第9讲数据链路层

1、刘宏刘宏月印月印2022-3-18College of Information Science and Technology, HAUT3/442022-3-18College of Information Science and Technology, HAUT4/442022-3-18College of Information Science and Technology, HAUT5/442022-3-18College of Information Science and Technology, HAUT6/442022-3-18College of Information Scie

2、nce and Technology, HAUT7/44以太网以太网交换机交换机A4B1以太网以太网交换机交换机VLAN3C3B3VLAN1VLAN2C1A2A1A3C2B2以太网以太网交换机交换机以太网以太网交换机交换机三个虚拟局域网三个虚拟局域网: VLAN1, VLAN2 和和 VLAN32022-3-18College of Information Science and Technology, HAUT8/44以太网以太网交换机交换机A4B1以太网以太网交换机交换机VLAN3C3B3VLAN1VLAN2C1A2A1A3C2B2以太网以太网交换机交换机以太网以太网交换机交换机三个虚拟局

3、域网三个虚拟局域网VLAN1,VLAN2和和VLAN3的构成的构成当当B1向向VLAN2工作组内成员发送数据时，工作站工作组内成员发送数据时，工作站B2和和B3将会收到广播的信息。将会收到广播的信息。2022-3-18College of Information Science and Technology, HAUT9/44以太网以太网交换机交换机A4B1以太网以太网交换机交换机VLAN3C3B3VLAN1VLAN2C1A2A1A3C2B2以太网以太网交换机交换机以太网以太网交换机交换机三个虚拟局域网三个虚拟局域网VLAN1,VLAN2和和VLAN3的构成的构成B1发送数据时，工作站发送数据

4、时，工作站A1,A2和和C1都不会收到都不会收到B1发出的发出的广播信息。广播信息。 2022-3-18College of Information Science and Technology, HAUT10/44以太网以太网交换机交换机A4B1以太网以太网交换机交换机VLAN3C3B3VLAN1VLAN2C1A2A1A3C2B2以太网以太网交换机交换机以太网以太网交换机交换机三个虚拟局域网三个虚拟局域网VLAN1,VLAN2和和VLAN3的构成的构成VLAN限制了接收广播信息的工作站数，使得网络不会因限制了接收广播信息的工作站数，使得网络不会因传播过多的广播传播过多的广播信息而信息而引起性

5、能恶化引起性能恶化( (即即“”) ) 。2022-3-18College of Information Science and Technology, HAUT11/442022-3-18College of Information Science and Technology, HAUT12/442 字节字节2 字节字节 802.3MAC帧帧字节字节66246 15004MAC 帧帧目地地址目地地址源地址源地址长度长度/类型类型数数 据据FCS4用户优先级用户优先级 802.1Q标记类型标记类型 标记控制信息标记控制信息 1000 0001 0000 0000 VLAN ID规范格式指标符

6、规范格式指标符CFI插入插入4字节的字节的VLAN标记标记2022-3-18College of Information Science and Technology, HAUT13/442022-3-18College of Information Science and Technology, HAUT14/442022-3-18College of Information Science and Technology, HAUT15/442022-3-18College of Information Science and Technology, HAUT16/442022-3-18Co

7、llege of Information Science and Technology, HAUT17/442022-3-18College of Information Science and Technology, HAUT18/442022-3-18College of Information Science and Technology, HAUT19/442022-3-18College of Information Science and Technology, HAUT20/442022-3-18College of Information Science and Technol

8、ogy, HAUT21/442022-3-18College of Information Science and Technology, HAUT22/44AP1AP22022-3-18College of Information Science and Technology, HAUT23/44AP1AP22022-3-18College of Information Science and Technology, HAUT24/44AP1AP22022-3-18College of Information Science and Technology, HAUT25/44AP1AP220

9、22-3-18College of Information Science and Technology, HAUT26/44AP1AP22022-3-18College of Information Science and Technology, HAUT27/44AP1AP22022-3-18College of Information Science and Technology, HAUT28/442022-3-18College of Information Science and Technology, HAUT29/44自组织网络自组织网络AEDCBF源结点源结点目的结点目的结点

10、转发结点转发结点转发结点转发结点转发结点转发结点2022-3-18College of Information Science and Technology, HAUT30/442022-3-18College of Information Science and Technology, HAUT31/442022-3-18College of Information Science and Technology, HAUT32/442022-3-18College of Information Science and Technology, HAUT33/44A的作用范围的作用范围C的作用范

11、围的作用范围ABCD2022-3-18College of Information Science and Technology, HAUT34/44ADCBB的作用范围的作用范围C的作用范围的作用范围？2022-3-18College of Information Science and Technology, HAUT35/442022-3-18College of Information Science and Technology, HAUT36/442022-3-18College of Information Science and Technology, HAUT37/44存储器

12、CPU传感器硬件电池无线收发器(a)(b)2022-3-18College of Information Science and Technology, HAUT38/442022-3-18College of Information Science and Technology, HAUT39/44802.11n覆盖范围覆盖范围1Gb/s100Mb/s10Mb/s1Mb/s100kb/s10kb/s用户用户数据率数据率PAN LAN MAN WAN802.15.4ZigBee802.15.1蓝牙蓝牙802.15.3超宽带超宽带802.11g, a802.11b802.162G移动通信移动通信3G移动通信移动通信4G移动通信移动通信Wi-FiWiMAX2022-3-18College of Information Science and Technology, HAUT40/442022-3-18College of Information Science and Technology, HAUT41/442022