INFORMATION IS MOVED FROM Tx

1
Introduction
2
Channels
TRANSMITTER
RECEIVER
Tx Rx
CHANNEL

• INFORMATION IS MOVED FROM Tx Rx
• THE SPEED AT WHICH THE INFORMATION IS MOVED
  BETWEEN Tx Rx IS SET BY ITS BIT RATE ON THE
  CHANNEL

3
Channels II

• CHANNELS ARE PHYSICAL AND CAN EITHER BE (BUT NOT
  LIMITED TO)
• COPPER
• FIBRE
• WIRELESS
• ALSO KNOWN AS THE TRANSMISSION MEDIUM

4
Bit Rate 1

• 1,000 bit/s 1 kbit/s (one kilobit or one
  thousand bits per second)
• 1,000,000 bit/s 1 Mbit/s (one megabit or one
  million bits per second)
• 1,000,000,000 bit/s 1 Gbit/s (one gigabit or
  one billion bits per second)

5
Bit Rate 2

• SECTION OF TEXT THIS IS A TEST
• TEXT CONTAINS 14 CHARACTERS
• ASSUME 8 BITS PER CHARACTER
• TOTAL 112 BITS OF INFORMATION

COMPARISON OF BIT RATE AND TRANSMISSION TIME
6
Bit Rate 3

• IMAGE FROM NASA SURFACE OF MARS
• PICTURE CONTAINS 1080 x 602 PIXELS, AT 8 BITS PER
  PIXEL THERE IS 5.2 Mbits OF INFORMATION IN THE
  PICTURE

COMPARISON OF BIT RATE AND TRANSMISSION TIME
7
Bit Rate 4

• Audio (MP3)
• 32 kbit/s MW (AM) quality
• 96 kbit/s FM quality
• 128160 kbit/s Standard Bitrate quality
  difference can sometimes be obvious (e.g. bass
  quality)
• 192 kbit/s DAB (Digital Audio Broadcasting)
  quality. Quickly becoming the new 'standard'
  bitrate for MP3 music difference can be heard by
  few people.
• 224320 kbit/s Near CD Quality. Sound is near
  indistinguishable from most CDs.
• Other audio
• 800 bit/s minimum necessary for recognizable
  speech (using special-purpose FS-1015 speech
  codecs)
• 8 kbit/s telephone quality (using speech
  codecs)
• 500 kbit/s1 Mbit/s lossless audio as used in
  formats such as FLAC, WavPack or Monkey's Audio
• 1411 kbit/s PCM sound format of Compact Disc
  Digital Audio

8
Bit Rate 5

• Video (MPEG2)
• 16 kbit/s videophone quality (minimum necessary
  for a consumer-acceptable "talking head" picture)
  
• 128 384 kbit/s business-oriented
  videoconferencing system quality
• 1 Mbit/s VHS quality
• 5 Mbit/s DVD quality
• 15 Mbit/s HDTV quality
• 36 Mbit/s HD DVD quality
• 54 Mbit/s Blu-ray Disc quality

9
Bandwidth

• THERE ARE LIMITS ON BIT RATE
• ALL CHANNELS HAVE AN UPPER LIMIT ON BIT RATE
• THE LIMIT IS SET BY THE SO CALLED CHANNEL
  BANDWIDTH
• BANDWIDTH IS MEASURED IN MHz GHz
• MEGAHERTZ GIGAHERTZ (MILLIONS BILLIONS OF
  HERTZ)
• IN GENERAL THE LARGER THE BANDWIDTH THE GREATER
  THE INFORMATION CARRYING CAPACITY IN Bits/sec

10
What is a Network?

• A NETWORK CONSISTS OF A COLLECTION OF NODES AND
  CHANNELS
• A NODE CAN CAN BE ANY NUMBER OF THINGS, FOR
  EXAMPLE
• COMPUTER
• PRINTER
• SCANNER
• BACKUP DRIVE
• SECURITY CAMERA
• SENSORS

11
What is Topology?

• TOPOLOGY DETERMINES THE WAY IN WHICH NODES AND
  CHANNELS ARE INTERCONNECTED
• AN ANALOGY WOULD BE THAT OF A RAIL NETWORK
• STATIONS (NODES) ARE CONNECTED TOGETHER BY RAIL
  TRACK (CHANNEL)

12
Network Topologies Point to Point
13
Network Topologies Bus
14
Network Topologies Ring
15
Network Topologies Star
16
Network Topologies

• PHYSICAL STAR
• RING CONFIGURATION
• STAR TOPOLOGY

17
Network Topologies

• COLLAPSED BACKBONE
• SIMILAR TO STAR

18
Network Topologies

• Shared Bandwidth network

19
Network Topologies

• Switched Bandwidth network

20
Network Topologies
21
ETHERNET
22
Ethernet

• Ethernet is the most popular LAN standard in the
  world with over 1 Billion installed nodes
  (1Billion nodes - IET Computing Control
  Engineering February/March 2007)
• The original Ethernet came out around 1979 at 10
  Mbps, and thats where it stayed for more than 10
  years
• Ethernet runs over co-axial cable or twisted pair
  copper wires and provides a 10 Mbps to share
  between all users

23
To Slow

• Users were finding the 10 Mbps performance of
  Ethernet too slow. This bandwidth crunch is the
  result of three technological changes
• the increased speed of computer processors
• the increased number of users on networks
• new bandwidth-intensive applications on networks

24
Ethernet Types

• ETHERNET
• 2/5 BASE T 10Mbps
• THIN/THICK COAX ETHERNET
• 10 BASE T 10Mbps
• ORIGINAL TWISTED PAIR ETHERNET
• 100 BASE T 100Mbps
• FAST ETHERNET
• 1000 BASE T 1000Mbps
• GIGABIT ETHERNET

25
Ethernet History

• 802.3 1985
• 10Mbps THICK THIN ETHERNET
• 802.3u 1995
• 100Mbps FAST ETHERNET
• 802.3z 1998
• 1000Mbps GIGABIT ETHERNET (FIBRE)
• 802.3ab 1999
• 1000Mbps GIGABIT ETHERNET (COPPER)

26
Ethernet

• PROTOCOL
• CSMA/CD
• PHYSICAL MEDIUM
• COAX
• TWISTED PAIR
• MULTIMODE FIBRE
• SINGLEMODE FIBRE

27
CSMA/CD
START TRANSMITTING
CARRIER SENSE MULTIPLE ACCESS WITH
COLLISION DETECT
LISTEN FOR COLLISION
BACK OF FOR RANDOM PERIOD
COLLISION
YES
NO
CONTINUE TRANSMITTING
28
Ethernet Over Copper

• THIN/THICK COAX
• OBSOLETE 2/5BASET
• CAT 3
• OLD INSTALLATIONS 10BASET
• CAT 4
• CAT5 MADE CAT4 OBSOLETE
• CAT 5
• IN MAJORITY OF INSTALLATIONS