1. Networking (week 11)
LIS 3353 Technologies
Networking and the Internet

2. Networking (week 11)
Agenda
 IT News
 Networking
 Thursday – bring your laptop!

3. IT News
 Apple – Foxconn – Daisey – TAL
 Windows 8

4. Why do we network?
 http://www.youtube.com/watch?v=7_LPdtt
KXPc&feature=related
 Reduce hardware and software costs
 Provide access to a wide range of services
and specialized peripheral devices
 Enable people to work together,
regardless of time and place

5. Networks 101

6. Network 101

7. Networks 101
Refresher
– Client/server – contains servers and clients
– Peer-to-peer (P2P) – every computer is
considered an equal

8. Ring Topology
Tree Topology
Star Topology
Bus Topology Mesh Topology

9. Networks 101
 A network is a collection of computer
systems configured to share digital data
and resources
 Computer to Computer 
 Local Area Network (LAN) 
 LANs extend across limited
– geographical area
 servers, terminals, etc.

10. How LANs work
 Connectivity supporting two-way communication
 Resource sharing
 Limited geographical area
 Transparency of use
 Support from hardware and software
 Positives
– communications
– management control
– cost-effectiveness
 Negatives
– need for additional equipment
– maintenance
– support staff

11. Lots of Networks
 LAN (Local Area Network)
 WAN (Wide Area Network)
 MAN (Metropolitan Area
Network)
 PAN (Personal Area Network)
 And more – NFC, BAN, NAN,
CAN…

12. Networks
 Internetwork:
 collection of autonomous networks
 Ex: the Internet, intranets
 The Internet:
 ARPAnet - late 1960s
 decentralized
 loosely-coupled
 redundant
 Apps
 e-mail
 telnet
 FTP (file transfer protocol)
 www

13. Networks
 ARPANET
 The ARPANET, created in 1969,
connected computers at four
universities
 WWW
 Hypertext system
 This was an open system, evolved to
I2

14. Networks - Shannon
 an information source generates a message
 a transmitter encodes the message as a signal
 the signal is transmitted over a communications channel
 the receiver extracts a signal from the communications
channel and converts it back into the form of a message
 the destination receives the message
 a source of noise is usually present in the
communication channel—this is a random element that
modifies the signal in unpredictable ways

15. Networks
 Messages are encoded as a stream of
binary numbers (0s and 1s)
 Signals are transmitted as electro-magnetic
energy (electrical, optical, or radio waves)
 Rate of reliable transmissions depends on
the properties of the channel and the
complexity of the message
 Two types of signals:
 Analog
 Digital

16. iSpace Model
 CLIENT--(local)
system requesting
services
 SERVER--(remote)
system that receives
and handles
requests from many
clients concurrently

17. Peer-To-Peer (P2P)
 Another Model: Peer to Peer
 Each entity can act as a client or a server
 File sharers use this P2P terminology for file
exchanges (ex.: Gnutella, Napster, Grokster,
bittorrent)
 P2P (workgroups) - typically <10 people
 No central communication control device
 Inexpensive
 Each computer’s resources are used

18. Other models (like FSU)
 Dedicated servers
 File, application, mail, fax, communication
 Centralized, shared resources
 Security
 Backup
 Testing (iSpace)
 Virtual servers

19. Bandwidth
 Broadband
– multiple signals transmitted on the same channel
simultaneously
– channel is divided into separate frequency bands,
each capable of carrying a signal
 Narrowband/baseband
– employs [the entirety of its available] bandwidth
for one signal

20. Bandwidth Terms
 The bandwidth of a communications channel
determines its capacity to transmit data—it’s
analogous to the size of plumbing pipes (10MB,
100MB, 1GB, 10GB)
 Analog signals may contain independent
waveforms of various frequencies
 The number of frequencies supported by a
channel determines its bandwidth
 The bandwidth of a digital channel is usually
measured in bits per second (bps)

21. Bandwidth Terms
 What affects bandwidth?
 media used for transmission of signals

23. Networks 101
 Physical layer supports
basic carrier signals
 Data link layer manages
point-to-point
connectivity
 Network layer routes
data from sender to
destination
 Transport layer
provides messaging
services
 Application layer
provides user functions

24. Layers

25. Layers

26. Sending Information
 When you transmit data, it is broken up into small
pieces called packets
 A packet is a parcel of data that is sent across a
network
– Has the address of its sender
– Has the address of the destination
– Has some data
 When packets reach their ultimate destination,
they are put back together into the data that was
originally transmitted

27. Sending Information
 Data can be sent in two ways:
– Synchronous protocols
– Asynchronous protocols
 Handshaking

28. Networking
 Packet Switching
– The message is made of separate data packets,
each addressed to the destination
– Packets are transmitted over any available
connection to the destination
– The receiving node reassembles the message

31. Networks
 www @ FSU
 Comcast

32. Connecting
 Modem / Dial-up
– “modem” = modulate-demodulate
 Modulation – changing the characteristics of a
signal (digital to analog)
 Demodulation – changing the signal back to its
original state (analog to digital)

33. Cables
 Most networks use twisted-pair cables
– UTP (unshielded twisted pair)
– STP (shielded twisted pair)
– Looks similar to telephone cable
– Has a square plastic RJ-45 connector
 Twisted Pair Wire Cable
– Insulated pairs of wires historically used in
telephone service
• Category 1 – Telephones
• Category 3 – Up to 10Mbps
• Category 5 – Up to 100Mbps

34. Cables
 Another option is coaxial cable
– Resembles cable-TV cable
– Round, silver BNC or F-type connector
 Coaxial Cable (BNC)
– Consists of an inner conductor wire surrounded by
insulation, called the dielectric. The dielectric is
surrounded by a conductive shield, which is surrounded
by a non-conductive jacket. Coaxial cable has a better
data transmission rate than twisted pair.

35. Cables
Fiber-optic cable is a bundle of extremely
thin tubes of glass
– Many extremely thin fibers of glass or plastic,
coated with a cladding and bound together in a
sheathing which transmits signals with light beams
•Fast transfer rates
•Immune to electrical interference (emi occurs
over long distances)
•Hard to tap into
•Takes less space
– Each optical fiber (tube) is thinner than a human hair

36. Cable Signals

37. Connection Speeds
Comcast
6mps

38. Networks
 Repeaters
– boost the signal strength over transmission
medium
 Bridges
– isolate LANs from unnecessary traffic, but connect
LANs to neighboring networks
 Switches?, Routers?, Hubs?

39. Networks
 Datagrams:
 TCP/IP:
 IP address:
 Domain names are pseudonyms for IP
addresses

40. Networks
 Protocols:
– A communications protocol is a set of rules for efficiently
transmitting data from one network node to another
– The best-known protocol is probably TCP/IP
– Sending Computer:
• Breaks the data into packets; adds addressing
information; prepares the data for transmission
– Receiving Computer:
• Takes packets off the cable; strips the packets of
addressing information; reassembles the data from the
packets

41. Networks
TCP/IP provides a standard that is public,
free, extensible, and fairly easy to
implement. TCP/IP is the glue that holds
the Internet together.

42. Networks
 The IP part of TCP/IP defines the format for
the addresses that identify computers on
the Internet
 These addresses are called IP addresses
 An IP address is a series of numbers, such
as 204.127.129.001
 IP addresses

43. Networks
 ISPs need static IP addresses
– Clients typically use dynamic IP addresses, as the IP
addressing scheme provides approximately only 4.3
billion unique addresses
 Numbers are hard to remember, so host
computers also have names called domain
names; a domain names corresponds to an
IP address; domain name system – huge
database that houses the names and IP
addresses of key computers
 Domain name servers – computers that
house this database

44. Networks
 Internet 2
– consortium of government, industry, and
education
 The consortium
– establishes network capabilities to support
national research
– develops the next generation of Internet
applications
– transfers these to worldwide Internet

45. Networks
 Internet 2
– remote instrumentation and virtual laboratories
– distance learning
– digital libraries
– Tele-immersion
– multicasting

46. Networks
 National LambdaRail
– High-speed national network running on fiber
– LambdaRail will merge with I2
– Testing service network
– University-based and -owned initiative

47. Networks
 Wireless
– infrared broadcasting
– radio frequency
broadcasting
• spread spectrum (cell
telephony)
• direct sequence spread
spectrum (DSSS)
• frequency hopping
spread spectrum (FHSS)

48. Networks – Wireless
Protocols
Release Data Rate Data Rate
Protocol Op. Frequency Range (Indoor)
Date (Typ) (Max)
Legacy 1997 2.4 GHz 1 Mbit/s 2 Mbit/s ?
~30 meters
802.11a 1999 5 GHz 25 Mbit/s 54 Mbit/s
(~100 feet)
~30 meters
802.11b 1999 2.4 GHz 6.5 Mbit/s 11 Mbit/s
(~100 feet)
2003 ~30 meters
802.11g 2.4 GHz 25 Mbit/s 54 Mbit/s
(June) (~100 feet)
2008 2.4 GHz or ~50 meters
802.11n 200 Mbit/s 540 Mbit/s
(April) 5 GHz (~160 ft)

49. Networks

50. Networks
Support for the creation of 

802.11a - 54 Mbps standard, 5 GHz signaling (ratified 1999)
802.11b - 11 Mbps standard, 2.4 GHz signaling (1999)
technologies for wireless local 

802.11c - operation of bridge connections (moved to 802.1D)
802.11d - worldwide compliance with regulations for use of wireless signal
spectrum (2001)
area networking: 

802.11e - Quality of Service (QoS) support (not yet ratified)
802.11F - Inter-Access Point Protocol recommendation for communication
between access points to
 support roaming clients (2003)
 802.11g - 54 Mbps standard, 2.4 GHz signaling (2003)
 802.11h - enhanced version of 802.11a to support European regulatory
requirements (2003)
 802.11i - security improvements for the 802.11 family (2004)
 802.11j - enhancements to 5 GHz signaling to support Japan regulatory
requirements (2004)
 802.11k - WLAN system management (in progress)
 802.11l - skipped to avoid confusion with 802.11i
 802.11m - maintenance of 802.11 family documentation
 802.11n - 100+ Mbps standard improvements over 802.11g (in progress)
 802.11o - skipped
 802.11p - Wireless Access for the Vehicular Environment
 802.11q - skipped
 802.11r - fast roaming support via Basic Service Set transitions
 802.11s - ESS mesh networking for access points
 802.11T - Wireless Performance Prediction - recommendation for testing
standards and metrics
 802.11u - internetworking with 3G / cellular and other forms of external
networks
 802.11v - wireless network management / device configuration
 802.11w - Protected Management Frames security enhancement
 802.11x - skipped (generic name for the 802.11 family)
 802.11y - Contention Based Protocol for interference avoidance

51. Networks
 Using “ping” or “traceroute,” you can
discover the length of time that data is in
transit
 On average, data within the US usually
arrives at its destination 110-120
milliseconds (ms) after it is sent
 Overseas transmissions require a little
more time
 NetTraffic

52. Networks

53. Networks
 Network Monitors
– Keep track of network traffic, number of
packets, packet size, collisions, re-
transmissions, etc.
– Enable planning for growth and quality
 Network Analyzers
– Randomly dissect packets, analyze problems,
and determine the source of errors

54. Portals
 Web entry stations that offer quick and
easy access to a variety of services
– Consumer portals include search engines, e-mail
services, chat rooms, references, news headlines,
shopping malls, and other services
– Corporate portals on intranets serve the
employees of particular corporations
– Vertical portals are targeted at members of a
particular industry or economic sector
 Other Web Stuff
– Push (auto-updates) versus Pull (browser in client-
server model) technology

55. Nets
 Intranets
 Extranets
 Electronic data interchange (EDI)

56. Questions?