Ethan's Notes

Appearance

数据链路层 ​

image-20251222163512000

1. 数据链路层概述 ​

image-20251222162943630

数据链路层三个重要问题 ​

封装成帧 ​

image-20251222163131317

差错检测 ​

image-20251222163210459

可靠传输 ​

image-20251222163318549

2. 封装成帧 ​

image-20251222163957385

面向字节的透明传输，对于数据载荷部分的帧定界符，使用转义字符填充

image-20251222164201555

面向比特的透明传输，对于帧定界符，按照约定添加比特，接收后，再按照约定移除即可

image-20251222164402283

3. 差错检测 ​

image-20251222164520808

奇偶校验 ​

image-20251222164637109

CRC ​

image-20251222164748502

image-20251222165355609

image-20251222165721429注意： 最后余数的位数应与生成多项式的最高次数相同，位数不够前面补0

image-20251222170110741

image-20251222170226232

4.可靠传输 ​

基本概念 ​

image-20251222170405625

image-20251222170554282

实现机制1 停止等待协议 SW（Stop-and-Wait）image-20251222171350573 ​

image-20251222171616657

image-20251222171924188

image-20251222172423029

image-20251222172515897

实现机制2 回退N帧协议GBN（Go-Back-N） ​

image-20251222173558770

image-20251222174155742

image-20251222174351242

image-20251222175101939

实现机制3 选择重传协议SR（Selective Request） ​

image-20251222175232589

image-20251222175715116

image-20251222180029073

image-20251222180410203

5. 点对点协议 PPP ​

image-20251222180600669

image-20251222190630070

image-20251222191058444

image-20251222191937622

image-20251222192134335

image-20251222192155732

image-20251222192557759

6. 媒体接入控制（MAC） ​

image-20251222193318756

静态划分信道 ​

image-20251223083639969

频分复用FDM ​

image-20251223083919799

时分复用TDM ​

image-20251223083957474

波分复用WDM ​

image-20251223084102925

码分复用CDM ​

image-20251223084324844

image-20251223084646880

image-20251223092559092

image-20251223092755962

image-20251223095725370

动态接入控制-随机接入（CSMA/CD） ​

image-20251223101024896

image-20251225144418100

image-20251225151720365

image-20251225153124284

image-20251225153258619

image-20251225153350325

image-20251225153500288

image-20251225153633128

image-20251225153731931

image-20251225153802341

image-20251225153815438

image-20251225153930958

image-20251225154210348

image-20251225154635601

7. MAC地址、IP地址、ARP协议 ​

7.1 MAC地址 ​

image-20251225160504239

image-20251225155749634

image-20251225155859363

image-20251225160201823

7.2 IP地址 ​

image-20251225161403364

image-20251225160735535

image-20251225160955800

image-20251225161145321

image-20251225161348361

7.3 ARP协议 ​

image-20251225161724925

image-20251225161814621

8. 集线器和交换机的区别 ​

集线器 ​

image-20251225162239462

image-20251225162259914

交换机 ​

image-20251225162331937

image-20251225162440689

image-20251225162656855

image-20251225162707528

9. 以太网交换机自学习和转发帧的流程 ​

image-20251225173012075

image-20251225171316723

image-20251225172315898

image-20251225172438121

image-20251225172955269

10. 以太网交换机的生成树协议STP ​

image-20251225182113984

image-20251225182230696

11. 虚拟局域网VLAN ​

image-20251225182534491

image-20251225182713824

image-20251225182812592

image-20251225183000968

image-20251225183234653

image-20251225184017565

image-20251225184347648