海车家大 TCP/IP Example 1950 End System Y End System Y Router 1 LAN,WAN, Router 2 or ▣ point-to-point link LAN LAN Appli- Appli- cation cation TCP TCP P P IP P LLC LLC LLC LLC MAC MAC MAC MAC Physical Physical Physical Physical Physica Physical 2022/10/9 现代密码学理论与实践-16：P的安全 6/452022/10/9 现代密码学理论与实践-16：IP的安全 6/45 TCP/IP Example