Interface commands allow-unsupported-transceiver default interface 描述 energy-efficient-ethernet 流-control interface 接口环回 interface vlan ip address ip mtu ip source-interface ipv6 address ipv6 source-interface l3-counters mtu routing show allow-unsupported-transceiver 显示界面 显示界面dom 显示界面energy-efficient ethernet 显示界面transceiver show ip interface show ip source-interface show ipv6 interface show ipv6 source-interface shutdown