1. Application Transport Network Link Physical

2. Software Socket Socket Socket Host Host Node Node Node Signals Application Transport Network Link Physical

3. Messages Segments Datagrams Frames Signals Application Transport Network Link Physical

4. Software SocketApplication Applications send messages to each other

5. Socket SocketTransport Sockets send segments

6. Host HostNetwork Networks communicate via datagrams

7. Node NodeLink Switches/routers communicate with frames

8. Node SignalsPhysical 10100101010101010100 10101010110111010110 10100101110101011101 00101110110011101010 10101011000101101011 01001010100101001011 01010101010111001010 Modulation/Demodulation : MoDem Switches/routers change 1s and 0s into electromagnetic waves

9. Each layer in the 5-layer TCP/IP Internet Model offers different services , has different protocols running on top of it resulting in different message structures, and has different modes of addressing.

10. Process-process communication Logical communication, segment level error detection/correction, guaranteed delivery Host-host communication, data fragmentation, forwarding/routing, best effort delivery Node-node communication, bit-level error detection/correction, best effort delivery Bit-level data delivery, best effort delivery Application Transport Network Link Physical

11. DHCP, DNS, RIP, HTTP, FTP, SMTP TCP, UDP, ICMP*, TLS/SSL IP, ICMP*, ARP*, IPSec ARP*, MAC (Ethernet, DSL, DOCSIS) RZ, NRZ-I/L, Manchester, Differential Manchester, ASK, FSK, PSK, QPSK Application Transport Network Link Physical * - denotes protocols which span two layers

12. Process ID Port Number IP Address MAC Address - Application Transport Network Link Physical

13. Application Transport Network Data Link Physical Application