1. Service Providers & Data Link & Physical layers Week 4 Lecture 1

2. Internet Architecture Application layer – HTTP, SMTP etc Transport layer – TCP, UDP Network layer - IP Data link & Physical layers – the territory of the Lan & Telcos W3C IETF ITU IEEE

4. WAN Workstations Router & Firewall File server Application & Database Servers Printers

6. Bus topology using Co-axial cable

7. Hub topology using UTP

8. Floor 15 Floor 14 Floor 13 Machine room Router Servers WAN All wires would be 100mbps UTP Cat 5 Backbone could be Optic fibre

11. TCP/IP Frame Relay/ATM ATM/Fibre CSMA/CD CSMA/CD Routers Local ISP POP City carrier hubs

16. Floor 15 Floor 14 Floor 13 Machine room Router Servers WAN All wires would be 100mbps UTP Cat 5 Optic fibre

17. Network Devices Application Transport Network Link Physical Link Physical Network Link Physical Application Transport Network Link Physical Host Bridge or Switch Router Host Physical Hub

20. Application Application Process Application layer Message

21. Application Application Process Transport layer Message Transport Transport Segment Host

22. Application Application Process Network layer Message Transport Transport Segment Host Network Network Network Host & Router Datagram Datagram

23. Application Application Process Link layer Message Transport Transport Segment Host Network Network Host & Router Datagram Datagram Link Link Host, router & switch Frame Frame Link Link Link Link Link Network