帧中继子接口配置

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帧中继子接口配置

帧中继子接口

帧中继有两种类型的接口：主接口和子接口。其中子接口是一个逻辑结构，可以配置协议地址和虚电路等，一个物理接口可以有多个子接口。虽然子接口是逻辑结构，并不实际存在，但对于网络层而言，子接口和主接口是没有区别的，都可以配置虚电路与远端设备相连。帧中继的子接口又可以分为两种类型：点到点（point-to-point)子接口和点到多点(point-to-multipoint)子接口。点到点子接口用于连接单个远端目标，点到多点子接口用于连接多个远端目标。点到多点子接口在一个子接口上配置多条虚电路，每条虚电路都和它相连的远端网络地址建立一个地址映射，这样不同的虚电路就可以到达不同的远端而不会混淆。

地址映射的建立可以用手工配置的方法，也可以利用逆向地址解析协议来动态建立。点到点子接口和多点子接口配置虚电路及地址映射的方法是不同的。

点到点子接口：对点到点子接口而言，因为只有唯一的一个对端地址，所以在给子接口配置一条PVC 时实际已经确定了对端地址，不能配置静态地址映射，也不能动态学习地址映射。

多点子接口：对点到多点子接口，对端地址与本地DLCI映射可以通过配置静态地址映射，或者通过逆向地址解析协议来确定（Inverse ARP在主接口上配置即可）。如果要建立静态地址映射，则应该对每一条虚电路建立静态地址映射关系。

拓扑图

设备参数：

设备	接口	IP地址	子网掩码	默认网关	DLCI
R1	S0/0/0			N/A	102
R1	S0/0/0.12	192.168.123.1	255.255.255.0	N/A	102
R2	S0/0/0.21	192.168.123.2	255.255.255.0	N/A	201

实验内容：

帧中继配置：

R1配置：

Router>enableRouter#conf tEnter configuration commands, one per line. End with CNTL/Z.Router(config)#hoRouter(config)#hostname R1R1(config)#intR1(config)#interface s0/0/0R1(config-if)#no ip addressR1(config-if)#encapsulation frame-relayR1(config-if)#no frame-relay inverse-arpR1(config-if)#no shutdown

R1(config-if)#

%LINK-5-CHANGED: Interface Serial0/0/0, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0, changed state to up

R1(config)#interface s0/0/0.12 point-to-point

R1(config)#interface s0/0/0.12 point-to-point

R1(config-subif)#

%LINK-5-CHANGED: Interface Serial0/0/0.12, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0.12, changed state to up

R1(config-subif)#ip address 192.168.123.1 255.255.255.0R1(config-subif)#frame-relay interface-dlci 102R1(config-subif)#end

R1(config-subif)#ip address 192.168.123.1 255.255.255.0

R1(config-subif)#frame-relay interface-dlci 102

R1(config-subif)#end

R1#

%SYS-5-CONFIG_I: Configured from console by console

R1#show frame-relay map

Serial0/0/0.12 (up): point-to-point dlci, dlci 102, broadcast, status defined, active

R1#ping 192.168.123.1

R1#ping 192.168.123.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.123.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/30/43 ms

R1#ping 192.168.123.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.123.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 2/18/29 ms

R1#

R2配置：

Router>enable

Router#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)#hostname R2

R2(config)#interface s0/0/0

R2(config-if)#no ip address

R2(config-if)#encapsulation frame-relay

R2(config-if)#no frame-relay inverse-arp

R2(config-if)#no shutdown

Router>enableRouter#conf tEnter configuration commands, one per line. End with CNTL/Z.Router(config)#hostname R2R2(config)#interface s0/0/0R2(config-if)#no ip addressR2(config-if)#encapsulation frame-relayR2(config-if)#no frame-relay inverse-arpR2(config-if)#no shutdown

R2(config-if)#

%LINK-5-CHANGED: Interface Serial0/0/0, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0, changed state to up

R2(config-if)#exit

R2(config)#interface s0/0/0.12 point-to-point

R2(config)#interface s0/0/0.12 point-to-point

R2(config-subif)#

%LINK-5-CHANGED: Interface Serial0/0/0.12, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0.12, changed state to up

R2(config-subif)#ip address 192.168.123.2 255.255.255.0R2(config-subif)#frame-relay interface-dlci 201R2(config-subif)#no shutdownR2(config-subif)#end

R2(config-subif)#ip address 192.168.123.2 255.255.255.0

R2(config-subif)#frame-relay interface-dlci 201

R2(config-subif)#no shutdown

R2(config-subif)#end

R2#

%SYS-5-CONFIG_I: Configured from console by console

R2#show fr

R2#show frame-relay m

R2#show frame-relay map

Serial0/0/0.12 (up): point-to-point dlci, dlci 201, broadcast, status defined, active

R2#ping 192.168.123.1

Type escape sequence to abort.