本文主要以華為路由器為例，詳細的給大家介紹了如何進行單臂路由的配置，并且給出了單臂路由的拓撲圖，以及路由器的配置步驟，相信此文會讓你更深刻的理解單臂路由。

在局域網中,通過交換機上配置VLAN可以減少主機通信廣播域的范圍,當VLAN之間有部分主機需要通信,但交換機不支持三層交換時,可以采用一臺支持802.1Q的路由器實現VLAN的互通.這需要在以太口上建立子接口,分配IP地址作為該VLAN的網關,同時啟動802.1Q.
組網:路由器E0端口與交換機的上行trunk端口(第24端口)相連,交換機下行口劃分3個VLAN,帶若干主機.

拓撲圖如下：

1.華為路由器的配置

[Router]
[Router]inter e0
[Router-Ethernet0]ip add 10.0.0.1 255.255.255.0
[Router-Ethernet0]inter e0.1 //定義子接口E0.1
[Router-Ethernet0.1]ip add 172.16.1.1 255.255.255.0
[Router-Ethernet0.1]vlan-type dot1q vid 1 //指定以太網子接口屬于VLAN1,此命令應用在以太網子接口上。只有配置了該命令之后，以太網子接口才會根據配置的VLAN ID 號在以太網幀頭中嵌入VLAN 標簽，與該網口相連的交換機接口才能正確處理接收到的幀。
[Router-Ethernet0.1]inter e0.2 //定義子接口E0.2
[Router-Ethernet0.2]ip add 172.16.2.1 255.255.255.0
[Router-Ethernet0.2]vlan-type dot1q vid 2 //指定以太網子接口屬于VLAN2
[Router-Ethernet0.2]inter e0.3 //定義子接口E0.3
[Router-Ethernet0.3]ip add 172.16.3.1 255.255.255.0
[Router-Ethernet0.3]vlan-type dot1q vid 3 //指定以太網子接口屬于VLAN3
[Router-Ethernet0.3]inter e0
[Router-Ethernet0]undo shut
% Interface Ethernet0 is up
[Router-Ethernet0] //用網線將E0端口連到S3026第24端口
%19:46:32: Interface Ethernet0 changed state to UP
%19:46:32: Line protocol ip on interface Ethernet0, changed state to UP
%19:46:32: Line protocol ip on interface Ethernet0.1, changed state to UP
%19:46:32: Line protocol ip on interface Ethernet0.2, changed state to UP
%19:46:32: Line protocol ip on interface Ethernet0.3, changed state to UP

2.交換機的配置
<Quidway>
<Quidway>sys
Enter system view , return user view with Ctrl+Z.
[Quidway]vlan 1
[Quidway-vlan1]vlan 2
[Quidway-vlan2]port ethernet 0/17 to eth 0/19 eth 0/22 //將第17至19端口，和第22端口加入VLAN2
[Quidway-vlan2]vlan 3
[Quidway-vlan3]port eth 0/21 //將第21端口加入VLAN2
[Quidway-vlan3]inter e0/24
[Quidway-Ethernet0/24]port link-type trunk //將第24端口設為trunk口
[Quidway-Ethernet0/24]port trunk permit vlan all　　//允許所有VLAN流量通過
Please wait........................................... Done.
[Quidway-Ethernet0/24]dis port trunk //檢驗TRUNK口配置
Now, the following trunking ports exist:
Ethernet0/24
[Quidway-Ethernet0/24]dis vlan 2　　　　　　　//檢驗VLAN2的配置
VLAN ID: 2
VLAN Type: static
Route Interface: not configured
Description: VLAN 0002
Tagged Ports:
Ethernet0/24
Untagged Ports:
Ethernet0/17 Ethernet0/18 Ethernet0/19 Ethernet0/22

[Quidway-Ethernet0/24]dis vlan 3　　　　　　　//檢驗VLAN3的配置
VLAN ID: 3
VLAN Type: static
Route Interface: not configured
Description: VLAN 0003
Tagged Ports:
Ethernet0/24
Untagged Ports:
Ethernet0/21

3.在工作站上檢查網絡是否連通。

此工作站連接S3026第21端口，屬于VLAN2。

C:\Documents and Settings\Administrator>ipconfig

Windows 2000 IP Configuration

Ethernet adapter 本地連接:

Connection-specific DNS Suffix . :
IP Address. . . . . . . . . . . . : 172.16.2.22
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 172.16.2.1

C:\Documents and Settings\Administrator>ping 172.16.3.1

Pinging 172.16.3.1 with 32 bytes of data:

Reply from 172.16.3.1: bytes=32 time<10ms TTL=255
Reply from 172.16.3.1: bytes=32 time<10ms TTL=255
Reply from 172.16.3.1: bytes=32 time<10ms TTL=255
Reply from 172.16.3.1: bytes=32 time<10ms TTL=255

Ping statistics for 172.16.3.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms

4.在華為路由器上查看路由表。

可以發現，由于172.16各網段都是直連路由，故不需啟用路由協議或靜態路由即能實現VLAN之間的通訊。

[Router]display ip routing-table
Routing Tables:
Destination/Mask Proto Pref Metric Nexthop Interface
10.0.0.0/24 Direct 0 0 10.0.0.1 Ethernet0
10.0.0.1/32 Direct 0 0 127.0.0.1 LoopBack0
127.0.0.0/8 Direct 0 0 127.0.0.1 LoopBack0
127.0.0.1/32 Direct 0 0 127.0.0.1 LoopBack0
172.16.1.0/24 Direct 0 0 172.16.1.1 Ethernet0.1
172.16.1.1/32 Direct 0 0 127.0.0.1 LoopBack0
172.16.2.0/24 Direct 0 0 172.16.2.1 Ethernet0.2
172.16.2.1/32 Direct 0 0 127.0.0.1 LoopBack0
172.16.3.0/24 Direct 0 0 172.16.3.1 Ethernet0.3
172.16.3.1/32 Direct 0 0 127.0.0.1 LoopBack0