《计算机导论》课程教学课件（英文讲稿）5-b- LANS_WANS

Wireless Networks Wireless network: Transports data from one devices to another without the use of cables or wire. Advantages: Mobility,the devices are not tethered to network cable. Disatvantages: security,speed,range can be limited by thick walls or distance, licensing. Wi-Fi: Is the most popular LAN technology. Wi-Fi is defined by IEEE 802.11,the Wi-Fi transmit data as radio waves. How fast is Wi-Fi: From 11Mbps>>>>>>>>>>200Mbps IEEE 802.11n 200Mbps with range 8-45 meter

Wireless network: Transports data from one devices to another without the use of cables or wire. Advantages: Mobility, the devices are not tethered to network cable. Disatvantages: security, speed, range can be limited by thick walls or distance, licensing. Wi-Fi: Is the most popular LAN technology. Wi-Fi is defined by IEEE 802.11, the Wi-Fi transmit data as radio waves. How fast is Wi-Fi: From 11Mbps>>>>>>>>>>200Mbps IEEE 802.11n 200Mbps with range 8-45 meter Wireless Networks

Wireless Networks Wi-Fi Equipment: Wireless Computers (embedded or extern wireless card-USB adapter or Wi-Fi card) Wireless router Surge strip or UPS MIMO(multiple-input multiple-output)to improve the speed and range Device managers >>Network adapters >>>Wifi.Adapter Important: Access to the wireless router by browsing http:/and the router's LAN address(192.168.1.1or192.168.1.100) Before using the wireless network,you have to adjust the configuration settings for default password,SSID(service set identifier)and encryption. Can I mix wirelees and wired devices?

Wi-Fi Equipment: - Wireless Computers (embedded or extern wireless card –USB adapter or Wi-Fi card) - Wireless router - Surge strip or UPS - MIMO (multiple-input multiple-output) to improve the speed and range Device managers >>> Network adapters >>> Wifi. Adapter Important: Access to the wireless router by browsing http:// and the router’s LAN address (192.168.1.1 or 192.168.1.100). Before using the wireless network, you have to adjust the configuration settings for default password, SSID (service set identifier) and encryption. Can I mix wirelees and wired devices? Wireless Networks

Using LANs How I access network resources? My network Places(through Windows Explorer) Drive mapping (through Network Drive tool in My network Places). Sharing folders and drives can be shared by other workstations. Page:277. Sharing printers: Printer attaches directly to router Printer attaches to printer server Printer attaches to one workstation Printer built-in wireless card Printer built-in networking

Using LANs How I access network resources? - My network Places (through Windows Explorer) - Drive mapping (through Network Drive tool in My network Places). Sharing : folders and drives can be shared by other workstations. Page: 277. Sharing printers: - Printer attaches directly to router - Printer attaches to printer server - Printer attaches to one workstation - Printer built-in wireless card - Printer built-in networking

Security Through Encryption How can I secure wireless network? By wireless encryption e.g.WEP(Wired Equivalent privacy) WPA2 much better security than WEP and WPA My network Places(through Windows Explorer) Drive mapping (through Network Drive tool in My network Places). Encryption: The contents of the message that wil be transforms are hidden from unauthorized readers.To keep the messages secret. How does encryption works? The message has not yet been encrypted is plaintext An encrypted message is referred to as ciphertext Converting plaintext >>>ciphertext Encryption Converting ciphertext >>>plaintext Decryption Most encryption today uses a 128bit key

Security Through Encryption How can I secure wireless network? - By wireless encryption e.g. WEP ( Wired Equivalent privacy) - WPA2 much better security than WEP and WPA. My network Places (through Windows Explorer) - Drive mapping (through Network Drive tool in My network Places). Encryption: The contents of the message that wil be transforms are hidden from unauthorized readers. To keep the messages secret. How does encryption works? The message has not yet been encrypted is plaintext An encrypted message is referred to as ciphertext Converting plaintext >>>> ciphertext = Encryption Converting ciphertext >>>> plaintext = Decryption Most encryption today uses a 128bit key