Chapter 1: Wireless Networking/Technology

Wireless Networking Definition: –the technologies that enable computers to communicate using standard network protocols broadcasted on a radio frequency rather than on cable. Nowadays has grown with various products and very popular with homes, businesses and schools, and handheld equipment.

Wireless Networking

Two kinds of wireless networks: –ad-hoc or peer-to-peer networking –infrastructure networking

Ad-hoc or peer-to-peer networking Consists of a number of computers that each equipped with wireless networking interface card (figure 1). figure 1figure 1 Each computer can communicate directly with the other entire wireless enabled computer but may not be able to access wired resources. Fixable if one of the computers acts as a bridge to the wired LAN using special software and/or additional hardware to connect to the wired LAN.

Figure 1: Wireless Network IC

Ad-hoc or peer-to-peer networking

Infrastructure networking A wireless network can also use an access point, or base station. Two types of access point: –dedicated hardware –integrated The access point acts like a hub, providing connectivity for the wireless computers. Can connect the wireless LAN to a wired LAN, allowing wireless computer access to LAN resources, such as file servers or existing internet connectivity.

Dedicated Hardware Access Point (HAP) Usually used as an extension of a wired network, providing additional access in remote areas or for a mobile workforce.

Figure 2: Figure 2: 2:Dedicated hardware access point

Integrated Access Points Multi functional devices which include features not commonly found in access points, such as integrated PPPoE support and extensive configuration flexibility. Provide both wired and wireless access in one unit. With appropriate networking support, users on the wireless LAN can share files and printers located on the wired LAN and vice versa. All current configurations provide total support of the TCP/IP

Figure 3: Figure 3: Integrated access point

Infrastructure networking There could be many networked computers using a single access point. Some hardware access points limit to 10. Newer models will support up to 225 wireless connections. It is a shared media, using more computers than recommended will cause performance and reliability to suffer.

Infrastructure networking For large networks, designers could have / use more than one access points to connect to a wired LAN, or even to a second wireless LAN if the access point supports this. In most cases, separate access points are interconnected via a wired LAN, providing wireless connectivity in specific areas such as offices or classrooms, but connected to a main wired LAN for access to network resources, such as file servers (figure 4).

Figure 4: Figure 4: Large network with multiple access points

Infrastructure networking When using multiple access points, each access point wireless area should overlap its neighbors. This provides a seamless area for users to move around in using a feature called roaming. Roaming: –the extending of connectivity service in a network that is different than the network with which a station is registered.

Infrastructure networking A wireless computer can “roam” from one access point to another, with the software and hardware maintaining a steady network connection by monitoring the signal strength from in-range access points and locking on to the one with the best quality (figure 5).

Figure 5: Roaming

Wireless network interconnects two or more LANs Ohhs…. It is too difficult to install fiber for networking the schools, campuses… “ahh.. Wireless networking…”

Wireless LAN Need to bridge to create WLAN. There are two types of bridging: –point-to-point –point-to-multipoint WLAN bridging connections can be significantly less costly and a much faster installation compared to time consuming permit process and trenching needed for installing fiber.

Wireless LAN IEEE (Wireless LAN) standard has various versions. IEEE : –a standard produced by the Institute of Electrical and Electronic Engineers (IEEE). –define all aspects of Radio Frequency Wireless. –Series  b, a, g, n. –Not all networks are compatible –Wi-Fi Certified (Wi-Fi.org).

Wireless LAN Antennas are often used to increase the range of WLAN systems, but proper antenna selection can also enhance the security of WLAN. Using a directional antenna will decrease the chances of signal interception. Some bridges support repeater mode.

Figure 6: Point to Point

Figure 7: Point to Multipoint

Figure 8: Repeater Mode

Wireless Technology Bluetooth

Bluetooth Technology Is an open specification for short-range wireless communication between electronic devices. Has become a standard for interconnecting small mobile devices in wireless world. Its specification is developed, published and promoted by Bluetooth Special Interest Group (SIG).

Bluetooth Technology Used for Wireless Personal Area Networks (WPANs) with range around 10 m. –it is a low-power short-range radio communication technology. The characteristic of the technology offers lot of advantages: –Low power requirement –Low Cost –Short Range of 10 m –Bluetooth Security –Transmission speed of 800 Kbps –2.4 GHz ISM

Bluetooth vs. WLAN Bluetooth products work over shorter distances and are designed to solve different problems. Functionality WLAN stand alone as a network component, the functionality of a Bluetooth component requires a host. The host can be any number of Bluetooth enabled devices: –cell phones, headsets, keyboards, PDAs, vending machines, cameras and bar code readers

BluetoothWLAN (802.11, b) Data rate4-700 kbps4-6 Mbps Range10 m, up to 100 m100 meter # simultaneous users 710 – 50 depending on application Frequency band 2,4 GHz Transmitt power1 mW, 2.5 or 100 mW 100 mW InterfacesADSL, Ethernet, ISDN, PSTN, USB, RS232 Primary Ehernet Support for voiceYesOnly VoIP Type of clientsInbuilt in PC, PDA, Mobile Phone, PC- card, CF-card, Memory Stick (Sony), SSD-card, USB dongle, RS-232 Dongle Inbuilt in PC, PC-card, CF-card, RS- 232 dongle and Ethernet dongle Power management YesProprieatairy solutions # of parallel systems 15 – 50 depending on application3 InteroperabilityYesThrough WECA, not through standard