Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay
 

　　Packet Tracer 5.0是一款非常不错的Cisco(思科)网络设备模拟器，对于想考思科初级认证（如CCNA）的朋友们来说，Packet Tracer 5.0是非常不错的选择。通常我们周围并没有那么多思科的设备供我们学习调试，参加培训费用很贵，上机实践的机会还是有限的，利用Packet Tracer 5.0练习思科IOS操作命令很不错的。近日，在网上下载了思科CCNA640-802指导用书，打算根据此教程与诸位网友共同分享Packet Tracer 5.0的使用方法与技巧，也借此抛砖引玉。
　　帧中继是一种用于连接计算机系统的面向分组的通信方法。它主要用在公共或专用网上的局域网互联以及广域网连接。大多数公共电信局都提供帧中继服务，把它作为建立高性能的虚拟广域连接的一种途径。帧中继是进入带宽范围从56Kbps到1．544Mbps的广域分组交换网的用户接口。帧中继是从综合业务数字网中发展起来的，并在1984年推荐为国际电话电报咨询委员会（CCITT）的一项标准，另外，由美国国家标准协会授权的美国TIS标准委员会也对帧中继做了一些初步工作。
　　数据链路连接标识符（DLCI） 这个信息包含标识号，它标识多路复用到通道的逻辑连结。帧中继交换机将两端的DLCI关联起来，它是帧中继帧格式中地字段的一个重要部分之一，这是个6位标识，表示正在进行的客户和服务器之间的连接，用于RFCOMM 层。 帧中继使用DLCI来标识DTE和服务商交换机之间的虚电路。DLCI字段的长度一般为10bit，但也可扩展为16bit，前者用二字节地址字段，后者是三字节地址字段。23bit用四字节地址字段。DLCI值用于标识永久虚电路（PVC），呼叫控制或管理信息。DLCI只具有本地意义。
　　一、使用Packet Tracer 5.0构建帧中继仿真
　　添加三个2811路由器和一个云
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay
图一
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay

图二　给2811添加一个具有串口的模块
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay

图三
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay

图四　把路由器2811的串口与云的串口相连，路由器的串口为DTE
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay

图五　实验拓扑图及IP地址、DLCI分配
　　二、配置Frame Relay
以Router2为例，其它两个路由器相似，＼＼后是人为添加的注释，在实际配置时不存在
Router>en　　　＼＼进入特权配置模式
Router#conf t　　＼＼进入全局配置模式
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#no ip domain-lookup　＼＼取消名称解析
Router(config)#hostname Router2　　＼＼配置路由器的名字
Router2(config)#int fa0/1　　　　　　＼＼进入接口配置模式
Router2(config-if)#ip address 172.18.1.1 255.255.255.0　　＼＼配置ip地址
Router2(config-if)#no shut　　＼＼**端口
%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
Router2(config-if)#int serial0/3/0
Router2(config-if)#encapsulation frame-relay　　＼＼对串口serial0/3/0进行frame-relay封装
Router2(config-if)#no shut
%LINK-5-CHANGED: Interface Serial0/3/0, changed state to up
Router2(config-if)#
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3/0, changed state to up
Router2(config-if)#interface serial0/3/0.1 point-to-point　　＼＼进入串口的子接口配置模式
%LINK-5-CHANGED: Interface Serial0/3/0.1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3/0.1, changed state to upRouter2
(config-subif)#ip address 192.168.1.1 255.255.255.0   ＼＼为子接口配置IP地址
Router2(config-subif)#description Link Router1 DLCI 30　　＼＼为子接口添加描述
Router2(config-subif)#frame-relay interface-dlci 40　　　　　＼＼配置DLCI
Router2(config-subif)#interface serial0/3/0.2 point-to-point
%LINK-5-CHANGED: Interface Serial0/3/0.2, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3/0.2, changed state to upRouter2
(config-subif)#ip address 192.168.3.1 255.255.255.0
Router2(config-subif)#description link to Router0 DLCI20
Router2(config-subif)#frame-relay interface-dlci 41
Router2(config-subif)#end
%SYS-5-CONFIG_I: Configured from console by console
Router2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router2(config)#router eigrp 100　　　　　　＼＼在路由器上启用EIGRP路由协议
Router2(config-router)#network 172.18.0.0　　＼＼通告与自己直接想连的网段
Router2(config-router)#network 192.168.3.0
Router2(config-router)#network 192.168.1.0
Router2(config-router)#
%SYS-5-CONFIG_I: Configured from console by console
Router2#copy running-config startup-config　　＼＼保存配置
Destination filename [startup-config]?
Building configuration...
[OK]
Router2#
路由器Router0的配置：
Router0#sh running-config
Building configuration...
Current configuration : 830 bytes
!
version 12.4
no service password-encryption
!
hostname Router0
!
!
!
!
!
ip ssh version 1
no ip domain-lookup
!
!
interface FastEthernet0/0
no ip address
duplex auto
speed auto
shutdown
!
interface FastEthernet0/1
ip address 172.16.1.1 255.255.255.0
duplex auto
speed auto
!
interface Serial0/3/0
no ip address
encapsulation frame-relay
!
interface Serial0/3/0.1 point-to-point
description Link to Router 2
ip address 192.168.3.2 255.255.255.0
frame-relay interface-dlci 20
!
interface Serial0/3/0.2 point-to-point
description Link to Router1
ip address 192.168.2.2 255.255.255.0
frame-relay interface-dlci 21
!
interface Vlan1
no ip address
shutdown
!
router eigrp 100
network 172.16.0.0
network 192.168.3.0
network 192.168.2.0
auto-summary
!
ip classless
!
!
!
!
!
line con 0
line vty 0 4
login
!
!
end
路由器Router1的配置
Router1#sh running-config
Building configuration...
Current configuration : 843 bytes
!
version 12.4
no service password-encryption
!
hostname Router1
!
!
!
!
!
ip ssh version 1
no ip domain-lookup
!
!
interface FastEthernet0/0
no ip address
duplex auto
speed auto
shutdown
!
interface FastEthernet0/1
ip address 172.17.1.1 255.255.255.0
duplex auto
speed auto
!
interface Serial0/3/0
no ip address
encapsulation frame-relay
!
interface Serial0/3/0.1 point-to-point
description link to Router2 DLCI40
ip address 192.168.1.2 255.255.255.0
frame-relay interface-dlci 30
!
interface Serial0/3/0.2 point-to-point
description link to router0 DLCI21
ip address 192.168.2.1 255.255.255.0
frame-relay interface-dlci 31
!
interface Vlan1
no ip address
shutdown
!
router eigrp 100
network 192.168.1.0
network 192.168.2.0
network 172.17.0.0
auto-summary
!
ip classless
!
!
!
!
!
line con 0
line vty 0 4
login
!
!
end
路由器Router2的配置
Router2#sh running-config
Building configuration...
Current configuration : 841 bytes
!
version 12.4
no service password-encryption
!
hostname Router2
!
!
!
!
!
ip ssh version 1
no ip domain-lookup
!
!
interface FastEthernet0/0
no ip address
duplex auto
speed auto
shutdown
!
interface FastEthernet0/1
ip address 172.18.1.1 255.255.255.0
duplex auto
speed auto
!
interface Serial0/3/0
no ip address
encapsulation frame-relay
!
interface Serial0/3/0.1 point-to-point
description Link Router1 DLCI 30
ip address 192.168.1.1 255.255.255.0
frame-relay interface-dlci 40
!
interface Serial0/3/0.2 point-to-point
description link to Router0 DLCI20
ip address 192.168.3.1 255.255.255.0
frame-relay interface-dlci 41
!
interface Vlan1
no ip address
shutdown
!
router eigrp 100
network 172.18.0.0
network 192.168.3.0
network 192.168.1.0
auto-summary
!
ip classless
!
!
!
!
!
line con 0
line vty 0 4
login
!
!
end
路由器配置完毕后，还需要配置Cloud0。
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay
图六　根据路由器的相关配置，给Cloud0的serial0配置DLCI及LMI类型
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay

图七　根据路由器的相关配置，给Cloud0的serial1配置DLCI及LMI类型
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay

图八　根据路由器的相关配置，给Cloud0的serial2配置DLCI及LMI类型
Packet Tracer 5.0建构CCNA实验攻略(13)——帧中继Frame Relay

图九　根据路由器的相关配置，配置Cloud0的Frame Relay
　　三、配置各个计算机，并使用ping命令校验网络的连通性
pc0
PC>ipconfig
IP Address......................: 172.16.1.2
Subnet Mask.....................: 255.255.255.0
Default Gateway.................: 172.16.1.1
PC>ping 192.168.1.1
Pinging 192.168.1.1 with 32 bytes of data:
Reply from 192.168.1.1: bytes=32 time=141ms TTL=254
Reply from 192.168.1.1: bytes=32 time=110ms TTL=254
Reply from 192.168.1.1: bytes=32 time=143ms TTL=254
Reply from 192.168.1.1: bytes=32 time=110ms TTL=254
Ping statistics for 192.168.1.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 110ms, Maximum = 143ms, Average = 126ms
PC>ping 192.168.2.2
Pinging 192.168.2.2 with 32 bytes of data:
Reply from 192.168.2.2: bytes=32 time=62ms TTL=255
Reply from 192.168.2.2: bytes=32 time=62ms TTL=255
Reply from 192.168.2.2: bytes=32 time=47ms TTL=255
Reply from 192.168.2.2: bytes=32 time=63ms TTL=255
Ping statistics for 192.168.2.2:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 47ms, Maximum = 63ms, Average = 58ms
PC>ping 192.168.3.1
Pinging 192.168.3.1 with 32 bytes of data:
Reply from 192.168.3.1: bytes=32 time=109ms TTL=254
Reply from 192.168.3.1: bytes=32 time=125ms TTL=254
Reply from 192.168.3.1: bytes=32 time=93ms TTL=254
Reply from 192.168.3.1: bytes=32 time=94ms TTL=254
Ping statistics for 192.168.3.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 93ms, Maximum = 125ms, Average = 105ms

PC>ping 172.17.1.1
Pinging 172.17.1.1 with 32 bytes of data:
Reply from 172.17.1.1: bytes=32 time=110ms TTL=254
Reply from 172.17.1.1: bytes=32 time=112ms TTL=254
Reply from 172.17.1.1: bytes=32 time=123ms TTL=254
Reply from 172.17.1.1: bytes=32 time=110ms TTL=254
Ping statistics for 172.17.1.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 110ms, Maximum = 123ms, Average = 113ms
PC>ping 172.18.1.1
Pinging 172.18.1.1 with 32 bytes of data:
Reply from 172.18.1.1: bytes=32 time=140ms TTL=254
Reply from 172.18.1.1: bytes=32 time=109ms TTL=254
Reply from 172.18.1.1: bytes=32 time=110ms TTL=254
Reply from 172.18.1.1: bytes=32 time=125ms TTL=254
Ping statistics for 172.18.1.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 109ms, Maximum = 140ms, Average = 121ms