Unit 5. internet and lan TECHNOLOGY

Text A

Pre-reading. Match the terms with the appropriate definitions.

ProtocolsFunctions

HTTP(Hypertext Transfer Protocol) - responsible for address packets

FTR (File Transfer Protocol) - breaks a message or file into packets

POP (Post Office Protocol) - allows users who are logged on to one host to access another host

TCP (Transmission Control Protocol) - provides secure data transfer over the

Internet

IP (Internet Protocol) - transfer mail from an e-mail server to a

client Inbox

SMTP (Simple Mail Transfer Protocol) - exchanges information over the Web

IMAP (Internet Mail Access Protocol) - transfers e-mail messages from client

computers to an e-mail server

TELNET (Telecommunication Network) - transfers files between local and remote

host computers

SSL ( Secure Sockets Layer) - an alternative to POP

Reading. Read the text and try to guess the meaning of the words in bold. Check your variants in the dictionary.

INTERNET TECHNOLOGY

In 1969 was developed a project called APRANET designed to help scientists communicate and share valuable computer resources. Educators and scientists used primitive command-line user interfaces to send e-mail, transfer files and run scientific calculations on Internet supercomputers. At that time finding the information was not easy. Only in the early 1990s software developers сreated new user-friendly Internet access tools and Internet became available to anyone. Although exact figure cannot be determined, it is estimated that with approximately 200 nodes and 500 million users, Internet traffic exceeds 100 terabytes each week.

The Internet is not “owned” or operated by any single corporation or government. It’s a data communication network that grew over time in a somewhat haphazard configuration as networks connected to other networks.

The Internet backbone consists of high-speed fiber-optic links connecting high-capacity routers that direct network traffic. Backbones links and routers are maintained by network service providers (NSPs). NSP equipment and links are tired together by network access points (NAPs).

Large ISPs connect directly to backbone routers. Smaller ISPs typically connect to a larger ISP to gain Internet access and supply it to their customers.

You can track the route of data you send using Internet utilities, such as Ping and Traceroute. An Internet utility called Ping (Packet Internet Groper) sends a signal to a specific Internet address and waits for a reply. If a reply arrives, Ping reports that the computer is online and displays the elapsed time for the round-trip message. Ping is useful for finding out if the site is up and running. Ping is also useful for determining whether a connection offers adequate speed for videoconferencing or online computer games.

Ping also shows whether packets were lost in transmission. Packets can become lost when signal interference or network congestion overwhelms Internet servers and routers. Too many lost packets during an online gaming session can cause the game to stutter or stall. And if packets don’t arrive in the correct order, your game character might seem to act randomly for a few seconds.

A utility called Tracerouter records a packet’s path-including intermediate routers-from your computer to its destination.

An ISP operates network devices that handle the physical aspects of transmitting and receiving data from your computer. Many ISPs operate e-mail servers to handle incoming and outgoing mail for their subscribers and some also have Web servers for subscriber Web sites. ISPs can also maintain servers for chat groups, instant messaging, music file sharing, FTR (File Transfer Protocol) and other file transfer services.

Computer connects to the Internet in one of two ways: it can link directly to ISP using a device such as a voiceband modem, cable modem, satellite dish, or DSL modem. Or, if your computer is part of a LAN, an Internet connection can be provided by a LAN link.

A local area network is called an intranet. Intranets are popular with businesses that want to store information as Web pages but not provide them for public access. An intranet that provides external access is called extranet.

A computer can have a permanently assigned static IP address or a temporally assigned dynamic IP address. As a general rule, computers on the Internet that act as servers use static IP address. Typically, ISPs, web sites, web hosting services, and e-mail servers are constantly connected to the Internet and require static addresses.

Although IP addresses work for communication between computers, people find it difficult to remember long string of numbers. Therefore, many Internet servers also have an easy-to-remember name, i. e. nike.com . The official term for this name is “fully qualified domain name” (FQDN), but most people just refer to it as a domain name. Every domain name corresponds to a unique IP address that has been entered into a huge database called the Domain Name System( DNS).Computers that host this database are referred to as domain name servers. A domain name, such as travelocity.com, must be converted into an IP address before any packets can be routed to it.

The Domain Name System is based on a distributed database. This database is not stored as a whole in any single location; instead, it exists in parts all over the Internet. Your Internet connection is set up to access one of the many domain servers that reside on the Internet. Some domain names are not currently in use, but they are reserved. Internet entrepreneurs have made a business of registering high-profile domain names with the intention of reselling them.

Comprehension check. Mark the following statements as True or False.

1. The Internet backbone consists of high-speed fiber-optic links.

2. A local area network is called extranet.

3. A computer must have a permanently assigned static IP address.

4. The Internet is not “owned” by any single corporation or government.

5. Computer connects to the Internet only by linking directly to ISP.

6. You can track the route of data you send using Internet utilities, such as Ping and Traceroute.

Vocabulary practice

1. Match the words with their synonyms.

computations congestion

knot node

connect find out

run calculations

overloading tire

learn base

backbone to be up

2. Fill in the blanks choosing from the variants given.

1. The Internet is not … a single company or country.

a) controlled b) operated by c) correspond to

2. The Internet backbones links and … are supported by network service providers.

a) wires b)connectors c) routers

3. Intranet allows businesses to store information but not provide them for … .

a) anyone b) public c) other companies

4. Pockets can be lost if network congestion … Internet services.

a) overwhelms b) corrupts c) stops

5. Each Internet server’s name … a the only IP address.

a) is converted into b) corresponds to c) acts as

6. Internet connection is set up access domain servers that … on the Internet.

a) reside b) exist c) register

3. Make two-word combination using the words in columns and then fill in the gaps in the following sentences.

A: distributed B: modem

elapsed name

voiceband dish

dynamic interference

domain database

signal time

satellite address

1. Packets can become lost when … or network congestion overwhelms Internet routers.

2. Ping reports that the computer is online and displays the … for the message.

3. Most people refer to the name of many Internet servers as a … .

4. A computer can have either or permanent static address or a temporal … .

5. A … exists in parts all over the Internet.

6. … and … are used for direct connection of a computer to ISP.

4. Fill in the gaps in the text.

Network service providers supply ___ links for the Internet backbone. The acronym ___ refers to points were equipment and ___ from this companies intersect.

An Internet utility called ___ helps you discover whether a host, such as web server is “alive”. This utility reports the ___ for a packet to travel from your computer to the host and back. Another utility, called ___, records the path of a packet as it travels from your computer to its destination. Most people access the Internet through an ISP, which provides modems, e-mail servers, domain name servers, and ___.

Speaking. Discuss the following questions.

1. How did the Internet get started?

2. How is the Internet structured?

3. Is it possible to track data as it travels over the Internet?

4. What kinds of network devices are part of an ISP?

5. What’s a domain name?

Text B

Reading. Read the text and try to guess the meaning of the words in bold. Check your variants in the dictionary.

Date: 2015-01-12; view: 1666