問題1:簡述虛電路交換的實現流程?
在源和目的主機之間的每個交換機上建立“連接通道”,分組只需攜帶鏈路範圍內有效的VCI決定途徑路徑可到達目的地網絡。
問題2:描述FR(幀中繼)網絡的基本構成及通信機制?
幀中繼是在數據鏈路層用簡化的方法傳送和交換數據單元的快速分組交換技術,是在簡化X.25分組交換技術的基礎上發展起來的。幀中繼是一種統計複用協議,它在一條單一物理鏈路上能夠提供多條虛電路,有效利用了骨幹網的帶寬,降低了網絡成本。
問題3:介紹在FR網絡中DCE、DTE、PVC、NBMA、DLCI的含義?
PVC:是永久虛電路,建立之後永久存在,通常手工配置。
DLCI:是幀中繼網絡進行數據交換的虛電路地址。
問題4:幀中繼地址映射的類型及配置上有什麼區別?
類型:靜態映射、動態映射
靜態映射:由網絡管理人員手工配置地址映射
動態映射:通過Inverse ARP 由幀中繼交換機自動生成映射。
如果手工配置靜態映射,則設備不會將該該虛電路在發送Inverse ARP 請求報文給對端。
問題5:幀中繼主接口和子接口的含義?子接口有那些類型?配置上有何區別?
主接口:幀中繼設備的同步串行接口
子接口是由物理接口衍生出來的邏輯接口
子接口可分爲:點到點子接口、點到多點子接口
點到點子接口:不用配置動態、靜態映射
點到多點子接口:不適合使用動態映射
問題6:幀中繼網絡的拓撲結構有哪些?
1.全網狀拓撲 2.星型拓撲 3.部分網狀拓撲
1.全網狀拓撲:即幀中繼網絡中所有的路由器相連,實際就是全互聯,需要配置所有路由器之間的PVC,但是由於目前的幀中繼網絡都是租用運行商的鏈路,所以這樣做的成本很高。
2.星形拓撲:即所有路由器只和一個總節點路由器之間配置PVC鏈路,而其他路由器之間由於沒有PVC鏈路而無法通信,
3.部分網狀拓撲:該拓撲是全網狀拓撲和星形拓撲的折中,即在星形拓撲的基礎上又有部分分公司由於某種需要建立了PVC,實現了不同網絡的通信。
工作任務描述
A、B兩公司都建有自己的獨立局域網,並分別與CNC的路由器進行連接(三個路由器連接四個子網),要求使用DDN專線來實現該項目。
工作任務實施
1.網絡拓撲結構設計
2. 使用動態映射配置幀中繼網絡(採用主接口配置)
(1)各個路由器的配置命令
R1路由器配置
R2路由器配置:
R3路由器配置:
(2)查看各個路由器的PVC信息
R1#show frame-relay pvc
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 103, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
R2#show frame-relay pvc
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 203, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
R3#show frame-relay pvc
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 301, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
DLCI = 302, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
(3)單段測試結果,
Pc0ping網關能連通
Pc1ping網關能連通
(4)綜合測試結果
Pc0能連通pc3
Pc1能連通pc3
1. 使用靜態映射配置(採用主接口配置)
(1)各個路由器的配置命令
R1(config)#interface serial 0/0
R1(config-if)#frame-relay map ip 172.16.1.3 103 broadcast
R2(config)#interface serial 0/0
R2(config-if)#frame-relay map ip 172.16.1.3 203 broadcast
R3(config)#interface serial 0/0
R3(config-if)#frame-relay map ip 172.16.1.1301 broadcast
R3(config-if)#frame-relay map ip 172.16.1.2302 broadcast
(2)查看各個路由器的PVC信息
R1#show frame-relay pvc
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 103, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
R2#show frame-relay pvc
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 203, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
R3#show frame-relay pvc
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 301, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
DLCI = 302, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155
(3)單段測試結果
pc0能連通網關地址
pc1能連通網關地址
pc2能連通網關地址
(4)綜合測試結果
pc0能連通pc2
pc1連通pc2
4. 述網絡配置爲全互聯網絡的兩種不同配置方式,配置各個路由器的配置命令
R1(config)#interface serial 0/0
R1(config-if)#frame-relay map ip 172.16.1.2 103 broadcast
R1(config)#ip route 將上192.168.2.0 255.255.255.0 172.16.1.2
R2(config)#ip route 192.168.1.0 255.255.255.0 172.16.1.1
R2(config)#interface serial 0/0
R2(config-if)#frame-relay map ip 172.16.1.1 203 broadcast
R2(config-if)#exit
R2(config)ip route 192.168.1.0 172.16.1.1
工作擴展
使用點到點子接口配置方式來重複上述實驗
(1) 拓撲結構圖
(1) 各個路由器的配置文件
(1) 各個路由器的配置文件
R1
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0
ip address 172.16.1.2 255.255.255.0
encapsulation frame-relay
frame-relay map ip 172.16.1.1 103
!
ip classless
ip route 192.168.3.0 255.255.255.0 172.16.1.1
R2
interface FastEthernet0/0
ip address 192.168.2.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0
ip address 172.16.2.2 255.255.255.0
encapsulation frame-relay
frame-relay map ip 172.16.2.1 203
!
ip classless
ip route 192.168.3.0 255.255.255.0 172.16.2.1
R3
interface FastEthernet0/0
ip address 192.168.3.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0
no ip address
encapsulation frame-relay
clock rate 64000
!
interface Serial0/0.1 point-to-point
ip address 172.16.1.1 255.255.255.0
frame-relay interface-dlci 301
!
interface Serial0/0.2 point-to-point
ip address 172.16.2.1 255.255.255.0
frame-relay interface-dlci 302
!
ip classless
ip route 192.168.1.0 255.255.255.0 172.16.1.2
ip route 192.168.2.0 255.255.255.0 172.16.2.2