When I show a switch interface information, there are line protocol and Link:

Switch-A(config-if)# show interface gigabitethernet 0/3 

Gi0/3 up, line protocol is up (connected)
Bridge Port Type: Customer Bridge Port

Hardware Address is 0c:c4:7a:fd:ca:1e 
MTU  1500 bytes, Full duplex, 1 Gbps,  No-Negotiation
HOL Block Prevention enabled.
Input flow-control is off,output flow-control is off

Link Up/Down Trap is enabled 

I want to know what's them? I know one is administrator can shutdown and the other is physical connect.

2 Answers 2


For this particular interface, the line protocol is ethernet.

The Link Up/Down Trap is enabled message is telling you that the SNMP trap for when the link goes up or down, for whatever reason (admin up/down, cable inserted/disconnected, etc.), is enabled.

  • do you mean the admin up/down will cause the Link up/down?
    – 244boy
    Commented May 16, 2019 at 6:02
  • when I admin down it, there will Gi0/3 down.
    – 244boy
    Commented May 16, 2019 at 9:44

On Cisco equipment, the physical interface can have the following states:

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