4/2) # noswitch port->; Configure detection interface 2 as a routing port.

Ruijie (Configuration -if)# Exit

Ruijie (configuration) # interface gi 1/4/2

Ruijie (config-if-gigabit Ethernet1/4/2) # noswitch port->; Configure the detection interface 1 as a routing port.

Ruijie (Configuration -if)# Exit

Ruijie (Configuration) # Switch Virtual Domain1->; Enter the VSU parameter configuration.

Ruijie (config-vs-domain)# double activity detection bfd->; Turn on the BFD switch and turn it off by default.

Ruijie (config-vs-domain)# active bfd interface GI1/4/2->; Configure a pair of BFD detection interfaces.

Ruijie (configuration opposite domain) # Dual-active bfd interface gi2/4/2

Ruijie (config-vs-domain)# active/passive exclusion interface ten11/2-> specifies the exception port, reserves the upstream routing port, and telnet when there are two hosts.

Ruijie (config-vs-domain)# dual-active exclusion interface TEN2/1/2->; Specify exception port