This document provides an overview of the OSI and TCP/IP network models. It describes the seven layers of the OSI model and defines the functions of each layer. It also discusses the layers of the TCP/IP model and compares it to the OSI model. While TCP/IP does not strictly adhere to the seven-layer model, it incorporates similar functions. The document outlines the layers of both models and their similarities and differences, such as how TCP/IP combines some of the upper layers of OSI.

1. Parul Institute of Engineering & Technology
Subject Code : 150702
Name Of Subject : COMPUTER NETWORK
Name of Unit : INTRODUCTION TO NETWORKS
Topic : OSI MODEL , TCP/IP MODEL AND COMPARISON
OF OSI & TCP/IP MODEL
Name of Student :Agrawal Swapnil J.

2. • OSI MODEL
• THE OSI MODEL
• DIFFERENT LAYERS OF OSI REFERENCE MODEL
• EXCHANGE OG INFORMATION IN OSI MODEL
• OSI FEATURES
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON
CONTENTS

3. • TCP/IP MODEL
• INTRODUCTION TO TCP/IP
• LAYERS IN TCP/IP
• TCP/IP STACK
• TCP/IP ENCAPSULATION
• TCP/IP PROTOCOL
• COMPARISON OF OSI & TCP/IP MODEL
CONTENTS
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COMPARISON

4. Established in 1947, the International
Standards Organization (ISO) is a multinational
body dedicated to worldwide agreement on
international standards.
Almost three-fourths of countries in the world are
represented in the ISO. An ISO standard that covers
all aspects of network communications is the Open
Systems Interconnection (OSI) model. It was first
introduced in the late 1970s.
THE OSI MODEL
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

5. The OSI model
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COMPARISON

6. OSI LayersOSI Layers
OSI Model
Data unit Layer Function
Host
layers
Data
7. Application
Network process to
application
6. Presentation
Data representation,
encryption and decryption
5. Session Innermost communication
Segments 4. Transport
End-to-end connections and
reliability, Flow control
Media
layers
Packet 3. Network
Path determination and
logical addressing
Frame 2. Data Link Physical addressing
Bit 1. Physical
Media, signal and binary
transmission
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COMPARISON

7. OSI LayersOSI Layers
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COMPARISON

8. Layer1: Physical LayerLayer1: Physical Layer
• The Physical Layer defines the electrical and
physical specifications for devices. In
particular, it defines the relationship between
a device and a physical medium.
• This includes the layout of pin, voltages, cable
specification, hubs, repeaters, network
adapters, host bus adapters, and more.
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

9. • The Data Link Layer provides the functional
and procedural means to transfer data
between network entities and to detect and
possibly correct errors that may occur in the
Physical Layer.
• Originally, this layer was intended for point-to-
point and point-to-multipoint media,
characteristic of wide area media in the
telephone system.
• The data link layer is divided into two sub-
layers by IEEE.
Layer 2: Data Link LayerLayer 2: Data Link Layer
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

10. • The Network Layer performs
–network routing functions,
–perform fragmentation and reassembly,
–report delivery errors.
• Routers operate at this layer—sending data
throughout the extended network and making
the Internet possible.
Layer 3: Network LayerLayer 3: Network Layer
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COMPARISON

11. • The Network Layer provides the functional
and procedural means of transferring variable
length data sequences from a source to a
destination via one or more networks, while
maintaining the quality of service requested
by the Transport Layer.
Layer 3: Network LayerLayer 3: Network Layer
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COMPARISON

12. • The Transport Layer provides transparent
transfer of data between end users, providing
reliable data transfer services to the upper
layers.
• The Transport Layer controls the reliability of a
given link through flow control,
segmentation/documentation, and error
control.
Layer 4: Transport LayerLayer 4: Transport Layer
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

13. • The Session Layer controls the dialogues
(connections) between computers.
• It establishes, manages and terminates the
connections between the local and remote
application.
• It provides for full-duplex, half-duplex,
or simplex operation, and establishes check
pointing, adjournment, termination, and
restart procedures.
Layer 5: Session LayerLayer 5: Session Layer
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COMPARISON

14. • This layer provides independence from
differences in data representation (e.g.,
encryption) by translating from application to
network format, and vice versa.
• This layer formats and encrypts data to be
sent across a network, providing freedom
from compatibility problems.
• It is sometimes called the syntax layer.
Layer 6: Presentation LayerLayer 6: Presentation Layer
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

15. • The application layer is the OSI layer closest
to the end user, which means that both the
OSI application layer and the user interact
directly with the software application.
• Application layer functions typically include:
–identifying communication partners,
–determining resource availability,
–synchronizing communication.
Layer 7: Application LayerLayer 7: Application Layer
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COMPARISON

16. An exchange using the
OSI model
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COMPARISON

17. Summary of OSI Layers
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COMPARISON

18. OSI FeatureOSI Feature
Open system standards over the world
Rigorously defined structured, hierarchical
network model
Complete description of the function
Provide standard test procedures
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COMPARISON

19. Introduction TCP/IPIntroduction TCP/IP
• The Internet Protocol Suite (commonly known
as TCP/IP) is the set of communications
protocols used for the Internet and other
similar networks.
• It is named from two of the most important
protocols in it:
–the Transmission Control Protocol (TCP) and
–the Internet Protocol (IP), which were the
first two networking protocols defined in
this standard.
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COMPARISON

20. Layers in the TCP/IP Protocol Suite
Original Layers
(Practically)
Layers According to Book
(Theoretically)
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COMPARISON

21. The Upper Layers
OSI TCP / IP
Application (Layer7)
ApplicationPresentation (Layer6)
Session (Layer 5)
SessionSession
PresentationPresentation
ApplicationApplication
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COMPARISON

22. The Session Layer
 The Session layer permits two parties to hold
ongoing communications called a session across a
network.
 Not found in TCP/IP model
 In TCP/IP , its characteristics are provided by the TCP
protocol.
(Transport Layer)
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COMPARISON

23. The Presentation Layer
 The Presentation Layer handles data format
information for networked communications. This is
done by converting data into a generic format that
could be understood by both sides.
 Not found in TCP/IP model
 In TCP/IP, this function is provided by the Application
Layer.
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

24. The Application Layer
 The Application Layer is the top layer of the reference
model. It provides a set of interfaces for applications
to obtain access to networked services as well as
access to the kinds of network services that support
applications directly.
 OSI - FTAM,VT,MHS,DS,CMIP
TCP/IP - FTP,SMTP,TELNET,DNS,SNMP
 Although the notion of an application process is
common to both, their approaches to constructing
application entities is different.
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COMPARISON

25. TCP/IP Transport Layer
 Defines two standard transport protocols: TCP and
UDP
 TCP implements a reliable data-stream protocol
– connection oriented
 UDP implements an unreliable data-stream
– connectionless
 TCP provides reliable data transmission
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COMPARISON

26. TCP/IP StackTCP/IP Stack
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COMPARISON

27. TCP/IP EncapsulationTCP/IP Encapsulation
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COMPARISON

28. TCP/IP Some ProtocolTCP/IP Some Protocol
Layer Protocol
Application
DNS, TFTP, TLS/SSL, FTP, Gopher, HTTP, IMAP, IRC,
NNTP, POP3, SIP, SMTP, SMPP, SNMP, SSH, Telnet, Echo
, RTP, PNRP, rlogin, ENRP
Routing protocols like BGP and RIP which run over
TCP/UDP, may also be considered part of the Internet
Layer.
Transport TCP, UDP, DCCP, SCTP, IL, RUDP, RSVP
Internet
IP (IPv4, IPv6), ICMP, IGMP, and ICMPv6
OSPF for IPv4 was initially considered IP layer protocol
since it runs per IP-subnet, but has been placed on the
Link since RFC 2740.
Link ARP, RARP, OSPF (IPv4/IPv6), IS-IS, NDP
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

29. Comparison of Both LayersComparison of Both Layers
OSI TCP/IP
Application Layer
Application Layer
TELNET, FTP, SMTP, POP3,
SNMP, NNTP, DNS,NIS, NFS,
HTTP, ...
Presentation Layer
Session Layer
Transport Layer Transport Layer
TCP , UDP , ...
Network Layer Internet Layer
IP , ICMP, ARP, RARP, ...
Data Link Layer
Link Layer
FDDI, Ethernet, ISDN, X.25,...
Physical Layer
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COMPARISON

30. Comparison of TCP/IP
and OSI model
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COMPARISON

31. Comparing Transport for both
Models
• The features of UDP and TCP defined at TCP/IP
Transport Layer correspond to many of the
requirements of the OSI Transport Layer.
• There is a bit of bleed over for requirements in the
session layer of OSI since sequence numbers, and
port values can help to allow the Operating System
to keep track of sessions, but most of the TCP and
UDP functions and specifications map to the OSI
Transport Layer.
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COMPARISON

32. Comparing Transport for both
Models
• The TCP/IP and OSI architecture models both employ
all connection and connectionless models at
transport layer. However, the internet architecture
refers to the two models in TCP/IP as simply
“connections” and datagram's.
• But the OSI reference model, with its penchant for
“precise” terminology, uses the terms connection-
mode and connection-oriented for the connection
model and the term connectionless-mode for the
connectionless model.
Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL &
COMPARISON

33. THANK YOU

34. REFERENCES
Books:-
1.COMPUTER NETWORKS
Fourth Edition by Andrew S. Tanenbaum
Web Resources:-
1.Google
2.Wikipedia

35. ANY QUERIES???