Computer Networking Blog

Local area network (LAN)

2008-07-23T14:50:00.000-07:00

A local area network is a network that spans a relatively small space and provides services to a small number of people. Depending on the number of people that use a Local Area Network, a peer-to-peer or client-server method of networking may be used. A peer-to-peer network is where each client shares their resources with other workstations in the network. Examples of peer-to-peer networks are: Small office networks where resource use is minimal and a home network. A client-server network is where every client is connected to the server and each other. Client-server networks use servers in different capacities. These can be classified into two types: Single-service servers, where the server performs one task such as file server, print server, etc.; while other servers can not only perform in the capacity of file servers and print servers, but they also conduct calculations and use these to provide information to clients (Web/Intranet Server). Computers are linked via Ethernet Cable, can be joined either directly (one computer to another), or via a network hub that allows multiple connections.

Historically, LANs have featured much higher speeds than WANs. This is not necessarily the case when the WAN technology appears as Metro Ethernet, implemented over optical transmission systems.

How Wi Fi works

2008-07-19T10:42:00.001-07:00

If you've been in an airport, coffee shop, library or hotel recently, chances are you've been right in the middle of a wireless network. Many people also use wireless networking, also called WiFi or 802.11 networking, to connect their computers at home, and an increasing number of cities use the technology to provide free or low-cost Internet access to residents. In the near future, wireless networking may become so widespread that you can access the Internet just about anywhere at any time, without using wires.

Wi Fi

2008-07-19T10:40:00.001-07:00

Wi-Fi is the trade name for a popular wireless technology used in home networks, mobile phones, video games and more. Wi-Fi is supported by nearly every modern personal computer operating system and most advanced game consoles, printers, and other peripherals.

The name of a popular wireless networking technology that uses radio waves to provide wireless high-speed Internet and network connections. The Wi-Fi Alliance, the organization that owns the Wi-Fi (registered trademark) term specifically defines Wi-Fi as any "wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards."

Initially, Wi-Fi was used in place of only the 2.4GHz 802.11b standard, however the Wi-Fi Alliance has expanded the generic use of the Wi-Fi term to include any type of network or WLAN product based on any of the 802.11 standards, including 802.11b, 802.11a, dual-band, and so on, in an attempt to stop confusion about wireless LAN interoperability.

Wi-Fi works with no physical wired connection between sender and receiver by using radio frequency (RF) technology, a frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space. The cornerstone of any wireless network is an access point (AP). The primary job of an access point is to broadcast a wireless signal that computers can detect and "tune" into. In order to connect to an access point and join a wireless network, computers and devices must be equipped with wireless network adapters (See "How Wireless Networks Work" in the "Did You Know..." section of Webopedia).

Wi-Fi is supported by many applications and devices including video game consoles, home networks, PDAs, mobile phones, major operating systems, and other types of consumer electronics. Any products that are tested and approved as "Wi-Fi Certified" (a registered trademark) by the Wi-Fi Alliance are certified as interoperable with each other, even if they are from different manufacturers. For example, a user with a Wi-Fi Certified product can use any brand of access point with any other brand of client hardware that also is also "Wi-Fi Certified". Products that pass this certification are required to carry an identifying seal on their packaging that states "Wi-Fi Certified" and indicates the radio frequency band used (2.5GHz for 802.11b, 802.11g, or 802.11n, and 5GHz for 802.11a).

A common misconception is that the term Wi-Fi is short for "wireless fidelity," however this is not the case. Wi-Fi is simply a trademarked term meaning IEEE 802.11x.

ZigBee

2008-07-18T22:23:00.000-07:00

ZigBee® is a low-power, short-distance wireless standard that has great possibilities in applications from home automation to industrial control. We see the potential for ZigBee applications everywhere, and we're helping to build that world with a comprehensive ZigBee solution that includes RF ICs, MCUs, sensors, reference designs, protocol stack software, sample application software and development tools.

What is ZigBee?

ZigBee® Overview

ZigBee is a low-power wireless communications technology and international standard protocol for the next-generation wireless network, reducing data size and allowing for lower-cost network construction with simplified protocol and limited functionality. ZigBee uses the PHY and MAC layers defined by IEEE® 802.15.4, which is the short-distance wireless communication standard for 2.4 GHz band. ZigBee comprises the ZigBee platform specifications and ZigBee profiles defined by the ZigBee Alliance.

Freescale is a driver of the IEEE 802.15.4 standard and a promoter of the ZigBee Alliance.

ZigBee Key Features:

Low Power

The benefits of simple, cost-effective, low-power wireless connectivity that ZigBee technology provides address a variety of markets, including industrial and home monitoring, control and automation, as well as health care diagnostics.Freescale provides all the building blocks used in a complete ZigBee-compliant platform solution: the RF transceiver, MAC and ZigBee software, microcontrollers and sensors. The development hardware and reference designs provide developers with the tools they need to easily and quickly implement these building blocks. One solution, one provider—built, tested, compatible and ready for integration.

Robust

802.15.4 provides a robust foundation for ZigBee, ensuring a reliable solution in noisy environments. Features such as energy detection, clear channel assessment and channel selection help the device pick the best possible channel, avoiding other wireless networks such as Wi-Fi®. Message acknowledgement helps to ensure that the data was delivered to its destination. Finally, multiple levels of security ensure that the network and data remain intact and secure.

Mesh Networking

The ability to cover large areas with routers is one of the key features of ZigBee that helps differentiate itself from other technologies. Mesh networking can extend the range of the network through routing, while self healing increases the reliability of the network by re-routing a message in case of a node failure

Interoperability

The ZigBee Alliance helps ensure interoperability between vendors by creating testing and certification programs for ZigBee devices. Users can be assured the devices that go through certification testing and use the ZigBee logo will work with other devices based on the same applications. This provides end customers with the customers with peace of mind while creating brand awareness of products with the ZigBee logo.

Freescale offers a comprehensive ZigBee solution, including RF chipsets, MCUs, sensors, reference designs, protocol stack software, and development tools. For more information on our ZigBee Family offering see www.freescale.com/zigbee

How Bluetooth Works

2008-07-18T21:51:00.000-07:00

The technology of Bluetooth wireless is a short range communications method intended to replace the cables that connect portable or fixed devices while maintaining the highest levels of security. The key features offered by Bluetooth include low power and low cost. The specification in Bluetooth defines a uniform structure for a wide range of devices to communicate and connect with one another. The technology behind Bluetooth has achieved global satisfaction such as enabled devices, almost everywhere in the world. Bluetooth devices will connect and communicate without wires through short range and networks known as piconets.

Each device will simultaneously communicate with up to seven other devices within a single piconet, meaning that each device can also belong to several piconets simultaneously. The piconets are dynamically established as Bluetooth enabled devices enter and leave the proximity of radio. A fundamental to Bluetooth strength is the ability to handle both data and voice transmissions simultaneously. This will enable users to enjoy varieties of innovative solutions such as hands free talking, printing and fax capabilities, and other applications.

Bluetooth

2008-07-18T21:44:00.000-07:00

Bluetooth is a wireless protocol utilizing short-range communications technology facilitating data transmissions over short distances from fixed and/or mobile devices, creating wireless Personal Area Network - PAN

The intent behind the development of Bluetooth was the creation of a single digital wireless protocol, capable of connecting multiple devices and overcoming issues arising from synchronization of these devices.

Bluetooth provides a way to connect and exchange information between devices such as mobile phones, telephones, laptops, personal computers, printers, GPS receivers, digital cameras, and video game consoles over a secure, globally unlicensed Industrial, Scientific, and Medical (ISM) 2.4 GHz short-range radio frequency bandwidth. The Bluetooth specifications are developed and licensed by the Bluetooth Special Interest Group (SIG).

The Bluetooth SIG consists of companies in the areas of telecommunication, computing, networking, and consumer electronics.

Wireless Personal Area Networks (WPAN)

2008-07-18T21:22:00.000-07:00

Wireless communication is the transfer of information over a distance without the use of electrical conductors or "wires".The distances involved may be short (a few meters as in television remote control) or very long (thousands or even millions of kilometers for radio communications). When the context is clear the term is often simply shortened to "wireless". Wireless communications is generally considered to be a branch of telecommunications.

A wireless personal area network (WPAN for short) is a low-range wireless network which covers an area of only a few dozen metres. This sort of network is generally used for linking peripheral devices (like printers, cellphones, and home appliances) or a personal assistant (PDA) to a computer, or just two nearby computers, without using a hard-wired connection. There are several kinds of technology used for WPANs:

It encompasses various types of fixed, mobile, and portable two way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of wireless technology include GPS units, garage door openers and or garage doors, wireless computer mice and keyboards, satellite television and cordless telephones.

The main WPAN technology is Bluetooth, launched by Ericsson in 1994, which offers a maximum throughput of 1 Mbps over a maximum range of about thirty metres. Bluetooth, also known as IEEE 802.15.1, has the advantage of being very energy-efficient, which makes it particularly well-suited to use in small devices.

Hide the USB Drive inside a USB Cable

2008-07-18T10:34:00.001-07:00

Are you looking for some place to hide your secret documents in safe place so that no one can find it. Than you have to try this trick. Windell Oskay post a tutorial how to Hide USB drive inside a USB cable, so that no one can judge that it was a USB Drive. Check Out the below Pics for how do that.

FireWire - IEEE 1394 interface

2008-07-09T10:09:00.000-07:00

What is FireWire?

FireWire is a method of transferring information between digital devices, especially audio and video equipment. Also known as IEEE 1394, FireWire is fast -- the latest version achieves speeds up to 800 Mbps. At some time in the future, that number is expected to jump to an unbelievable 3.2 Gbps when manufacturers overhaul the current FireWire cables.
You can connect up to 63 devices to a FireWire bus.
Windows operating systems (98 and later) and Mac OS (8.6 and later) both support it.

Let's say you have your digital camcorder connected to your home computer. When your computer powers up, it queries all of the devices connected to the bus and assigns each one an address, a process called enumeration. FireWire is plug-and-play, so if you connect a new FireWire device to your computer, the operating system auto-detects it and asks for the driver disc. If you've already installed the device, the computer activates it and starts talking to it. FireWire devices are hot pluggable, which means they can be connected and disconnected at any time, even with the power on.

Now let's take a look at FireWire's specifications.

interface (although the 1394 standard also defines a backplane interface) is a serial bus interface standard, for high-speed communications and isochronous real-time data transfer, frequently used in a personal computer (and digital audio and digital video). The interface is also known by the brand names of FireWire (Apple's name) and i.LINK (Sony's name).
FireWire has replaced Parallel SCSI in many applications, due to lower implementation costs and a simplified, more adaptable cabling system. IEEE 1394 has been adopted as the High Definition Audio-Video Network Alliance (HANA) standard connection interface for A/V (audio/visual) component communication and contro FireWire is also available in wireless, fiber optic, and coaxial versions using the isochronous protocols. Almost all modern digital camcorders have included this connection since 1995, as do the vast majority of high end professional audio interfaces. Since 2003 many computers intended for home or professional audio/video use have built-in FireWire/i.LINK ports, including all Sony computers, all but one of Apple's computers (the new MacBook Air), and many of its older iPods. It is also available on many retail motherboards.

Universal Serial Bus (USB)

2008-07-09T09:02:00.000-07:00

Short for Universal Serial Bus, USB is a standard that was introduced in 1995 by Intel, Compaq, Microsoft and several other IT computer companies. USB 1.x is an external bus standard that supports data transfer rates of 12 Mbps and is capable of supporting up to 127 peripheral devices. The image to the right is an example of a USB device, the SMC EZ Connect Wireless Bluetooth adapter adds Bluetooth connectivity for your computer.

Universal Serial Bus (USB) is a serial bus standard to interface devices. USB was designed to allow many peripherals to be connected using a single standardized interface socket and to improve the plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer (hot swapping). Other convenient features include providing power to low-consumption devices without the need for an external power supply and allowing many devices to be used without requiring manufacturer specific, individual device drivers to be installed.

USB is intended to help retire all legacy varieties of serial and parallel ports. USB can connect computer peripherals such as computer mouse, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, and flash drives. For many of those devices USB has become the standard connection method. USB was originally designed for personal computers, but it has become commonplace on other devices such as PDAs and video game consoles. As of 2008, there are about 2 billion USB devices in the world.

Personal Area Network - PAN

2008-07-09T08:54:00.000-07:00

A personal area network - PAN - is a computer network organized around an individual person. Personal area networks typically involve a mobile computer, a cell phone and/or a handheld computing device such as a PDA. You can use these networks to transfer files including email and calendar appointments, digital photos and music. Personal area networks can be constructed with cables or wirelessly.

USB and FireWire technologies often link together a wired PAN while wireless PANs typically use Bluetooth or sometimes infrared connections. Bluetooth PANs are also called piconets.

Personal area networks generally cover a range of less than 10 meters (about 30 feet).

Personal area networks may be wired with computer buses such as USB and FireWire . A wireless personal area network (WPAN) can also be made possible with network technologies such as IrDA, Bluetooth, UWB, and ZigBee.

Computer network

2008-07-09T08:49:00.000-07:00

A computer network is an interconnected group of computers. Networks may be classified by the network layer at which they operate according to basic reference models considered as standards in the industry, such as the five-layer Internet Protocol Suite model. While the seven-layer Open Systems Interconnection (OSI) reference model is better known in academia, the majority of networks use the Internet Protocol Suite (IP).

By scale

Computer networks may be classified according to the scale: Personal area network (PAN) , Local Area Network (LAN), Campus Area Network (CAN), Metropolitan area network (MAN), or Wide area network (WAN). Also a business area network

As Ethernet increasingly is the standard interface for networks, these distinctions are more important to the network administrator than the user. Network administrators may have to tune the network, to correct delay issues and achieve the desired performance level.

By connection method

Computer networks can also be classified according to the hardware technology that is used to connect the individual devices in the network such as Optical fibre, Ethernet, Wireless LAN, HomePNA, or Power line communication.

Ethernets use physical wiring to connect devices. Often they employ hubs, switches, bridges, and/or routers.

Wireless LAN technology is built to connect devices without wiring. These devices use a radio frequency to connect.

By functional relationship (Network Architectures)

Computer networks may be classified according to the functional relationships which exist between the elements of the network, e.g., Active Networking, Client-server and Peer-to-peer (workgroup) architecture.

By network topology

Computer networks may be classified according to the network topology upon which the network is based, such as Bus network, Star network, Ring network, Mesh network, Star-bus network, Tree or Hierarchical topology network, etc.

Network Topology signifies the way in which intelligent devices in the network see their logical relations to one another. The use of the term "logical" here is significant. That is, network topology is independent of the "physical" layout of the network. Even if networked computers are physically placed in a linear arrangement, if they are connected via a hub, the network has a Star topology, rather than a Bus Topology. In this regard the visual and operational characteristics of a network are distinct; the logical network topology is not necessarily the same as the physical layout.

What is networking?

2008-07-09T08:43:00.000-07:00

What is (Wireless / Computer) Networking?

:In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.

A given network can also be characterized by the type of data transmission technology in use on it (for example, a TCP/IP or Systems Network Architecture network); by whether it carries voice, data, or both kinds of signals; by who can use the network (public or private); by the usual nature of its connections (dial-up or switched, dedicated or nonswitched, or virtual connections); and by the types of physical links (for example, optical fiber, coaxial cable, and Unshielded Twisted Pair). Large telephone networks and networks using their infrastructure (such as the Internet) have sharing and exchange arrangements with other companies so that larger networks are created.

Keith Ferrazzi: What is Networking?