How to Increase Your Wi-Fi Signal

How to make a Cat5e Network/Ethernet Cable

Comparing Media Types

Presented in Table 8-1 are comparisons of the features of the common network media. This chart provides an overview of various media that you can use as a reference. The medium is possibly the single most important long-term investment made in a network. The choice of media type will affect the type of NICs installed, the speed of the network, and the capability of the network to meet future needs.

Table 8-1 Media Type Comparison

Media Type	Maximum Segment Length	Speed	Cost	Advantages	Disadvantages
UTP	100 m	10 Mbps to 1000 Mbps	Least expensive	Easy to install; widely available and widely used	Susceptible to interference; can cover only a limited distance
STP	100 m	10 Mbps to 100 Mbps	More expensive than UTP	Reduced crosstalk; more resistant to EMI than Thinnet or UTP	Difficult to work with; can cover only a limited distance
Coaxial	500 m (Thicknet) 185 m (Thinnet)	10 Mbps to 100 Mbps	Relatively inexpensive, but more costly than UTP	Less susceptible to EMI interference than other types of copper media	Difficult to work with (Thicknet); limited bandwidth; limited application (Thinnet); damage to cable can bring down entire network
Fiber-Optic	10 km and farther (single-mode) 2 km and farther (multimode)	100 Mbps to 100 Gbps (single mode) 100 Mbps to 9.92 Gbps (multimode)	Expensive	Cannot be tapped, so security is better; can be used over great distances; is not susceptible to EMI; has a higher data rate than coaxial and twisted-pair cable	Difficult to terminate

Wireless Communication

Wireless Communication

Wireless communication uses radio frequencies (RF) or infrared (IR) waves to transmit data between devices on a LAN. For wireless LANs, a key component is the wireless hub, or access point, used for signal distribution (see Figure 8-8).

Figure 8-8 Wireless Network

To receive the signals from the access point, a PC or laptop must install a wireless adapter card (wireless NIC). Wireless signals are electromagnetic waves that can travel through the vacuum of outer space and through a medium such as air. Therefore, no physical medium is necessary for wireless signals, making them a very versatile way to build a network. Wireless signals use portions of the RF spectrum to transmit voice, video, and data. Wireless frequencies range from 3 kilohertz (kHz) to 300 gigahertz (GHz). The data-transmission rates range from 9 kilobits per second (kbps) to as high as 54 Mbps.

The primary difference between electromagnetic waves is their frequency. Low-frequency electromagnetic waves have a long wavelength (the distance from one peak to the next on the sine wave), while high-frequency electromagnetic waves have a short wavelength.

Some common applications of wireless data communication include the following:

• Accessing the Internet using a cellular phone
• Establishing a home or business Internet connection over satellite
• Beaming data between two hand-held computing devices
• Using a wireless keyboard and mouse for the PC

Another common application of wireless data communication is the wireless LAN (WLAN), which is built in accordance with Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. WLANs typically use radio waves (for example, 902 megahertz [MHz]), microwaves (for example, 2.4 GHz), and IR waves (for example, 820 nanometers [nm]) for communication. Wireless technologies are a crucial part of the today's networking. See Chapter 28, "Wireless LANs," for a more detailed discuss on wireless networking.

Coaxial Cable

Coaxial Cable

Coaxial cable consists of a hollow outer cylindrical conductor that surrounds a single inner wire made of two conducting elements. One of these elements, located in the center of the cable, is a copper conductor. Surrounding the copper conductor is a layer of flexible insulation. Over this insulating material is a woven copper braid or metallic foil that acts both as the second wire in the circuit and as a shield for the inner conductor. This second layer, or shield, can help reduce the amount of outside interference. Covering this shield is the cable jacket. (See Figure 8-4.)

Figure 8-4 Coaxial Cable

Coaxial cable supports 10 to 100 Mbps and is relatively inexpensive, although it is more costly than UTP on a per-unit length. However, coaxial cable can be cheaper for a physical bus topology because less cable will be needed. Coaxial cable can be cabled over longer distances than twisted-pair cable. For example, Ethernet can run approximately 100 meters (328 feet) using twisted-pair cabling. Using coaxial cable increases this distance to 500m (1640.4 feet).

For LANs, coaxial cable offers several advantages. It can be run with fewer boosts from repeaters for longer distances between network nodes than either STP or UTP cable. Repeaters regenerate the signals in a network so that they can cover greater distances. Coaxial cable is less expensive than fiber-optic cable, and the technology is well known; it has been used for many years for all types of data communication.

When working with cable, you need to consider its size. As the thickness, or diameter, of the cable increases, so does the difficulty in working with it. Many times cable must be pulled through existing conduits and troughs that are limited in size. Coaxial cable comes in a variety of sizes. The largest diameter (1 centimeter [cm]) was specified for use as Ethernet backbone cable because historically it had greater transmission length and noise-rejection characteristics. This type of coaxial cable is frequently referred to asThicknet. As its nickname suggests, Thicknet cable can be too rigid to install easily in some situations because of its thickness. The general rule is that the more difficult the network medium is to install, the more expensive it is to install. Coaxial cable is more expensive to install than twisted-pair cable. Thicknet cable is almost never used except for special-purpose installations.

A connection device known as a vampire tap was used to connect network devices to Thicknet. The vampire tap then was connected to the computers via a more flexible cable called the attachment unit interface (AUI). Although this 15-pin cable was still thick and tricky to terminate, it was much easier to work with than Thicknet.

In the past, coaxial cable with an outside diameter of only 0.35 cm (sometimes referred to as Thinnet) was used in Ethernet networks. Thinnet was especially useful for cable installations that required the cable to make many twists and turns. Because it was easier to install, it was also cheaper to install. Thus, it was sometimes referred to asCheapernet. However, because the outer copper or metallic braid in coaxial cable comprises half the electrical circuit, special care had to be taken to ensure that it was properly grounded. Grounding was done by ensuring that a solid electrical connection existed at both ends of the cable. Frequently, however, installers failed to properly ground the cable. As a result, poor shield connection was one of the biggest sources of connection problems in the installation of coaxial cable. Connection problems resulted in electrical noise, which interfered with signal transmittal on the networking medium. For this reason, despite its small diameter, Thinnet no longer is commonly used in Ethernet networks.

The most common connectors used with Thinnet are BNC, short for British Naval Connector or Bayonet Neill Concelman, connectors (see Figure 8-5). The basic BNC connector is a male type mounted at each end of a cable. This connector has a center pin connected to the center cable conductor and a metal tube connected to the outer cable shield. A rotating ring outside the tube locks the cable to any female connector. BNC T-connectors are female devices for connecting two cables to a network interface card (NIC). A BNC barrel connector facilitates connecting two cables together.

Figure 8-5 Thinnet and BNC Connector

The following summarizes the features of coaxial cables:

• Speed and throughput—10 to 100 Mbps
• Average cost per node—Inexpensive
• Media and connector size—Medium
• Maximum cable length—500 m (medium)

Plenum Cable

Plenum cable is the cable that runs in plenum spaces of a building. In building construction, a plenum (pronounced PLEH-nuhm, from Latin meaning "full") is a separate space provided for air circulation for heating, ventilation, and air-conditioning (sometimes referred to as HVAC), typically in the space between the structural ceiling and a drop-down ceiling. In buildings with computer installations, the plenum space often is used to house connecting communication cables. Because ordinary cable introduces a toxic hazard in the event of fire, special plenum cabling is required in plenum areas.

In the United States, typical plenum cable sizes are AWG sizes 22 and 24. Plenum cabling often is made of Teflon and is more expensive than ordinary cabling. Its outer material is more resistant to flames and, when burning, produces less smoke than ordinary cabling. Both twisted-pair and coaxial cable are made in plenum cable versions.

Twisted-Pair Cable

Twisted-pair cable is a type of cabling that is used for telephone communications and most modern Ethernet networks. A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs. When electrical current flows through a wire, it creates a small, circular magnetic field around the wire. When two wires in an electrical circuit are placed close together, their magnetic fields are the exact opposite of each other. Thus, the two magnetic fields cancel each other out. They also cancel out any outside magnetic fields. Twisting the wires can enhance this cancellation effect. Using cancellation together with twisting the wires, cable designers can effectively provide self-shielding for wire pairs within the network media.

Two basic types of twisted-pair cable exist: unshielded twisted pair (UTP) and shielded twisted pair (STP). The following sections discuss UTP and STP cable in more detail.

UTP Cable

UTP cable is a medium that is composed of pairs of wires (see Figure 8-1). UTP cable is used in a variety of networks. Each of the eight individual copper wires in UTP cable \is covered by an insulating material. In addition, the wires in each pair are twisted around each other.

Figure 8-1 Unshielded Twisted-Pair Cable

UTP cable relies solely on the cancellation effect produced by the twisted wire pairs to limit signal degradation caused by electromagnetic interference (EMI) and radio frequency interference (RFI). To further reduce crosstalk between the pairs in UTP cable, the number of twists in the wire pairs varies. UTP cable must follow precise specifications governing how many twists or braids are permitted per meter (3.28 feet) of cable.

UTP cable often is installed using a Registered Jack 45 (RJ-45) connector (see Figure 8-2). The RJ-45 is an eight-wire connector used commonly to connect computers onto a local-area network (LAN), especially Ethernets.

Figure 8-2 RJ-45 Connectors

When used as a networking medium, UTP cable has four pairs of either 22- or 24-gauge copper wire. UTP used as a networking medium has an impedance of 100 ohms; this differentiates it from other types of twisted-pair wiring such as that used for telephone wiring, which has impedance of 600 ohms.

UTP cable offers many advantages. Because UTP has an external diameter of approximately 0.43 cm (0.17 inches), its small size can be advantageous during installation. Because it has such a small external diameter, UTP does not fill up wiring ducts as rapidly as other types of cable. This can be an extremely important factor to consider, particularly when installing a network in an older building. UTP cable is easy to install and is less expensive than other types of networking media. In fact, UTP costs less per meter than any other type of LAN cabling. And because UTP can be used with most of the major networking architectures, it continues to grow in popularity.

Disadvantages also are involved in using twisted-pair cabling, however. UTP cable is more prone to electrical noise and interference than other types of networking media, and the distance between signal boosts is shorter for UTP than it is for coaxial and fiber-optic cables.

Although UTP was once considered to be slower at transmitting data than other types of cable, this is no longer true. In fact, UTP is considered the fastest copper-based medium today. The following summarizes the features of UTP cable:

• Speed and throughput—10 to 1000 Mbps
• Average cost per node—Least expensive
• Media and connector size—Small
• Maximum cable length—100 m (short)

Commonly used types of UTP cabling are as follows:

• Category 1—Used for telephone communications. Not suitable for transmitting data.
• Category 2—Capable of transmitting data at speeds up to 4 megabits per second (Mbps).
• Category 3—Used in 10BASE-T networks. Can transmit data at speeds up to 10 Mbps.
• Category 4—Used in Token Ring networks. Can transmit data at speeds up to 16 Mbps.
• Category 5—Can transmit data at speeds up to 100 Mbps.
• Category 5e —Used in networks running at speeds up to 1000 Mbps (1 gigabit per second [Gbps]).
• Category 6—Typically, Category 6 cable consists of four pairs of 24 American Wire Gauge (AWG) copper wires. Category 6 cable is currently the fastest standard for UTP.

Shielded Twisted-Pair Cable

Shielded twisted-pair (STP) cable combines the techniques of shielding, cancellation, and wire twisting. Each pair of wires is wrapped in a metallic foil (see Figure 8-3). The four pairs of wires then are wrapped in an overall metallic braid or foil, usually 150-ohm cable. As specified for use in Ethernet network installations, STP reduces electrical noise both within the cable (pair-to-pair coupling, or crosstalk) and from outside the cable (EMI and RFI). STP usually is installed with STP data connector, which is created especially for the STP cable. However, STP cabling also can use the same RJ connectors that UTP uses.

Figure 8-3 Shielded Twisted-Pair Cable

Although STP prevents interference better than UTP, it is more expensive and difficult to install. In addition, the metallic shielding must be grounded at both ends. If it is improperly grounded, the shield acts like an antenna and picks up unwanted signals. Because of its cost and difficulty with termination, STP is rarely used in Ethernet networks. STP is primarily used in Europe.

The following summarizes the features of STP cable:

• Speed and throughput—10 to 100 Mbps
• Average cost per node—Moderately expensive
• Media and connector size—Medium to large
• Maximum cable length—100 m (short)

When comparing UTP and STP, keep the following points in mind:

• The speed of both types of cable is usually satisfactory for local-area distances.
• These are the least-expensive media for data communication. UTP is less expensive than STP.
• Because most buildings are already wired with UTP, many transmission standards are adapted to use it, to avoid costly rewiring with an alternative cable type.

star topology

Definitions of star topology on the Web:

• the topology of a network whose components are connected to a hub
  wordnetweb.princeton.edu/perl/webwn
• One of the three principal topologies used in LANs. All devices are connected to a central hub. Star networks are relatively easy to install and manage, but bottlenecks can occur because all data must pass through the hub. See also bus topology and ring topology.
  www.visionael.com/services/glossary/index.html
• This is also known as a bush. Effectively there is no successive splitting of lineages, rather, all lineages split at the same time, resulting in a topology with a single origin where all external branches radiate from the centre.
  www.dbbm.fiocruz.br/james/GlossaryS.html
• In star topology the transmission stations are connected in a star shape to a central node. Star topologies can only exchange data indirectly via the central node. There is a difference between active and passive star systems. ...
  ourinstrumentationgroup.com/IndustrialEthernetGlossary.htm
• A LAN configured such that all nodes are connected individually to one common point or hub.
  www.computer-crafts.com.hk/glossary/Glossary.html

In star topology a number of workstations (or nodes) are directly linked to a central node (see, Fig. 4.3). Any communication between stations on a star LAN must pass through the central node. There is bi-directionalcommunication between various nodes. The central node controls all the activities of the nodes. The advantages of the star topology are:

• It offers flexibility of adding or deleting of workstations from the network.
• Breakdown of one station does not affect any other device on the network.

The major disadvantage of star topology is that failure of the central node disables communication throughout the whole network.

Star Topology

Advantages of Star Topology
Due to its centralized nature, the topology offers simplicity of operation.
It also achieves an isolation of each device in the network.

Disadvantage of Star Topology
The network operation depends on the functioning of the central hub. Hence, the failure of the central hub leads to the failure of the entire network.

For a detailed description of the various network topologies, you must go through the different types of network topologies.

Mesh Topology

Definitions of mesh topology on the Web:

• the topology of a network whose components are all connected directly to every other component
  wordnetweb.princeton.edu/perl/webwn
• Mesh networking is a type of networking wherein each node in the network may act as an independent router, regardless of whether it is connected to another network or not. ...
  en.wikipedia.org/wiki/Mesh_topology
• Mesh Toplogies connect devices with multiple paths so that redundancies exist. All devices are cross-connected so the best path can be chosen at any given moment.
  www.nationmaster.com/encyclopedia/Network-topologies

Mesh Topology

Mesh Network is a network where all the nodes are connected to each other and is a complete network. In a Mesh Network every node is connected to other nodes on the network through hops. Some are connected through single hops and some may be connected with more than one hope.

Mesh Topology

Advantage of Mesh Topology
The arrangement of the network nodes is such that it is possible to transmit data from one node to many other nodes at the same time.

Disadvantage of Mesh Topology
The arrangement wherein every network node is connected to every other node of the network, many of the connections serve no major purpose. This leads to the redundancy of many of the network connections.

Ring Topology

Definitions of Ring topology on the Web:

• A ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node - a ring. Data travels from node to node, with each node along the way handling every packet.
  en.wikipedia.org/wiki/Ring_topology
• A layout scheme in which the network takes the form of a closed loop with the devices attached into the ring. Every workstation is linked to two others, one on each side. All data is passed from node to node in one direction only, each PC acting as a repeater for the next one in the loop. ...
  www.nettedautomation.com/glossary_menue/glossary_r.html
• One of the three principal topologies used in LANs. All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. ...
  www.visionael.com/services/glossary/index.html
• A basic networking configuration in which all nodes are connected in a circle with no terminated ends on the cable.
  www.watchguard.net/glossary/r.asp
• Ring topology do not have a central connection point. Instead, a cable connects one node to another, until a "ring" is formed. When a node sends a message, the message is processed by each computer in the ring. ...
  www.nationmaster.com/encyclopedia/Network-topologies

Ring Topology
In ring topology each station is attached nearby stations on a point to point basis so that the entire system is in the form of a ring. In this topology data is transmitted in one direction only. Thus the data packets circulate along the ring in either clockwise or anti-clockwise direction. The advantage of this topology is that any signal transmitted on the network passes through all the LAN stations. The disadvantage of ring network is that the breakdown of any one station on the ring can disable the entire system.

Ring Topology

Advantage of Ring Topology
The data being transmitted between two nodes passes through all the intermediate nodes. A central server is not required for the management of this topology.

Disadvantages of Ring Topology
The failure of a single node of the network can cause the entire network to fail.
The movement or changes made to network nodes affects the performance of the entire network.

bus topology

Definition:- 

• the topology of a network whose components are connected by a busbar
  wordnetweb.princeton.edu/perl/webwn
• A bus network topology is a network architecture in which a set of clients are connected via a shared communications line, called a bus. There are several common instances of the bus architecture, including one in the motherboard of most computers, and those in some versions of Ethernet networks.
  en.wikipedia.org/wiki/Bus_topology
• A network in which all nodes share a common pathway called the bus.
  www.angelfire.com/tx/antagonizer/glossarya.html
• All devices are connected to a central cable, called the bus or backbone.
  myweb.wssu.edu/dalmadgec/3360/3360ppt/3360Chap03.PPT
• The original coaxial cable-based LAN topology in which the medium forms a single bus to which all stations are attached. The bus topology is rarely used in LAN installations today because it is relatively difficult to add new users or more existing users from one location to another. ...
  learn-networking.blogspot.com/2006/12/glossarybrief.html
• Bus topology networks require that all computers, or nodes, connect to the same cable.
  www.nationmaster.com/encyclopedia/Network-topologies

 n bus topology all workstations are connected to a single communication line called bus. In this type of network topology there is no central node as in star topology. Transmission from any station travels the length of the bus in both directions and can be received by all workstations. The advantage of the bus topology is that

• It is quite easy to set up.
• If one station of the topology fails it does not affect the entire system.

The disadvantage of bus topology is that any break in the bus is difficult to identify.

Bus Topology

Advantages of Bus Topology
It is easy to handle and implement.
It is best suited for small networks.

Disadvantages of Bus Topology
The cable length is limited. This limits the number of stations that can be connected.
This network topology can perform well only for a limited number of nodes.

network topology

Topology

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Network Topology

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Introduction to Repeaters

        A repeater is a communication device that retransmits the weak signals with greater power.  It receives the signals over the wireless, optical transmission and network cable mediums such as copper wire, UTP/STP and fiber optic cables and regenerates the analog or digital signals.  It can relay the data signals between the different subnetworks. 

      Repeater operates at the physical layer of the OSI layers model and it is not such as intelligent device like the switches and routers that perform the smart routing based on the MAC and IP addresses of the source and destination computers.  Repeaters are also used in the broadcasting, where they are known as the relay transmitters and boosters.   Repeaters restrengthen the data signals in the telecommunications.  Normally a repeater consists of the following things.

• Amplifier
• Transmitter
• Isolator
• Antennas
• Radio Receiver

In a fiber optic network, a repeater consists of the following.

• Amplifier
• Photocell
• IRED
• IR
• LED

      Fiber optic repeaters are less expensive and operate at low power.
Repeaters were also used to connect the segments of the cables.  Repeaters are of mainly two types i.e. with internal antenna and with external antenna.   If you are using repeater in your network make sure that is it compatible with other devices in your network. 

NIC Card

          NIC Stands for Network Interface card.  It is one of the most important computer network devices that are used for the data communication and to connect the computers with each other.  It is plugged inside the computer either in the PCI slot or it is built-in the motherboard.

        A twisted pair UTP/STP with RJ45 connector is used to connect the computer with the Hub or Switch. Fiber optic cable can also be used to connect the computer with the hub or switch. 

      

       A NIC can be wired or wireless and it has digital circuitry and microprocessor.  A wireless NIC is used to connect the computers with each other wirelessly. There are different vendors of the NIC such as D-Link, 3Com, Intel, Realtek, Baylan and Baynet. 

    

      Before buying and installing a network interface card in your computer make sure that it is compatible with the other network devices.  NIC card operates on the Data Link and physical layer of the OSI layers model.
       For every computer in a network, it is required to have a NIC to communicate with other computers.

Every NIC has unique MAC address and no two NIC cards from two different vendors can have the same MAC address.  NIC has twisted pair, BNC and AUI sockets.  The one end of the network cable is used to connect with the NIC and the other end is used to connect with the hub or switch.  

      NIC provides the fulltime connectivity for the data transmission.  Sometimes computers do not communicate with each other due to the malfunctioning of the NIC.  The network interface cards problems can be resolved with the following tips.

• Make sure that you have the updated and correct version of the LAN card’s driver.
• Ensure that the LEDs of the NIC are working properly.
• Check that the network cable is properly connected at both ends.
• Right click on the network status icon on the right bottom of the desktop and click repair.
• Ensure that the TCP/IP settings are accurate.
• Disable the antivirus and firewall.
• If the problem still persists then try to replace the NIC with a new one.

      Hub or a switch in a computer network acts as a relay that passes the information from one computer to another.  It is important that the LAN card is compatible with the hub or switch to make the data flow faster to avoid the packet loss and network congestion.

What is Bridge

    A bridge is a network communication device that is used to connect one segment of the network with another that uses the same protocol.  It operates at the Data link layer of the OSI layers model.  In the Ethernet network, the bridge is also known as IEEE 802.1D.  A bridge process the information at the data link layer of the OSI layers model.  There are two types of the bridging.

• Transparent bridging
• Source route bridging

The main advantages of the bridges include the following.

• Inexpensive
• Self Configuring
• Reduced size of the collision domains.
• Transmits the data based on the MAC address.
• Supports relatively big networks.

    Bridges are fast devices for forwarding the data but not as fast as the routers and switches.  A bridge cannot be used as a firewall device as a router.  In the bridged network, the messages are sent to all the nodes and are picked up only by the destined computers.  A bridged when combined with the router, known as a brouter.  Bridges has now replaced the switches and routers.

Introduction to Switch Computer Networking Devices

     A switch is a network communication device that is used to send and receive the data over the LAN and WAN. In Ethernet a switch is considered as a best replacement to the hub as it does not broadcast the data like in the hub.  A switch is an intelligent device and it maintains a switching table that contains the information of the MAC address and IP addresses of all the computers in a network.

A switch comes in different ports like 6, 8, 16, 24 and uplink ports, which are used to connect to other switches in the network.   Switch is very important device in the WAN communications too.

    Advance switches are used in the telecommunication networks, ISPs and corporate networks.  A LAN or WAN switch routes the data packets based on the MAC and IP address of the data. There are different vendors of the switches and Cisco is the biggest manufacturer and provider of the routers and switches.  Other manufacturers include Juniper, Jupiter, D-Link, Linksys and Baynet etc.
To make a switched network make sure that all the switches and other network communication devices are compatible with each other. 

      It is recommended that purchase all the devices from the same vendor to avoid any incompatibility issues.  A switch plays an important role in the network communications.  It operates at the Data link layer of the OSI layers model.

     A typical Switch supports 10 Mbps to 10/100, 1000 and 10,000 Mbps data transmission speed.  Network switches can be connected with each other which allows the more computers and devices to join the same network.  A typical switch provides the following features.

• MAC address filtering.
• Turn on and off ports.
• Port mirroring
• Duplex settings
• Use of the Spanning Tree Protocol

Advanced switches can be configured according to your requirements.

Introduction to Hub Computer Networking Devices

                   A hub is a centralized network communication device. In an Ethernet network, every computer is directly connected with the hub through the twisted pair UTP/STP cables.  When data reaches at the hub, it broadcasts the data to all the connected computers and the destined computer picks up the data.  This process makes some delay and congestions in the communication. 

                  Hub is not an intelligent device.  It is mostly used in the star topology and when a failure occurs at one computer, it does not affect the other computers. There are three types of the hub i.e. passive, active and intelligent.

                 Hub is replaced by an intelligent network device known as Switch.  A Switch is network communication device and unlike hub it does not broadcast the data to all the connected computers. Switch maintains a switching table, which includes the IP address and the MAC address of every computer.  

             When data packets arrive at the Switch, switch matches the destination address of the data through its switching table and sends data only to the destination computer. It makes the communication process faster and no network congestions occur.  Though in the functionality both the hub and switch are same but the difference lies in the following.

• Hub broadcasts the data
• Switch does not broadcast the data and sends it only to the destination computer.

              Both hubs and switches and available in different ports capacities like 6, 8, 16 and 24 ports. There are different manufacturers of the hub and switch D-Link, Baynet, Baylan, RealTek, Gigabyte, Cisco and Nortel etc.
Before purchasing hub for your computer network you need to consider the following things.

Hub Buying Tips

• Make sure that your hubs and other network devices should be from the same vendor.  In this way you will get performance and compatibility.
• Make sure that there are enough ports in the hub to accommodate all your network computers.  If your computes are more than the ports in the hub then you need to buy another hub and connect both the hubs with the uplink ports.
• It is recommended to buy a hub that has built-in firewall features to block the intruders, hackers and unauthorized users.
• Make sure that your hub is compatible with all the other devices in your network.

Introduction to Router Computer Networking Devices

            Router is a network communication device that is used to connect logically and physically different networks. It can be used in the Ethernet, FDDI, Token Ring, ATM, Frame Relay, ISDN and other types of the LAN/WAN.  The router’s main purpose is the sorting and distribution the data packets.  Router contains and maintains the routing table that has the information of the adjacent routers and other connected networking devices. 

            Router selects the shortest possible path to send the data packets at the destination. It is an intelligent device that can connect ATM with Frame Relay, ISDN with Frame Relay, SONET with ATM or any other two dissimilar networks. Router uses different protocols such as RIP (Routing Information Protocol), OSPF (Open Shortest Path First) and BGP and IGRP (Interior Gateway Routing Protocol) and EIGRP (Enhanced Interior Gateway Routing Protocol. Routing protocols specifies that how routers will communicate with each other in the WAN.  

They determine that which path to select to send the data towards its destination. There are three main types of the routing protocols i.e. link state, path vector and distance vector.  Router contains the operating system, Flash memory, NVRAM and processor.  High level routers contain the Application Specific Integrated Circuits to perform parallel processing.  A router is also act as a gateway that connects LAN with the internet. 

 For communications between the routers, ports, protocols and the IP addresses are used. Today many types of the routers contain the built-in firewall to fulfill the security needs of the home or office networks.  There are different manufactures of the router such as Cisco, Nortel, D-Link, Lucent, Juniper, Motorola and Novell. Cisco Systems is the biggest manufacturer of the routers.  There are many different types of the routers manufactured by Cisco.

 These types include Cisco 12000 Series Routers, Cisco 7600 Series Routers, Cisco 3600 Series Multiservice Platforms, Cisco 1700 Series Modular Access Routers, Cisco 3800 Series Integrated Services Routers, Cisco 7300 Series Routers and Cisco 7200 Series Routers etc. Cisco has the maximum shares of the routers manufacturing in the world. Some types of the routes are used in the ISP, some in the Enterprise networks and others are used in the home or office network.   

For home and business users that use the high speed DSL connection a router also act as a hardware firewall device.  It filters and blocks the unwanted traffic based on the IP address, port, protocol, application and service.   Before buying router for deploying in your home or office network make sure it is compatible with other devices in your networks. It is recommend that you buy and deploy the all the network devices from the same vendor.

Computer Networking Devices

Computer network devices also known as communication devices and they constitute a data communication network.  These devices are routers, switches, hubs, LAN cards, gateway, modems, hardware firewall, CSU/DSU, ISDN terminals and transceivers.  In an Ethernet or WAN network, the data communication cannot be performed without these devices.  Being an IT professional or a network administrator, you must have the good understanding of these devices.

Based on your business requirements, you have the select the best devices for your network and before selection, make sure that they are compatible with each other.  It is recommended that you select all the devices for your IT infrastructure from the same vendor.
The top vendors are Cisco, D-Link, LinkSys, Baynet, RealTek, 3Com, NetGear, Intel, Nortel, and Lucent etc.  A well designed IT infrastructure with the proper placement of the routers, servers, gateway and switches can reduce the operational cost and enhances the overall performance dramatically.

Routers
A router is a communication device that is used to connect two logically and physically different networks, two LANs, two WANs and a LAN with WAN.  The main function of the router is to sorting and the distribution of the data packets to their destinations based on their IP addresses. Routers provides the connectivity between the enterprise businesses, ISPs and in the internet infrastructure, router is a main device.  Cisco routers are widely used in the world.  Every router has routing software, which is known as IOS.  Router operates at the network layer of the OSI model.  Router does not broadcast the data packets.
Switches
Like the router, a switch is an intelligent device that maps the IP address with the MAC address of the LAN card.  Unlike the hubs, a switch does not broadcast the data to all the computers, it sends the data packets only to the destined computer.  Switches are used in the LAN, MAN and WAN.  In an Ethernet network, computers are directly connected with the switch via twisted pair cables.  In a network, switches use the three methods to transmit the data i.e. store and forward, cut through and fragment free.
Hubs
The central connecting device in a computer network is known as a hub.  There are two types of a hub i.e. active hub and passive hub.  Every computer is directly connected with the hub.  When data packets arrives at hub, it broadcast them to all the LAN cards in a network and the destined recipient picks them and all other computers discard the data packets.  Hub has five, eight, sixteen and more ports and one port is known as uplink port, which is used to connect with the next hub.
Modems
A modem is a communication device that is used to provide the connectivity with the internet.  Modem works in two ways i.e. modulation and demodulation. It coverts the digital data into the analog and analog to digital
LAN Cards
LAN cards or network adapters are the building blocks of a computer network. No computer can communicate without a properly installed and configured LAN card. Every LAN card is provided with a unique IP address, subnet mask, gateway and DNS (if applicable).  An UTP/STP cable connects a computer with the hub or switch.  Both ends of the cable have the RJ-45 connectors one is inserted into the LAN card and one in the hub/switch.  LAN cards are inserted into the expansion slots inside the computer.  Different LAN cards support different speed from 10/100 to 10/1000.
Multiplexer
Multiplexer is a device that is used to combining the several electrical signals into one signal.

How To Create a LAN connection between 2 PCs

In this tutorial we see how to connect to computers together to share files and resources. We can go about it either the wired way or the wireless one. But the wireless way is pretty expensive. So in this tut, we consider the wired way.

To do it the wired way, we need either 2 normal ethernet cables and a Hub / Switch. OR a crossover ethernet cable. We choose the 2nd way as it is more cost effective.

To create a LAN network using a crossover cable, we just need a crossover (Cross crimped RJ45 / CAT5) cable and a LAN (Ethernet) card in both computers. Most computer motherboards have onboard ethernet these days.

We refer to the 2 computers as PC1 and PC2.

First of all, we connect the cross crimped ethernet cable in the LAN RJ45 ports of both the computers.
Now we start with configuring the computers.

PC1:

1. Just right-click “My Computer” and click Properties.
2. Select the “Computer Name” tab and click the “Change” button.
3. Change the computer name to whatever you want, here we name it PC1. Change the workgroup to WG. (The workgroup name should be the same in both computers)
4. Click OK.

Now, to configure the TCP/IP connection settings,
1. Goto “Control Panel” >> “Network connections”
2. Right-click on your LAN connection and click “Properties”. In the “General” tab, select “Internet Protocol (TCP/IP)”. Click the “Properties” button.
3. Set the Values
IP Address – 192.168.0.1
Subnet Mask – 255.255.255.0
Default Gateway – 192.168.0.2
4. Click OK and you are done for PC1.

PC2:

1. Just right-click “My Computer” and click Properties.
2. Select the “Computer Name” tab and click the “Change” button.
3. Change the computer name to PC2. Change the workgroup to WG. (The workgroup name should be the same in both computers)
4. Click OK.

Now, to configure the TCP/IP connection settings,
1. Goto “Control Panel” >> “Network connections”
2. Right-click on your LAN connection and click “Properties”. In the “General” tab, select “Internet Protocol (TCP/IP)”. Click the “Properties” button.
3. Set the Values
IP Address – 192.168.0.2
Subnet Mask – 255.255.255.0
Default Gateway – 192.168.0.1
4. Click OK and you are done for PC2 as well.

If you have done the above part correctly, the computers will have detected each other. If they don’t, just restart both the computers.

You can access the other computer in “My network Places”. You can also play multi-player games using this connection. For easier access you can map a drive on the network to a local drive by “Tools” >> “Map network drive

Basics Computer Network

An internet work is a collection of individual networks, connected by intermediate networking devices, that functions as a single large network. The networking devices are the vital tools for communication. Whenever you have a set of computers or networking devices to be connected, you make the connections, depending on the physical layout and your requirements Depending on the physical layout or topology of the network, there are three types of networks.

LAN

LAN stands for Local Area Network. These networks evolved around the PC revolution. LANs enabled multiple users in a relatively small geographical area to exchange files and messages, as well as access shared resources such as file servers.

CAN

 campus area network is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area.^[1][2] The networking equipments (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc) are almost entirely owned (by the campus tenant / owner: an enterprise, university, government etc).^[3]

MAN

MAN stands for Metropolitan Area Network. It is usually the interconnection between various LAN’s in a particular geographical area like a metropolitan city like Bombay. Hence the name.

WAN

WAN stands for Wide Area Network. The interconnection of various LAN’s through telephone network, which unites geographically distributed users is achieved through WAN. In short when we log on to the internet, we become a part of a WAN.