| > 编者按：我们在这篇文章将通过一个例子对路由器网络接口进行全面的介绍和分析。 Router# show interface e0/0
Ethernet0/0 is up, line protocol is down
Hardware is AmdP2, address is 0009.4375.5e20 (bia 0009.4375.5e20)
Internet address is 192.168.1.53/24
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 172/255, txload 3/255, rxload 39/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:07, 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
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
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
50 packets output, 3270 bytes, 0 underruns
50 output errors, 0 collisions, 2 interface resets
0 babbles, 0 late collision, 0 deferred
50 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out (1) 接口和活动状态 在上面的显示中，内容表示硬件接口是活动的，而处理行协议的软件过程相信此接口可用。如果路由器操作员拆卸此硬件接口，第一个字段将显示信息is administratively down.如果路由器在活动间隔内收到5000个以上的错误，单词Disabled将出现在此字段中，以显示连路由器自动禁用此端口。行协议字段还显示以前提到的三个描述之一：up、down、administratively down.如果字段项是up,则表示处理行协议和软件过程相信此接口可用，因为她正在接收keepalives的目的也是如此，其他设备可以确定某个空闲连接是否仍然活动。对于以太网接口，Keepalives的默认值是10s。我们不久将注意到，Keepalives设置可以通过为特定接口使用show interfaces命令来获得。可以用keepalive interface 命令来改变keepalives设置。此命令的格式如下：Keepalive seconds |
