广域网的另一种技术:帧中继
一、点到点的配置
实验拓扑图:
封装为帧中继
RT1(S0/2/0)--------------------------------(S0/2/0)RT2
IP:192.168.1.1/24 IP:192.168.1.2/24
RT1:
interface s0/2/0
ip address 192.168.1.1 255.255.255.0
undo shutdown
link-protocol fr
fr interface-type dce (必须指明是DCE端)
fr dlci 100
fr inarp (可省略,默认IARP是开启的)
RT2:
interface s0/2/0
ip address 192.168.1.2 255.255.255.0
undo shutdown
link-protocol fr
fr interface-type dte(可省略,路由器默认就是DTE端)
fr inarp (可省略,默认IARP是开启的)
二、点到多点:
实验拓扑图:
(S0/2/2)----------(S0/2/1)RT2
| 12.12.12.2/24
RT1(S0/2/1)-------(S0/2/1)ATM交换机(RT10)
12.12.12.1/24 |
(S0/2/3)-----------(S0/2/1)RT3
12.12.12.3/24
注意事项:
1、其中的帧中继交换机是用路由器模拟出来的
2、帧中继是DCE设备,路由器是DTE设备
3、有两条虚链路:
RT1到RT2上的虚链路:
RT1------(DLCI=50)-------ATM-------(DLCI=60)-----RT2
RT1到RT3上的虚链路:
RT1-------(DLCI=70)------ATM-------(DLCI=80)-----RT3
4、关于水平分割
5、配置子接口
实验要求:
1、先做好帧中继的配置,让各个虚链路都能是active的状态
2、做好帧中继后,再来做路由(RIP2),关闭水平分割
3、配置子接口,启动水平分割,让各个网段都可以ping通
实验配置:
第一步:ATM基本配置
RT10:
[RT10]fr switching
[RT10]interface s0/2/1
[RT10-Serial0/2/1]link-protocol fr
[RT10-Serial0/2/1]fr interface-type dce
[RT10-Serial0/2/1]fr dlci-switch 50 interface s0/2/2 dlci 60
[RT10-Serial0/2/1]fr dlci-switch 70 interface s0/2/3 dlci 80
[RT10-Serial0/2/1]interface s0/2/2
[RT10-Serial0/2/2]link-protocol fr
[RT10-Serial0/2/2]fr interface-type dce
[RT10-Serial0/2/2]fr dlci-switch 60 interface s0/2/1 dlci 50
[RT10-Serial0/2/2]interface s0/2/3
[RT10-Serial0/2/3]link-protocol fr
[RT10-Serial0/2/3]fr interface-type dce
[RT10-Serial0/2/3]fr dlci-switch 80 interface s0/2/1 dlci 70
[RT10-Serial0/2/3]display fr dlci
[RT10-Serial0/2/3]display fr dlci-switch
Frame relay switch statistics
Status Interface(Dlci) <----------> Interface(Dlci)
Inactive Serial0/2/1(50) Serial0/2/2(60)
Inactive Serial0/2/1(70) Serial0/2/2(80)
Inactive Serial0/2/2(60) Serial0/2/1(50)
Inactive Serial0/2/3(80) Serial0/2/1(70)
RT1:
[R1]sysname RT1
[RT1]user-interface console 0
[RT1-ui-console0]idle
[RT1-ui-console0]idle-timeout 0
[RT1]interface s0/2/1
[RT1-Serial0/2/1]link-protocol fr
RT2:
System View: return to User View with Ctrl+Z.
[R2]sysname RT1
[RT2]user-interface console 0
[RT2-ui-console0]idle
[RT2-ui-console0]idle-timeout 0
[RT2]interface s0/2/1
[RT2-Serial0/2/1]link-protocol fr
RT3:
System View: return to User View with Ctrl+Z.
[R3]sysname RT1
[RT3]user-interface console 0
[RT3-ui-console0]idle
[RT3-ui-console0]idle-timeout 0
[RT3]interface s0/2/1
[RT3-Serial0/2/1]link-protocol fr
配置完成以后:(display fr dlci-switch)
RT10:
[RT10-Serial0/2/3]display fr dlci-switch
Frame relay switch statistics
Status Interface(Dlci) <----------> Interface(Dlci)
Active Serial0/2/1(50) Serial0/2/2(60)
Active Serial0/2/1(70) Serial0/2/3(80)
Active Serial0/2/2(60) Serial0/2/1(50)
Active Serial0/2/3(80) Serial0/2/1(70)
第二步:给各个物理接口配置好IP地址,用display fr map-info来查看协议地址与帧中继地址映射表,配置好以后路由器之间就可以ping通了
RT1:
interface loopback 1
ip address 171.16.1.1 255.255.255.0
interface loopback 2
ip address 171.16.2.1 255.255.255.0
interface loopback 3
ip address 171.16.3.1 255.255.255.0
[R1]interface s0/2/1
[R1-Serial0/2/1]ip address 12.12.12.1 255.255.255.0
[R1-Serial0/2/1]un shutdown
[R1-Serial0/2/1]display fr map-info
Map Statistics for interface Serial0/2/1 (DTE)
DLCI = 50, IP INARP 12.12.12.2, Serial0/2/1
create time = 2011/11/19 18:23:46, status = ACTIVE
encapsulation = ietf, vlink = 1, broadcast
DLCI = 70, IP INARP 12.12.12.3, Serial0/2/1
create time = 2011/11/19 18:24:31, status = ACTIVE
encapsulation = ietf, vlink = 2, broadcast
RT2:
interface loopback 1
ip address 172.16.1.1 255.255.255.0
interface loopback 2
ip address 172.16.2.1 255.255.255.0
interface loopback 3
ip address 172.16.3.1 255.255.255.0
[R2]interface s0/2/1
[R2-Serial0/2/1]ip address 12.12.12.1 255.255.255.0
[R2-Serial0/2/1]un shutdown
[R2-Serial0/2/1]display fr map-info
Map Statistics for interface Serial0/2/1 (DTE)
DLCI = 60, IP INARP 12.12.12.1, Serial0/2/1
create time = 2011/11/19 18:23:44, status = ACTIVE
encapsulation = ietf, vlink = 1, broadcast
RT3:
interface loopback 1
ip address 173.16.1.1 255.255.255.0
interface loopback 2
ip address 173.16.2.1 255.255.255.0
interface loopback 3
ip address 173.16.3.1 255.255.255.0
[R3]interface s0/2/1
[R3-Serial0/2/1]ip address 12.12.12.1 255.255.255.0
[R3-Serial0/2/1]un shutdown
[R3-Serial0/2/1]display fr map-info
Map Statistics for interface Serial0/2/1 (DTE)
DLCI = 80, IP INARP 12.12.12.1, Serial0/2/1
create time = 2011/11/19 18:24:29, status = ACTIVE
encapsulation = ietf, vlink = 1, broadcast
第三步:配置路由(RIP2)
RT1:
[RT1]rip
[RT1-rip-1]version 2
[RT1-rip-1]undo summary
[RT1-rip-1]network 171.16.0.0
[RT1-rip-1]network 12.0.0.0
RT2:
[R2]rip
[R2-rip-1]version 2
[R2-rip-1]un summary
[R2-rip-1]network 172.16.0.0
[R2-rip-1]network 12.0.0.0
RT3:
[R3]rip
[R3-rip-1]version 2
[R3-rip-1]un summary
[R3-rip-1]network 173.16.0.0
[R3-rip-1]network 12.0.0.0
问题:
配置完成以后用"display ip routing"查看各个路由器的路由表会发现:在RT1上可以看到所有的路由条目,但是在RT2上看不到RT3上路由条目,在RT3上看不到RT2的路由条目 !
原因:水平分割机制导致的
水平分割:从同一个接口学到的路由条目,不能再从同一个接口出去
解决办法:
从拓扑图中可以分析得出,只要在RT1上的S0/2/1接口上关闭水平分割,RT2与RT3就可以相互学到对方路由!
第四步:关闭水平分割
RT1:
[RT1]interface s0/2/1
[RT1-Serial0/2/1]un rip split-horizon
问题:
现在在RT2与RT3上"display ip routing "就可以看到全部的路由条目!但是还有一个问题:虽然现在RT2与RT3上面都有对方的路由条目,但是他们相互之间是ping不通的,只能ping通RT1(在RT1上可以ping通所有的网段)
解决办法:
配置子接口!!
第五步:配置子接口
实验拓扑图:
(S0/2/2)----------(S0/2/1)RT2
|
RT1(S0/2/1)-------(S0/2/1)ATM交换机(RT10)
|
(S0/2/3)-----------(S0/2/1)RT3
注意事项:
1、配置子接口的物理接口上不能配置IP地址
2、每个子接口,都是一个单独的网段!
RT1到RT2上的虚链路:
S0/2/1.1 1.1.1.0/24
RT1------(DLCI=50)-------ATM-------(DLCI=60)-----RT2
RT1到RT3上的虚链路:
S0/2/1.2
2.2.2.0/24
RT1-------(DLCI=70)------ATM-------(DLCI=80)-----RT3
3、现在要开启水平分割
实验配置:
RT1:
[RT1]interface s0/2/1
[RT1-Serial0/2/1]undo ip address
[RT1-Serial0/2/1]un shutdown
[RT1-Serial0/2/1]rip split-horizon
[RT1-Serial0/2/1]interface s0/2/1.1
[RT1-Serial0/2/1.1]ip address 1.1.1.1 255.255.255.0
[RT1-Serial0/2/1.1]fr dlci 50
[RT1]interface s0/2/1
[RT1-Serial0/2/1]interface s0/2/1.2
[RT1-Serial0/2/1.2]ip address 2.2.2.1 255.255.255.0
[RT1-Serial0/2/1.2]fr dlci 70
RT2:
[R2]interface s0/2/1
[R2-Serial0/2/1]undo ip address
[R2-Serial0/2/1]undo shutdown
[R2-Serial0/2/1]ip address 1.1.1.2 255.255.255.0
RT3:
[R3]interface s0/2/1
[R3-Serial0/2/1]undo ip address
[R3-Serial0/2/1]un shutdown
[R3-Serial0/2/1]ip address 2.2.2.2 255.255.255.0
配置路由:
RT1:
[RT1]rip
[RT1-rip-1]version 2
[RT1-rip-1]un summary
[RT1-rip-1]network 1.0.0.0
[RT1-rip-1]network 2.0.0.0
[RT1-rip-1]network 171.16.0.0
RT2:
[R2]rip
[RT1-rip-1]version 2
[RT1-rip-1]un summary
[R2-rip-1]network 1.0.0.0
[R2-rip-1]network 172.16.0.0
RT3:
[R3]rip
[RT1-rip-1]version 2
[RT1-rip-1]un summary
[R3-rip-1]network 2.0.0.0
[R3-rip-1]network 173.16.0.0
现在在每台路由器上用“display ip routing”查看路由表信息,可以看到所有的路由条目,相互之间也可以ping通