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7.VLAN通信之单臂路由与三层交换2023-07-12

8.网络层2023-07-14 9.传输层相关简述2023-07-15 10.路由相关简述2023-07-16 11.VRRP相关简述2023-07-17 12.acl与nat2023-07-17

VLAN之间通信

再次提及，vlan是虚拟局域网，用于分隔广播域，解决广播风暴。但是vlan之间无法直接通信。所有我们要用三层交换、单臂路由来实现vlan之间的通信。

单臂路由

使用场景：规划错误，只有二层交换机。

作用：实现不同VLAN通信

链路类型

交换机连接主机的端口为access链路
交换机连接路由器的端口为Trunk链路

子接口（逻辑划分）

路由器的物理接口可以被划分成多个逻辑接口
每个子接口对应一个VLAN网段的网关

原理：路由器重新封装MAC地址、转换VLAN标签。

实验一

#交换机配置（不同网段通信需要配置网关）
<Huawei>undo t m
<Huawei>sys
[Huawei]vlan batch 10 20
[Huawei]int g0/0/2
[Huawei-GigabitEthernet0/0/2]port link-type access
[Huawei-GigabitEthernet0/0/2]port default vlan 10
[Huawei-GigabitEthernet0/0/2]undo sh

[Huawei-GigabitEthernet0/0/2]int g0/0/3
[Huawei-GigabitEthernet0/0/3]port link-type access
[Huawei-GigabitEthernet0/0/3]port default vlan 20
[Huawei-GigabitEthernet0/0/3]undo sh

[Huawei-GigabitEthernet0/0/3]int g0/0/1
[Huawei-GigabitEthernet0/0/1]port link-type trunk
[Huawei-GigabitEthernet0/0/1]port trunk allow-pass vlan all
[Huawei-GigabitEthernet0/0/1]undo sh

#路由器配置
<Huawei>sys
[Huawei]u t m
[Huawei]int g0/0/0.10
#0-4095划分范围
[Huawei-GigabitEthernet0/0/0.10]dot1q termination vid 10
#“dot1q”里的1是数字1
[Huawei-GigabitEthernet0/0/0.10]ip add 192.168.10.1 24
[Huawei-GigabitEthernet0/0/0.10]arp broadcast enable
#arp协议默认关闭，一定要开启
[Huawei-GigabitEthernet0/0/0.10]undo sh
[Huawei-GigabitEthernet0/0/0.10]int g0/0/0.20
[Huawei-GigabitEthernet0/0/0.20]dot1q termination vid 20
[Huawei-GigabitEthernet0/0/0.20]ip add 192.168.20.1 24
[Huawei-GigabitEthernet0/0/0.20]undo sh
[Huawei-GigabitEthernet0/0/0.20]arp broadcast enable
[Huawei-GigabitEthernet0/0/0.20]q
[Huawei]q
<Huawei>display interface brief
PHY: Physical
*down: administratively down
(l): loopback
(s): spoofing
(b): BFD down
^down: standby
(e): ETHOAM down
(d): Dampening Suppressed
InUti/OutUti: input utility/output utility
Interface                   PHY   Protocol InUti OutUti   inErrors  outErrors
GigabitEthernet0/0/0        up    down        0%     0%          0          0
GigabitEthernet0/0/0.10     up    up          0%     0%          0          0
GigabitEthernet0/0/0.20     up    up          0%     0%          0          0
GigabitEthernet0/0/1        down  down        0%     0%          0          0
GigabitEthernet0/0/2        down  down        0%     0%          0          0
NULL0                       up    up(s)       0%     0%          0          0

#LSW1里
<Huawei>
<Huawei>u t m
Info: Current terminal monitor is off.
<Huawei>sys
Enter system view, return user view with Ctrl+Z.
[Huawei]vlan batch 10 20
Info: This operation may take a few seconds. Please wait for a moment...done.
[Huawei]int g0/0/1
[Huawei-GigabitEthernet0/0/1]p l a
[Huawei-GigabitEthernet0/0/1]p d v 10
[Huawei-GigabitEthernet0/0/1]int g0/0/2
[Huawei-GigabitEthernet0/0/1]undo sh
[Huawei-GigabitEthernet0/0/2]p l a
[Huawei-GigabitEthernet0/0/2]p d v 10
[Huawei-GigabitEthernet0/0/2]int g0/0/3
[Huawei-GigabitEthernet0/0/2]undo sh
[Huawei-GigabitEthernet0/0/3]p l a
[Huawei-GigabitEthernet0/0/3]p d v 20
[Huawei-GigabitEthernet0/0/3]int g0/0/4
[Huawei-GigabitEthernet0/0/3]undo sh
[Huawei-GigabitEthernet0/0/4]p l a
[Huawei-GigabitEthernet0/0/4]p d v 20
[Huawei-GigabitEthernet0/0/4]undo sh

[Huawei-GigabitEthernet0/0/4]int g0/0/5
[Huawei-GigabitEthernet0/0/5]port link-type trunk
[Huawei-GigabitEthernet0/0/5]port trunk allow-pass vlan 10 20
[Huawei-GigabitEthernet0/0/5]undo sh

#LSW2里

<Huawei>u t m
<Huawei>sys
[Huawei]vlan batch 10 20
[Huawei]int g0/0/1
[Huawei-GigabitEthernet0/0/1]p l a
[Huawei-GigabitEthernet0/0/1]p d v 10
[Huawei-GigabitEthernet0/0/1]int g0/0/2
[Huawei-GigabitEthernet0/0/1]undo sh
[Huawei-GigabitEthernet0/0/2]p l a
[Huawei-GigabitEthernet0/0/2]p d v 20
[Huawei-GigabitEthernet0/0/2]int g0/0/5
[Huawei-GigabitEthernet0/0/2]undo sh
[Huawei-GigabitEthernet0/0/5]p l t
[Huawei-GigabitEthernet0/0/5]p t a v 10 20
[Huawei-GigabitEthernet0/0/5]undo sh

#AR1里

<Huawei>u t m
Info: Current terminal monitor is off.
<Huawei>sys
Enter system view, return user view with Ctrl+Z.
[Huawei]int g0/0/0.10
##划分有范围0--4095
[Huawei-GigabitEthernet0/0/0.10]dot1q termination vid 10
##dot1q,“1”是数字1##将此端口与vlan id 10关联上
[Huawei-GigabitEthernet0/0/0.10]ip add 192.168.1.254 24
#分别配置网关与不同网络段的主机网关对应
[Huawei-GigabitEthernet0/0/0.10]arp broadcast enable
##因为华为ARP广播功能默认关闭的 思科是开启的##一定要记得
[Huawei-GigabitEthernet0/0/0.10]undo shutdown 
Info: Interface GigabitEthernet0/0/0.10 is not shutdown.
[Huawei-GigabitEthernet0/0/0.10]int g0/0/0.20
[Huawei-GigabitEthernet0/0/0.20]dot1q termination vid 20
[Huawei-GigabitEthernet0/0/0.20]ip add 192.168.2.254 24
[Huawei-GigabitEthernet0/0/0.20]undo shutdown
Info: Interface GigabitEthernet0/0/0.20 is not shutdown.
[Huawei-GigabitEthernet0/0/0.20]arp broadcast enable

不同网段之间终端可联通则成功

单臂路由缺点：

“单臂”为网络骨干链路，容易形成网络瓶颈
子接口依然依托于物理接口，应用不灵活
VLAN间转发需要查看路由表，严重浪费设备资源

三层交换

三层交换虚拟出多个接口实现VLAN间通信（vlanif=vlaninterface）

传统的MLS

一次路由多次转发。交换ASIC从3层引擎中获悉2层重写信息在硬件中创建一个MLS条目。

负责重写和转发数据流中的后续数据包

基于CEF的MLS

CEF是一种基于拓扑转发的模型

转发信息表(FIB)——就是路由表

邻接关系表——MAC

为什么要用这个方法：

路由器端口有限，三层交换机可分出虚拟接口，连接更多主机

实验一

<Huawei>u t m
<Huawei>sys
[Huawei]vlan b 10 20 30
##创建10 20 30 三条vlan
[Huawei]int e0/0/1
[Huawei-Ethernet0/0/1]p l a
[Huawei-Ethernet0/0/1]p d v 10
[Huawei-Ethernet0/0/1]int e0/0/2
[Huawei-Ethernet0/0/1]undo sh
##undo shoutdown 作用在真实交换机上
##因为交换机端口默认关闭，一定要记得输命令
[Huawei-Ethernet0/0/2]p l a
[Huawei-Ethernet0/0/2]p d v 20
[Huawei-Ethernet0/0/2]int e0/0/3
[Huawei-Ethernet0/0/2]undo sh

[Huawei-Ethernet0/0/3]p l a
[Huawei-Ethernet0/0/3]p d v 30
[Huawei-Ethernet0/0/3]undo sh
[Huawei-Ethernet0/0/3]int e0/0/4
[Huawei-Ethernet0/0/4]p l t
[Huawei-Ethernet0/0/4]p t a v a
[Huawei-Ethernet0/0/4]dis th
#
interface Ethernet0/0/4
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
#
return

#在三层交换机上配置
[SW2]int g0/0/1
[SW2-GigabitEthernet0/0/1]p l t
[SW2-GigabitEthernet0/0/1]p t a v a
[SW2-GigabitEthernet0/0/1]q
[SW2]vlan batch 10 20 30
[SW2]int vlanif 10
[SW2-Vlanif10]ip address 192.168.1.254 24     
[SW2-Vlanif10]int vlanif 20
[SW2-Vlanif20]ip address 192.168.2.254 24
[SW2-Vlanif20]int vlanif 30
[SW2-Vlanif30]ip address 192.168.3.254 24
[SW2-Vlanif30]dis ip interface brief
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 5
The number of interface that is DOWN in Physical is 1
The number of interface that is UP in Protocol is 4
The number of interface that is DOWN in Protocol is 2

Interface                         IP Address/Mask      Physical   Protocol  
MEth0/0/1                         unassigned           down       down      
NULL0                             unassigned           up         up(s)     
Vlanif1                           unassigned           up         down      
Vlanif10                          192.168.1.254/24     up         up        
Vlanif20                          192.168.2.254/24     up         up        
Vlanif30                          192.168.3.254/24     up         up

测试PC3pingPC1，连通，成功。

倘若三层路由器上连接另一台路由器与主机呢

实验二

####LSW1中设置不同端口下的模式
[SW1]vlan batch 10 20 30
Info: This operation may take a few seconds. Please wait for a moment...done.
[SW1]int e0/0/1
[SW1-Ethernet0/0/1]p l a
[SW1-Ethernet0/0/1]p d v 10
##prot default vlan 10
[SW1-Ethernet0/0/1]undo sh

[SW1-Ethernet0/0/1]int e0/0/2
[SW1-Ethernet0/0/2]p l a
[SW1-Ethernet0/0/2]p d v 20
[SW1-Ethernet0/0/2]undo sh

[SW1-Ethernet0/0/2]int e0/0/3
[SW1-Ethernet0/0/3]p l a
[SW1-Ethernet0/0/3]p d v 30
[SW1-Ethernet0/0/3]undo sh

[SW1-Ethernet0/0/3]int g0/0/1
[SW1-GigabitEthernet0/0/1]p l t
[SW1-GigabitEthernet0/0/1]p t a v a
##prot trunk allow-pass vlan all

####LSW2中设置不同端口
<Huawei>u t m
<Huawei>sys
[Huawei]sys SW2
[SW2]vlan batch 10 20 30 100
##创建vlan分别接纳四段网络
[SW2]
[SW2]int g0/0/2
[SW2-GigabitEthernet0/0/2]p l a
[SW2-GigabitEthernet0/0/2]p d v 100
[SW2-GigabitEthernet0/0/2]int g0/0/1
[SW2-GigabitEthernet0/0/1]p l t
[SW2-GigabitEthernet0/0/1]p t a v a
##之后针对不同子接口添加地址
[SW2]int vlanif 10
[SW2-Vlanif10]ip address 192.168.1.254 24
[SW2-Vlanif10]int vlanif 20
[SW2-Vlanif20]ip address 192.168.2.254 24
[SW2-Vlanif20]int vlanif 30
[SW2-Vlanif30]ip address 192.168.3.254 24
[SW2-Vlanif30]int vlanif 100
[SW2-Vlanif100]ip address 192.168.4.1 24
[SW2-Vlanif100]dis ip interface brief
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 6
The number of interface that is DOWN in Physical is 1
The number of interface that is UP in Protocol is 5
The number of interface that is DOWN in Protocol is 2

Interface                         IP Address/Mask      Physical   Protocol  
MEth0/0/1                         unassigned           down       down      
NULL0                             unassigned           up         up(s)     
Vlanif1                           unassigned           up         down      
Vlanif10                          192.168.1.254/24     up         up        
Vlanif20                          192.168.2.254/24     up         up        
Vlanif30                          192.168.3.254/24     up         up        
Vlanif100                         192.168.4.1/24       up         up        
[SW2-Vlanif100]ip route-static 192.168.5.0 24 192.168.4.2

DHCP

动态主机配置协议，自动给主机分配IP地址

DHCP服务器会为大量主机分配IP地址，能够集中管理。

先问当前局域网中是否有DHCP服务器

如果有，服务器返回网络参数报文

主机接收进行配置并发送，我已配置，并将刚刚的地址从地址池中剔除

服务器，我已剔除。

报文类型	含义
DHCP DISCOVER	客户端用来寻找DHCP服务器
DHCP OFFER	DHCP服务器用来响应DHCP DISCOVER报文，此报文携带了各种配置信息
DHCP REQUEST	客户端请求配置确认，或者续借租期
DHCP ACK	服务器对REQUEST报文的确认响应
DHCP NAK	服务器对REQUEST报文的拒绝响应
DHCP RELEASE	客户端要释放地址时用来通知服务器