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LOCAL foilset Introduction To Multimedia Internet Systems

Given by Marek Podgorny at CPS640 MultiMedia and WWW on Spring 97 Semester. Foils prepared 31 January97
Abstract * Foil Index for this file

See also color IMAGE
Data networking term refers to exchange of digital information between remote systems
  • Data can be exchange between any kind of devices
Computer networking is a special case of data networking
  • While communication between computer components over a bus is clearly a case of digital data transmission, this is not considered data networking example
Differentiating factors: media, parallel vs. serial, distance, protocol standardization

Table of Contents for full HTML of Introduction To Multimedia Internet Systems

1 Multimedia Networking: Elementary Introduction
2 Data Networking
3 Physical Data Transmission
4 Physical Data Transmission
5 Baseband vs. Broadband
6 Time Division Multiplexing
7 Broadband Transmission
8 Circuit vs. Packet Switching
9 Circuit vs. Packet Switching
10 Are the examples right?!!!
11 Layering - an example
12 Layering - an example
13 Connection vs. Connectionless
14 Connection vs. Connectionless
15 Confusing?
16 Popular Network Topologies
17 Case study: Ethernet
18 Case study: Token Ring
19 Case study: FDDI

This table of Contents Abstract

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Foil 1 Multimedia Networking: Elementary Introduction

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Basics of the Data Networking
Marek Podgorny
CPS600, January `97
HELP! * GREY=local HTML version of LOCAL Foils prepared 31 January97

Foil 2 Data Networking

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Data networking term refers to exchange of digital information between remote systems
  • Data can be exchange between any kind of devices
Computer networking is a special case of data networking
  • While communication between computer components over a bus is clearly a case of digital data transmission, this is not considered data networking example
Differentiating factors: media, parallel vs. serial, distance, protocol standardization
HELP! * GREY=local HTML version of LOCAL Foils prepared 31 January97

Foil 3 Physical Data Transmission

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Terrestrial media: metallic cables and optical fibers
  • metallic cables: coaxial cables and twisted pair cables
    • carrier: electrical pulses
    • problems: signal attenuation, noise, bandwidth and length limitations, price
  • optical fiber
    • carrier: modulated light
    • problems: expensive end optic
    • advantages: high bandwidth, sleuth-resistant, long distance
HELP! * GREY=local HTML version of LOCAL Foils prepared 31 January97

Foil 4 Physical Data Transmission

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Aerial systems: surface transmission and satellite transmission
  • both less reliable (higher error rates) as compared to cable/fiber
  • high latency (~540 msec) for satellite transmission lines
  • limited frequency domain and, hence, global transmission capacity
  • significant chunk of global capacity assigned to analog transmission
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Foil 5 Baseband vs. Broadband

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Baseband transmission
  • Electrical signal applied directly between the wires
    • example: Ethernet technology
  • Basic limitation: only one bit can be transmitted at any given time
  • Overall efficiency increased by Time Division Multiplexing (TDM)
    • Why? Idle time costs money....
    • TDM flavors: synchronous and asynchronous
  • Signal attenuation is a big problem for baseband networks
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Foil 6 Time Division Multiplexing

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Synchronous TDM: moderately efficient
Time
Asynchronous TDM: more flexible and efficient
Asynchronous
Time
Division
Multiplexing
Input A
Input B
Input C
Output line
Time
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Foil 7 Broadband Transmission

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Signal is sent by modulating a carrier
Applicable over both cable and fiber
Amplitude and frequency modulation
In data transmission world, Frequency Division Multiplexing (FDM) term is used
Using narrow band filters, receivers are able to separate multiple signals
Using FDM, multiple transmissions may be concurrently sent over a single cable/fiber
Example: a modem
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Foil 8 Circuit vs. Packet Switching

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Circuit Switching Networks
  • Originally, a connection was set up by physically connecting segments of physical wire to form a continuous electrical circuit.
  • At present, the circuit is formed using TDM in the synchronous mode
  • Circuit switched network guarantees the bit rate and, usually, constant, predictable latency.
  • Downside: cost of the connection depends on the reserved bandwidth, not on actual amount of data transferred over the circuit. No statistical multiplexing.
  • Examples: phone lines, ISDN lines
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Foil 9 Circuit vs. Packet Switching

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Packet switching networks
  • Multiplex several data streams more efficiently over single wire/fiber/switch
  • Information chopped into small units (packets) sent one a time
  • Many sources of packets can coexist attached to one transmission medium
  • Multiplexing is statistical and network behavior is not entirely predictable
  • Packets carry their destination addresses in headers
  • Examples: Ethernet, FDDI, Frame Relay, IP
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Foil 10 Are the examples right?!!!

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Ethernet and IP both listed as packet switching networks - is this right?
YES - the are both packet switching albeit in different layers!
This leads us to the concept of the layering
Networks run on top of other networks; protocols run on top of other protocols.
Layering is used to separate network functionality into logical entities.
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Foil 11 Layering - an example

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Secretary-assisted phone conversation
  • Need phone set with right connectors and internal electronics. This is layer 1 - physical/electrical
  • Need microphone (voice to electrical signal) and forwarding mechanism to pass voice generated electrical signal end to end. This is layer 2 - link
  • Need keypad/rotary and a way to setup connection. This is layer 3 - network
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Foil 12 Layering - an example

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Need secretary to get another secretary, to agree on the language for their conversation and to request your interlocutor. This is layer 4 - transport
Need a common language for your own conversation. This is layer 6 - presentation
Now you can talk business - this is layer 7 - application
Each layer depends/rides on top of other layers.
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Foil 13 Connection vs. Connectionless

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Packet vs. circuit switching determines how information is routed once inside the network
Connection mode determines under what condition data can be accepted
Connection-oriented networks are aware about two systems communicating. The network must admit a communication stream before data exchange starts
Connectionless network has no idea that two systems communicate. Connection is never refused
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Foil 14 Connection vs. Connectionless

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Connection-oriented network
  • Implementation: virtual circuits, signaling protocols
  • Advantages: more predictable traffic
  • Disadvantages: need call set-up which introduces delay; wastes network resources
Connectionless networks
  • Implementations: addresses in packet headers
  • Advantages: no call set-up delay, no busy signal
  • Disadvantages: difficult to reserve resources
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Foil 15 Confusing?

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Very much so. The features listed above can be combined in every possible way, leading to an extremely complex topologies and interdepen-dencies
It is possible to have connectionless and circuit switched network, as well as connection oriented packet switching network
It is possible to have asynchronous services running over synchronous carriers (ATM)
It is possible to combine multiple contradictory features over the same physical medium
HELP! * GREY=local HTML version of LOCAL Foils prepared 31 January97

Foil 16 Popular Network Topologies

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Star/tree/mesh topologies.
  • Used mostly for circuit switched networks (then…)
  • Also used to interconnect broadcast networks (now…)
  • Support packet switching layers….
Bus networks - shared media
  • All connected workstations see all information
Ring networks - shared media
  • Use broadcast but assign time slots differently
Internetworks connect all of the above
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Foil 17 Case study: Ethernet

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Bus topology, connectionless, baseband, packet switching
CSMA-CD (Carrier Sense Multiple Access - Collision Detection) principle - contention protocol
  • Only one station can send at any given time
  • Automatic signal detect (remember baseband?)
  • Attached stations send at randomized intervals
Fixed-length frames (1516 bytes)
Very unpredictable. CSMA-CD leads to exponential saturation.
HELP! * GREY=local HTML version of LOCAL Foils prepared 31 January97

Foil 18 Case study: Token Ring

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Ring, packet switching, connectionless, baseband
Unidirectional transmission, token circulates at full speed
Token may be either free (no data) or busy (data attached)
Station wishing to transmit waits for a free token. It sets it to busy and attaches data with header
The addressee copies the data and sets "data copied" bit
Originating station sets token to free and removes data
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Foil 19 Case study: FDDI

From Introduction To Multimedia Internet Systems CPS640 MultiMedia and WWW -- Spring 97 Semester. * See also color IMAGE
Full HTML Index
Ring, connectionless, packet switching.
FDDI tokens are "captured" and "reissued"
Multiple frames can be in transit concurrently
"Token holding time" may support priorities
"Token rotation time" limits ring latency
FDDI uses larger frames (4kB) and supports bandwidth of 100 Mbps (in practice, ~60 Mbps)
Token ring protocols are "non-contention" and do not suffer from exponential saturation.
Northeast Parallel Architectures Center, Syracuse University, npac@npac.syr.edu

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