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INTRODUCTION TO
LOCAL AREA NETWORKS
INTRODUCTION TO
LOCAL AREA NETWORKS
Professor Saad Haj Bakry, PhD, CEng, FIEEProfessor Saad Haj Bakry, PhD, CEng, FIEE
NETWORK ARCHITECTURENETWORK ARCHITECTURE
CONTENTSCONTENTS
Saad Haj Bakry
BASIC ISSUESBASIC ISSUES
LAN TOPOLOGYLAN TOPOLOGY
REFERENCES REFERENCES LAN PROTOCOLSLAN PROTOCOLS
LAN
PERFORMANCE
LAN
PERFORMANCE
Introduction to LANs
SUGGESTED
WORK
SUGGESTED
WORK
BASIC ISSUESBASIC ISSUES
Saad Haj Bakry
LAN OBJECTIVESLAN OBJECTIVES
NETWORK
CLASSIFICATIONS
NETWORK
CLASSIFICATIONS
Introduction to LANs
NETWORK
STRUCTURE
NETWORK
STRUCTURE
STANDARDS
ORGANIZATIONS
STANDARDS
ORGANIZATIONS
LAN OBJECTIVESLAN OBJECTIVES
Saad Haj Bakry
SHARING:
Information / HW / SW
SHARING:
Information / HW / SW
Introduction to LANs
ENABLED: by Microprocessors..
ENABLED: by Microprocessors..
APPLICATIONS: Data & Image Processing / Speech Recognition / Video
Conferencing / Multimedia / Scope: “Intranet” with “Extranet” & “ Internet” Extension
APPLICATIONS: Data & Image Processing / Speech Recognition / Video
Conferencing / Multimedia / Scope: “Intranet” with “Extranet” & “ Internet” Extension
Basic Issues
Basic IssuesIntroduction to LANs
Saad Haj Bakry
108
107
106
105
104
10-1 100 101 102 103 104 105 106
Distance (meter)
Data Rate (bps)
Multi -
Processor
Multi -
Processor Traditional
LANs
Traditional LANs
Traditional WANs
Traditional WANs
High Speed WANs
High Speed WANs
Metrop. Area
Networks
Metrop. Area
Networks
High-Speed LANs
High-Speed LANs
Network Classifications
NETWORK STRUCTURENETWORK STRUCTURE
Saad Haj Bakry
Introduction to LANs
SS
COMMUNICATIONS SUBNETWORK:
LAN Medium / Topology / Protocols / Interfacing
SS
SS
SS
SS SS
SS SSS: ACCESS STATION
ACCESS SUBNETWORK
Basic Issues
ISOISO
INTERNATIONAL STANDARDS ORGANIZATIONINTERNATIONAL STANDARDS ORGANIZATION
ADDRESS: PO Box
56, 1211 Geneva 20, Switzerland
ADDRESS: PO Box
56, 1211 Geneva 20, Switzerland
STARTED: 1946
200 (TCs) Technical
Committees
5000 (Standards)
STARTED: 1946
200 (TCs) Technical
Committees
5000 (Standards)
MEMBERS: 89 Countries ANSI: USA BSI: UK SASO:
Saudi Arabia
MEMBERS: 89 Countries ANSI: USA BSI: UK SASO:
Saudi Arabia
Saad Haj Bakry
Introduction to LANsBasic Issues
IEEEIEEE
INSTITUTE OF ELECTRICAL & ELECTRONICS ENGINEERSINSTITUTE OF ELECTRICAL & ELECTRONICS ENGINEERS
ADDRESS: 345 East 47th Street, New York,
NY 10017-2394
ADDRESS: 345 East 47th Street, New York,
NY 10017-2394
STARTED: 1963 A Merger of the
American Institute of Electrical
Engineers (Started in 1884) and The Institute of Radio
Engineers
STARTED: 1963 A Merger of the
American Institute of Electrical
Engineers (Started in 1884) and The Institute of Radio
Engineers
MEMBERS: Translational
Individual Member Society
MEMBERS: Translational
Individual Member Society
Saad Haj Bakry
Introduction to LANs
AROUND: 10 Divisions 40 Societies 300 Journals
500 (k) Members
Groups for Standards:
LAN IEEE 802 the basis for
ISO 8802
AROUND: 10 Divisions 40 Societies 300 Journals
500 (k) Members
Groups for Standards:
LAN IEEE 802 the basis for
ISO 8802
Basic Issues
LAN TOPOLOGYLAN TOPOLOGY
Saad Haj Bakry
TRANSMISSION
MEDIUM
TRANSMISSION
MEDIUM
Introduction to LANs
BUSS / TREE / RING / STAR
BUSS / TREE / RING / STAR
STRUCTURED
CABLING
STRUCTURED
CABLING
BASEBAND
BROADBAND
BASEBAND
BROADBAND
TOPOLOGY /
MEDIUM
ISSUES
TOPOLOGY /
MEDIUM
ISSUES
TRANSMISSION MEDIUMTRANSMISSION MEDIUM
TWISTED PAIR: Unshielded / Shielded
TWISTED PAIR: Unshielded / Shielded
Topology
Saad Haj Bakry
Introduction to LANs
COAXIAL CABLE: Baseband /
Broadband
COAXIAL CABLE: Baseband /
Broadband
OPTICAL FIBER: Single Mode /
Graded-index / Step-index
OPTICAL FIBER: Single Mode /
Graded-index / Step-index
UNGUIDED MEDIA
MICROWAVE (in Use): 902-928 MHz /
2.4-2,4835 GHz / 5.725-5.825 GHz /
18.825-19.205 GHz
INFRATRD: Total Range (1012 -1014)
Enhances security
UNGUIDED MEDIA
MICROWAVE (in Use): 902-928 MHz /
2.4-2,4835 GHz / 5.725-5.825 GHz /
18.825-19.205 GHz
INFRATRD: Total Range (1012 -1014)
Enhances security
BUSS TOPOLOGYBUSS TOPOLOGY
Saad Haj Bakry
Introduction to LANs
TT TT TT TT
T: Tap “Hardware Interface”
RRRR
R: “Terminating Resistance”
TT
Data Flow
SS SS SS SS SS
Transmitting / Receiving Stations
Topology
TREE TOPOLOGYTREE TOPOLOGY
Saad Haj Bakry
Introduction to LANs
RR
RR
RRTT
SS
TT
SS
TT
SS
TT
SS
TT
SS
TT TT TT
SS SS SS
HHH:
Head End
Topology
RING TOPOLOGYRING TOPOLOGY
Saad Haj Bakry
Introduction to LANs
SSSS RP
RP
RP
RP
SSSS RP
RP
RP
RP
RP: Repeater
Data Flow
Topology
STAR TOPOLOGYSTAR TOPOLOGY
Saad Haj Bakry
Introduction to LANs
SS
SS
SS
CENTRAL HUB /
SWITCH /
REPEATER
CENTRAL HUB /
SWITCH /
REPEATER
SS
SS
SS SS
SS
Topology
STRUCTURED CABLING: 1/3STRUCTURED CABLING: 1/3
Saad Haj Bakry
Introduction to LANsTopology
OBJECTIVE:
Generic cabling layout.
Supports all types of information networking
in buildings.
Enables flexible movement of equipment
(no rewiring / only plugging)
OBJECTIVE:
Generic cabling layout.
Supports all types of information networking
in buildings.
Enables flexible movement of equipment
(no rewiring / only plugging)
STANDARDS:
EIA/TIA-6682 Electronic &
Telecommunications Industries Associations, USA
ISO 11 801 Similar to the above
STANDARDS:
EIA/TIA-6682 Electronic &
Telecommunications Industries Associations, USA
ISO 11 801 Similar to the above
PRINCIPLES: Hierarchical / Star Layout
PRINCIPLES: Hierarchical / Star Layout
STRUCTURED CABLING: 2/3STRUCTURED CABLING: 2/3
Saad Haj Bakry
Introduction to LANsTopology
HORIZONTAL CABLING:
Single floor cabling. Backbone to wall outlets.
Maximum distance: 90 (m). Fore more: multiple
HC.
HORIZONTAL CABLING:
Single floor cabling. Backbone to wall outlets.
Maximum distance: 90 (m). Fore more: multiple
HC.
BACKBONE
“VERTICAL” CABLING:
Between floors
BACKBONE
“VERTICAL” CABLING:
Between floors
LEVELS / CONNECT:
W: Work Area T: Telecom. Outlet TC: Telecom Closet
ER: Equipment Room
X: Cross Connect HC: Horizontal Connect IC: Intermediate Connect MC: Main Cross Connect
TR: Termination
LEVELS / CONNECT:
W: Work Area T: Telecom. Outlet TC: Telecom Closet
ER: Equipment Room
X: Cross Connect HC: Horizontal Connect IC: Intermediate Connect MC: Main Cross Connect
TR: Termination
STRUCTURED CABLING: 3/3STRUCTURED CABLING: 3/3
Saad Haj Bakry
Introduction to LANsTopology
ER / MC
ER / MC
TRTR
ER / ICER / IC XX TRTRTRTR
TC
TC
XX TRTRTRTR
T
T
W: Work Area Outlets
TC
TC
T
T
XX TRTRTRTR
W: Work Area OutletsHORIZONTAL CABLING
BACKBONE “VERTICAL”
CABLING
TRANSMISSION TECHNIQUES: BASEBANDTRANSMISSION TECHNIQUES: BASEBAND
SIGNALING:
Digital: No Carrier / No FDM
Entire bandwidth is given to a
signal
Bidirectional
SIGNALING:
Digital: No Carrier / No FDM
Entire bandwidth is given to a
signal
Bidirectional
BUSS TOPOLOGYBUSS TOPOLOGY
Saad Haj Bakry
Introduction to LANs
DISTANCE: Up to a “few kms”
DISTANCE: Up to a “few kms”
Topology
TRANSMISSION TECHNIQUES: BROADBANDTRANSMISSION TECHNIQUES: BROADBAND
SIGNALING:
Analog: RF Modem / FDM possible
Multiple Data Channels / Audio / Video
Unidirectional
SIGNALING:
Analog: RF Modem / FDM possible
Multiple Data Channels / Audio / Video
Unidirectional
BUSS / TREE TOPOLOGY
BUSS / TREE TOPOLOGY
Saad Haj Bakry
Introduction to LANs
DISTANCE: Up to a “10s of kms”
DISTANCE: Up to a “10s of kms”
Topology
BROADBAND BUSS BROADBAND BUSS
Saad Haj Bakry
Introduction to LANs
Receive on “f2” Transmit on “f1”
SS SS SS
“f2”“f2”“f2” “f1” “f1” “f1”
Single Buss
SS SS SSDual Buss
Transmit on “f1”
Receive on “f1”
Topology
LAN TOPOLOGY / MEDIUMLAN TOPOLOGY / MEDIUM
Saad Haj Bakry
i
N
j
N
1 1
Twisted Pair
Coax. Cable: Baseband
Optical Fiber
Wireless
RING
Y
Y
BUSS
Y
TREE STAR
Y
Y
N
Y
Y
Y
Y
Y
Y
Coax. Cable: Broadband
MEDIUM / TOPOLOGY
Y
Y
N
N
N
N
N
N
Introduction to LANsTopology
BUSS / TREE TOPOLOGYBUSS / TREE TOPOLOGY
Saad Haj Bakry
i
N
j
N
1 1
Unshielded Twisted Pair
Optical Fiber
Wireless
RATE (Mbps)
50
RANGE(km)
TAPS
10s
10s
10-50
45
<30
500
Coax. Cable: Baseband
MEDIUM / SPECIFICATION
1
10
<2
<3
<150
<1
100s-1000s
100s
Coax. Cable: Broadband
Introduction to LANsTopology
RING TOPOLOGYRING TOPOLOGY
Saad Haj Bakry
i
N
j
N
1 1
Unshielded Twisted Pair
Optical Fiber
Wireless
RATE (Mbps)
16
RP.SP. (m) TAPS
10s
70
16
100
1000
250
Coax. Cable: Baseband
MEDIUM / SPECIFICATION
4
100
100
300
2000
100
250
250Shielded Twisted Pair
Introduction to LANsTopology
STAR TOPOLOGYSTAR TOPOLOGY
Saad Haj Bakry
Optical Fiber
Wireless 10s
100 10s
10
100
<1000
i
N
j
N
1 1
Unshielded Twisted Pair
RATE (Mbps)
S-H Distanc
e (m)Stations
10s
100
MEDIUM / SPECIFICATION
10-100 100
100 10sShielded Twisted Pair
Introduction to LANsTopology
LAN PROTOCOLSLAN PROTOCOLS
Saad Haj Bakry
ISO / OSIISO / OSI
Introduction to LANs
LAN LAYERSLAN LAYERS
IEEE 802 STANDARDS
IEEE 802 STANDARDS
CSMA / CD
CSMA / CD
TOKEN BUS / RINGTOKEN BUS / RING
WIRELESS LANWIRELESS LAN
ATM LANATM LAN
ISO- OSIISO- OSI
TRANSPORT
DATA LINK
PHYSICAL
NETWORK
SESSION
PRESENTATION
APPLICATION
OPEN SYSTEM
INTERCONNECTION:
REFERENCE MODEL
OPEN SYSTEM
INTERCONNECTION:
REFERENCE MODEL
STARTED: 1983STARTED: 1983
Protocols
Saad Haj Bakry
Introduction to LANs
ISO-OSI LAYERSISO-OSI LAYERS
APPLICATIONAPPLICATION
PRESENTATIONPRESENTATION
SESSIONSESSION
TRANSPORT`TRANSPORT`
NETWORKNETWORK
DATA LINKDATA LINK
PHYSICALPHYSICAL
APPLICATIONAPPLICATION
PRESENTATIONPRESENTATION
SESSIONSESSION
TRANSPORT`TRANSPORT`
NETWORKNETWORK
DATA LINKDATA LINK
PHYSICALPHYSICAL
COMMUNICATION MEDIUM
COMMUNICATION MEDIUM
PHYSICALPHYSICAL
DATA LINKDATA LINK
NETWORKNETWORK
COMMUNICATION SUBNETWORKCOMMUNICATION SUBNETWORK
COMMUNICATION MEDIUM
COMMUNICATION MEDIUM
PEER LEVELS
Protocols
Saad Haj Bakry
Introduction to LANs
ISO-OSI FUNCTIONSISO-OSI FUNCTIONS
APPLICATION: Supporting Services at Access Points
APPLICATION: Supporting Services at Access Points
PRESENTATION: Representation of
Information
PRESENTATION: Representation of
Information
SESSION: User Interface to the Network
SESSION: User Interface to the Network
TRANSPORT: End to End QOS
TRANSPORT: End to End QOS
NETWORK: Sub-network Operation
NETWORK: Sub-network Operation
DATA LINK: Point to Point Error FreeDATA LINK: Point to Point Error Free
PHYSICAL: Interface to the MediumPHYSICAL: Interface to the Medium
INTERNETWORKINGINTERNETWORKING INTERCONNECTIONINTERCONNECTION
Protocols
Saad Haj Bakry
Introduction to LANs
REPEATERS / BRIDGES / ROUTERS / GATEWAYSREPEATERS / BRIDGES / ROUTERS / GATEWAYS
APPLICATIONAPPLICATION
PRESENTATIONPRESENTATION
SESSIONSESSION
TRANSPORT`TRANSPORT`
NETWORKNETWORK
DATA LINKDATA LINK
PHYSICALPHYSICAL
APPLICATIONAPPLICATION
PRESENTATIONPRESENTATION
SESSIONSESSION
TRANSPORT`TRANSPORT`
NETWORKNETWORK
DATA LINKDATA LINK
PHYSICALPHYSICAL
COMMUNICATION MEDIUM
COMMUNICATION MEDIUM
COMMUNICATION MEDIUM
COMMUNICATION MEDIUM
Protocols
Saad Haj Bakry
Introduction to LANs
GATEWAY
ROUTER
BRIDGE
REPEATER
GATEWAY
ROUTER
BRIDGE
REPEATER
USING ISO-OSIUSING ISO-OSI
APPLICATIONAPPLICATION
PRESENTATIONPRESENTATION
SESSIONSESSION
TRANSPORT`TRANSPORT`
NETWORKNETWORK
DATA LINKDATA LINK
PHYSICALPHYSICAL
APPLICATIONAPPLICATION
PRESENTATIONPRESENTATION
SESSIONSESSION
TRANSPORT`TRANSPORT`
NETWORKNETWORK
DATA LINKDATA LINK
PHYSICALPHYSICAL
COMMUNICATION MEDIUMCOMMUNICATION MEDIUM
DATA
DATA
DATA
DATA
DATA
DATA
DATA
DATA
A P S T N L H
A
A
A
A
A
A
P
P
P
P
P
S
S
S
S
T
T
T
N
N L
Protocols
Saad Haj Bakry
Introduction to LANs
Protocols
LAYERED PROTOCOLSLAYERED PROTOCOLS
Saad Haj Bakry
Introduction to LANs
PHYSICAL LAYER: Electrical & Mechanical “Characteristics” of “Interconnections” /
Related to the Communication “Medium” to be Used
PHYSICAL LAYER: Electrical & Mechanical “Characteristics” of “Interconnections” /
Related to the Communication “Medium” to be Used
MEDIUM ACCESS CONTROL (SubLayer): Converts the “Shared”
physical link into “Virtual” point-to-point links between pairs of computers
MEDIUM ACCESS CONTROL (SubLayer): Converts the “Shared”
physical link into “Virtual” point-to-point links between pairs of computers
LOGICAL LINK CONTROL (SubLayer): Supervises
“Transmission” between Nodes / Related to “Higher” Layers
LOGICAL LINK CONTROL (SubLayer): Supervises
“Transmission” between Nodes / Related to “Higher” Layers
DATA
LINK
LAYER
LLC +
MAC
IEEE 802 : 1/8 IEEE 802 : 1/8
Saad Haj Bakry
Introduction to LANs
HILI: IEEE 802.1 “Higher Level Interface”
Concerned with LAN Architecture, Internetworking, & Management
HILI: IEEE 802.1 “Higher Level Interface”
Concerned with LAN Architecture, Internetworking, & Management
Protocols
LLC: IEEE 802.2 “Logical Link Control”LLC: IEEE 802.2 “Logical Link Control”
CSMA/CD “MAC Ethernet”: IEEE 802.3 “Carrier Sense Multiple Access / Collision Detection”
Originally Designed for: Commercial / Light Industrial Environment (Random Use / Simple)
CSMA/CD “MAC Ethernet”: IEEE 802.3 “Carrier Sense Multiple Access / Collision Detection”
Originally Designed for: Commercial / Light Industrial Environment (Random Use / Simple)
IEEE 802: 2/8 IEEE 802: 2/8
Saad Haj Bakry
Introduction to LANsProtocols
TOKEN BUS
“MAC”: IEEE 802.4
Originally Designed for:
Office Environment / Factories & Industrial
Environment / Military Environment
TOKEN BUS
“MAC”: IEEE 802.4
Originally Designed for:
Office Environment / Factories & Industrial
Environment / Military Environment
TOKEN RING
“MAC”: IEEE 802.5
Originally Designed for: Commercial / Light
Industrial Environment (Like Ethernet: 802.3)
TOKEN RING
“MAC”: IEEE 802.5
Originally Designed for: Commercial / Light
Industrial Environment (Like Ethernet: 802.3)
IEEE 802: 3/8 IEEE 802: 3/8
Saad Haj Bakry
Introduction to LANsProtocols
DQDB: IEEE 802.4 Distributed
Queue “Access Control” Dual
Bus “Topology”
Designed for:
Metropolitan Area Networks “MANs”
DQDB: IEEE 802.4 Distributed
Queue “Access Control” Dual
Bus “Topology”
Designed for:
Metropolitan Area Networks “MANs”
FDDI “Fiber Distributed Data Interface” :
ANSI X3T9.5 / ISO 9314 / TOKEN RING: IEEE 802.5
(But Higher Speed / Fiber)
Designed for the Role of both LAN / MAN
FDDI “Fiber Distributed Data Interface” :
ANSI X3T9.5 / ISO 9314 / TOKEN RING: IEEE 802.5
(But Higher Speed / Fiber)
Designed for the Role of both LAN / MAN
Saad Haj Bakry
Introduction to LANs
BBTAG IEEE 802.7
“Broadband Technical Advisory Group”
Produced a Document on “Broadband Cabling
Systems”
BBTAG IEEE 802.7
“Broadband Technical Advisory Group”
Produced a Document on “Broadband Cabling
Systems”
ISLAN: IEEE 802.9 “Integrated Services LAN Interface” (Desktop Devices “to” 802 LANs & ISDN)
ISLAN: IEEE 802.9 “Integrated Services LAN Interface” (Desktop Devices “to” 802 LANs & ISDN)
Protocols
IEEE 802: 4/8 IEEE 802: 4/8
FOTAG IEEE 802.8
“Fibre Optics Technical Advisory
Group”
Using Optical Fiber for: IEEE 802.3/4/5
FOTAG IEEE 802.8
“Fibre Optics Technical Advisory
Group”
Using Optical Fiber for: IEEE 802.3/4/5
Saad Haj Bakry
Introduction to LANs
SILS IEEE 802.10
“Standard for Interoperable LAN
Security” Functions: “Secure Data Exchange /
Security & Encryption Key Management / Application of OSI
Security”
SILS IEEE 802.10
“Standard for Interoperable LAN
Security” Functions: “Secure Data Exchange /
Security & Encryption Key Management / Application of OSI
Security”
Protocols
IEEE 802: 5/8 IEEE 802: 5/8
CATVB-BCN IEEE 802.14
“Cable TV Based
Broadband Comm. Network” Multi-services Capabilities over CATV Systems: “Data, Voice & Video / 2-Way / Remote Access & LAN
Interconnection”
CATVB-BCN IEEE 802.14
“Cable TV Based
Broadband Comm. Network” Multi-services Capabilities over CATV Systems: “Data, Voice & Video / 2-Way / Remote Access & LAN
Interconnection”
Saad Haj Bakry
Introduction to LANs
WLAN IEEE 802.11 “Wireless LAN”
Saves Cabling / Provides: LAN Extensions,
Cross-Building Interconnection,
Nomadic Access, ..
WLAN IEEE 802.11 “Wireless LAN”
Saves Cabling / Provides: LAN Extensions,
Cross-Building Interconnection,
Nomadic Access, ..
Protocols
IEEE 802: 6/8 IEEE 802: 6/8
Demand Priority IEEE 802.12
“Priority Order is Assigned to the Nodes Sharing
the Network”
Used with Higher Speed: 100 Mbps:
100VG-ANYLAN
Demand Priority IEEE 802.12
“Priority Order is Assigned to the Nodes Sharing
the Network”
Used with Higher Speed: 100 Mbps:
100VG-ANYLAN
IEEE 802: 7/8IEEE 802: 7/8
Saad Haj Bakry
Introduction to LANs
PLPL
MAC
MAC
IEEE 802.2IEEE 802.2LLC
LLC
IEEE 802.3
CSMA / CD
IEEE 802.3
CSMA / CD
IEEE
802.4
Token Bus
IEEE
802.4
Token Bus
IEEE 802.12
Demand Priority
IEEE 802.12
Demand Priority
Bus / Tree / Star
Topology
Bus / Tree / Star
Topology
IEEE 802.5 Token Ring
IEEE 802.5 Token Ring
Ring Topology
Ring Topology
IEEE 802.6
DQDB: Distr.
Queue Dual Bus
IEEE 802.6
DQDB: Distr.
Queue Dual Bus
FDDI
Token Ring
FDDI
Token Ring
Dual Bus Topology
Dual Bus Topology
Protocols
IEEE 802: 8/8IEEE 802: 8/8
Saad Haj Bakry
Introduction to LANsProtocols
LLC BASIC
FUNCTIONS:
Frame Multiplexing
Error Control
Flow Control (if required)
LLC BASIC
FUNCTIONS:
Frame Multiplexing
Error Control
Flow Control (if required)
802.2 LLC SERVICES TYPES: Connection Oriented Service:
packet streams are delivered in their correct order without error.
Connectionless Service: Data gram transmission. Correct order is not
guaranteed
Acknowledged Connectionless: For point to point connections. No frame is
sent before the previous one is acknowledged.
802.2 LLC SERVICES TYPES: Connection Oriented Service:
packet streams are delivered in their correct order without error.
Connectionless Service: Data gram transmission. Correct order is not
guaranteed
Acknowledged Connectionless: For point to point connections. No frame is
sent before the previous one is acknowledged.
ETHERNET CSMA / CDETHERNET CSMA / CD
Saad Haj Bakry
Introduction to LANs
ALOHA / SLOTTED ALOHA:
A station transmits whenever it has data to send. Un
acknowledged transmissions are repeated.
With “slotted ALOHA” data packets are transmitted in well
defined time slots.
“Collision / interference” is resolved by retransmission after
random intervals.
ALOHA / SLOTTED ALOHA:
A station transmits whenever it has data to send. Un
acknowledged transmissions are repeated.
With “slotted ALOHA” data packets are transmitted in well
defined time slots.
“Collision / interference” is resolved by retransmission after
random intervals.
Protocols
CSMA: Stations sense
the medium, and may send only if it is idle
CSMA: Stations sense
the medium, and may send only if it is idle
CSMA / CD: Transmission is
ceased if a collision is detected
CSMA / CD: Transmission is
ceased if a collision is detected
These are “contention techniques”
TOKEN BUS / RINGTOKEN BUS / RING
Saad Haj Bakry
Introduction to LANsProtocols
TOKEN BUS:
Stations on “Bus / Tree” form a logical ring around which a token
is passed (played).
A station receiving a token may transmit (insert data into token).
Data (into token) travel from source to destination through the
logical ring
TOKEN BUS:
Stations on “Bus / Tree” form a logical ring around which a token
is passed (played).
A station receiving a token may transmit (insert data into token).
Data (into token) travel from source to destination through the
logical ring
TOKEN RING:
Stations are connected to a
“Physical Ring”, through which
the “token game” is
played
TOKEN RING:
Stations are connected to a
“Physical Ring”, through which
the “token game” is
played
“No Contention”
Saad Haj Bakry
i
N
j
N
1 1
Diffused Infrared
Direct Beam Inf.
Radio
RATE (Mbps)
1-4
BAND
908-928 MHz 2.4-2.4835 GHz 5.725-5.85 GHz
ACC. MTH. SEC.
BEST
1-3
2-20
5-10
CSMASpSp: Freq. Hop.
LAN / Characteristics
800-900 nm
18.825-19.205 GHZ
(ISM)
CSMA
CSMA / Tok Rin
CSMA / Res.
ALOHA
Introduction to LANsTopology
WIRELESS LANSWIRELESS LANS
SpSp: Dir. Seq.
10
MOD.
LEAST
ATM LAN: 1/2ATM LAN: 1/2
Saad Haj Bakry
Introduction to LANsProtocols
AAL: ATM ADAPTATION LAYER The layer that maps information transfer protocols onto ATM
AAL: ATM ADAPTATION LAYER The layer that maps information transfer protocols onto ATM
ATM: ASYNCHRONOUS TRANSFER MODE A form of packet switching using fixed size packets, called cells. It is a data transfer interface for BISDN. No error
control and no flow control mechanisms
ATM: ASYNCHRONOUS TRANSFER MODE A form of packet switching using fixed size packets, called cells. It is a data transfer interface for BISDN. No error
control and no flow control mechanisms
PHYSICAL LAYER Related to BISDN channels (Optical Fiber): 155 & 622 Mbps and
above. Also used on High Speed digital channels: 45 Mbps (sat.)
PHYSICAL LAYER Related to BISDN channels (Optical Fiber): 155 & 622 Mbps and
above. Also used on High Speed digital channels: 45 Mbps (sat.)
Protocols
Saad Haj Bakry
Introduction to LANs
PHYSICALPHYSICAL
MACMAC
LLCLLC
PHYSICALPHYSICAL
ATMATM
ADAPTATIONADAPTATION LOWER LAYERSLOWER LAYERS
IPIP
TCPTCP
INTERNET APPLICATIONSINTERNET APPLICATIONS
HIGHER LAYERSHIGHER LAYERS
ATM LAN: 1/2ATM LAN: 1/2
BASIC PERFORMANCE MEASURESBASIC PERFORMANCE MEASURES
Saad Haj Bakry
Introduction to LANs
THROUGHPUTTHROUGHPUT
LATENCYLATENCY
THROUGHPUTTHROUGHPUT
Saad Haj Bakry
Introduction to LANs
DEFINITION: Average successful
transmission rate when the LAN is heavily loaded
DEFINITION: Average successful
transmission rate when the LAN is heavily loaded
EXAMPLES:
CSMA / Ethernet: 65 %
FDDI / Token Ring Close to 100 %
EXAMPLES:
CSMA / Ethernet: 65 %
FDDI / Token Ring Close to 100 %
Performance
MAC EFFICIENCY: (Throughput) / (Max. Rate) Can be given as (%)
MAC EFFICIENCY: (Throughput) / (Max. Rate) Can be given as (%)
Saad Haj Bakry
Introduction to LANs
DEFINITION: Latency is the
time from packet generation (its
arrival to network interface) until it
reaches its destination
DEFINITION: Latency is the
time from packet generation (its
arrival to network interface) until it
reaches its destination
CONVERSATION APPLICATIONS
“Voice / Data”: Max. Value 100
(ms)
CONVERSATION APPLICATIONS
“Voice / Data”: Max. Value 100
(ms)
LATENCYLATENCY
Performance
Conflict: Throughput Versus Latency
Conflict: Throughput Versus Latency
SUGGESTED WORKSUGGESTED WORK
Saad Haj Bakry
Introduction to LANs
EXTENSIONS:
Theory: Different LANs
Systems: Available LANs /
Management Issues
Components: LAN Architecture
EXTENSIONS:
Theory: Different LANs
Systems: Available LANs /
Management Issues
Components: LAN Architecture
PRACTICAL:
Applications: LANs in Use
(LAN Architecture / Users / Services)
Measurements: Performance Monitoring
PRACTICAL:
Applications: LANs in Use
(LAN Architecture / Users / Services)
Measurements: Performance Monitoring
ANALYSIS:
Practical Evaluations:
Criteria (Different LANs)
Planning & Design Issues: Requirements (Case Studies)
ANALYSIS:
Practical Evaluations:
Criteria (Different LANs)
Planning & Design Issues: Requirements (Case Studies)
REFERENCES: 1/2REFERENCES: 1/2
Saad Haj Bakry
Introduction to LANs
A. S. Tanenbaum, Computer Networks, 3rd Ed., Prentice Hall, 1996
A. S. Tanenbaum, Computer Networks, 3rd Ed., Prentice Hall, 1996
W. Stallings, Data and
Computer Communications,
5th Ed., Prentice Hall, 1997
W. Stallings, Data and
Computer Communications,
5th Ed., Prentice Hall, 1997
A. Macpherson, International Telecommunication Standards Organizations, Artech House, 1990
A. Macpherson, International Telecommunication Standards Organizations, Artech House, 1990
W. Stallings, Local & Metropolitan Area Networks, Prentice Hall, 1997
W. Stallings, Local & Metropolitan Area Networks, Prentice Hall, 1997
REFERENCES: 2/2REFERENCES: 2/2
Saad Haj Bakry
Introduction to LANs
R. P. Davidson, N. J. Muller, Internetworking LANs: Operation, Design & Management, Artech House, 1992
R. P. Davidson, N. J. Muller, Internetworking LANs: Operation, Design & Management, Artech House, 1992
J. Walrand, Communication Network: A First Course, 2nd Ed., McGraw-Hill, 1998
J. Walrand, Communication Network: A First Course, 2nd Ed., McGraw-Hill, 1998