华为路由器：ppp协议
PPP(Point-to-Point Protocol)，链路层协议。PPP是为了在点对点物理链路(例如RS232串口链路、电话ISDN线路等)上传输OSI模型中的网络层报文而设计的，它改进了之前的一个点对点协议-SLIP协议–只能同时运行一个网络协议、无容错控制、无授权等许多缺陷，PPP是现在最流行的点对点链路控制协议。这种连接提供了同时的双向的全双工操作，并且假定数据包是按顺序投递的。PPP连接提供了一种广泛的解决办法，方便地将多种多样不同的值作为最大接收单元的值。
帧格式与HDLC相似，不同的是PPP是面向字符，HDLC是面向位的。PPP属于广域网范畴，MAC是局域网范畴，按实际情况和环境就选用不同的协议，PPP支持的网络结构只能是点对点，MAC支持多点对多点。 这类广域网协议，其帧的结构与以太网的完全不同，当然，PPPOE除外，因为PPPOE是基于以太网上的，而其它的如PPP，FR，X.25等却并不是。 PPP协议是目前广域网上应用最广泛的协议之一，它的优点在于简单、具备用户验证能力、可以解决IP分配等。
实验拓扑
R1
The device is running!
<Huawei>
<Huawei>sys
Enter system view, return user view with Ctrl+Z.
[Huawei]
[Huawei]sys R1
[R1]int g0/0/0
[R1-GigabitEthernet0/0/0]ip address 192.168.1.254 24
[R1-GigabitEthernet0/0/0]int s2/0/0
[R1-Serial2/0/0]ip address 10.0.0.1 8
[R1-Serial2/0/0]q
[R1]aaa #启用aaa配置管理
[R1-aaa]local-user pokes password cipher 123456 #在数据库中创建1个以pokes为用户名，密码为ppp的本地账户
[R1-aaa]local-user pokes service-type ppp
[R1-aaa]q
[R1]int s2/0/0
[R1-Serial2/0/0]ppp authentication-mode pap #在主认证端上指明ppp的认证方式pap
[R1-Serial2/0/0]q
[R1]ip route-static 0.0.0.0 0.0.0.0 10.0.0.2
[R1]
R2
The device is running!
<Huawei>sys
Enter system view, return user view with Ctrl+Z.
[Huawei]sys R2
[R2]int g0/0/0
[R2-GigabitEthernet0/0/0]ip add 192.168.2.254 24
[R2-GigabitEthernet0/0/0]
[R2-GigabitEthernet0/0/0]int s2/0/0
[R2-Serial2/0/0]ip add 10.0.0.2 8
[R2-Serial2/0/0]
[R2-Serial2/0/0]ppp pap local-user pokes password cipher 123456 #使用pap认证方式，用户名为pokes,密码为123456（与主认证端一致）
[R2-Serial2/0/0]q
[R2]ip route-static 0.0.0.0 0.0.0.0 10.0.0.1
[R2]
查看ppp链路状态
[R2]display interface s2/0/0
Serial2/0/0 current state : UP
Line protocol current state : UP
Last line protocol up time : 2020-10-21 12:25:12 UTC-08:00
Description:HUAWEI, AR Series, Serial2/0/0 Interface
Route Port,The Maximum Transmit Unit is 1500, Hold timer is 10(sec)
Internet Address is 10.0.0.2/8
Link layer protocol is PPP
LCP opened, IPCP opened #这里LCP子层和IPCP子层都open，ppp链路正常建立了
Last physical up time : 2020-10-21 12:13:33 UTC-08:00
Last physical down time : 2020-10-21 12:13:27 UTC-08:00
Current system time: 2020-10-21 12:46:19-08:00
Physical layer is synchronous, Virtualbaudrate is 64000 bps
Interface is DTE, Cable type is V11, Clock mode is TC
Last 300 seconds input rate 6 bytes/sec 48 bits/sec 0 packets/sec
Last 300 seconds output rate 2 bytes/sec 16 bits/sec 0 packets/sec
Input: 427 packets, 13992 bytes
Broadcast: 0, Multicast: 0
Errors: 0, Runts: 0
Giants: 0, CRC: 0
Alignments: 0, Overruns: 0
Dribbles: 0, Aborts: 0
No Buffers: 0, Frame Error: 0
---- More ----
查看端口
[R2]display ip interface brief
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 3
The number of interface that is DOWN in Physical is 2
The number of interface that is UP in Protocol is 3
The number of interface that is DOWN in Protocol is 2
Interface IP Address/Mask Physical Protocol
GigabitEthernet0/0/0 192.168.2.254/24 up up
GigabitEthernet0/0/1 unassigned down down
NULL0 unassigned up up(s)
Serial2/0/0 10.0.0.2/8 up up #被认证端的接口自动获取到了ip地址
Serial2/0/1 unassigned down down
验证结果
PC1 ping PC2
Welcome to use PC Simulator!
PC>ping 192.168.2.1
Ping 192.168.2.1: 32 data bytes, Press Ctrl_C to break
Request timeout!
From 192.168.2.1: bytes=32 seq=2 ttl=126 time=15 ms
From 192.168.2.1: bytes=32 seq=3 ttl=126 time=32 ms
From 192.168.2.1: bytes=32 seq=4 ttl=126 time=15 ms
From 192.168.2.1: bytes=32 seq=5 ttl=126 time=31 ms
--- 192.168.2.1 ping statistics ---
5 packet(s) transmitted
4 packet(s) received
20.00% packet loss
round-trip min/avg/max = 0/23/32 ms
PC>