The weight of computer networking in the GATE exam is always high as well as if you are in your college then also it can help you to maintain good academics. If you want any PDF of computer networking you are in the right place. At collectallpdf. In this particular post, we are giving you access to download all PDF of computer networking subject. Click The Download Link again and again to download the pdf. If the link does not work, then you can send your request to us by clicking here or comment below.
List of books of computer Networking:. Computer networking- A top-down approach by James F. You can get the link from the below button:. This book continues to offer a fresh and timely approach to computer networking instruction. The most important aspects of this book are its top-down approach, its focus on the Internet and a modern treatment of computer Networking, its attention to both principles and practice, and its accessible style and approach toward learning about computer networking.
Kurose and Kieth W. Inside the LAN every computer is well identified and usually every user is known. It is considered a trusted area. It is considered a dangerous area. VPN is typically required to identify portable computers connected via wireless connection. Transfer speed The network connecting components are the cables, which determine the speed of the LAN. Cables have a speed measure in bps bits per second which indicates how many bits can flow through the cable in one second.
Page 14 of 33 Edition 8. To find out how much time does it take to transfer a file with a size expressed in bytes, divide the connection speed in bps by 8 to find out the byte rate per second and then divide the file size by the speed to find out the number of seconds it takes for the file transfer.
For example, to transfer a MB file through an Fast Ethernet connection, find out the speed of Communication Inside a computer network many communication programs are installed on Intranet computers to connect to the Internet or even to internal computers. Web browser A web browser is a client program to navigate the WWW and retrieve web pages. Mail reader A mail reader is a client program to send and retrieve emails. The market leader is Microsoft Outlook, a commercial proprietary software.
It has many competitors, the most famous being the open source Mozilla Thunderbird and the free Windows Live Mail. It can be useful for various reasons: it does not require the installation of a mail reader program; old received emails are always available on the website and can thus be accessed from home, office and while traveling, even without a personal laptop; the mailserver takes care of emails backup. But on the other hand it requires a continuous fast connection even to write a single long email, which can be costly and, in some situations, impossible and usually the email space is limited.
The most famous website interfaces are the Microsoft Outlook Web App, where the web interface looks exactly like Microsoft Outlook, and the Webmail interface, used and personalized by most Internet providers.
Posta Elettronica Certificata PEC When sending an email, the sender has no proof that it has been sent, for example to be used in a court of justice, and no guarantee that the email has been dispatched.
Some mail readers use a receipt system, but the receiver is not obliged to send back the receipt. In order to overcome these problems, many solutions have been proposed. When an email is sent from a PEC address to another PEC address, the sender receives two receipt: the first one is a proof that the email has been sent with date and time, while the second one is a proof that the email has been dispatched to the mailbox of the receiver or, equivalently, received by the sender.
However, it is important to note that PEC alone does not guarantee that the sender is really the person who claims to be and that content remains unread until it reaches destination. In order to overcome these last two problems, encryption and digital signature see section 4. The major difference with respect to most Internet communication systems is that WhatsApp uses a fully centralized architecture, i.
Search engines A search engine is a special program running on a website which offers to the user the possibility of searching other websites for specific web pages. The user needs to connect to the search engine website Page 16 of 33 Edition 8.
Paolo Coletti and digit the keywords, or sometimes even a complete question, and the website returns the list of relevant web pages. Search engines use a crawler technique: they continuously go through the known web pages memorizing their content and trying to discover other web pages through the contained links. The most popular search engines are Google, the current market leader, Yahoo! In order to choose the order in which web pages are displayed to the user, search engines use scoring system.
Internet connections There are many different ways to connect to the Internet. This phenomenon is called digital divide: there are people e. In order to overcome this social problem, WiMAX is spreading, a sort of very long range Wireless which arrives up to 10 Km but works only if the transmitting and receiving antennas are in line of sight and whose theoretical speed of 70 Mbps decreases with distances to about 40 Mbps.
Paolo Coletti Basic Computer course book 4. Computer security Being connected to the Internet means giving anybody access to the computer. This law requirements apply clearly to all companies and professionals which handle data, but they also apply to personal users who communicate data. To personal users who do not communicate data still the security requirements to avoid data theft apply. Encryption Encryption is a text masking technique, derived from military use, which transforms information in such a way that it may be correctly read only with a special password called key.
It uses two keys, a public key for encrypting, usually known only to one computer or person, and a private key for decrypting, usually known by all the computers or people which legitimately may read the information.
The size of these keys, and thus the difficulty to be guessed, is expressed in bits, with bits being the typically most secure size used. The sent messages are encrypted and later decrypted by A with his private key. In case somebody Page 20 of 33 Edition 8. Even when somebody uses the public key to decrypt, it does not work. The same process happens whenever a browser tries to send a password or secret information to a website using a secure connection see section 4.
In this case private and public keys coincides and are kept secret. The encryption and decryption process is done automatically by a program PDF creation programs or compression programs can do it, see page 11 for instructions how to do it or even by the operative system if the entire disk is encrypted , which asks the password to the user every time.
The two following schemas illustrate instead the usage of encryption for digital signature. A wants to publish a publicly available document with its signature. Paolo Coletti authority to distribute private and public keys. Even though theoretically a simple password is enough, to be sure that the user does not give the private password around, the certification authority gives him, after having identified him through a governmental identity card, a password usually together with another identification tool a smart card, a telephone number for an OTP to be send , which, when used together, correspond to his private key.
An automatic signature program takes care of automatically encrypting documents. The service to digitally sign documents is offered by private certification companies, with prices currently affordable also by private users and with alternative devices such as smartcards or OTP devices see section 4.
Documents for which it is important to determine the exact date of the signature have moreover a temporal mark signed directly by the certification authority. Passwords On the Intranet the user is identified only by his username, known to everybody, and his password, known only to him. Therefore it is absolutely necessary to keep passwords secret. Unfortunately many people use very trivial passwords.
This is the list of the most common passwords in password, , , , qwerty, dragon, pussy, baseball, football, letmein, monkey, , abc, There exist automatic programs which are able to try 4 billion passwords each second, and they usually start trying combinations of words and numbers the complete set of all Italian, German and English words can be tried in less than 1 second.
Unfortunately every website asks the user to register with a password and users who use always the same password are giving it away to every website they register, even untrustworthy ones. It is a good procedure to have at least three passwords: one for important use bank account , a second one for everyday use and a last one for unimportant use registering to unknown websites or to services that will not be used anymore. They seem to be unreadable, but computer experts can reveal them instantly.
Store passwords in programs only if that computer has a single user i. Page 24 of 33 Edition 8. Paolo Coletti 4. Usually biometric identification is considered to be very secure and thus it is used to replace completely the password system.
For very important activities, such as digital signature or bank operations, usually a personal device is instead added to the standard login and password system. The usual password is remembered personally by the user and a personal device provides the second part of the password. This device can be a smartcard, such as the national health card, which is inserted into a card reader or a USB token and they provide to the program or web site the second half of the password which is stored inside the object.
This big advantage of this second system is that, even if both parts of the password are intercepted or guessed, the second part can be used only that time and will expire after a few seconds.
Viruses From the Internet many unauthorized connection attempts arrive. Some of these are mistakenly authorized and manage to reach the Intranet or at least to come in contact with programs which are behind the firewall. If these connections carry malign intentions, usually their aim is to explore and use the Intranet computers, to destroy Intranet data or to stop some Intranet services which is a dangerous attack if these services are managing stock trades or telephone calls.
Defense against these kinds of attacks is in charge system administrators. The virus is a little program which has this name because its life cycle is the same of a biological organism: survive and duplicate. It arrives on the computer through email attachments, downloaded files, CDs and floppy disks or directly from the Intranet. It is often hidden inside other good files or programs, which are called infected.
As soon as the user mistakenly runs it often trying to run the good program or to open the good file , the virus orders the computer to run itself every time the computer is turned on, thus assuring its survival. It starts duplicating itself, infecting other files, CDs and floppy disks, and trying to send itself around by email or on the Intranet. No viruses are known to be able to damage hardware.
These types are not exclusive: for example a Trojan horse which is at the same time a spyware and an adware. An infected computer can be recognized by some symptoms.
To check the computer for viruses and to try to remove viruses from the computer, the user can run a special program called antivirus. If a virus is found, it tries to remove it and to repair damaged files. Some files can be unrecoverable. If there is an infected file, it tries to delete the virus and repair it. In this case, whenever a virus or a suspect file is run, the antivirus prevents it from running and warns the user.
A lot of antivirus programs, free and commercial, exist. Their most important feature is obviously the possibility to be constantly updated through the Internet.
Emails 4. Attachments For viruses, email attachments are a first class way of traveling, since they are very often opened by users without any precaution.
Sometimes viruses hide inside files which were really sent by the sender, unaware of having an infected computer. Other times a virus takes control of the mail reader program and sends itself to the whole address book, counterfeiting the sender address often using an address taken from the address book in order to avoid that the real infected computer be identified and to gain the thrust of the receiver, and writing in the email text smart sentences pretending to be a regular friend of the receiver.
The Edition 8. Paolo Coletti Basic Computer course book arrival of this kind of email usually creates havoc, since the receiver is sure that the fake sender has a virus, while the original infected computer is another one. The basic rule is never open any attachment from the mail reader program. Save the attached files on the desktop and run an antivirus program to check these files before opening them. This page book written by Dr. Internetworking Technologies — An Engineering Perspective includes 12 chapters organized into three parts:.
This free networking book is available online as a read-only PDF document. You can download the book to your computer, phone, etc. Written by Olivier Bonaventure, this free networking book covers primary concepts and even includes some exercises toward the end, as well as a full glossary defining lots of network concepts.
With over pages and six chapters, Computer Networking: Principles, Protocols and Practice covers the application layer, transport layer, network layer, and data link layer, as well as principles, access control, and technologies used in Local Area Networks. Here are the top 20 sites where you can find and download a wide variety of completely free books online, anything from romance novels to computer technology manuals.
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