基于安全的考量,很多公司可能采用广域网的技术进行内网通信
局域网 | 广域网 |
网线 | 串行线 |
传输距离近 | 传输距离远 |
<100m | >1000m |
异步传输 | 同步传输 |
传输速度快 | 传输速度较慢 |
为了实现同步传输,需要由DCE提供一个时钟频率
① DTE:数据通信设备,一般在用户端
② DCE:数据通信设备,一般在运营商
PPP协议作广域网连接时被广泛使用
PPP(点到点协议)能够支持点到点认证功能,其认证的方式有PAP,CHAP
现实生活主要是PAP,只要认证一次,下次就可以直接使用,免去了带宽的占用,流量的浪费
PAP | CHAP |
二次握手 | 三次握手 |
明文密码 | 密文密码 |
由客户端发起请求 | 由服务器发起请求 |
以下是PAP的配置案例:
网络拓扑图:
PAP客户端:
R1#ping 10.10.10.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/40/84 ms
PAP服务器配置:
R2#en R2#conf t Enter configuration commands, one per line. End with CNTL/Z. R2(config)#us R2(config)#username oracle pass R2(config)#username oracle password oracle R2(config)#int s0/0 R2(config-if)#en R2(config-if)#encapsulation ppp R2(config-if)#ppp *Mar 1 00:04:14.835: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down R2(config-if)#ppp authen R2(config-if)#ppp authentication pap R2(config-if)#no sh R2(config-if)#end
PAP客户端配置:
R1#ping 10.10.10.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.2, timeout is 2 seconds: ... *Mar 1 00:04:43.303: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down.. Success rate is 0 percent (0/5)
PAP客户端未配置之前,无法ping通
R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int s0/0 R1(config-if)#enc R1(config-if)#encapsulation ppp R1(config-if)#ppp pap se R1(config-if)#ppp pap sent-username oracle pa R1(config-if)#ppp pap sent-username oracle password oracle R1(config-if)#no *Mar 1 00:07:20.415: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0 changed state to up R1(config-if)#no sh R1(config-if)#end R1#ping *Mar 1 00:07:29.311: %SYS-5-CONFIG_I: Configured from console by console R1#ping 10.10.10.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 20/64/132 ms