功能：查看以太网接口的信息
实例：
chj#show inter fa0/0
FastEthernet0/0 is up, line protocol is up
Hardware is DEC21140, address is ca02.0b34.0000 (bia ca02.0b34.0000) #接口当前的MAC地址，BIA指烧入的地址
Description: xian jing #配置的接口描述
Internet address is 10.1.1.1/24 #配置的接口地址和掩码
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 100Mb/s, 100BaseTX/FX #接口是半双的，100Mb的带宽，介质类型是100Mbit/s基带快速双绞线以太网/多模光纤以太网
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:41, output 00:00:05, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo #在以太网接口上，默认的队列类型是先进先出
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
