Network Hardware DevicesComputer networking devices are units that mediate data in a computer network. Networking hardware includes all computers, peripherals, interface cards and other equipment needed to perform data-processing and communications within the networkComputer networking devices are also called N/W equipment or Intermediate Systems (IS).Units which are the last receiver are called hosts
List of computer networking devices1)Common basic networking devices: Router Bridge Switch Hub Repeater
Routers are devices which connect two or more networks that use similar protocol. A router consists of hard ware and software.Hard ware can be a computer is specific device.Software consists of special management program that controls flow of data between networks. Routers operate at a network layer of O.S.I model. Routers use logical and physical address to connect two or more logically separate network. They make this connection by organizing the large network into logical network segment (some times small sub network or sub nets). Each of these sub nets is given a logical address. Data is grouped into packets or block of data. Router are used to segment LAN’s that have become so large to conserve the network bandwidth. Cont...
Advantages of Router: They use high level of intelligence to rout data. Router allows filtering of data so called smart gateway.Disadvantages of Router: High level of intelligence take more processing time which can effect performance. Routers are very complicated which installation and maintenance difficult.
GatewayGateways are devices which connect two are morenetworks that use different protocols. A gateway is used to convert two differentenvironment, such as Frame Relay Network & an X.25network. For e.g. a gate way can receive email messagesin one format in convert them into another format. Gateway can operate at all seven layer of OSI model.They are similar in function to routers but they aremore powerful and intelligent devices. Cont...
Disadvantages: Since Gateway perform data conversion so they are slower in speed.Gateway are very expensive device.
RepeaterRepeater are used to take the signal that it receive from thecomputers & other devices on the LAN and regenerate thesignal in order for the signal to maintain its integrity whiletravelling along a longer media run that is normallypossible.Repeaters are used within network to extend the length ofcommunication.Repeaters work at the physical layer of OSI model.Repeater do not have any capability of directing networktraffic or deciding what particular route that certain datashould take, they are simply devices that sit on the networkand boost the data signal that they receive. Cont...
Advantages of Repeater Repeaters easily extend the length of network. They require no processing over head, so very little if any performancedegradation occurs.Disadvantages of RepeatersRepeaters can not be used to connect segments of different network types.They cannot be used to segment traffic on a network to reduce congestion .
BridgeBridge is an internetworking device used to connect similarnetwork segments.When the bridge receives the signals it read address of bothsender and receiver. If the sender is a computer in segment A andthe receiver is also segment A, it would not pass the signals to thesegments B. It will however pass signals if the sender is in onesegment and the receiver in other segment.Bridge works at the data link layer of O.S.I modelThey also use the software to help get the job done. Cont...
A B E F BRIDGE C D G H If A sends a frame to E - the frame must be forwarded by the bridge. If A sends a frame to B - there is no reason to forward the frame.Advantages of Bridges one logical network.Like repeaters they can connect similar network types with differentBridge extends network segments by connecting them together to make cabling.Disadvantages of Bridges Bridge possess information about the data they receive with can slow performance
HubHubs serve as central connection points for LAN’s that typically embrace the star topology.A Hub connects all the nodes of a network using twisted pair cable.The ports which are available on the hub, provide information point for the device on the network. computer and devicesare connected to the hub through network cable to individual ports.The more ports on the hub, the more expensive the hub.These are some hubs which are I. Passive Hub II. Active Hub III. Switch/ Intelligent Hub Cont...
Advantages of Hub Hubs need almost no configuration. Active hub can extend maximum network media distance.No processing is done at the hub.Disadvantages of Hub Passive hubs can greatly limit maximum media distance. Hubs have no intelligence to filter traffic so all data is send out on all ports whether it is need or not.
SwitchA switch is an internetworking device used to manage bandwidth on a largenetwork.Switches divide network into what is known as a virtual LAN or VLAN.Switches use a combination of software and hardware to switch packetbetween computer and other devices on the N/W. This software is the switchoperating system and because switch offer a high density of connectionports,they can easily replace hubs on the network this means that eachcomputer on the N/w can be connected to its own port to the switch,Whenthe comp. are directly connected to the switch,The switch can supply each ofthe comp. with a dedicated amount of bandwidth.For ex:Say users are on a 100 Mbps Ethernet N/W via a switch. Each user canrealize a bandwidth of 100 Mbps and thus have to compute for a bandwidththe way comp. do on a N/W via a Hub because each port on the switch has adedicated 100 Mbps this is why switches are rapidly replacing hubs. Cont...
SwitchSwitches also replaced bridges as the internetworking devices for conserving network bandwidth and expanding LANs into larger corporate internetworks.
2).Some hybrid network devices: Protocol ConverterBridge RouterDigital media receiver
Protocol ConverterProtocol Converter is a device used to convert standard or proprietary protocol of one device to the protocol suitable for the other device or tools to achieve interoperability.The protocol conv.can be s/w conv,H/W conv, or an integrated conv. Depending on the protocols.Protocol converter include an internal master protocol communicating to the external slave devices and the data collected is used to update the internal D/B of the converter.When the external master requests for the data, the internal slave collects the same from the d/b and send it to the external master.
Digital Media ReceiverA digital media receiver (DMR), also commonly referred to as a media extender, media streamer, or digital media adapter (DMA), is a home entertainment device that can connect to a home network to retrieve digital media files (such as music, pictures, or video) from a personal computer or other networked media server and play them back on a home theater system or TV. Cont...
A digital media receiver can connect to the home network using either a wireless or wired (Ethernet) connection.A DMR includes a user interface that allows users to navigate through their digital media library, search for, and play back media files. Different DMRs are designed to handle different tasks.Some DMRs only handle music; some handle music and pictures; some handle music, pictures, and video; while others go further to allow internet browsing or controlling Live TV from a PC with a TV tuner.
Bridge Router(Brouter)A network device that combines the functions of a bridge and a router in one unit.Brouters operate at both the network layer for routable protocols and at the data link layer for non-routable protocols.As networks continue to become more complex, a mix of routable and non-routable protocols has led to the need for the combined features of bridges and routers. Cont...
Brouters handle both routable and non-routable features by acting as routers for routable protocols and bridges for non- routable protocols.Bridged protocols might propagate throughout the network, but techniques such as filtering and learning might be used to reduce potential congestion.Brouters are used as connecting devices in the networking system, so it acts as a bridge in a network and as a router in an internetwork
Other hardware for establishing networks or dial-up connections Multiplexer Network Card Modem ISDN terminal adapter Line Driver
ModemA modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data.For e.g. Computer information is stored digitally, Whereas information transmitted over telephone lines is transmitted in the form of analogue wave. A modem converts between these two forms.
Network Interface Card .A Network Interface Card is an expansion card which installs into a comp. and enables that comp. to physically connect to a Local Area Network.The most command form of Network Interface Card in current use is the Ethernet card. Other types of Network Interface Cards include wireless Network Interface Cards and Token Ring Network Interface Cards.Network Interface Cards are becoming rare, as most motherboards now include built-in Network Interfaces Cont...
Every N/w card has a unique 48 bit serial number called a MAC address, which is stored in a rom carried on the card.Every comp. on the Ethernet N/W must have a card with a unique MAC address , A MAC address look similar to this:00:60:08:8F:5A:D9.The H/W address is used by dynamic host configuraton protocol to identify a specific host. it is also used by address resolution protocol and reverse address resolution protocol to map host to IP address.
ISDN Terminal AdapterISDN Terminal Adapter is a device that connects a terminal to the ISDN N/W.The TA therefore fulfills a similar function to the ones a modem has on the POTS network, and is therefore sometimes called an ISDN modem. The latter term, however, is partially misleading as there is no modulation or demodulation performed.ISDN can create multiple channel on a single line.It is a device with a high throughput rate.ISDN concept is the integration of both analog or voice data together with digital data over the same network
Line driverIn electronics, a line driver is an amplifier used to improve the strength of an analog or digital signal at its source by driving the input to the transmission line with a higher than normal signal level.This increases the quality of a transmission over a long run of cable.An example of a line driver is an amplifier used to extend the range of an digital signal. In mobile audio, use of a line driver allows an amplifiers gain to be set lower, reducing low-level noise. Line drivers may also be used to enhance distortion in guitar amplifiers.
MultiplexerA multiplexer or mux is a device that performs multiplexing; it selectsone of many analog or digital input signals and forwards the selectedinput into a single line. A multiplexer of 2n inputs has n select lines,which are used to select which input line to send to the output.An electronic multiplexer makes it possible for several signals to shareone device or resource, for example one A/D converter or onecommunication line, instead of having one device per input signal. Schematic of a 2-to-1 Multiplexer. It can be equated to a controlled switch. Cont...
Schematic of a 1-to-2 Demultiplexer. Like a multiplexer, it can be equated to a controlled switch.On the other end, a demultiplexer (or demux) is a device taking a single input signal and selecting one of many data-output-lines, which is connected to the single input.One use for multiplexer is cost saving by connecting a MUX & a DMUX together over a single channel.