Chapter 3. Discuss Network Architecture. Discuss Standards. Electronic Data Interchange Layered Models OSI Model TCP/IP Model 2 Prepared by

Network Models and Standards

Chapter 3

Prepared by Saher H. Mohammed 2

Discuss Network Architecture.

Discuss Standards.

Electronic Data Interchange

Layered Models

OSI Model

TCP/IP Model

Chapter Overview


Architecture is an overall system plan that is implemented in a

set of hardware, software, and communication products.

The architecture specifies components and interfaces that make

up the systems. It includes, protocols, formats and standards to

which all hardware and software in the network must conform.

Architecture should include documentation of system usage,

functionality and performance parameter of all the components.

Architecture


Network Architecture attempts to facilitate the operation,

maintenance and growth of the communication and

processing environment by isolating the user and the

application program from the details of the network.

Network architecture is necessary to support distributed data

processing with multiple computers in a network.

Network Architecture


Purpose

Provide an orderly structure for the communication network that ensures a specific

level of compatibility.

Provide isolation of the application systems from the physical hardware.

Support faster development and easier maintenance of application systems by using

system software utilities to perform communication functions.

Be reliable, modular and easy to use.

Accommodate new devices and software for the network without changing the

application systems.

Replace individual pieces of system without affecting other pieces.

Network Architecture


A standard is a set of rules or descriptions about a specific piece of

equipment, software or service.

A standard is a definition or format that has been approved by a

recognized standards organization or is accepted as a de facto

standard by the industry.

Commonly, there are two kinds of standards

Proprietary standards

Open standards

Standards


Standards that are specific and unique to an organization are

called proprietary standards.

These proprietary standards can only be used by the

organization that designed those standards.

Standards that can be used by all the organization are called

open standards.

Equipments from various supplier are interoperable.

Standards


In computing environment, middleware consist of software agents

acting as intermediary between different application components.

Total cost of ownership (TCO) considers all costs of using a specific

set of equipment, including purchase, installation, maintained, and

upgrade.

de facto – actually exercising power, although not legally or officially

established.

Example IBM SNA

Standards


A system is a group of interrelated and interdependent parts

working together to achieve is a common goal.

A cooperative system is a specialized type of system that

requires at least two parties with different objectives but

common goals to collaborate on the development and

operation of a joint system in support of those common goals.

Electronic Data Interchange (EDI)


EDI is the process of direct computer-to-computer

communication of information in a standard format between

organizations.

This communication permits the receiver and sender to

perform a specific set of business functions.

EDI is a set of standards for electronic transfer of business

documents.



The primary purpose of EDI is to provide communication

standards for the electronic transfer of common business

documents between the respective computer systems of

individual and diverse trading partners.

EDI provides a significant opportunity to reduce the cost of

doing business and strengthen the partnership. Thus,

offering a significant competitive advantage.



Benefits of using EDI

Improve customer service.

Improve accuracy of the data.

Reduce clerical errors.

Faster access to information.

Decreased administrative cost.

Reduced delivery times.

Improved cash flows.



Layered models are all about boundaries; honor the boundaries and

live in freedom within the layer.

Prototyping – The use of one capability to emulate another,

generally in a inexpensive manner and short time frame.

Simulation – The process of imitating a real phenomenon with a set

of mathematical formulas. It may be achieved on a working system

by use of equipment to simulate real conditions, such as network

traffic.

Layered Models


OSI Model stands for Open System Interconnection Model.

OSI model was created by the International Organization for

Standardization (ISO) and the Consultative Committee on

International Telephony and Telegraphy (CCITT).

Exponential growth of internet resulted in the heterogeneous

computing environment, this resulted in the creation of OSI

Model.

The OSI Model


The OSI Model consists of seven layers, each layer with specific

standards and functionality.

The upper most four layers are the host layers, they specify the

need of the user applications.

The lower most three layers are the media layers, they are

concerned with the actual communication, circuit establishment

and disconnection, message routing, and error correction and

detection.

The OSI Model


The layers are hierarchical in that the lower layers provide services such

as the control information to the layer just above it.

The adherence to OSI Model makes the development of software and

hardware easier.

The OSI Model is a plan by which communication software is designed.

The model facilitates control, upgradability, replacement, and

management of the resources that make up the communication network.

The OSI Model


The OSI Model – Layers

Application Layer

Presentation Layer

Session Layer

Transport Layer

Network Layer

Data Link Layer

Physical Layer

Data

Data

Data

Frames

Packets

Segments

Bits

Host

Layers

Media

Layers


The OSI Model – Layers


Physically transmits the bits.

Physically establishes the node-to-node connection when

requested by the data link layer.

Concerns with the establishing duplex, half-duplex and full-

duplex transmission.

Defines all electrical and physical specifications for the

devices.

Layer 1 – The Physical Layer


The data link layer concerns itself with the actual characters

and the sequencing in which they are transmitted.

This layer segments the bits into frames, and coordinates the

flow of data over multiple physical connections.

This layer attempts to deliver error free data, it includes error

detection, error recovery and error correction methods.

Layer 2 – The Data Link Layer


The network layer performs network routing, flow control,

segmentation/ de-segmentation, and error control functions.

The network layer defines message addressing and routing

methods.

This layer also controls congestion in the network is

overloading certain computers.

Handles the movements for data from one network to another.

Layer 3 – The Network Layer


The transport layer provides a transparent transfer of data

between end users.

The transport layer is responsible for maintaining a reliable

and cost-effective communication channel from user’s

applications software process in one computer to a user

process in another computer.

The transport layer monitors the status of the connections.

Layer 4 – The Transport Layer


The session layer provides the mechanism for managing the

dialogue between end-user application processes.

This layers deals with establishing a logical session between

the hosts.

The session layer establishes the communication between

applications, enforces the rules of carrying on the dialogue,

and tries to establish the connection if a failure occurs.

Layer 5 – The Session Layer


The presentation layer handles encoding, encryption, and

similar manipulation of the presentation of data.

The presentation layer is also responsible for formatting and

displaying the data to and from the application layer and

deals with the transmission format of the data.

This layer deals with the syntax of the data.

Layer 6 – The Presentation Layer


The application layer interfaces directly to and performs

common application services for the application processes.

This layer interfaces to user-oriented services such as

determining the data to be transmitted, the message or

record format for the data, and the transaction codes that

identify the data to the receiver.

Layer 7 – The Application Layer.


Layer Title Action

1 Physical Delivers bits to node to node

2 Data Link Deliver error-free data

3 Network Define message addressing and routing

4 Transport Maintains reliability and cost effective communication channel

5 Session Organize logical session

6 Presentation Formats and displays the data, provides security, encodes, and encrypts

7 Application Functionally defines by the user

The OSI Model – Layers Summary


The TCP/IP is the basic communication language or protocol

of the internet.

It is a collection of two communication protocols

Transmission Control Protocol

Internet Protocol

The TCP/IP Model


The TCP manages the assembly of messages or files into

smaller packets that are transmitted over the Internet and

received by a TCP layer at the receiving end, which then

reassembles the original massage.

TCP is responsible for verifying correct delivery of data from

client to sever.

Transmission Control Protocol (TCP)


The IP handles the address part of each packet so that it gets

to the right destination.

TCP/IP also can refer to an entire collection of protocols, called

TCP/IP suite. This includes

Hyper Text Transfer Protocol (HTTP).

File Transfer Protocol (FTP).

Terminal Emulation (Telnet).

Simple Mail Transfer Protocol (SMTP).

Internet Protocol (IP)


The TCP/IP Model

Application Layer

Transport Layer

Internet Layer

Data link Layer

Physical Layer

Network Access Layer


The physical layer and the data link layer of OSI Model combined is

called Network Access Layer of the TCP/IP Model.

The physical layer is concerned with the transmission of the actual

bits.

The Data link layer is concerned with the framing and transporting

the packets over the physical layer.

The data link layer in TCP/IP and OSI Model is sub divided into

Logical Link Control (LLC) and Media Access Control (MAC).

Network Access Layer


The internet layer used the Internet Protocol to send the

block of data (datagram) from one point to another.

This layer is also called as the Network Layer.

Internet protocol is the key component of TCP/IP as each

piece of data is sent over the network as an IP packet.

IP performs the basic task of getting packets from source to

destination.

Internet Layer


The transport layer is where the transmission control protocol

(TCP) is used by most of the Internet application such as FTP,

HTTP and Telnet.

TCP is a connection-oriented, the sender and receiver must

establish a connection before data can be transferred.

The transport layer provides a safe and reliable byte stream, which

makes sure that data arrives complete, undamaged, and in order

Transport Layer.


The application layer is the layer that most common network-

aware programs use in order to communicate across a

network with other programs.

The Application Layer


OSI vs. TCP/IP

Application Layer

Telnet

Network Interface Layer

Application Layer

Internet Layer

Presentation Layer

Session Layer

Transport Layer

Network Layer

Data Link Layer

Physical Layer

Transport Layer

FTP SMTP DNS SNMP

TCP

TCP/IP Protocol Suit

UDP

IPARPIGMP ICMP

Ethernet Token ring

Frame relay ATM

Documents

Chapter 3. Discuss Network Architecture. Discuss Standards. Electronic Data Interchange Layered Models OSI Model TCP/IP Model 2 Prepared by