Download Prace semestralne z języka angielskiego : wzory dla studentów

Prace semestralne z języka angielskiego : wzory dla studentów
Wymagania dotyczące formy wypracowania: Esej musi się mieścić na jednej stronie
Marginesy: lewy 2.0 cm. , prawy 1.0 cm , u dołu strony podać ilość wyrazów.
1. Tytuł esesju: Times New Roman CE - 14 Bold
2. Informacje o autorze : Times New Roman CE - 10
Definition Essay by : imię i nazwisko i koniecznie dopisek np. Binarians, 2008
3. Tekst właściwy eseju : Times New Roman CE – 11
4.Ilość słów : 550 -600
5. Źródło : np. http://en.wikipedia.org/wiki/Internet#Internet_structure
SAMPLE DEFINITION ESSAY
How Internet Infrastructure Works
Definition Essay by: Jakub Numericus, Binarians, 2008
Source : http://en.wikipedia.org/wiki/Internet#Internet_structure
The Internet is a global collection of networks, both big and small. These networks are connected together
forming one large network known as the Internet.
All the networks the Internet consists of are hierarchically grouped. Every computer connected to the
Internet is part of a network. Computers typically are grouped in local area networks (LANs) and then LANs are
connected to local Internet Service Providers (ISPs). Of course ISPs connect together and form another level of
hierarchic Internet model abstraction. Group of local ISPs create regional network, etc.
All levels of Internet hierarchy use devices functioning in a similar way. These are routers and backbones.
Routers are devices that control a part of network topology and determine the way (route) the network packets
should travel through backbones. Routers are simply specialized computers that connect smaller networks into larger
ones. The backbone is a physical link that connects two networks. Nowadays it is a fiber optic cable that is capable
of transmitting information at very high speed ( up to 10 Gbps through one fiber pair).
Transmitting information around the world needs to identify particular computers by unique addresses.
Every computer (or router) connected to the Internet has its own unique number known as Internet Protocol (IP)
address. Internet Protocol is the main protocol that provides addressing scheme in the Internet and allow routers to
choose the best path to the destination. A typical IP address looks like this: 216.27.61.137 and consists of four octets
(i.e. four bytes). The IP address is often presented in a dotted decimal form to make it easier for humans to
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remember it. Combination of all possible values on four octets gives us 2 possible combinations (ca. 4.3 billion IP
addresses). IP addresses are divided in classes to make hierarchical addressing scheme easier. Some of IP addresses
are reserved and have special meaning.
Whole transmission between computers on the Internet relies on IP addresses, but they are difficult to
remember for humans. A practical solution to this problem is the Domain Name System (DNS) which can map
human-readable names (domains) to IP addresses. Then we should remember only the name, e.g.
www.domain.com, instead of its IP address. DNS is also formed in hierarchical structure. There is a pool of toplevel domain servers for .com, .org, .net, .edu, etc. domains. Then hierarchically second-level domains are created,
e.g. microsoft.com, yahoo.com. Third-level domains often designate computer (server) names, e.g.
www.microsoft.com, where ‘www’ is a host name. Every name on particular level must be unique. DNS servers
recognize only locally hosted domains. If one needs to know an IP address of some host that DNS server does not
know, the DNS server performs recursive queries to achieve requested information from higher-level domain
servers. DNS servers can also temporarily store (cache) information from other DNS servers achieved during
queries.
Internet servers make the Internet possible. All computers on the Internet are either servers or clients.
Servers are the computers that provide services to others and clients are the computers that connect to those services.
There are plenty of different types of servers in the Internet: web servers, e-mail servers, FTP servers, etc.
Web servers are servers that send clients requested documents stored on server storage device (e.g. hard
drive). The client sends a request to a web server then the server locates the requested file on its hard drive and sends
it back to the client. All web servers conform to the HyperText Transfer Protocol (HTTP).
All these components make the Internet possible. It is amazing that all this information travels around the
world in a matter of microseconds. Without the Internet life would be very different and perhaps difficult for many
of us.
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