(1)网络基本情况
        网络拓扑结构为:中心交换机采用Cisco Catalyst 4006-S3,Supervisor Engine III G引擎位于第1插槽,用于实现三层交换;1块24口1000Base-T模块位于第2插槽,用于连接网络服务器;1块6端口1000Base-X模块位于第3插槽,用于连接6台骨干交换机。一台交换机采用Cisco Catalyst 3550-24-EMI,并安装1块1000Base-X GBIC千兆模块。一台交换机采用Cisco Catalyst 3550-24-SMI,也安装1块1000Base-X GBIC千兆模块。另外四台交换机采用Cisco Catalyst 2950G-24-SMI,安装1块1000Base-T GBIC千兆模块。
        所有服务器划分为一个VLAN,即VLAN 50。四台Catalyst 2950G-24-SMI交换机也只划分为一个VLAN,分别为VLAN 60、VLAN 70、VLAN 80和VLAN 90。Catalyst 3550-24-EMI划分为4个VLAN,分别为VLAN 10、VLAN 20、VLAN 30和VLAN 40。Catalyst 3550-24-SMI划分2个VLAN,分别为VLAN 60和VLAN 80,与另外两台Catalyst 2950G-24-SMI交换机分别位于同一VLAN。

(2)实例分析
        由于所有Catalyst 2950G交换机都是一个独立的VLAN,因此,必须先在这些交换机上创建VLAN(VLAN 60~VLAN 90),并将所有端口都指定至该VLAN。然后,再在Catalyst 4006交换机相应端口上分别创建VLAN。Catalyst 4006的1000Base-X端口分别与各Catalyst 2950G的1000Base-X端口连接。其中,GigabitEthernet3/2端口连接至1号Catalyst 2950交换机(VLAN 60),GigabitEthernet3/3端口连接至2号Catalyst 2950交换机(VLAN 70),GigabitEthernet3/4端口连接至3号Catalyst 2950交换机(VLAN 80),GigabitEthernet3/5端口连接至4号Catalyst 2950交换机(VLAN 90),GigabitEthernet3/6端口连接至6号楼交换机(VLAN 80)。
        由于在Catalyst 3550-24-EMI上划分有4个VLAN(VLAN 10~VLAN 40),而4个VLAN都需借助于一条1000Base-X链路实现与Catalyst 4006的GigabitEthernet3/1端口连接,因此,必须在Catalyst 4006与Catalyst 3550-24- EMI之间创建一个Trunk。
        同样,在Catalyst 3550-24-SMI上划分有2个VLAN(VLAN 60和VLAN 80),而4个VLAN都需借助于一条1000Base-X链路实现与Catalyst 4006的GigabitEthernet3/6端口连接,因此,必须在Catalyst 4006与Catalyst 3550-24- EMI之间创建一个Trunk。
        另外,所有服务器均连接至Catalyst 4006的1000Base-T模块,并单独成为一个VLAN(VLAN 90),因此,也必须为这些交换机创建一个VLAN,并将所有端口指定至该VLAN。需要注意的是,考虑到网络管理的需要,也可以剩余几个RJ-45端口(如21至24端口)不指定至任何VLAN,从而便于连接网络管理设备。默认状态下,所有端口都属于VLAN1,而且也只有在VLAN1中才能实现对网络中所有设备的管理。

(3)配置清单
●Cisco Catalyst 4006交换机配置清单
Current configuration : 5594 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
service compress-config
!
hostname hsnc
!
boot system bootflash:cat4000-is-mz.121-8a.EW1.bin
no logging console
enable secret level 1 5 $1$rkQW$1HKyKdN5f.Ri5zxeoF8Yv/
!
ip subnet-zero
!
!
!
interface GigabitEthernet1/1
 no snmp trap link-status
!–不为Supervisor Engine III G引擎中的1000Base-X插槽指定VLAN
interface GigabitEthernet1/2
 no snmp trap link-status
!
!
interface GigabitEthernet2/1
switchport access vlan 50
 no snmp trap link-status
!–将端口GigabitEthernet2/1指定至VLAN 50
!
interface GigabitEthernet2/2
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/3
switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/4
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/5
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/6
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/7
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/8
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/9
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/10
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/11
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/12
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/13
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/14
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/15
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/16
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/17
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/18
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/19
 switchport access vlan 50
 no snmp trap link-status
!
interface GigabitEthernet2/20
 switchport access vlan 50
 no snmp trap link-status
!–不将GigabitEthernet2/20~24指定至任何VLAN
!
interface GigabitEthernet3/1
 switchport trunk encapsulation dot1q
!–启用802.1Q Trunk封装协议,即在该端口创建Trunk
 switchport trunk allowed vlan 1-80
!–允许vlan 1-90在该中继线通讯
!–可以拒绝或允许某个VLAN访问该Trunk
!–确保未被授权的VLAN通过该Trunk,实现VLAN的访问安全
 switchport mode trunk
!–将该端口设置为Trunk
 description netcenter
 no snmp trap link-status
!
interface GigabitEthernet3/2
 switchport access vlan 60
 no snmp trap link-status
!–将端口GigabitEthernet3/2指定至VLAN 60
!
interface GigabitEthernet3/3
 switchport access vlan 70
 no snmp trap link-status
!–将端口GigabitEthernet3/3指定至VLAN 70
!
interface GigabitEthernet3/4
 switchport access vlan 80
 no snmp trap link-status
!–将端口GigabitEthernet3/4指定至VLAN 80
!
interface GigabitEthernet3/5
switchport access vlan 90
 no snmp trap link-status
!–将端口GigabitEthernet3/5指定至VLAN 90
!
interface GigabitEthernet3/6
switchport trunk encapsulation dot1q
!–启用802.1Q Trunk封装协议,即在该端口创建Trunk
 switchport trunk allowed vlan 1-80
!–允许vlan 1-90在该中继线通讯
!–可以拒绝或允许某个VLAN访问该Trunk
!–从而确保未被授权的VLAN通过该Trunk,实现VLAN访问安全
 switchport mode trunk
!–将该端口设置为Trunk
 description netcenter
 no snmp trap link-status
!
interface Vlan1
 description netmanger
no ip address
!
!–对VLAN1进行描述
interface Vlan10
 description network center
 no ip address
!–对VLAN2进行描述
!
interface Vlan20
 description computer center
no ip address
!
interface Vlan30
 description network lab
no ip address
!
interface Vlan40
 description huaxuelou
no ip address
!
interface Vlan50
 description wulilou
no ip address
!
interface Vlan60
 description shengwulou
no ip address
!
interface Vlan70
 description zhongwenxi
no ip address
!
interface Vlan80
 description tushuguan
no ip address
!
!
line con 0
 stopbits 1
line vty 0 4
 password aaa
 login
!
end

●Cisco Catalyst 3550-EMI配置清单
Building configuration…

Current configuration : 4055 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname office
!
enable secret 5 $1$p0fU$JeyPOM0RuL.Fqfe71efHF1
!
ip subnet-zero
!
!
spanning-tree extend system-id
!
!
!
interface FastEthernet0/1
 switchport access vlan 10
!–将端口FastEthernet0/1指定至VLAN 10
 no ip address
!
interface FastEthernet0/2
 switchport access vlan 10
 no ip address
!
interface FastEthernet0/3
 switchport access vlan 10
 no ip address
!
interface FastEthernet0/4
 switchport access vlan 10
 no ip address
!
interface FastEthernet0/5
 switchport access vlan 10
 no ip address
!
interface FastEthernet0/6
 switchport access vlan 20
 no ip address
!–将端口FastEthernet0/6指定至VLAN 20
!
interface FastEthernet0/7
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/8
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/9
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/10
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/11
 switchport access vlan 30
 no ip address
!–将端口FastEthernet0/6指定至VLAN 30
!
interface FastEthernet0/12
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/13
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/14
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/15
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/16
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/17
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/18
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/19
 switchport access vlan 40
 no ip address
!–将端口FastEthernet0/6指定至VLAN 40
!
interface FastEthernet0/20
 switchport access vlan 40
 no ip address
!
interface FastEthernet0/21
 switchport access vlan 40
 no ip address
!
interface FastEthernet0/22
 switchport access vlan 30
 no ip address
!
interface FastEthernet0/23
 switchport access vlan 40
 no ip address
!
interface FastEthernet0/24
 switchport access vlan 40
 no ip address
!
interface GigabitEthernet0/1
 switchport trunk encapsulation dot1q
!–启用802.1Q Trunk封装协议,即在该端口创建Trunk
 switchport trunk allowed vlan 1-80
!–允许vlan 1-80在该中继线通讯
switchport mode trunk
!–将该端口设置为Trunk
 no ip address
!
interface GigabitEthernet0/2
 no ip address
!
interface Vlan1
 ip address 172.16.100.12 255.255.255.0
!–LAN1指定IP地址
 no ip route-cache
 no ip mroute-cache
!
ip classless
ip http server
!
!
!
!
line con 0
line vty 0 4
 password aaa
 login
line vty 5 15
login
!
end
●Cisco Catalyst 3550-SMI配置清单
Building configuration…

Current configuration : 4055 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname office
!
enable secret 5 $1$p0fU$JeyPOM0RuL.Fqfe71efHF1
!
ip subnet-zero
!
!
spanning-tree extend system-id
!
!
!
interface FastEthernet0/1
 switchport access vlan 60
!–将端口FastEthernet0/1指定至VLAN 60
 no ip address
!
interface FastEthernet0/2
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/3
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/4
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/5
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/6
 switchport access vlan 20
 no ip address
!–将端口FastEthernet0/6指定至VLAN 20
!
interface FastEthernet0/7
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/8
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/9
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/10
 switchport access vlan 20
 no ip address
!
interface FastEthernet0/11
 switchport access vlan 80
 no ip address
!–将端口FastEthernet0/6指定至VLAN 80
!
interface FastEthernet0/12
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/13
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/14
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/15
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/16
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/17
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/18
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/19
 switchport access vlan 80
 no ip address
!–将端口FastEthernet0/6指定至VLAN 80
!
interface FastEthernet0/20
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/21
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/22
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/23
 switchport access vlan 80
 no ip address
!
interface FastEthernet0/24
 switchport access vlan 80
 no ip address
!
interface GigabitEthernet0/1
 switchport trunk encapsulation dot1q
!–启用802.1Q Trunk封装协议,即在该端口创建Trunk
 switchport trunk allowed vlan 1-80
!–允许vlan 1-80在该中继线通讯
switchport mode trunk
!–从将该端口设置为Trunk
 no ip address
!
interface GigabitEthernet0/2
 no ip address
!
interface Vlan1
 ip address 172.16.100.13 255.255.255.0
!–为LAN1指定IP地址
 no ip route-cache
 no ip mroute-cache
!
ip classless
ip http server
!
!
!
!
line con 0
line vty 0 4
 password aaa
 login
line vty 5 15
 login
!
end

●Cisco Catalyst 2950G配置清单
四台Cisco Catalyst 2950G的配置基本相同,下面仅列出VLAN 60的配置情况。
Building configuration…

Current configuration : 2143 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname msl
!
enable password aaa
!
ip subnet-zero
!
!
spanning-tree extend system-id
!
!
interface FastEthernet0/1
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/2
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/3
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/4
 no ip address
!
interface FastEthernet0/5
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/6
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/7
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/8
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/9
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/10
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/11
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/12
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/13
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/14
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/15
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/16
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/17
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/18
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/19
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/20
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/21
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/22
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/23
 switchport access vlan 60
 no ip address
!
interface FastEthernet0/24
 switchport access vlan 60
 no ip address
!
interface GigabitEthernet0/1
 no ip address
!
interface GigabitEthernet0/2
 no ip address
!
interface Vlan1
 ip address 172.16.100.10 255.255.255.0
!
ip classless
ip http server
!
!
!
!
line con 0
line vty 0 4
 password aaa
 login
line vty 5 15
 login
!
end