说明这是一个比较综合的实例，从拓扑图上可以看出，它所包含的设备和技术。以下对这个例子作些说明。 对于内部局域网，选用Cisco的Catalyst 6506作为中心交换机，二级交换采用Catalyst 3500，同时为了说明Trunk，又加了一个Catalyst 2900 作为三级交换，对于终端连接用了Catalyst 1900交换机，这样就可以在Catalyst 6506与Catalyst 3500之间以及Catalyst 3500与Catalyst 2900 之间建立Trunk，实现跨交换机的VLAN。 注：Catalyst 2900系列如果要实现Trunk，软件必须是企业版的。 对于外连上,主要是专线连接和拨号访问,当然种类比较多.包括了DDN、 ISDN、 Frame Relay、 E1 线路等。 本例给出设备的基本配置。 对于多设备的连接问题,值得注意的是路由问题,本实例外连部分采用静态路由而内部局域网采用动态路由. 在本例的帧中继配置中,运用了IP Unnumbered ,可以节省地址资源,有兴趣可以注意一下。网络拓扑：VLAN划分问题对于交换设备本例中划到VLAN 1中,而对于外连设备的所有以太网端口,均划到VLAN 2中,下面给出各VLAN的名称和网关地址,本例划分8个VLAN. VLAN ID VLAN Name Gateway VLAN 1 Bluestudy 1 10.1.0.1/16 VLAN 2 Bluestudy 2 10.2.0.1/16 VLAN 3 Bluestudy 3 10.3.0.1/16 VLAN 4 Bluestudy 4 10.4.0.1/16 VLAN 5 Bluestudy 5 10.5.0.1/16 VLAN 6 Bluestudy 6 10.6.0.1/16 VLAN 7 Bluestudy 7 10.7.0.1/16 VLAN 8 Bluestudy 8 10.8.0.1/16Catalyst 6506 的配置 Enter password:enable Enter password:config t set system name Bluestudy set time 10/30/2000 9:30:00 set password set enablepass set interface sc0 10.1.0.2/16 set ip route default 10.1.0.1 set ip dns server 10.1.0.100 set ip dns domain bluestudy.com set ip dns enable set vtp domain bluestudy mode server set vlan 1 name Bluestudy 1 set vlan 2 name Bluestudy 2 set vlan 3 name Bluestudy 3 set vlan 4 name Bluestudy 4 set vlan 5 name Bluestudy 5 set vlan 6 name Bluestudy 6 set vlan 7 name Bluestudy 7 set vlan 8 name Bluestudy 8 set port negotiation 2/1-8 enable set port name 2/1-8 GEC 802.1Q Trunk set trunk 2/1-8 desirable dot1q set port speed 2/1-8 1000 set vlan 1 3/1-48 对于6506的交换机方面的配置只需做出Trunk即可,因为要实现跨交换机之间的虚网,下面配置6506的路由模块,因为6506的路由模块现在与管理引擎模块集成在了一起,所以,默认命令是:Session 15 ,详情请见 6506 路由设置. Catalyst 6506RSM模块的配置 (enable) session 15 Trying Router-15. Connected to Router-15. Escape character is . enable configure terminal hostname bluestudy enable password password line vty 0 6 password secret_word ip domain-name bluestudy.com ip name-server 10.1.0.100 interface vlan 1 ip address 10.1.0.1 255.255.0.0 no shutdown interface vlan 2 ip address 10.2.0.1 255.255.0.0 no shutdown interface vlan 3 ip address 10.3.0.1 255.255.0.0 no shutdown interface vlan 4 ip address 10.4.0.1 255.255.0.0 no shutdown interface vlan 5 ip address 10.5.0.1 255.255.0.0 no shutdown interface vlan 6 ip address 10.6.0.1 255.255.0.0 no shutdown interface vlan 7 ip address 10.7.0.1 255.255.0.0 no shutdown interface vlan 8 ip address 10.8.0.1 255.255.0.0 no shutdown router rip version 2 network 10.0.0.0 ip route 0.0.0.0 0.0.0.0 10.2.0.12 ip route 192.168.2.0 255.255.255.0 10.2.0.13 ip route 192.168.3.0 255.255.255.240 10.2.0.11 ip route 192.168.4.0 255.255.255.0 10.2.0.11 ip route 192.168.5.0 255.255.255.0 10.2.0.11 ip route 192.168.6.0 255.255.255.0 10.2.0.11 copy running-config startup-config Building configuration. OK 这里给出的是单纯的命令行,略去了一些默认状况的设置.Catalyst 3500 的配置 ! version 12.0 no service pad service timestamps debug uptime service timestamps log uptime service password-encryption ! hostname bluestudy ! enable password password ! username bluestudy password password username test password password ! 省略端口的显示 ! interface GigabitEthernet0/1 switchport trunk encapsulation dot1q switchport mode trunk ! interface GigabitEthernet0/2 ! interface VLAN1 ip address 10.1.0.4 255.255.0.0 ip helper-address 10.1.0.100 ip directed-broadcast no ip route-cache ! ip default-gateway 10.1.0.1 interface Ethernet1/1(与2900对接) switchport trunk encapsulation dot1q switchport mode trunk ! interface Ethernet1/2(与1900 A对接) switchport access VLAN 3 no shut ! interface Ethernet1/3(与1900 B对接) switchport access VLAN 4 no shut ! snmp-server engineID local 000000090200000216BE4E80 snmp-server community public RO snmp-server community private RW snmp-server chassis-id 0x17 (打开简单的网络管理，便于以后，Cisco 网管软件识别和管理） ! line con 0 login local transport input none stopbits 1 line vty 0 4 login local line vty 5 15 login ! end Catalyst 2900 的配置 2900的配置与3500的相似,命令如下 hostname bluestudy ! enable password password ! username bluestudy password password username test password password ! 省略端口的显示 ! interface Ethernet0/1(与3500对接) switchport trunk encapsulation dot1q switchport mode trunk ! interface VLAN1 ip address 10.1.0.3 255.255.0.0 ip helper-address 10.1.0.100 ip directed-broadcast no ip route-cache ! ip default-gateway 10.1.0.1 ! interface Ethernet0/2(与1900 C对接) switchport access VLAN 5 no shut ! interface Ethernet0/3(与1900 D对接) switchport access VLAN 6 no shut ! snmp-server engineID local 000000090200000216BE4E80 snmp-server community public RO snmp-server community private RW snmp-server chassis-id 0x17 ! line con 0 login local tra