数据链路层详细解剖,并完成实现不同交换机相同VLAN主机之间的通信实验-爱代码爱编程
一、功能
链路创建,维护,管理,帧封装,传输,同步,差错校验
二、地址
MAC(Media Access Control Address)地址:媒体访问控制地址,结构为48位2进制数字或12位16进制数字,比如:00-21-CC-C3-8C-B0,前六位为厂商标识,后六位为硬件唯一标识。
三、帧封装
MAC地址写到信息当中:
目标MAC||源MAC||数据||CRC
四、交换机工作原理
1.学习
交换机了解每一端口相连设备的MAC地址,并将地址同相应的端口映射起来存放在交换机缓存中的MAC地址表中。
2.广播
如果交换机没有在MAC地址表中找到数据帧目的地所对应的条目,交换机就无法确定该从那个接口将数据帧转发出去,于是它被迫选用了广播的方式,即除了发送该数据帧之外的所有接口都将转发这个数据帧,当目的机器无回应时丢弃,有回应时发送,并记录学习,下次遇到该MAC地址直接发送,不在进行广播程序。
3.转发
当一个数据帧的目的地址在MAC地址表中有映射时,它被转发到连接目的节点的端口而不是所有端口。
4.更新
当一个MAC地址与交换机一段时间(五分钟)内无信息交流,交换机就会抹去该MAC地址,防止交换机存储过多数据导致查找麻烦等。
五、组建局域网
需要通过Cisco Packte Tracert软件来组建一个局域网,建议下载之后进行汉化处理。
1.安装cisco cpt软件
2.部署交换机和主机
3.直通线连线,主机和交换机
4.为每个主机配置IP,互相ping测试
点击主机—>桌面—>IP地址配置,依次类推配置四台主机IP地址。
5.通过show mac-address-table。观察交换机工作原理。
点击交换机—>命令行—>回车
Switch>show mac-address-table
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
1 0001.976a.8e26 DYNAMIC Fa0/1
1 0005.5e93.9e5e DYNAMIC Fa0/4
1 0060.2fd3.de24 DYNAMIC Fa0/2
1 00d0.58ed.646d DYNAMIC Fa0/3
6.更换某个主机于交换机连接的接口,ping测试后, 再次观察交换机的mac地址表更新。
例如将主机PC0的接口换为Fa0/5,然后ping测试,接着观察MAC地址表。
PC>ping 192.168.1.2
Pinging 192.168.1.2 with 32 bytes of data:
Reply from 192.168.1.2: bytes=32 time=6ms TTL=128
Reply from 192.168.1.2: bytes=32 time=0ms TTL=128
Reply from 192.168.1.2: bytes=32 time=0ms TTL=128
Ping statistics for 192.168.1.2:
Packets: Sent = 3, Received = 3, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 6ms, Average = 2ms
Control-C
^C
Switch>show mac-address-table
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
10 0030.f227.4482 DYNAMIC Fa0/1
10 00d0.58a7.26d4 DYNAMIC Fa0/2
20 0009.7cba.bdeb DYNAMIC Fa0/3
20 000c.cf6e.b6be DYNAMIC Fa0/4
六、VLAN
1.简介
VLAN:(Virtual Local Area Network)虚拟局域网络
原理:进入交换机前在帧文件上加入VLAN标签,出来之后去掉标签
划分:2~1024,VLAN1是交换机原始的包含所有接口的。
2.配置VLAN
Switch>enable //进入特权模式
Switch#config t //进入配置模式
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#vlan 10 //创建局域网10
Switch(config-vlan)#vlan 20 //创建局域网20
Switch(config-vlan)#interface f0/1 //进入到0/1接口
Switch(config-if)#sw ac vl 10 //switch access vlan 10,将该接口划分到VLAN10中
Switch(config-if)#exit //退出
Switch(config)#exit
Switch#exit
Switch>show vlan brief //查看VLAN划分
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active 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, Fa0/15, Fa0/16, Fa0/17
Fa0/18, Fa0/19, Fa0/20, Fa0/21
Fa0/22, Fa0/23, Fa0/24
10 VLAN0010 active Fa0/1
20 VLAN0020 active
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
同理配置0/2接口到VLAN10里,0/3,0/4接口配置到VLAN20里
3.验证
Switch>show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/5, Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/10, Fa0/11, Fa0/12
Fa0/13, Fa0/14, Fa0/15, Fa0/16
Fa0/17, Fa0/18, Fa0/19, Fa0/20
Fa0/21, Fa0/22, Fa0/23, Fa0/24
10 VLAN0010 active Fa0/1, Fa0/2
20 VLAN0020 active Fa0/3, Fa0/4
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
·在IP地址为192.168.1.1的主机上ping测试:
(使用相同vlan主机通信成功,不同vlan主机通信不成功。)
PC>ping 192.168.1.2
Pinging 192.168.1.2 with 32 bytes of data:
Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
Ping statistics for 192.168.1.2:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 1ms, Average = 1ms
PC>ping 192.168.1.3
Pinging 192.168.1.3 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 192.168.1.3:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
七、TRUNK
1.简介
TRUNK核心技术是打标,目的是通过一根网线来传递不同的VLAN信息。
2.图示
3.配置
像上图一样配置,然后在另一台交换机上switch1像switch0一样配置,实现划分vlan 的行为。
Switch>enable
Switch#config t
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#vlan 10
Switch(config-vlan)#vlan 20
Switch(config-vlan)#int f0/1
Switch(config-if)#sw ac vl 10
Switch(config-if)#int f0/2
Switch(config-if)#sw ac vl 10
Switch(config-if)#int f0/3
Switch(config-if)#sw ac vl 20
Switch(config-if)#int f0/4
Switch(config-if)#sw ac vl 20
Switch(config-if)#int f0/5 //进入到0/5接口
Switch(config-if)#switch mode trunk //将0/5接口配置为链路
Switch(config-if)#exit
Switch(config)#exit
Switch#exit
Switch>show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/6, Fa0/7, Fa0/8, Fa0/9
Fa0/10, Fa0/11, Fa0/12, Fa0/13
Fa0/14, Fa0/15, Fa0/16, Fa0/17
Fa0/18, Fa0/19, Fa0/20, Fa0/21
Fa0/22, Fa0/23, Fa0/24
10 VLAN0010 active Fa0/1, Fa0/2
20 VLAN0020 active Fa0/3, Fa0/4
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
(Fa0/5已不在VLAN中,说明配置成功,同理配置switch0的链路)
4.测试
在IP地址为192.168.1.5的PC4上操作:
PC>ping 192.168.1.1
Pinging 192.168.1.1 with 32 bytes of data:
Reply from 192.168.1.1: bytes=32 time=1ms TTL=128
Reply from 192.168.1.1: bytes=32 time=1ms TTL=128
Reply from 192.168.1.1: bytes=32 time=1ms TTL=128
Reply from 192.168.1.1: bytes=32 time=1ms TTL=128
Ping statistics for 192.168.1.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 1ms, Average = 1ms
PC>ping 192.168.1.4
Pinging 192.168.1.4 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 192.168.1.4:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
(实现不同交换机上,相同VLAN主机通信成功。
实现不同交换机上,不相同VLAN主机通信不成功。)
5.总结
·交换机接口工作模式,分为acces和trunk
·access是指定接口连接的是主机
·trunk是指定接口连接的是交换机,需要通过多个VLAN的数据
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