network devices

Networking devices

 

 

  The Network devices need to be included in the network for regulation and organization of the Network .The Network Devices Increase the rate at which data travels over the network.They also organize the data reducing data traffic on the network 

❶  Hubs

❷  Routers

❸  Switches

❹  Bridges

❺  Repeaters 

Hubs

A hub joins multiple network segment together to form a single segment.A hub contains a seeries of port to which computers can connect .At a particular Time ,only one computer connected to the hub can transmit data the number of ports in a hub range from 4 to 24 the port are used for connecting different devices or for uplinking . Uplinking  refers to the process of connecting a hub to a hub or a networking device the main function of hubs is to transmit signals .signal may include data packets and tokens that the network exchange before and after data transfer .they also include acknowledgement message that the networks send after they receive the data packets.

Hub

 There Are three type hubs:

①  Active :- Require electricity to run .These hubs regenerate the signals sent over the network reducing attenuation .Attenuation refers to the phenomenon of weakening signals transmitted over the network .for exmp, the network consists of 500 computers Distributed throughout the city.The signals sent from the first computer get weak as they  . An active hub restores the signal and retransmits it over the network.

②  Passive :- Transmits the received signals over the network passive hubs do not regenerate the signal but pass them to all the port on the network .passive hubs do not require electricity for operating .they are cheaper than active hubs. 

③ Hybrid :- Allow you to create a hub -based network.hybrid hub support various type of networking cables such as coaxial, twisted pair and fiber -optic Network Cables are used to connect different networking devices.

Switches

Switches are data-link  layer devices that connect multiple LAN segments to from a single network segment Switches examine the data packets for source and destination address .The switches then forward the data packet  to the appropriate  destination .The forwarding of data only to the specified destination enables you to conserve bandwidth.Bandwidth is the amount of data is transmitted in a specific amount of time A. switch appears 

Switches

Switches Minimize the possibility of collisions of data packets by reducing collision domains .Collision domain are the network segment between two network devices. When two network devices simultaneously try to transfer a data packet over the same rout on the network , a collision occurs .in such case both devices stop transmitting data for a particular time.They Try to retransmit the data after the specified time

Switches reduce the collision domain using micro segmentation . Micro segmentation is a technique by which the switches cut down the collision domain into smaller segments.The final Segment consist of only two nodes or devices , the source and destination eliminating of collision .A few of the switches offered by Cisco include , Cisco catalyst 3550 24 port Switch , Cisco Catalyst 2950T 24 port switch and Cisco system 2950 Switch .

Routers 

Routers are devices that forward data to their appropriate destination .The router Decide the best possible route that  packet needs to take to reach its destination .The routers maintain a routing table to Decide the route for the data .A router appears 

Router

 A router is capable of joining multiple networks using different protocol .Routers operate at the network layerof the OSI mode .The router is the only device in the network that sees  all the data passing through the network when a data packet needs to be transmitted , the router verifies the address of the destination computer picks the optimal router for transmission . Cisco recommends the latest Cisco 2800 Series integrated Service Router and the Cisco 3800 Series integrated  Services Routers for small and large business entrepreneurs ..

Function of  router  

1 ) Provide Traffic  Management 

2) Do not pass broadcast traffic 

3) Connect different network segments.

Repeaters 

A repeater is a device that increase the strength of the data Signals sent across the network .The Signal weaken as they travel along large network segments. A Repeater does not filter data as it travels along the  network ,thereby it  does not help in reducing network traffic .A repeater Appears 

Repeater

The rear panel of a repeater Consists of different LAN Ports to which computers can be connected .A  few of the repeater devices offered by Cisco are Cisco FastHub 400 10/100 Series Repeaters and FastHub  100 , 200 and 300 Series Repeaters .



Bridges 

Bridges are devices that divide the network into different thereby , enabling you to reduce traffic on the network .The Bridge Decides the network segment where the data has to travel in order to reach its destination the bridges verify the source and destination address of the data packet from the routing table that it builds if the destination address is present in the routing table.the bridge forwards the data packet to that destination if the destination address is not present in the routing table ,the bridge sends the data packet to all network segments . The bridges operate at the data link layer of the OSI model. A bridge appears

Network Bridge

The rear panel of a network bride consists of LAN port to Which Computers can be connected . A few of the Several Bridges offered by Cisco  involve , Cisco Aironet  1400 Series Bridges and Cisco System 350 Series Wireless Bridge. 

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