一、HDLC

HDLC是CISCO路由器使用的缺省协议，一台新路由器在未指定封装协议时默认使用HDLC封装。

1. 有关命令

端口设置

注:1.以下给出一个显示Cisco同步串口状态的例子.

Router#show interface serial 0

Serial 0 is up, line protocol is up

Hardware is MCI Serial

Internet address is 150.136.190.203, subnet mask is 255.255.255.0

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255

Encapsulation HDLC, loopback not set, keepalive set (10 sec)

Last input 0:00:07, output 0:00:00, output hang never

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

Five minute input rate 0 bits/sec, 0 packets/sec

Five minute output rate 0 bits/sec, 0 packets/sec

16263 packets input, 1347238 bytes, 0 no buffer

Received 13983 broadcasts, 0 runts, 0 giants

2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort

22146 packets output, 2383680 bytes, 0 underruns

0 output errors, 0 collisions, 2 interface resets, 0 restarts

1 carrier transitions

2. 举例

设置如下：

Router1:

interface Serial0

ip address 192.200.10.1 255.255.255.0

clockrate 1000000

Router2:

interface Serial0

ip address 192.200.10.2 255.255.255.0

3. 举例使用E1线路实现多个64K专线连接.