Every computer connected to the Internet has its own unique IP address, which distinguishes it from all other computers.

• An address consists of four decimal numbers, each ranging from 0 to 255, separated by a dot.

• For example: 193.126.7.29; 128.29.15.124.

By first number can be determined computer belonging to one or another network class: 1) class A(large networks): network addresses - from 0 to 127(up to 256*256*256 computers); 2) class B(medium networks): network addresses - from 128.0 to 191.255(up to 256*256 computers); 3) class C(small networks): network addresses - from 192.0.0 to 255.254.255(contains 254 addresses)

In binary notation the first three bits address records are reserved for class identification, and the rest are divided into network address And computer address on the network.

Domain Name System.

• The word “domain” means a site, a zone.

• DNS assigns a unique domain name to a numeric IP address.

• The domain name system is built on hierarchical principle , a domain name consists of several domains separated from each other by a dot.

• The top-level domain is first on the right, then the domain levels descend.

• For example, address educom.spb.ru stands for:

• top level domain ru– the computer under this name is located in Russia;

• second level domain spb– the computer is located in St. Petersburg;

• third level domain edicom- reports the name of the organization to which the entire given domain address is registered (Education Committee of the Administration of St. Petersburg).

• The domain name space has a hierarchical structure

• Root domain is located at the very top of the hierarchy and is indicated by a dot.

• Top level domains are created according to a certain characteristic. They combine network computers based on geography or type of activity. For example:

• ru, uk etc. - determine the geographical location (ru - Russia, uk - Ukraine)

• com- commercial organizations (for example, microsoft.com);

• edu- educational (for example, mit.edu);

• gov- government organizations (for example, congress.gov);

• org- non-profit organizations (for example, rfc-editor.org);

• net- organizations that support parts of the Internet (for example, nsf.net).

• Second level domains usually refer to company names and are registered by the owners of top-level domains.

• Third level domains usually refer to divisions within companies.

• When a domain name is formed, the name of the parent domain is added to it. For example, the second-level domain microsoft.com, the third-level domain eng.microsoft.com.

• Domains below the third level are generally rare.

Some top level domain names

URL format: ://

Answer the questions

• Explain the IP addressing system using the following examples: a) 101.67.12.1 b) 184.201.201.201 c) 205.205.205.205

• Explain the principle of constructing a domain name system and the concept and structure of a URL.

Things to remember:

• Each computer connected to the Internet must have its own address, which is called an IP address (IP = Internet Protocol)

• An IP address consists of four numbers separated by dots; each of these numbers is in the range 0...255, for example: 192.168.85.210

• document address on the Internet (URL = Uniform Resource Locator) consists of the following parts:

• protocol, most often http(for Web pages) or ftp(for file archives)
• signs :// , separating the protocol from the rest of the address
• domain name (or IP address) of the site
• directory on the server where the file is located
• file name

• It is customary to separate directories using a non-backslash "\" (as in Windows), and straight “/”, as in the system UNIX and her “relatives”, for example, in Linux

• example address (URL)

• here the protocol is highlighted with a yellow marker, the domain name of the site is purple, the directory on the site is blue, and the file name is gray

Petya wrote down the IP address of the school server on a piece of paper and put it in his jacket pocket. Petya's mother accidentally washed her jacket along with the note. After washing, Petya found four pieces of paper in his pocket with fragments of an IP address. These fragments are designated by the letters A, B, C and D. Recover the IP address. In your answer, indicate the sequence of letters indicating the fragments in order corresponding to the IP address .

• Each of the 4 numbers in the IP address must be in the range from 0 to 255.

• Therefore, fragment A is the very last one, since otherwise one of the numbers turns out to be greater than 255 (643 or 6420).

• Fragment D (number 20) can only be the first, since options 3.1320 and 3.13320 give a number greater than 255.

• Of the fragments B and C, B must be the first, otherwise we get 3.1333.13 (1333 > 255).

• Thus, the correct answer is GBVA.

The htm.net file located on the com.edu server is accessed via the ftp protocol. In the table, fragments of the file address are encoded with letters from A to J. Write down the sequence of these letters that encodes the address of the specified file on the Internet.

» [To the teacher][Tests][Computer communications]

COMPUTER COMMUNICATIONS

TEST

1. A set of hardware and software that allows computers to exchange data:

1. interface;
2. highway;
3. computer network;
4. adapters.

2. A group of computers connected by information transmission channels and located within a territory limited in size: rooms, buildings, enterprises, is called:

1. global computer network;
2. information system with hyperlinks;
3. local computer network;
4. by email;
5. regional computer network?

3. Global computer network is:

1. information system with hyperlinks;
2. many computers connected by information transmission channels and located within the same room or building;
3. a system for exchanging information on a specific topic;
4. a set of local networks and computers located over long distances and connected into a single system.

4. The exchange of information between computer networks, which have different standards for presenting information (network protocols), is carried out using:

1. highways;
2. host computers;
3. Email;
4. gateways;
5. file servers.

5. The configuration (topology) of a local computer network, in which all workstations are connected directly to the server, is called:

1. annular;
2. radial;
3. tire;
4. tree-like;
5. radial-ring.

6. To store files intended for public access by network users, the following is used:

1. file server;
2. work station;
3. client-server;
4. switch.

7. Network protocol is:

1. a set of agreements on interactions in a computer network;
2. sequential recording of events occurring on a computer network;
3. rules for interpreting data transmitted over the network;
4. rules for establishing communication between two computers on a network;
5. coordination of various processes over time.

8. Transport protocol (TCP) - provides:

1. splitting files into IP packets during transmission and assembling files during receiving;
2. reception, transmission and delivery of one communication session;
3. providing the user with already processed information;
4. delivery of information from the sending computer to the receiving computer.

9. Routing Protocol (IP) provides:

1. delivery of information from the sending computer to the receiving computer;
2. interpreting data and preparing it for the user level;
3. preservation of mechanical, functional parameters of physical communication in a computer network;
4. control of data transmission equipment and communication channels.
5. splitting files into IP packets during transmission and assembling files during reception.

10. A computer connected to the Internet must have:

1. IP address;
2. web page;
3. home web page;
4. Domain name;
5. URL.

11. The modem provides:

1. converting binary code to analog signal and vice versa;
2. converting binary code into an analog signal;
3. converting an analog signal into binary code;
4. analog signal amplification;
5. weakening of the analog signal.

12. Teleconference is:

1. exchange of letters in global networks;
2. information system in hyperlinks;
3. information exchange system between computer network subscribers;
4. service for receiving and transmitting files of any format;
5. the process of creating, receiving and transmitting web pages.

13. The email subscriber's mailbox is:

1. some area of ​​RAM of the file server;
2. area on the mail server hard drive allocated for the user;
3. part of the memory on the workstation's hard drive;
4. a special electronic device for storing text files.

14. Web pages have the extension:

1. *.htm;
2. *.txt;
3. *.web;
4. *.exe;
5. *.www

15. HTML (HYPER TEXT MARKUP LANGUAGE) is:

1. web page markup language;
2. programming system;
3. text editor;
4. database management system;
5. expert system.

16. The Internet FTP service is intended to:

1. for creating, receiving and transmitting web pages;
2. to ensure the functioning of email;
3. to support teleconferencing;
4. for receiving and transmitting files of any format;
5. for remote control of technical systems.

17. A computer that provides its resources for use by other computers when working together is called:

1. adapter;
2. switch;
3. station;
4. server;
5. client-server.

18. Theoretically, a modem transmitting information at a speed of 57600 bps can transmit 2 pages of text (3600 bytes) within:

1. 0.5 h;
2. 0.5 min;
3. 0.5 s;
4. 3 min 26 sec.

KEY

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
3	3	4	4	2	1	1	1	1	1	1	3	2	1	1	4	4	3

Long gone are the days when computers were isolated computing complexes - sort of “number crushers” for solving scientific and technical calculations. The stage in which unconnected small and large local networks prevailed is also a thing of the past.

Today it is difficult to find a computer that is not connected to the global Internet. There is a gradual transfer of functions from conventional to network applications. Network-based operating systems are being developed, the only interface of which will be some kind of browser. A computer connected to the Internet must have certain hardware and software.

What exactly are we talking about? About internal and externally connected equipment and special software included in the operating system or installed separately.

It makes no sense to describe each of these devices or each of these programs separately, because there are countless of them.

If earlier the number of network protocols could be counted on one hand, today it is difficult to even say how many of them there are and how they differ from each other. Only a view from above will help you understand the essence of the matter.

Hardware package

To access the network, your computer needs the following equipment:

• It must have a network card, or so-called. network adapter.
• If we are talking about a wired network, then a piece of cable is needed, one end goes into the provider’s network, and the other end is connected to the LAN connector of the adapter’s external panel.
• To organize a wireless network you will need Bluetooth equipment. Bluetooth is a whole group of wireless access protocols.
• A small wireless network on the scale of an apartment or house will require the so-called. router.
• You can connect to the Internet wirelessly using a USB modem.
• Any more or less modern laptop can be used as an Internet distribution point inside an apartment - its network card allows you to do such things.

That's probably all. To start. Each of the listed equipment groups is represented by a huge number of models.

Software package

If desired, you can also access the Internet from MS-DOS - craftsmen can do anything. But this path is unlikely to suit the average user. To work normally on the Internet, he will need one of the latest Windows or Linux distributions. Anything above WinXP or a Debian-family OS with a graphical user interface will do. The network card will definitely require a driver - a program that controls the operation of this device. Typically, drivers are automatically installed by the OS, but if we are talking about a not very recent distribution, then it may not contain drivers for the new device.

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1. A group of web pages belonging to the same Company, organization or individual and related in content
website
server
host
folder
domain

2. WEВ - pages have the extension ...
.NTM
.TNT
.WEB
.EXE
.WWW

3. Method of connecting to the Internet that provides the greatest opportunities for access to information resources
permanent connection via fiber optic channel
remote access via telephone channels
permanent connection over a dedicated channel
terminal connection via dial-up telephone channel
temporary access via telephone channels

4. To store Files intended for public access by network users,...
host computer;
file server
work station
client-server
switch

5. Transport Protocol (TCP) provides...
splitting files into IP packets during transmission and assembling Files during receiving
reception, transmission and delivery of one communication session
providing the user with already processed information
delivery of information from the sending computer to the receiving computer
splitting Files into IP packets during transmission and reassembling Files during receiving

6. The configuration (topology) of a local computer network, in which all workstations are connected to the File Server, is called ...
annular
radial (star-shaped)
tire
tree-like
radial-ring

7. The speed of data transmission over a communication channel is measured by the number of transmitted ...
bytes per minute
bits of information per second
words per minute
characters per second

8. Internet FTP service is designed for...
creating, receiving and transmitting WEB pages
ensuring the functioning of email
support for teleconferences
receiving and transmitting files of any format
remote control of technical systems

9. In the OSI model, all network functions are divided into ... layers.
8
7
6
5

10. Top-level domain corresponding to the Russian segment of the Internet
ha
su
us
ru

11. A computer connected to the Internet must have...
IP - address
WEВ - page
home WEB page
Domain name
URL - address

12. Information and computing systems (networks) according to their size are divided into ...
local, regional, global
terminal, administrative, mixed
wired, wireless
digital, commercial, corporate

13. The layer of the OSI model that provides services that directly support user applications is called ... layer.
applied
representative
sessional
transport
network

14. The “Network topology” attribute characterizes...
diagram of wired connections in the network (servers and workstations)
how the network works
network depending on its size
composition of technical means

15. A provider is...
Internet connection device
Internet service provider
Internet service consumer
Internet connection agreement

16. Network protocol is...
a set of agreements on interactions in a computer network
sequential recording of events occurring on a computer network
rules for interpreting data transmitted over the network
rules for establishing communication between two computers on a network
coordination of various processes over time

17. Electronic mail (e-mail) allows you to transfer...
messages and attached files
text messages only
executable programs
www pages
exclusively databases

18. Local area network (LAN) is...
computer network operating within a division or divisions of an enterprise
unification of computer networks at the state level
network operating within one federal subject
planetary networking

19. The reference model of open system information exchange is called the model ...
ISO
OSI
OIS
OIOS

20. Global computer network is...
hyperlinked information system
many computers connected by information transmission channels and located within the same room or building
a collection of host computers and File servers
system for exchanging information on a specific topic
a set of local networks and computers located over long distances and connected via communication channels into a single system

a) IP address

b) Web server

c) home web page

d) domain name

12. URL is...

a) basic Internet protocol

b) resource address on the Internet

c) the name of the language in which Web pages are created

d) universal site name registration system

13. The page that loads when you start the browser (Internet Explorer browser) is...

a) website home page

b) browser home page

c) the last page you worked with in the last session

d) user's home page

a) active elements of web pages

b) passive elements of web pages

c) elements used to fill out forms

d) only texts that lead to new Web pages

15. To obtain from the Internet only a previously unobtained drawing, you should use...

a) the Update button on the Toolbar

b) Browser panel

c) context menu of this picture

d) execute the command View\Download

16. To save a graphic element from a Web page to a file, you should use...

17. If too many links are found when using a search engine, then to refine the search you should...

a) use wildcard characters *, ?

b) use modifiers +, -

c) reduce the number of keywords entered

d) clarify the endings in the entered keywords

18. The Temporary Internet files folder is used for…

a) acceleration to already viewed Web pages

b) speed up access to web pages that have not yet been viewed

c) remembering links to previously viewed Web pages

d) remembering the addresses of the most frequently downloaded Web pages

19. To get a Web page that has not been accessed before, it is enough...

a) Enter its address in the Browser Address panel

b) Open the Address panel and select the desired page from the list of addresses

c) Use the Journal

d) Use the command File \ Open file...

Laboratory work No. 11. Viewing Internet resources

1) Download Internet Explorer and view the program window elements.

2) Download the page www.sst.edurm.ru and make this page your home page.

3) Browse the page by scrolling and selecting links. To open a link in a new Internet Explorer window, right-click on the link and select from the context menu Open link in new window. Familiarize yourself with the components of a Web page. When working, adhere to the following rules:

 use scroll bars to scroll through the page;

 to go to the previous page, press the button Back, and to return - a button Forward;

 if the address does not load or takes a long time to load, click the button Stop and enter a different address;

 if the page has partially loaded, click the button Update.

4) Save the information from the page: in the format Full web page, in the format html only, as text. Save the drawing.

5) Load a second Internet Explorer window and open the saved files in it (menu File, team Open).

6) Switch to the first Internet Explorer window and follow the link to another Web page.

7) Download the page http:// www.testland.ru (site with tests) and add it to your favorites. Go to the home page. Call the added resource from the folder Favorites.

8) Follow the chain of links Save several drawings.

9) Go to the website of the Saransk Construction College. In the Correspondence Students section, select Schedule and click the download link and save the file on your disk.

10) Unzip and open the saved item in Internet Explorer.

11) Using a button Magazine open the panel containing links to the pages you have viewed. Review the pages you visited today.

Topic 3.2. Email

Basic requirements for the level of study

The student must:

have an idea: about the operation of e-mail;

know: the purpose and capabilities of computer networks at various levels; basic principles of information search technology on the Internet;

be able to: send and receive electronic information.

Basic computer network services: email. Purpose, overview, working methods, types of software.

Questions for self-control:

1. How does email work?

Test

Choose the correct answer:

1. The very first of the Internet servers is:

2. Which of these entries is an email address:

1. [email protected]

2. www.rnd.runnet.ru

3. What is the name of the server where the mailbox is located in the address [email protected]?

4. Given E-mail: [email protected]. The symbols of Moscow are: ...

1. Destination city

2. Provider name

3. Postal protocol

4. Username