INTRODUCTION TO LOCAL AREA NETWORKS

1
INTRODUCTION TO LOCAL AREA NETWORKS
NETWORK ARCHITECTURE
Professor Saad Haj Bakry, PhD, CEng, FIEE
2
CONTENTS
Introduction to LANs
LAN PERFORMANCE
BASIC ISSUES
LAN TOPOLOGY
SUGGESTED WORK
LAN PROTOCOLS
REFERENCES
Saad Haj Bakry
3
BASIC ISSUES
Introduction to LANs
NETWORK STRUCTURE
LAN OBJECTIVES
NETWORK CLASSIFICATIONS
STANDARDS ORGANIZATIONS
Saad Haj Bakry
4
LAN OBJECTIVES
Basic Issues
Introduction to LANs
SHARING Information
/ HW / SW
ENABLED by Microprocessors..
APPLICATIONS
Data Image Processing / Speech Recognition /
Video Conferencing / Multimedia / Scope
Intranet with Extranet Internet Extension
Saad Haj Bakry
5
Basic Issues
Introduction to LANs
6
NETWORK STRUCTURE
Basic Issues
Introduction to LANs
ACCESS SUBNETWORK
S
S
COMMUNICATIONS SUBNETWORK LAN
Medium / Topology / Protocols / Interfacing
S
S
S ACCESS STATION
Saad Haj Bakry
7
ISO
Basic Issues
Introduction to LANs
INTERNATIONAL STANDARDS ORGANIZATION
STARTED 1946 200 (TCs) Technical
Committees 5000 (Standards)
MEMBERS 89 Countries ANSI USA BSI UK
SASO Saudi Arabia
ADDRESS PO Box 56, 1211
Geneva 20, Switzerland
Saad Haj Bakry
8
IEEE
Basic Issues
Introduction to LANs
INSTITUTE OF ELECTRICAL ELECTRONICS ENGINEERS
AROUND 10 Divisions 40 Societies 300
Journals 500 (k) Members Groups for Standards
LAN IEEE 802 the basis for ISO 8802
MEMBERS Translational Individual Member Society
STARTED 1963 A Merger of the American
Institute of Electrical Engineers (Started in
1884) and The Institute of Radio Engineers
ADDRESS 345 East 47th Street,
New York, NY 10017-2394
Saad Haj Bakry
9
LAN TOPOLOGY
Introduction to LANs
TRANSMISSION MEDIUM
STRUCTURED CABLING
TOPOLOGY / MEDIUM ISSUES
BASEBAND BROADBAND
BUSS / TREE / RING / STAR
Saad Haj Bakry
10
TRANSMISSION MEDIUM
Topology
Introduction to LANs
TWISTED PAIR Unshielded / Shielded
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
COAXIAL CABLE Baseband / Broadband
OPTICAL FIBER Single Mode /
Graded-index / Step-index
Saad Haj Bakry
11
BUSS TOPOLOGY
Topology
Introduction to LANs
Saad Haj Bakry
12
TREE TOPOLOGY
Topology
Introduction to LANs
T
S
H Head End
H
R
S
S
S
T
T
T
Saad Haj Bakry
13
RING TOPOLOGY
Topology
Introduction to LANs
Saad Haj Bakry
14
STAR TOPOLOGY
Topology
Introduction to LANs
Saad Haj Bakry
15
STRUCTURED CABLING 1/3
Topology
Introduction to LANs
STANDARDS EIA/TIA-6682
Electronic Telecommunications Industries
Associations, USA ISO 11 801
Similar to the above
OBJECTIVE Generic cabling layout. Supports
all types of information networking in
buildings. Enables flexible movement of equipment
(no rewiring / only plugging)
PRINCIPLES Hierarchical / Star Layout
Saad Haj Bakry
16
STRUCTURED CABLING 2/3
Topology
Introduction to LANs
HORIZONTAL CABLING Single floor cabling.
Backbone to wall outlets. Maximum distance 90
(m). Fore more multiple HC.
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
BACKBONE VERTICAL CABLING
Between floors
Saad Haj Bakry
17
STRUCTURED CABLING 3/3
Topology
Introduction to LANs
ER / MC
TR
BACKBONE VERTICAL CABLING
ER / IC
X
TR
TR
TC
TC
X
TR
TR
X
TR
TR
HORIZONTAL CABLING
T
Outlets
W Work Area
Outlets
W Work Area
Saad Haj Bakry
18
TRANSMISSION TECHNIQUES BASEBAND
Topology
Introduction to LANs
SIGNALING Digital No Carrier / No
FDM Entire bandwidth is given to a
signal Bidirectional
BUSS TOPOLOGY
DISTANCE Up to a few kms
Saad Haj Bakry
19
TRANSMISSION TECHNIQUES BROADBAND
Topology
Introduction to LANs
SIGNALING Analog RF Modem / FDM possible
Multiple Data Channels / Audio /
Video Unidirectional
BUSS / TREE TOPOLOGY
DISTANCE Up to a 10s of kms
Saad Haj Bakry
20
BROADBAND BUSS
Topology
Introduction to LANs
Receive on f1
Saad Haj Bakry
21
LAN TOPOLOGY / MEDIUM
Topology
Introduction to LANs
Saad Haj Bakry
22
BUSS / TREE TOPOLOGY
Topology
Introduction to LANs
Saad Haj Bakry
23
RING TOPOLOGY
Topology
Introduction to LANs
Saad Haj Bakry
24
STAR TOPOLOGY
Topology
Introduction to LANs
Saad Haj Bakry
25
LAN PROTOCOLS
Introduction to LANs
CSMA / CD
ISO / OSI
TOKEN BUS / RING
LAN LAYERS
WIRELESS LAN
IEEE 802 STANDARDS
ATM LAN
Saad Haj Bakry
26
ISO- OSI
Protocols
Introduction to LANs
APPLICATION
PRESENTATION
OPEN SYSTEM INTERCONNECTION REFERENCE MODEL
SESSION
TRANSPORT
NETWORK
DATA LINK
STARTED 1983
PHYSICAL
Saad Haj Bakry
27
ISO-OSI LAYERS
Protocols
Introduction to LANs
PEER LEVELS
APPLICATION
APPLICATION
PRESENTATION
PRESENTATION
SESSION
SESSION
TRANSPORT
TRANSPORT
COMMUNICATION SUBNETWORK
NETWORK
NETWORK
NETWORK
DATA LINK
DATA LINK
DATA LINK
PHYSICAL
PHYSICAL
PHYSICAL
COMMUNICATION MEDIUM
COMMUNICATION MEDIUM
Saad Haj Bakry
28
ISO-OSI FUNCTIONS
Protocols
Introduction to LANs
INTERNETWORKING
INTERCONNECTION
APPLICATION Supporting Services at Access
Points
TRANSPORT End to End QOS
PRESENTATION Representation of Information
NETWORK Sub-network Operation
DATA LINK Point to Point Error Free
SESSION User Interface to the Network
PHYSICAL Interface to the Medium
Saad Haj Bakry
29
REPEATERS / BRIDGES / ROUTERS / GATEWAYS
Protocols
Introduction to LANs
GATEWAY ROUTER BRIDGE REPEATER
APPLICATION
APPLICATION
PRESENTATION
PRESENTATION
SESSION
SESSION
TRANSPORT
TRANSPORT
NETWORK
NETWORK
DATA LINK
DATA LINK
PHYSICAL
PHYSICAL
COMMUNICATION MEDIUM
COMMUNICATION MEDIUM
Saad Haj Bakry
30
USING ISO-OSI
Protocols
Introduction to LANs
DATA
APPLICATION
APPLICATION
A
DATA
PRESENTATION
PRESENTATION
A
P
DATA
SESSION
SESSION
A
P
S
DATA
TRANSPORT
TRANSPORT
A
P
S
T
DATA
NETWORK
NETWORK
A
P
S
T
N
DATA
DATA LINK
DATA LINK
A
P
S
T
N
L
DATA
PHYSICAL
PHYSICAL
A
P
S
T
N
L
H
DATA
COMMUNICATION MEDIUM
Saad Haj Bakry
31
Protocols
Introduction to LANs
LAYERED PROTOCOLS
LOGICAL LINK CONTROL (SubLayer)

Supervises Transmission between Nodes /
Related to Higher Layers
DATA LINK LAYER
LLC MAC
MEDIUM ACCESS CONTROL (SubLayer)

Converts the Shared physical link into
Virtual point-to-point links between pairs
of computers
PHYSICAL LAYER
Electrical
Mechanical Characteristics of
Interconnections / Related to the Communication
Medium to be Used
Saad Haj Bakry
32
Protocols
Introduction to LANs
IEEE 802 1/8
HILI IEEE 802.1 Higher Level Interface
Concerned with LAN Architecture, Internetworking,
Management
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)
Saad Haj Bakry
33
Protocols
Introduction to LANs
IEEE 802 2/8
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)
Saad Haj Bakry
34
Protocols
Introduction to LANs
IEEE 802 3/8
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
Saad Haj Bakry
35
Protocols
Introduction to LANs
IEEE 802 4/8
BBTAG IEEE 802.7
Broadband Technical Advisory Group Produced
a Document on Broadband Cabling Systems
FOTAG IEEE 802.8
Fibre Optics Technical Advisory Group Using
Optical Fiber for IEEE 802.3/4/5
ISLAN IEEE 802.9 Integrated Services LAN
Interface (Desktop Devices to 802 LANs ISDN)
Saad Haj Bakry
36
Protocols
Introduction to LANs
IEEE 802 5/8
SILS IEEE 802.10
Standard for Interoperable LAN Security
Functions Secure Data Exchange / Security
Encryption Key Management / Application of OSI
Security
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
37
Protocols
Introduction to LANs
IEEE 802 6/8
WLAN IEEE 802.11 Wireless LAN
Saves Cabling / Provides
LAN Extensions, Cross-Building
Interconnection, Nomadic Access, ..
Demand Priority IEEE 802.12 Priority
Order is Assigned to the Nodes Sharing the
Network Used with Higher Speed 100 Mbps
100VG-ANYLAN
Saad Haj Bakry
38
Protocols
Introduction to LANs
IEEE 802 7/8
IEEE 802.2
LLC
IEEE 802.6 DQDB Distr. Queue Dual Bus
MAC
IEEE 802.3 CSMA / CD
IEEE 802.4 Token Bus
IEEE 802.12 Demand Priority
IEEE 802.5 Token Ring
FDDI Token Ring
PL
Bus / Tree / Star Topology

Ring Topology
Dual Bus Topology
Saad Haj Bakry
39
Protocols
Introduction to LANs
IEEE 802 8/8
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.
LLC BASIC FUNCTIONS Frame Multiplexing Error
Control Flow Control (if
required)
Saad Haj Bakry
40
Protocols
Introduction to LANs
ETHERNET CSMA / CD
CSMA Stations sense the medium,
and may send only if it is idle
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.
CSMA / CD Transmission is ceased if
a collision is detected
These are contention techniques
Saad Haj Bakry
41
Protocols
Introduction to LANs
TOKEN BUS / 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
No Contention
Saad Haj Bakry
42
Topology
Introduction to LANs
WIRELESS LANS
ACC. MTH.
RATE (Mbps)
LAN / Characteristics
BAND
SEC.
800-900 nm
CSMA
1-4
Diffused Infrared
BEST
CSMA / Tok Rin
Direct Beam Inf.
10
908-928 MHz 2.4-2.4835 GHz 5.725-5.85 GHz
SpSp Freq. Hop.
1-3
MOD.
CSMA
SpSp Dir. Seq.
2-20
CSMA / Res. ALOHA
18.825-19.205 GHZ (ISM)
LEAST
Radio
5-10
Saad Haj Bakry
43
Protocols
Introduction to LANs
ATM LAN 1/2
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
PHYSICAL LAYER
Related to BISDN channels
(Optical Fiber) 155 622 Mbps and above. Also
used on High Speed digital channels 45 Mbps
(sat.)
Saad Haj Bakry
44
Protocols
Introduction to LANs
ATM LAN 1/2
INTERNET APPLICATIONS
HIGHER LAYERS
TCP
IP
LLC
LOWER LAYERS
ADAPTATION
MAC
ATM
PHYSICAL
PHYSICAL
Saad Haj Bakry
45
BASIC PERFORMANCE MEASURES
Introduction to LANs
THROUGHPUT
LATENCY
Saad Haj Bakry
46
Performance
Introduction to LANs
THROUGHPUT
DEFINITION Average successful
transmission rate when the LAN is heavily loaded
EXAMPLES CSMA / Ethernet 65 FDDI / Token
Ring Close to 100
MAC EFFICIENCY (Throughput) /
(Max. Rate) Can be given as ()
Saad Haj Bakry
47
Performance
Introduction to LANs
LATENCY
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)
Conflict Throughput Versus Latency
Saad Haj Bakry
48
SUGGESTED WORK
Introduction to LANs
EXTENSIONS Theory Different LANs Systems
Available LANs / Management Issues Components
LAN Architecture
ANALYSIS Practical Evaluations Criteria
(Different LANs) Planning Design Issues
Requirements (Case Studies)
PRACTICAL Applications LANs in Use (LAN
Architecture / Users / Services) Measurements
Performance Monitoring
Saad Haj Bakry
49
REFERENCES 1/2
Introduction to LANs
A. S. Tanenbaum, Computer Networks, 3rd Ed.,
Prentice Hall, 1996
W. Stallings, Data and Computer Communications,
5th Ed., Prentice Hall, 1997
A. Macpherson, International Telecommunication
Standards Organizations, Artech House, 1990
W. Stallings, Local Metropolitan Area Networks,
Prentice Hall, 1997
Saad Haj Bakry
50
REFERENCES 2/2
Introduction to LANs
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
Saad Haj Bakry