三层交换
三层交换
1.1 组网需求
随着网络的迅速发展，对网络设备处理数据的能力也要求越来越高。三层交换机通过硬件来交换和路由数据，吞吐量能达到和接近线速转发。单臂路由确实可以实现不同子网间通信，但是会造成性能瓶颈，三层交换技术的出现为vlan间的通信带来了新的冲击
1.2组网拓扑
1.3实验目标
①掌握三层交换的配置命令
②掌握MLS和CEF 的工作原理
③分析PC间的通信过程
1.4实验步骤
1.4.1基本信息配置
Router#enable
Router#configure terminal
Enter configuration commands, one perline. End with CNTL/Z.
Router(config)#no ip domain-lookup
Router(config)#line console 0
Router(config-line)# logging synchronous
Router(config-line)# exec-timeout 0 0
Router(config-line)# no login
Router(config-line)#
Router(config-line)#line vty 0 4
Router(config-line)# no login
Router(config-line)#
Router(config-line)#exit
1.4.2二层链路及vlan配置和调试
sw1#vlan data
sw1(vlan)#vlan 11
VLAN 11 added:
Name: VLAN0011
sw1(vlan)#vlan 21
VLAN 21 added:
Name: VLAN0021
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1(config)#int f0/2
sw1(config-if)#swi m tr
sw1(config-if)#swi t all vlan all
sw1(config-if)#no shut
sw1(config-if)#int f0/3
sw1(config-if)#swi m tr
sw1(config-if)#swi tr
sw1(config-if)#swi tr all vlan all
sw1(config-if)#no shut
sw2#vlan data
sw2(vlan)#vlan 11
VLAN 11 added:
Name: VLAN0011
sw2(vlan)#vlan 21
VLAN 21 added:
Name:VLAN0021
sw2(vlan)#exit
APPLY completed.
Exiting....
sw2#conf t
Enter configuration commands, one perline. End with CNTL/Z.
sw2(config)#int f0/2
sw2(config-if)#swi m acc
sw2(config-if)#swi acc vlan 11
sw2(config-if)#int f0/3
sw2(config-if)#swi m acc
sw2(config-if)#swi acc vlan 21
sw2(config-if)#no shut
sw2(config-if)#int f0/2
sw2(config-if)#no shut
sw2(config)#int f0/1
sw2(config-if)#swi m tr
sw2(config-if)#swi tr all vlan all
sw2(config)#no ip routing
sw3#vlan data
sw3(vlan)#vlan 11
VLAN 11 added:
Name: VLAN0011
sw3(vlan)#vlan 21
VLAN 21 added:
Name: VLAN0021
sw3(vlan)#exit
APPLY completed.
Exiting....
sw3(config)#int f0/2
sw3(config-if)#swi acc vlan 11
sw3(config-if)#no shut
sw3(config-if)#int f0/3
sw3(config-if)#swi m acc
sw3(config-if)#swi acc vlan 21
sw3(config-if)#no shut
sw3(config-if)#int f0/1
sw3(config-if)#swi m tr
sw3(config-if)#swi tr all vlan all
sw3(config-if)#no shut
sw3(config)#no ip routing //关闭交换机的路由功能
1.4.3 三层svi接口配置和调试
sw1(config)#ip routing
sw1(config)#int vlan 11
sw1(config-if)#ip add 192.168.11.1255.255.255.0
sw1(config-if)#int vlan 21
sw1(config-if)#ip add 192.168.21.1255.255.255.0
sw1(config-if)#no shut
sw1(config-if)#int vlan 11
sw1(config-if)#no shut
sw1(config-if)#exit
sw1#show ip route
Codes: C - connected, S - static, R - RIP,M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-ISlevel-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.11.0/24 is directly connected, Vlan11
C 192.168.21.0/24 is directly connected, Vlan21
1.4.4全网连通性测试
1.4.5 单臂路由和三层交换的区别以它们间的优缺点
三层交换机通过硬件来交换和路由数据，吞吐量能达到和接近线速转发。单臂路由确实可以实现不同子网间通信，但是会造成性能瓶颈