Networking Devices and Networking Topologies

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Networking DevicesNetworking TopologiesComputer NetworkingNetworking Devices Hubs Switch Router Modem Repeater MultiplexerNetworking Topologies Bus Topology Star Topology Ring TopologyNetworking Devices Networking=Working together The devices that help the network to be linked to each other Objective of helping share data and/or hardwares or softwares

Hubs connects two or more devices without having to connect to each other directly uses twisted pair cable basic function: forward the data it received from a connected device to all other connected devices regardless of whether the data is destined for the device. creates bottleneck on larger busy networks comes in variety of shapes and sizes: workgroup hubs: consists of 5-8 ports high density devices: consists up to 32 ports

Hubs: how they work!!

HubsAre of three types:Passive Hubs:provides a pathway for signals to traveldoes not need power to operateActive Hubs:provides a pathway for signals to travelregenerates the signals before passing it onrequires power to operateIntelligent Hubs:performs all the jobs of active and passive helps in troubleshooting by pointing the actual location of the problem

Switch forwards data packages to only the destined device checks the MAC address found in the NIC to do so by forwarding the data to only the destined device, it reduces the number of collision in the network uses three methods to deal with the datas as they arrive:Cut through: Begins to forward the package as soon as it arrivesNo error checking performedPacket is moved quicklyStore and forwardWaits to receive the entire package before forwarding itBasic error checking is performedFragment FreeBuilt on the speed advantage of cut throughForwards package in fragmentsSwitch: how it works!!

Router increasingly common sight in any networking environment most commonly used to connect a home computer to an ISP used to create large networks by joining two network segments derives its name from the fact that it can route data from one network to another when it receives a packet of data, it reads the header of the packet to determine the destination address when address is determined, it looks in its routing table to see whether it knows how to reach the destinationIf it does know how to reach the destination it then forwards the data to the next hop on the routeThe next hop could be the final destination or another routerRouter: how it works!!

Modem short for modulizer-demodulizer converts data being used by a computer into an audio signal that is able to be transmitted over a phone line When the signal gets to its intended destination, another modem then reconverts the signal back into data the process of converting data into audible sound is known as modulation converting it back to the data is known as demodulation Modems provide a relatively slow method of communication the fastest modem available on the market today has a maximum speed of 56Kbps unsuitable for downloading large files. Modem: how it works!!

Repeaters send signals over long distances function of a repeater is to receive incoming signals or a packet of data, regenerate the signals to their original strength and retransmit them helps computers maintain stronger wireless signals by taking in signals from routers and remitting them primary advantage of using a wireless repeater is that it can improve wireless signal strength without having to move a computer or router further a computer is from the wireless router it connects to, the weaker its wireless signal will tend to be Placing a wireless repeater at some point between a computer and the router it connects to can enable the computer to receive a stronger signal Another benefit of using a wireless repeater is that it can help you reduce the impact of obstructions that may impact your wireless connection Physical objects can weaken wireless signals so we should place a repeater in a location where few objects rest between itMultiplexer accepts multiple inputs and allows only one to go through as an output receiving end accepts this complex signal and reconverts it into its individual components multiplexing is used in both digital and analog data transmission provides great cost advantages, since it reduces the need for additional wires and/or communication channels but, the initial cost of setting it up is expensive multiplexing can slow down the communication process, since shifting from one frequency to another causes time delays another disadvantage of it requires constant source of electrical power to operateMultiplexerMultiplexers are of three types:Frequency division multiplexing : divides a single bandwidth into various different frequencies so it can be used by multiple users each different frequency carries a separate signal at the same time

Time division multiplexing : allows multiple signals to travel across the same transmission channel but allocates different time slots to each.

3. Dense wavelength division multiplexing :is a version of frequency division multiplexingit sends colored lasers to transmit data over the same bandwidth

Network Topologies network layout of connected devicesArrangement of networkLayout of connected device

Bus topology: the setup!!

AdvantagesEasy to add and remove nodesRequires small amount of cable compared to other topologies so is less expensive and easier to setup and troubleshoot.

Bus topology DisadvantagesA failure in the central line means the whole network will go down.Only one route for data to take so will performance will decrease as more data is transmitted.

Bus topologyRing Topology: the setup!!

AdvantagesAs all the data can only travel in one direction the transmission of messages is simple and high rates can be achieved.There is no dependence or need of a central computer or mainframe.Ring Topology DisadvantagesIf one node or line fails then data cannot continue to be transmitted between all the rest of the nodes in the network.Harder to add new nodes into the system, requires the network to be disrupted.

Ring TopologyStar Topology: its setup!!

AdvantagesMore secure connection as data is sent directly between nodes (unlike ring networks)A failure of the cable will only affect one node, hence faults are easier to pinpoint.Easy to add new nodes without any disruption

Star Topology DisadvantagesRequires and is dependant upon a central computer.Requires more cable and is therefore more expensive to setup.

Star Topology