VLAN实验——三层交换原理_三层交换1 创建vlan
Switch#vlan database
% Warning: It is recommended to configure VLAN from config mode,
  as VLAN database mode is being deprecated. Please consult user
  documentation for configuring VTP/VLAN in config mode.
Switch(vlan)# vlan 2 name marking
VLAN 2 added:
    Name: marking
Switch(vlan)# vlan 3 name counting
VLAN 3 added:
    Name: counting
 
2 分配端口
Switch(config)#interface FastEthernet0/1
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 2
Switch(config-if)#exit
Switch(config)#interface FastEthernet0/2
Switch(config-if)#switchport access vlan 2
Switch(config-if)#interface FastEthernet0/3
Switch(config-if)#switchport access vlan 3
Switch(config-if)#interface FastEthernet0/4
Switch(config-if)#switchport access vlan 3
Switch(config-if)#exit
Switch(config)#exit
Switch#
 
 
3 Show vlan 查看信息
 
Switch#show vlan
 
VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/5, Fa0/6, Fa0/7, Fa0/8
                                                Fa0/9, Fa0/10, Fa0/11, Fa0/12
                                                Fa0/13, Fa0/14, Fa0/15, Fa0/16
                                                Fa0/17, Fa0/18, Fa0/19, Fa0/20
                                                Fa0/21, Fa0/22, Fa0/23, Fa0/24
2    marking                          active    Fa0/1, Fa0/2
3    counting                         active    Fa0/3, Fa0/4
1002 fddi-default                     active   
1003 token-ring-default               active   
1004 fddinet-default                  active   
1005 trnet-default                    active   
 
VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1    enet  100001     1500  -      -      -        -    -        0      0
2    enet  100002     1500  -      -      -        -    -        0      0
3    enet  100003     1500  -      -      -        -    -        0      0
1002 enet  101002     1500  -      -      -        -    -        0      0
1003 enet  101003     1500  -      -      -        -    -        0      0
 
其实做这个实验很简单就是划分子网,主要是为了说明三层交换机最本质工作原理,即一次路由,多次交换
结合arp的工作原理,两台主机通讯时,传统的2层交换机进行arp广播寻找目标mac地址,,当目的主机在同一网段内时,不需涉及网关。否则由网关回复arp广播。
传统的2层交换模块不能实现网间互访,而三层交互交换机的三层路由模块把源和目的IP地址缓存交换机中,随后第3层中跨子网的包传送将不再由路由器来进行。实验中的三层交换机充当了传统网络中的路由器的角色,通过它可以实现网间互访。