4/2/2023 0 Comments Wifi pdf basics![]() ![]() Students can easily make use of all these Internet Technology Notes PDF by downloading them. We have provided multiple complete Internet Technology Notes PDF for any university student of BCA, MCA, B.Sc, B.Tech CSE, M.Tech branch to enhance more knowledge about the subject and to score better marks in the exam. The student will have an insight that how the search engine works and web crawls. In the next part we will discuss about Wireless Encoding, popular Wireless Security Standard and some sources of wireless interference.In these “ Internet Technology Notes PDF”, we will study the protocols used on the Internet, its architecture, and the security aspect of the Internet. In most Linksys APs (a product of Cisco), the default SSID is “linksys”. SSID is also the minimum requirement for a WLAN to operate. SSIDs are case sensitive text strings and have a maximum length of 32 characters. In public places, SSID is set on the AP and broadcasts to all the wireless devices in range. SSID is the unique name shared among all devices on the same wireless network. When configuring ESS, each of the APs should be configured with the same Service Set Identifier (SSID) to support roaming function. Roaming: The ability to use a wireless device and be able to move from one access point’s range to another without losing the connection. The most popular non-overlapping channels are channels 1, 6 and 11 (will be explained later). The two adjacent APs should use non-overlapping channels to avoid interference. The overlapped area should be more than 10% (from 10% to 15%) to allow users moving between two APs without losing their connections (called roaming). Usually there is an overlapped area between two APs to support roaming. + Extended Service Set (ESS): uses more than one AP to create a WLAN, allows roaming in a larger area than a single AP. + Basic Service Set (BSS): uses only a single AP to create a WLAN * Infrastructure mode: Connect to a wired LAN, supports two modes (service sets): * Ad-hoc mode: In this mode devices send data directly to each other without an AP. Products certified as Wi-Fi compliant are interoperable with each other even if they are made by different manufacturers.Īccess points can support several or all of the three most popular IEEE WLAN standards including 802.11a, 802.11b and 802.11g. The term Wi-Fi was created by the Wireless Ethernet Compatibility Alliance (WECA). Wi-Fi: stands for Wireless Fidelity and is used to define any of the IEEE 802.11 wireless standards. To accommodate wireless LAN’s, the FCC has set aside bandwidth for unlicensed use including the 2.4Ghz spectrum where many WLAN products operate. ISM Band: The ISM (Industrial, Scientific and Medical) band, which is controlled by the FCC in the US, generally requires licensing for various spectrum use. Maximum transmission speed is 54Mbps and approximate wireless range is 100-200 feet indoors. * 802/11g: operates in the 2.4 GHz ISM band. Maximum transmission speed is 11Mbps and approximate wireless range is 100-200 feet indoors. * 802.11b: operates in the 2.4 GHz ISM band. ![]() ![]() Maximum transmission speed is 54Mbps and approximate wireless range is 25-75 feet indoors. * 802.11a: operates in the 5.7 GHz ISM band. + Wi-Fi Alliance: improves the interoperability of wireless products among vendorsīut the most popular type of wireless LAN today is based on the IEEE 802.11 standard, which is known informally as Wi-Fi. + IEEE: specifies how RF is modulated to transfer data + ITU-R: is responsible for allocation of the RF bands Nowadays there are three organizations influencing WLAN standards. + If no acknowledgment is received, resend the data + Wait for an acknowledgment that data has been sent successfully ![]() + When the random time has passed, listen again. If it is free, set a random time before sending data WLAN can’t use CSMA/CD as a sending device can’t transmit and receive data at the same time. The major difference between wired LAN and WLAN is WLAN transmits data by radiating energy waves, called radio waves, instead of transmitting electrical signals over a cable.Īlso, WLAN uses CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) instead of CSMA/CD for media access. Unlike a wired network which operates at full-duplex (send and receive at the same time), a wireless network operates at half-duplex so sometimes an AP is referred as a Wireless Hub. Below is an example of a simple WLAN:Įach WLAN network needs a wireless Access Point (AP) to transmit and receive data from users. Wireless LANs enable users to communicate without the need of cable. Maybe you have ever used some wireless applications on your laptop or cellphone. Wireless LAN (WLAN) is very popular nowadays. In this article we will discuss about Wireless technologies mentioned in CCNA. ![]()
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