barcode project in vb.net Protocols in Software

Encoder Code-39 in Software Protocols

Protocols
Code 39 Extended Recognizer In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Creating Code 39 In None
Using Barcode generator for Software Control to generate, create Code39 image in Software applications.
Protocols
Read Code 3 Of 9 In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
Encoding Code 3 Of 9 In Visual C#.NET
Using Barcode generation for VS .NET Control to generate, create Code 39 Full ASCII image in .NET applications.
ers of functionality. To understand data communications, we must break it into its component parts and examine each part individually, relying on the old adage that the only way to eat an elephant is one bite at a time. Like a Russian Matreshka doll, data communications are made up of layer upon layer of operational functionality that work together to accomplish the task at hand namely, the communication of data. These component parts are known as protocols, and they have one responsibility: to ensure the integrity of the data that they transport from the source device to the receiver. This integrity is measured in a variety of ways including bit-level integrity, which ensures that the bits themselves are not changed in value as they transit the network; data integrity, which guarantees that the bits are recognizable as packaged entities called frames or cells; network integrity, which provides for the assured delivery of those entities, now in the form of packets, from a source to a destination; message integrity, which not only guarantees the delivery of the packets, but, in fact, their sequenced delivery to ensure the proper arrival of the entire message; and finally, application integrity, which provides for the proper execution of the responsibilities of each application. This is shown graphically in Figure 2-1. Protocols exist in a variety of forms and are not limited to data communications applications. Military protocols define the rules of engagement that modern armies agree to abide by; diplomatic protocols define the manner in which nations interact and settle their political and geographic differences; in addition, medical protocols document the manner in which medications are used to treat illness. The word protocol is defined as a set of rules that facilitates communication. Data communications, then, is the science built around the protocols that govern the exchange of digital data between computing systems.
Code 39 Full ASCII Creator In .NET Framework
Using Barcode creation for ASP.NET Control to generate, create ANSI/AIM Code 39 image in ASP.NET applications.
Code 3 Of 9 Creation In VS .NET
Using Barcode creator for VS .NET Control to generate, create Code39 image in Visual Studio .NET applications.
Data Communications Networks
Code 39 Creation In Visual Basic .NET
Using Barcode generation for .NET Control to generate, create Code 39 image in VS .NET applications.
ECC200 Creation In None
Using Barcode creator for Software Control to generate, create Data Matrix image in Software applications.
Data communications networks are often described in terms of their architectures, as are protocols. Protocol architectures are often said to be layered because they are carefully divided into highly related but nonoverlapping functional entities. This division of labor not only makes it easier to understand how data communications works, but also makes the deployment of complex networks far easier. The amount of code (lines of programming instructions) required to successfully carry out the complex task of data transmission is quite large. If the program that carries out all of the functions in that process
GS1 - 12 Maker In None
Using Barcode creator for Software Control to generate, create UPC-A Supplement 5 image in Software applications.
ANSI/AIM Code 39 Maker In None
Using Barcode generator for Software Control to generate, create Code 39 Extended image in Software applications.
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
European Article Number 13 Generator In None
Using Barcode maker for Software Control to generate, create UPC - 13 image in Software applications.
Barcode Creator In None
Using Barcode creation for Software Control to generate, create barcode image in Software applications.
Protocols
Create Code 2 Of 7 In None
Using Barcode creation for Software Control to generate, create ANSI/AIM Codabar image in Software applications.
Recognize EAN13 In .NET
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET applications.
Figure 2-1 The various integrity levels of the OSI Model
Code 39 Extended Encoder In .NET
Using Barcode printer for Visual Studio .NET Control to generate, create Code 3 of 9 image in .NET applications.
Bar Code Recognizer In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
2
DataMatrix Generator In Objective-C
Using Barcode generator for iPhone Control to generate, create Data Matrix ECC200 image in iPhone applications.
Code 128 Code Set A Creator In Java
Using Barcode printer for Java Control to generate, create Code 128 Code Set C image in Java applications.
Application Integrity
Encoding EAN-13 In Java
Using Barcode generator for Java Control to generate, create EAN13 image in Java applications.
Linear Barcode Creation In VB.NET
Using Barcode printer for Visual Studio .NET Control to generate, create 1D image in Visual Studio .NET applications.
Message Integrity
Network Integrity
Data Integrity
Bit-Level Integrity
were written as a single, large, monolithic chunk of code, then it would be difficult to make a change to the program when updates were required, simply because of the monolithic nature of the program. Now imagine the following: Instead of a single set of code, we break the program into functional pieces, each of which handles a particular specific function required to carry out the transmission task properly. With this model, changes to a particular module of the overall program can be accomplished in a way that only affects that particular module, making the process far more efficient. This modularity is one of the great advantages of layered protocols.
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
Protocols
Protocols
Consider the following simple scenario, shown in Figure 2-2: A PCbased e-mail user in Madrid with an account at ISP Terra Networks wants to send a large, confidential message to another user in Marseilles. The Marseilles user is attached to a mainframe-based corporate e-mail system. In order for the two systems to communicate, a complex set of challenges must first be overcome. Let s examine them a bit more closely. The first and most obvious challenge that must be overcome is the difference between the actual user interfaces on the two systems. The PCbased system s screen presents information to the user in a Graphical User Interface (GUI, pronounced gooey ) format that is carefully designed to make it intuitively easy to use. It eliminates the need to rely on the old command line syntax that was used in DOS environments. The mainframe system was created with intuitive ease of use in mind, but because a different company designed the interface for a mainframe host, under a different design team, it bears minimal resemblance to the PC system s interface. Both are equally capable, but completely different. As a result of these differences, if we were to transmit a screen of information from the PC directly to the mainframe system, it would be unreadable simply because the two interfaces do not share common field names or locations. The next problem that must be addressed is security, illustrated in Figure 2-3. We mentioned earlier that the message that is to be sent from the user in Madrid is confidential, which means that it should probably be encrypted to protect its integrity. Also, because the message is large, the sender will probably compress it to reduce the time it takes to transmit it. Compression, which will be discussed in more detail later, is simply the process of eliminating redundant information from a file before it is transmitted or stored to make it easier to manage. Another problem has to do with the manner in which the information being transmitted is represented. The PC-based Eudora message encodes its characters using a seven-bit character set called the American Standard Code for Information Interchange (ASCII). A sample of the
Copyright © OnBarcode.com . All rights reserved.