1. 1 Introduction to Networking Lesson 01 NETS2150/2850

2. 2 A Communications Model Source generates data to be transmitted Transmitter Converts data into transmittable signals Transmission System Carries data Receiver Converts received signal into data Destination Takes incoming data

3. 3 Simplified Communications Model - Diagram

4. 4 What’s the Internet? millions of connected computing devices: hosts, end-systems PCs workstations, servers PDAs, phones running network apps communication links fiber, copper, radio, satellite routers: forward packets (chunks of data) local ISP enterprise network regional ISP router workstation server mobile

5. 5 Types of Networks Various categorisation of networks One way - geographical span Categories of Networks: Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN)

6. 6 Local Area Networks Smallest scope Building or small campus Below 10 km Usually owned by same organization as attached devices Much higher capacities Usually broadcast systems

7. 7 Typical LAN Configurations Switched LANs Switched Ethernet (802.3) May be single or multiple switches Asynchronous Transfer Mode (ATM) LAN Wireless (802.11) Supports mobility Ease of installation

8. 8 Metropolitan Area Networks (MAN) Middle ground between LAN and WAN Private or public network High speed Large area 10 – 100 km

9. 9 Wide Area Networks Large geographical area, > 100 km Crossing public rights of way Rely in part on public (ISP) network Alternative technologies Circuit switching Packet switching

10. 10 Circuit Switching Dedicated communications path (physical) established for the duration of the conversation E.g. telephone network

11. 11 Packet Switching Data sent out of sequence Small chunks (packets) of data at a time Packets passed from node to node between source and destination Used for computer to computer communications

12. 12 Summary Communications Model Network classification based on geographical span