Studijní materiály

Zpět

Hromadně přidat materiály

Prezentace wifi_Vančišin Jakub

Y04A2Z - Anglický jazyk 2-1

Hodnocení materiálu:

Zjednodušená ukázka:

Stáhnout celý tento materiál

ed when their instruction is performed. Beside this, each byte contains so called checksum – another type of standard information added by the transmitter for preventing errors. If the receiver discovers that the checksum is not what it expected, it requests sending the same byte from the transmitter again.

4. Advantages of Wi–Fi

One of the biggest advantages of wireless networks is that it allows LAN to be established without meters of unnecessary cables, reducing its cost at the same time. LANs can also, thanks to Wi–Fi, be created at places where cables cannot be run, such as outdoor areas or historical buildings. Wi-Fi products are widely available in the market. Different brands of access points and client network interfaces are interoperable. Wi–Fi is a global set of standards, so the same Wi–Fi client works in different countries around the world. It’s widely available in more than 250 000 public hotspots and milions of homes, corporate and university campuses worldwide.

5. Disadvantages of Wi–Fi

The main disadvantage is that Wi-Fi can be interrupted by other devices, for example 2.4 GHz cordless phones and microwave ovens. Its power consumption is also quite high, which is essential especially in laptop computers. Wi-Fi networks have a limited range - a typical Wi-Fi home router using 802.11b or 802.11g with a stock antenna might have a range of 45 m indoors and 90 m outdoors. The big problem is also security. Even if the majority of ordinarily available devices support the basic ways of encryption – WPA, WEP and WEP2, many of the access points are unsecured, so it’s not so difficult for a possible invader to get into the network and pose as any other user. There is also a plenty of security mistakes in WPA encrypting protocol that make getting a key necessary for getting access to the network quite easy. In addition, appropriate directions, as well as needed program equipment, are published on the internet and so accessible to the public.

6. Vocabulary

interoperable – schopný spolupracovat assignment – přidělení
transmit – vysílat to lie in sth. – spočívat v něčem
transmitter – vysílač encryption – šifrování
receiver – přijímač to pose as sb. – tvářit se jako někdo
band – skupina accessible – dostupný

7. Enclosures

Wi–Fi and Wi-Fi CERTIFIED logos

Table 1 - unlicensed 2.4 GHz frequency assignments

Table 2 – Wireless channel assignments

Wi-Fi doesn’t stand for anything:

Source: http://www.boingboing.net/2005/11/08/wifi_isnt_short_for_.html

Jakub Vančišin

Stáhnout celý tento materiál

Předchozí

1 2 3

Vloženo: 26.04.2009

Velikost: 138,50 kB

Stáhnout celý tento materiál

Komentáře

Tento materiál neobsahuje žádné komentáře.

Mohlo by tě zajímat:

Skupina předmětu Y04A2Z - Anglický jazyk 2-1
Reference vyučujících předmětu Y04A2Z - Anglický jazyk 2-1

Podobné materiály