Config: ``` interface Vlan721 ip address 192.168.72.254 255.255.255.0 ``` `sh int Vlan721` 顯示 ``` Vlan721 is up, line protocol is down ``` 會看到雖然 `Vlan721` 是 up 但是 line protocol 是 down 所以無法 ping 這是因為 cisco vlan svi 需要綁到 interface 上 (access、trunk 皆可) line protocol 才會起來 Reference: - https://community.cisco.com/t5/switching/vlan-svi-line-protocol-is-down-why/td-p/4796758