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NETWORK ARCHITECTURE
ISO-OSI PROTOCOLS
Professor
Saad Haj Bakry,
PhD, CEng, FIEE
Network Architecture
ISO-OSI Protocols
CONTENTS
ISO-OSI
ISO TERMS
USING OSI
LAYERED PROTOCOLS
ISO-OSI LAYERES
ASSOCIATED
STANDARDS
Saad Haj Bakry
PHYSICAL
DATA LINK
NETWORK STRUCTURE
MANAGEMENT
NETWORK
TRANSPORT
SECURITY
SESSION
STANDARDS
REFERENCES
PRESENTATION
APPLICATION
Network Architecture
ISO-OSI Protocols
ISO
INTERNATIONAL STANDARDS ORGANIZATION
MEMBERS:
89 Countries
ANSI: USA
BSI: UK
SASO:
Saudi Arabia
Saad Haj Bakry
ADDRESS:
PO Box 56,
1211 Geneva
20,
Switzerland
STARTED: 1946
200 (TCs)
Technical
Committees
5000
(Standards)
Network Architecture
ISO-OSI Protocols
OSI
OPEN SYSTEM
INTERCONNECTION:
REFERENCE MODEL
APPLICATION
PRESENTATION
SESSION
TRANSPORT
NETWORK
STARTED: 1983
Saad Haj Bakry
DATA LINK
PHYSICAL
Network Architecture
ISO-OSI Protocols
NETWORK STRUCTURE
H
U
Users
H
U
N
U
H
N
H
COMMUNICATIONS
SUBNETWORK
N
Node / DCE
H
N
SUBNETWORK
ACCESS / SERVICES
U
Saad Haj Bakry
H
Host / DTE
U
U
U
Network Architecture
ISO-OSI Protocols
ISO NETWORK TERMS: (1/4)
DATA:
A representation of facts, concepts, or
instructions in a formalized manner suitable for
communications, interpretation, or processing
INFORMATION: The meaning that is currently assigned
to “data” by means of conventions applied to that data.
FUNCTIONAL UNIT:
An entity of HW or SW, or both,
capable of accomplishing a specific purpose
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO NETWORK TERMS: (2/3)
SOURCE:
The “functional unit” that generates “data”
for transmission
SINK:
The “functional unit” that accepts transmitted
“data”.
PROTOCOL: A set of semantic and syntactic rules that
determines the behaviour of “functional units” in
achieving communications.
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO NETWORK TERMS: (3/4)
DATA TERMINAL EQUIPMENT (DTE): The part
of “data” station
that serves as a “data
source”, “data sink”, or both. (Host)
DATA COMMUNICATION EQUIPMENT
(DCE):
In a “data” station, the equipment that provides
the signal conversion and coding between the
“DTE”
and
the
communication
line.
(Communication Node)
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO NETWORK TERMS: (4/4)
DATA INTEGRITY
: The “data” quality that exists as
long as accidental or malicious destruction, alternation,
or loss of “data” does not occur.
ENCRYPTION:
Encryption methods and principles are
examples pf things considered by “cryptography”.
CRYPTOGRAPHY:
A discipline involving principles,
means, and methods for changing “data”, so that it is
not readable.
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
LAYERED PROTOCOLS
WHY DIVIDE:
WHY LAYERS:
Complex
Operation
Nature of Network
Structure
Divide & Rule
User Access
Use Demands
Presentation
Network Operation
Communication
Remember: it is
Integrated
(All in One)
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO-OSI LAYERS
APPLICATION
PRESENTATION
PEER LEVELS
APPLICATION
PRESENTATION
SESSION
SESSION
TRANSPORT`
COMMUNICATION SUBNETWORK
NETWORK
NETWORK
DATA LINK
DATA LINK
NETWORK
DATA LINK
PHYSICAL
PHYSICAL
PHYSICAL
Saad Haj Bakry
COMMUNICATI
ON MEDIUM
COMMUNICATI
ON MEDIUM
TRANSPORT`
Network Architecture
ISO-OSI Protocols
ISO-OSI FUNCTIONS
INTERNETWORKING
INTERCONNECTION
APPLICATION: Supporting
TRANSPORT:
Services at Access Points
End to End QOS
PRESENTATION:
NETWORK:
Representation of
Information
Subnetwork Operation
SESSION: User Interface
to the Network
Saad Haj Bakry
DATA LINK: Point to Point Error Free
PHYSICAL: Interface to the Medium
Network Architecture
ISO-OSI Protocols
PHYSICAL LAYER: (1/2)
An Interface to the Physical Medium
FUNCTIONS:
CIRCUIT IDENTIFICATION
CONNECTION: Activate / Maintain / Deactivate
SIGNAL & MEDIUM: Put on / Take off
FLOW: Sequencing & Transmission
FAULT: Detection Notification
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
PYSICAL LAYER: (2/2)
STANDARDS:
MECHANICAL: Plugs / Sockets / Pins Functions
ELECTRICAL: Voltage Levels on the Medium
FUNCTIONAL: Levels Assigned to: 0 / 1
PROCEDURAL: Rules of Operation, Sequencing
EXAMPLES:
ITU: V.24 / X.21; EIS: RS 232 / RS 449
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
DATA LINK LAYER: (1/2)
Point to Point Error Free Transmission
FUNCTIONS:
CONNECTION ESTABLISHMENT
BREAKING DATA INTO FRAMES
ERROR
CONTROL: Detection / Recovery
FLOW CONTROL: Buffer Limit / QOS
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
DATA LINK LAYER: (2/2)
ERROR CONTROL:
TECHNIQUES:
Adding Control Bits
Echo Checking
EXAMPLES:
ARQ:
Automatic
Repeat Request
IBM SNA: SDLC
(Synchronous DL Control)
ISO: HDLC
(High level DLC)
Saad Haj Bakry
FEC:
Forward Error
Correction
Network Architecture
ISO-OSI Protocols
NETWORK LAYER: 1/2
Control of Communications Subnetwork
FUNCTIONS:
SUBNETWORK PATH CONTROL:
Addressing, Set Up, Maintain, Clear Down
MULTIPLEXING / CONCENTRATION ROUTING
/ RELAYING: QOS
CONGESTION CONTROL: QOS
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
NETWORK LAYER: 2/2
ROUTING:
STATIC:
Shortest Path / Table
DYNAMIC:
Least Busy Link
HYBRID
CONGESTION
CONTROL:
PERMITS / TOKENS
SHARING
BUFFERING LIMITS
EXAMPLES: ITU: X.25 / EIA: RS-366
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
TRANSPORT LAYER: (1/2)
End to End Service Quality Control
FUNCTIONS:
END
END PATH CONTROL
BREAKING DATA INTO MANAGEBLE UNITS
ERROR / CONGESTION / COST / QOS
MONITORING & CONTROL
SPLITTING: (1) Transport to (n) Network Connections
MULTIPLEXING: (n) Transports to (1) Connection
Saad Haj Bakry
TO
Network Architecture
ISO-OSI Protocols
TRANSPORT LAYER: (2/2)
CLASS 0:
Simplest /
Assuming
High
Quality
Network
CLASS 1:
Basic
Error
Recovery
CLASS 4:
Assuming Low
Quality Network
Saad Haj Bakry
CLASS 2:
Multiplexing
Required
CLASS 3:
Both: Error
Recovery &
Multiplexing
EXAMPLE:
INTERNET: TCP / UDP
Network Architecture
ISO-OSI Protocols
SESSION LAYER
User Interface to the Network
Session
Connection
Establishment
Session
Interaction
Management
Session
Connection
Release
BRACKETING: (for Failure)
QUARANTINE: (for Security)
Retaining the Ability to
Retransmit Using the Last
Bracketed Message
Receiver Needs
Permission to Release
Information to Presentation
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
PRESENTATION LAYER
Representation of Information
TRANSFERRING / RECEIVING Information
CODING:
Syntax & Semantics of Information
CODE CONVERSION: ASCII / EBCDIC
Saad Haj Bakry
COMPRESSION
ENCRYPTION
Network Architecture
ISO-OSI Protocols
APPLICATION LAYER
Supporting Network Services at
Access Points (User End)
GENERAL FUNCTIONS:
AUTHORITY TO COMMUNICATE
SERVICE SELECTION
PARTNERS IDENTIFICATION
MESSAGE HANDLING
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
USING ISO-OSI
DATA
APPLICATION
PRESENTATION
APPLICATION
PRESENTATION
DATA
A
DATA
A
DATA
A
DATA
A
P
S
T
DATA
A
P
S
T
DATA
A
P
S
DATA
A
P
SESSION
SESSION
TRANSPORT`
NETWORK
DATA LINK
PHYSICAL
P
S
TRANSPORT`
P
S
NETWORK
DATA LINK
N
T
T
N
N
L
L
COMMUNICATION MEDIUM
Saad Haj Bakry
H
PHYSICAL
Network Architecture
ISO-OSI Protocols
ASSOCIATED STANDARDS
NAMING &
ADDRESSING:
DIRECTORY
SERVICES:
Identifying
Communicating
Entities
Distributed
Database to Hold
Standard Names &
Addresses
MANAGEMENT
SECURITY
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
NETWORK MANAGEMENT: (1/2)
FAULTS:
PERFORMANCE:
Testing / Detection / Isolation
/ Notification / Recovery
Congestion / Delay /
SECURITY:
Access / Records / Files
Reliability / Utilization
CONFIGURATION:
Addition / Deletion /
Initialization / Termination
ACCOUNTING: Usage / Charging / Billing
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
NETWORK MANAGEMENT: (2/2)
OSI PROTOCOL MANAGEMENT:
Management of a Function / Protocol of a Layer
OSI LAYER MANAGEMENT:
Management of Interaction between Peer Layers
OSI SYSTEM MANAGEMENT:
Management of Functions Related to All Layers
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
NETWORK SECURITY: 1/2
UNAUTHORIZED
MODIFICATION OF
DATA
DENIAL
OF SERVICE
Saad Haj Bakry
MASQUERADING
AS A FRIENDLY
ENTITY
MESSAGE
REPETITION
Network Architecture
ISO-OSI Protocols
NETWORK SECURITY: 2/2
AUTHENTICATION
FOR CONFIDENCE
ACCESS CONTROL
DATA INTEGRITY:
DATA CONFIDENTIALITY: No Disclosure
NON REPUDIATION: Proof of Sending / Receiving
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO POEM: 1/8
The APPLICATION layer is the top one;
to the user it’s connected.
It is where the transaction is begun,
or sometimes just rejected
The user may make many demands,
for lots of different things.
This layer that handles commands,
and output bells it rings
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO POEM: 2/8
The next layer down is PRESENTATION, it
handles different devices.
It
performs any necessary translation, so
there won’t be any surprises.
Saad Haj Bakry
A virtual terminal is the aim,
so the key that you will hit,
will always be just the same,
whatever kind of kit
Network Architecture
ISO-OSI Protocols
ISO POEM: 3/8
Below presentation we have SESSION,
in our network system.
The session layer is the one,
which contacts station distant.
Virtual calls by it are placed,
for a network task,
and when it has a contact made,
for a dialogue it will ask.
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO POEM: 4/8
Session is followed by TRANSPORTATION,
a data path it sets up.
It gives the layers above support,
in the form of error free network.
Below transport things become
closer to the hardware,
but the layers higher up
do not need to care.
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO POEM: 5/8
NETWORK is the next one down,
moving all the data.
It handles all the routing round,
like a network operator
Saad Haj Bakry
Data which is not for us,
must be passed along.
This is what the network does,
to keep the things moving on.
Network Architecture
ISO-OSI Protocols
ISO POEM: 6/8
DATA LINK is the next from the end,
an error free connection.
On the network it will send,
streams in one direction.
Saad Haj Bakry
Greatly error checked they are,
so if anything corrupts it,
the data link it can repair,
or cause retransmit.
Network Architecture
ISO-OSI Protocols
ISO POEM: 7/8
PHYSICAL is right down low,
at the base of communication.
This is where the signals go, to
their destination.
The changes to this layer are great,
for different communications.
The medium it does dictate,
how we send the data.
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
ISO POEM: 8/8
Making the network works in layers, is
not just for the standard players.
There are already more than one, who
with layered protocols have begun.
The ultimate aim in view,
is for them to use OSI too.
Saad Haj Bakry
Network Architecture
ISO-OSI Protocols
OSI LAYER PRINCIPLES
DIFFERENT
ABSTRACTION
DIFFERENT
DEFINED
FUNCTION
Saad Haj Bakry
LIMITED
BOUNDARY
FLOW
REASONABLE
NUMBER
OF LAYERS
CONCEPT OF INTERNATIONAL
STANDARD
Network Architecture
ISO-OSI Protocols
VIEWS
MODEL:
NOT A
REAL
SYSTEM
LIKE
SNA &
TCP/IP
Saad Haj Bakry
NEEDS PRACTICAL ADAPTATION
SESSION / PRESENTATION
LAYERS: Limited Use
BRITISH PROPOSAL: 5 Layers
ISO-OSI Protocols
Network Architecture
REFERENCES: (1/3)
D.E. Commer,
Computer Networks
and Internet,
Prentice Hall, 1997
K. Washburn, and J. Evans,
TCP/IP: Running a
Successful Network, 2nd
Ed., Addison Wesley, 1996
A. S. Tanenbaum,
Computer Networks,
3rd Ed.,
Prentice Hall, 1996
J. S. Quarterman, and
S. Carl-Mitchell,
The Internet Connection,
Addison- Wesley, 1994.
Saad Haj Bakry
ISO-OSI Protocols
Network Architecture
REFERENCES: (2/3)
W. Stallings, Data and
Computer Communications,
5th Ed., Prentice Hall, 1997
W. Stallings, High Speed
Networks: TCP/IP & ATM
Design Principles, Prentice
Hall, 1998
Saad Haj Bakry
F. Halsall, Data
Communications,
Computer
Networks, &
Open Systems,
4th Ed., Addison
Wesley, 1996
ISO-OSI Protocols
Network Architecture
REFERENCES: (3/3)
W. Hioki,
Telecommunications,
3rd Ed., Prentice Hall,
1998
T. Russel,
Telecommunications
Protocols, McGraw
Hill, 1997
Saad Haj Bakry
M van Steen, and H. Sips,
Computer & Network
Organization,
Prentice Hall, 1995.
A. Macpherson,
International
Telecommunication
Standards Organizations,
Artech House, 1990
Network Architecture
ISO-OSI Protocols
SUGGESTED WORK
STUDY THE
DETAILS OF
THE OSI
PROTOCOLS AT
DIFFERENT
LAYERS
Saad Haj Bakry
STUDY
PRACTICAL
NETWORKS
PROTOCOL
S AGAINST
OSI