1. What is a network?
Who am I?
Why am I here?
Steve Betts
2015

2. Math
A network is a collection of objects and the relationships between them
Graphs
Original

3. Metro DC Transit Network

4. Computer Networks
A computer network is a set of computers that can communicate with each other
There are at least 4 networks in the room right now
Wireless Ethernet
Wired Ethernet
Cellular
Bluetooth
Communcation medium

5. How do networks work? Open Systems Interconnect (OSI) model
What do the layers do?
Why use layers? Radio comm example / Cell phone example, complexity

6. What is a modem / router? Modem stands for Modulator / Demodulator
Modem translates from analog to digital and back
The real world is analog
Router decides where data should go – it “routes” the data
Most routers only have 1 choice – to the internet provider

7. Definitions LAN – local area network WAN – wide area network
PAN – personal area network
Internet – any two networks that are connected
ISP – Internet service provider – entity that connects you to the internet

8. Home network
Internet

9. The internet – circa 1998