应用场景描述：
某企业划分多个VLAN，连接在接入层交换机上，为了实现VLAN之间的通信，采用了三层交换机。企业需要与远程机构连接，三层交换机连接到路由器上，路由起连接到远
程机构。
使用到的相关知识点总结：
1.启动路由功能： ip routing
2.配置VLAN的IP地址：
Int vlan vlan-id
Ip address ip-address subnet-mask
No shut
3.查看FIB表 show ip cef
4.查看邻接关系表 show adjacency detail
5.在三层交换机上配置路由接口： no switchport
6.在三层交换机上配置静态或动态路由：
在三层交换机上配置静态路由或动态路由的方法与在路由器上配置路由的方法相同。
7.配置DHCP中继转发：
Int vlan vlan-id
Ip helper-address Dhcpserver-add
8.查看路由表： show ip route
9.释放IP：ipconfig /release
重新获取IP：ipconfig /renew
10.show ip cef ……………查看FIB表
11.show adjacency detail …………查看邻接关系表
12.show ip route ……………查看路由表
步骤：
配置三层交换机VLAN信息，设置VTP的相关信息，配置三层交换机VLAN IP地址，配置三层交换机DHCP中继
配置命令：
ena
vlan data
vtp dom abc
vlan 2
vlan 3
vlan 4
vlan 5
exit
conf t
ip routing
hostname mls3
int range F0/1 -2
switchport mode trunk
exit
int F/15
swit access vlan 5
exit
int vlan 5
ip address 10.0.0 .1 255.0.0.0
no sh
exit
int Vlan 1
ip address 192.168.10.1 255.255.255.0
ip helper-address 192.168.30.2
no sh
exit
int Vlan 2
ip address 192.168.20.1 255.255.255.0
ip helper-address 192.168.30.2
no sh
exit
int Vlan 3
ip address 192.168.30.1 255.255.255.0
no sh
exit
int Vlan 4
ip address 192.168.40.1 255.255.255.0
ip helper-address 192.168.30.2
no sh
exit
router rip
version 2
no auto-summary
network 10.0.0 .0
network 192.168.10.0
network 192.168.20.0
network 192.168.30.0
network 192.168.40.0
exit
exit
wri
验证结果
mls3#sh vlan b
*Mar 1 01:02:52.851: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet0/2 (not half duplex), with pc2 Ethernet0/0 (half duplex).s
VLAN Name Status Ports
1 default active Fa0/0, Fa0/3, Fa0/4, Fa0/5
Fa0/6, Fa0/7, Fa0/8, Fa0/9
Fa0/10, Fa0/11, Fa0/12, Fa0/13
Fa0/14
2 VLAN0002 active
3 VLAN0003 active
4 VLAN0004 active
5 VLAN0005 active Fa0/15
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
mls3#sh 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-IS level-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 192.168.30.0/24 is directly connected, Vlan3
C 192.168.10.0/24 is directly connected, Vlan1
C 192.168.40.0/24 is directly connected, Vlan4
C 192.168.20.0/24 is directly connected, Vlan2
10.0.0 .0/24 is subnetted, 1 subnets
C 10.0.0 .0 is directly connected, Vlan5
mls3#sh ip int b
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES unset up down
FastEthernet0/1 unassigned YES unset up up
FastEthernet0/2 unassigned YES unset up up
FastEthernet0/3 unassigned YES unset up down
FastEthernet0/4 unassigned YES unset up down
FastEthernet0/5 unassigned YES unset up down
FastEthernet0/6 unassigned YES unset up down
FastEthernet0/7 unassigned YES unset up down
FastEthernet0/8 unassigned YES unset up down
FastEthernet0/9 unassigned YES unset up down
FastEthernet0/10 unassigned YES unset up down
FastEthernet0/11 unassigned YES unset up down
FastEthernet0/12 unassigned YES unset up down
FastEthernet0/13 unassigned YES unset up down
FastEthernet0/14 unassigned YES unset up down
FastEthernet0/15 unassigned YES unset up up
Vlan1 192.168.10.1 YES manual up up
Vlan2 192.168.20.1 YES manual up up
Vlan3 192.168.30.1 YES manual up up
Vlan4 192.168.40.1 YES manual up up
Vlan5 10.0.0 .1 YES manual up
--More--
*Mar 1 01:07:52.731: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet0/2 (not half duplex), with pc2 Ethernet0/0 (halinterface FastEthernet0/15
switchport access vlan 5
!
interface Vlan1
ip address 192.168.10.1 255.255.255.0
ip helper-address 192.168.30.2
!
interface Vlan2
ip address 192.168.20.1 255.255.255.0
ip helper-address 192.168.30.2
!
interface Vlan3
ip address 192.168.30.1 255.255.255.0
!
interface Vlan4
ip address 192.168.40.1 255.255.255.0
ip helper-address 192.168.30.2
*Mar 1 01:07:58.347: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet0/15 (not half duplex), with r4 Ethernet0/0 (halinterface Vlan5
ip address 10.0.0 .1 255.255.255.0
router rip
version 2
network 10.0.0 .0
network 192.168.10.0
network 192.168.20.0
network 192.168.30.0
network 192.168.40.0
no auto-summary
配置路由器
ena
conf t
hostname r4
int e0/0
ip add 10.0.0 .2 255.0.0.0
no sh
exit
ip route 0.0.0 .0 0.0.0.0 e0/1
router rip
network 10.0.0 .0
version 2
no auto-summary
exit
exit
wri
验证结果
r4#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-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
R 192.168.30.0/24 [120/1] vi a 10.0.0 .1, 00:00:14, Ethernet0/0
R 192.168.10.0/24 [120/1] vi a 10.0.0 .1, 00:00:14, Ethernet0/0
R 192.168.40.0/24 [120/1] vi a 10.0.0 .1, 00:00:14, Ethernet0/0
R 192.168.20.0/24 [120/1] vi a 10.0.0 .1, 00:00:14, Ethernet0/0
C 10.0.0 .0/8 is directly connected, Ethernet0/0
配置接入层交换机B。C
ena
vlan database
vtp domain abc
vtp client
exit
conf t
hostname sw2
int f0/15
swit mode tru
exit
int f0/1
swit access vlan 2
exit
exit
wri
****************************
ena
vlan database
vtp domain abc
vtp client
exit
conf t
hostname sw3
int F0/1
switchport access vlan 4
exit
int F0/10
switchport access vlan 3
exit
interface FastEthernet0/15
switchport mode trunk
exit
exit
wri
*************************
3.2：验证结果
w2# sh vlan b
*Mar 1 01:12:42.443: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet0/15 (not half duplex), with pc3 Ethernet0/0 (half duplex)
VLAN Name Status Ports
1 default active Fa0/0, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/10, Fa0/11, Fa0/12
Fa0/13, Fa0/14
2 VLAN0002 active Fa0/1
3 VLAN0003 active
4 VLAN0004 active
5 VLAN0005 active
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
sw3#sh vlan b
VLAN Name Status Ports
1 default active Fa0/0, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/11, Fa0/12, Fa0/13
Fa0/14
2 VLAN0002 active
3 VLAN0003 active Fa0/10
4 VLAN0004 active Fa0/1
5 VLAN0005 active
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
*************************************
实验结果：
pc1#sh ip int b
Interface IP-Address OK? Method Status Protocol
Ethernet0/0 192.168.20.5 YES DHCP up up
Ethernet0/1 unassigned YES unset administratively down down
Ethernet0/2 unassigned YES unset administratively down down
Ethernet0/3 unassigned YES unset administratively down down
pc1#ping 192.168.30.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.30.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 72/120/172 ms
pc1#ping 192.168.20.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.30.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 240/298/456 ms
pc1#ping 192.168.10.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.10.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 72/111/124 ms
pc1#ping 192.168.40.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.40.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 96/135/220 ms
pc1#ping 10.0.0 .1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.0.0 .1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 148/207/312 ms
pc1#ping 10.0.0 .2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.0.0 .2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 144/216/288 ms
总结：
1. 把路由器模拟成一个PC。使用命令no ip routing
2. 三层交换机上可以把接入路由器的端口设置no swit
也可以把端口加入到一个VLAN 里，这样还可以做备份
3. ip add dhcp 这是自动获取IP地址命令
4. 如果是把三层交换机端口设置成路由接口，当配置了IP地址后不需要 no sh
5. 在三层交换机上设置路由信息和路由器上一样。
6. ip routing 配置三层交换机启动路由功能。
7. 在路由器上设置下一跳地址时，只要是可以ping的IP地址，都可以作为下一跳地址.
8. 在路由器上设置DHCP服务：
ip dhcp excluded-address 192.168.30.1 .........去除不给分配的IP地址
service dhcp ………………启用DHCP服务
ip dhcp pool v1 ……………创建DHCP池名字为V1
network 192.168.10.0 255.255.255.0 ……DHCP池的网段
dns-server 100.0.0.1 …………地址池的DNS地址
default-router 192.168.10.1 ………地址池网关