帧中继基础知识

1、笔记

实验

配置需求：

R1与R2动态建立,R1与R3静态建立PVC

R1

system-view
[Huawei]sysname R1
[R1]interface Serial0/0/0
[R1-Serial0/0/0]link-protocol fr
Warning: The encapsulation protocol of the link will be changed. Continue? [Y/N]:y
[R1-Serial0/0/0]quit
[R1]interface Serial 0/0/0.1 p2p
[R1-Serial0/0/0.1]ip address 12.1.1.1 24
[R1-Serial0/0/0.1]fr dlci 102
[R1-fr-dlci-Serial0/0/0.1-102]quit
[R1-Serial0/0/0.1]quit
[R1]interface Serial 0/0/0.2p2m
[R1-Serial0/0/0.2]ip address 13.1.1.1 24
[R1-Serial0/0/0.2]fr map ip 13.1.1.3 103

R2

system-view
[Huawei]sysname R2
[R2]interface Serial 0/0/0
[R2-Serial0/0/0]link-protocol fr
Warning: The encapsulation protocol of the link will be changed. Continue? [Y/N]:y
[R2-Serial0/0/0]ip address 12.1.1.2 24
[R2-Serial0/0/0]fr dlci 201 #动态的建立PVC

[R2-fr-dlci-Serial0/0/0-201]quit

R3

system-view
[Huawei]sysname R3
[R3]interface Serial0/0/0
[R3-Serial0/0/0]link-protocol fr
Warning: The encapsulation protocol of the link will be changed. Continue? [Y/N]:y
[R3-Serial0/0/0]ip address 13.1.1.3 24
[R3-Serial0/0/0]fr map ip 13.1.1.1 301 #静态建立PVC

[R3-Serial0/0/0]undo fr inarp

[R1]display fr pvc-info
PVC statistics for interface Serial0/0/0 (DTE, physical UP)
  DLCI = 102, USAGE = LOCAL (00000010), Serial0/0/0.1
    create time = 2018/11/25 17:55:31, status = ACTIVE
    InARP = Enable
    in BECN = 0, in FECN = 0
    in packets = 14, in bytes = 942
    out packets = 20, out bytes = 1470
  DLCI = 103, USAGE = LOCAL (00000100), Serial0/0/0.2
    create time = 2018/11/25 17:53:44, status = ACTIVE
    InARP = Enable
    in BECN = 0, in FECN = 0
    in packets = 5, in bytes = 440
    out packets = 10, out bytes = 880
[R1]display fr map-info
Map Statistics for interface Serial0/0/0 (DTE)
  DLCI = 102, Point-to-Point DLCI, Serial0/0/0.1
    create time = 2018/11/25 17:55:31, status = ACTIVE
  DLCI = 103, IP 13.1.1.3, Serial0/0/0.2
    create time = 2018/11/25 17:56:50, status = ACTIVE
    encapsulation = ietf, vlink = 1

[R1]ping 12.1.1.2
  PING 12.1.1.2: 56  data bytes, press CTRL_C to break
    Reply from 12.1.1.2: bytes=56 Sequence=1 ttl=255 time=80 ms
    Reply from 12.1.1.2: bytes=56 Sequence=2 ttl=255 time=90 ms
    Reply from 12.1.1.2: bytes=56 Sequence=3 ttl=255 time=60 ms
    Reply from 12.1.1.2: bytes=56 Sequence=4 ttl=255 time=60 ms
    Reply from 12.1.1.2: bytes=56 Sequence=5 ttl=255 time=30 ms

  --- 12.1.1.2 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 30/64/90 ms

FR网络特点
1、分组交换网络一个帧一个帧传输
2、异步模式传输，有帧触发才传，统计复用

PVC永久虚链路：互联的DTE，提前建立好的DLCI，一个DLCI代表一个PVC（面向连接的）
SVC交换虚链路：
帧中继上的交换表：入接口DLCI，出接口DLCI数据链路标志符：表示一条虚链路
每条虚电路采用数据链路连接标识符DLCI来进行标识
DCE和DTE之间存在LMI本地管理接口：状态查询消息，状态应答消息，决定链路状态
DCE和DTE通过LMI学习DLCI
逆向地址解析协议IARP的主要功能是获取