學校網路Vlan架構
===
章節

新北市校園網路Vlan應用-李煒老師主講
{%youtube TCLe3pmDbkY %}

## VLAN原理
> Switch因為有Mac Table所以不至於廣播無效率

> 龐大的switch會導致流量臃腫

## Access VS Trunk
> 比較表
> Access: A電腦出去打上VLAN2標籤, 出去B電腦拿下標籤

## Lab1

>Step 1 先把VLAN資料庫建立起來，三台都一樣

enable
conf t
vlan 25
name xxx

>Step 2

Core Switch
enable
conf t 
int fa0/23
switch trunk encapsulation dot1q
switch mode trunk
switch trunk allow vlan 3,5,10,20,25,31,32,33

Switch
enable
conf t 
int fa0/1
switch mod trunk
switch trunk allow vlan 3,5,10,20,25,31,32,33


do sh run


測試方式
interface FastEthernet0/20
switchport access vlan 31



gateway(vlan 5 10 121)
enable
conf t

Step3
在Coreswitch
int vlan3
ip add 10.228.56.254 255.255.255.0

int vlan5
ip add 163.20.66.254 255.255.255.0
ip helper 203.72.153.8

int vlan10
ip add 10.231.56.254 255.255.255.0
ip helper 203.72.153.8

int vlan25
ip add 10.243.56.254 255.255.255.0
ip helper 203.72.153.8

int vlan31
ip add 10.213.56.254 255.255.255.0
ip helper 203.72.153.8

int vlan32
ip add 10.215.56.254 255.255.255.0
ip helper 203.72.153.8

int vlan33
ip add 10.217.56.254 255.255.255.0
ip helper 203.72.153.8

因為他是交換機，需要下指令
no ip routing
ip routing


Step4
Add Vlan database 121:
vlan 121 name DHCP
int vlan121
ip add 203.72.153.254 255.255.255.0

Step5
int fa0/15
switch mode trunk
switchport trunk allowed vlan 31,32,33,3
在四個小支線裡面，把標籤三拿掉(變成都可以識別的)->用於新設備需要馬上被辨別
switchport trunk native vlan 3


買了話機為例
switch mode trunk
switchport trunk allowed vlan 25,5 (25:voice, 5:Lan)
switchport trunk native vlan 5

# 貢寮國小