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.

• 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

• 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

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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

The OSI model

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

OSI LayersOSI LayersOSI Model

Data unit Layer Function

Hostlayers

Data

7. ApplicationNetwork process to application

6. PresentationData representation, encryption and decryption

5. Session Innermost communication

Segments 4. TransportEnd-to-end connections and reliability, Flow control

Medialayers

Packet 3. NetworkPath determination and logical addressing

Frame 2. Data Link Physical addressing

Bit 1. PhysicalMedia, signal and binary transmission

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

OSI LayersOSI Layers

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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

• 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

• 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

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

• 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

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

• 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

• 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

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

• 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

• 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

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

An exchange using the OSI model

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

Summary of OSI Layers

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

OSI FeatureOSI Feature

Open system standards over the world

Rigorously defined structured, hierarchical network model

Complete description of the function

Provide standard test procedures

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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.

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

Layers in the TCP/IP Protocol Suite

Original Layers (Practically)

Layers According to Book(Theoretically)

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

The Upper Layers

OSI TCP / IP

Application (Layer7)

ApplicationPresentation (Layer6)

Session (Layer 5)

 

SessionSession

PresentationPresentation

ApplicationApplicationSub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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)

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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

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,CMIPTCP/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.

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

TCP/IP StackTCP/IP Stack

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

TCP/IP EncapsulationTCP/IP Encapsulation

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

TCP/IP Some ProtocolTCP/IP Some ProtocolLayer 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

Comparison of Both LayersComparison of Both LayersOSI TCP/IP

Application LayerApplication 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 LayerLink Layer 

 FDDI, Ethernet, ISDN, X.25,...Physical Layer

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

Comparison of TCP/IP and OSI model

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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.

Sub:-COMPUTER NETWORK Topic:-OSI,TCP/IP MODEL & COMPARISON

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

THANK YOU

REFERENCES

Books:-1.COMPUTER NETWORKS

Fourth Edition by Andrew S. TanenbaumWeb Resources:-

1.Google2.Wikipedia

ANY QUERIES???