CISCO

Computer Networking

The Internet

The Internet Yesterday

Basics of Computing

Parts of a Computer

• CPU - Central Processing Unit

• Memory - ROM, RAM, etc.

• Interface - Modem, Video Card, Floppy, etc.

All are connected by a bus which is plug in slots.

NIC

• Network Interface Card– PCs use IDE or PCI– Laptops use PCMCIA (“credit card”)

TCP/IP - the computers address on the network

Networks - a “conglomeration” of people or things focused on a common goal

• LAN– Local Area Network

– used within or between offices

• WAN– Wide Area Network

– used between buildings or within a “complex”

• By using the binary number system• The only possible symbols or "bits", are 1 and 0. • The bits represent text, pictures, and sounds• A 1 bit is often represented by the presence of voltage

on a copper conducting cable or light in an optical fiber

How is information stored in computers?

Imagine measuring the voltage at one point on the cable as time goes on (for a fiber, imagine measuring the light intensity versus time).

Your measurements would allow you to create a graph of voltage versus time (for a fiber, light intensity versus time).

A decimal numbering system is based on powers of 10:

100, 101, 102, 103, 104, etc.

100 = 1

101 = 10 X 1 or 10

102 = 10 X 10 or 100

103 = 10 X 10 X 10, or 1000

104 = ?????????

The numbering system most frequently used is the decimal numbering system.

Count 9, 10

Count 99, 100

Count 999, 1000

When counting in the decimal system when you reach the number 9 you must add another digit. Examples:

Binary numbering system (Bit - binary digit)

How does a binary number system differ from a decimal numbering system?

A binary numbering system is based on powers of 2

20, 21, 22, 23, 24, etc.

20 = 1

21 = 2 X 1 or 2

22 = 2 X 2 or 4

23 = 2 X 2 X 2, or 8

24 = ?????????

Let’s count in binary. Remember you can only use 0s and 1s.

0

1

10

11

100

101

110

111

Let’s take a break and complete a worksheet on converting decimal to binary and vice versa.

Bonus: What would an octet of all ones equal?

American Standard Computer Information Interchange

Bandwidth• Water• Hiway System• Radio• Audio

• Media– Coaxial Cable

– Category 5 Cable (Cat 5)

– Fiber Optic

Bandwidth determines throughput (because file are transferred faster)

– slow or fast– 14.4K or 56K