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Piatok, 23. augusta 2019
Dátum pridania: 20.05.2005 Oznámkuj: 12345
Autor referátu: Jakuuub
Jazyk: Angličtina Počet slov: 2 081
Referát vhodný pre: Vysoká škola Počet A4: 7.6
Priemerná známka: 3.00 Rýchle čítanie: 12m 40s
Pomalé čítanie: 19m 0s
Wireless gear costs somewhat more than the equivalent wired Ethernet products. At full retail prices, wireless adapters and access points may cost three or four times as much as Ethernet cable adapters and hubs/switches, respectively. 802.11b products have dropped in price considerably with the release of 802.11g, and obviously, bargain sales can be found if shoppers are persistent.

Wireless LANs suffer a few more reliability problems than wired LANs, though perhaps not enough to be a significant concern. 802.11b and 802.11g wireless signals are subject to interference from other home appliances including microwave ovens, cordless telephones, and garage door openers. With careful installation, the likelihood of interference can be minimized.
Wireless networking products, particularly those that implement 802.11g, are comparatively new. As with any new technology, expect it will take time for these products to mature.

Wireless LANs using 802.11b support a maximum theoretical bandwidth of 11 Mbps, roughly the same as that of old, traditional Ethernet. 802.11a and 802.11g WLANs support 54 Mbps, that is approximately one-half the bandwidth of Fast Ethernet. Furthermore, Wi-Fi performance is distance sensitive, meaning that maximum performance will degrade on computers farther away from the access point or other communication endpoint. As more wireless devices utilize the WLAN more heavily, performance degrades even further.
Overall, the performance of 802.11a and 802.11g is sufficient for home Internet connection sharing and file sharing, but generally not sufficient for home LAN gaming.
The greater mobility of wireless LANs helps offset the performance disadvantage. Mobile computers do not need to be tied to an Ethernet cable and can roam freely within the WLAN range. However, many home computers are larger desktop models, and even mobile computers must sometimes be tied to an electrical cord and outlet for power. This undermines the mobility advantage of WLANs in many homes.

In theory, wireless LANs are less secure than wired LANs, because wireless communication signals travel through the air and can easily be intercepted. To prove their point, some engineers have promoted the practice of wardriving that involves travelling through a residential area with Wi-Fi equipment scanning the airwaves for unprotected WLANs. On balance, though, the weaknesses of wireless security are more theoretical than practical. WLANs protect their data through the Wired Equivalent Privacy (WEP) encryption standard that makes wireless communications reasonably as safe as wired ones in homes.
No computer network is completely secure and homeowners should research this topic to ensure they are aware of and comfortable with the risks. Important security considerations for homeowners tend to not be related to whether the network is wired or wireless but rather ensuring:
• the home's Internet firewall is properly configured
• the family is familiar with the danger of Internet "spoof emails" and how to recognize them
• the family is familiar with the concept of "spyware" and how to avoid it
• babysitters, housekeepers and other visitors do not have unwanted access to the network
Which is better - wired or wireless?

You've studied the analysis and are ready to make your decision. Bottom line, then, which is better - wired or wireless? The table below summarizes the main criteria we've considered in this article. If you are very cost-conscious, need maximum performance of your home system, and don't care much about mobility, then a wired Ethernet LAN is probably right for you.
If on the other hand, cost is less of an issue, you like being an early adopter of leading-edge technologies, and you are really concerned about the task of wiring your home or small business with Ethernet cable, then you should certainly consider a wireless LAN.

Wired vs. Wireless
Installationmoderate difficultyeasier, but beware interference
Reliabilityhighreasonably high
Performancevery goodgood
Securityreasonably goodreasonably good

Pomôcky k prezentácii:
This presentation compares wired and wireless networking in the following five key areas:
• ease of installation
• total cost
• reliability
• performance
• security

Definition Wi-Fi :
Is the industry name for wireless LAN (WLAN) communication technology related to the IEEE 802.11 family of wireless networking standards. To some, the term Wi-Fi is synonymous with 802.11b, as 802.11b was the first standard in that family to enjoy widespread popularity. Today, however, Wi-Fi can refer to any of the three established standards 802.11b, 802.11a and 802.11g. WLANs provide wireless network communication over short distances using radio or infrared signals instead of traditional network cabling.
Examples: For WLANs that connect to the Internet, Wireless Application Protocol (WAP) technology allows Web content to be more easily downloaded to a WLAN and rendered on wireless clients like cell phones and PDAs
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Zdroje: ŽID, Norbert [et al.]. Orientace ve světě informatiky. Praha : Management Press, 1998. 391 s. ISBN 80-85943-58-1., SATRAPA, Pavel. IPv6: Internet Protokol verze 6. Praha : Neocortex, 2002. 238 s. ISBN 80-86330-10-9.
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