Thursday 23 August 2012

Networking Devices

                                                         REPEATERS

Repeaters regenerate incoming signals.
Repeaters work at the physical layer of the OSI model.
Repeaters can be into two categories
Amplifiers:-- simply amplify the signal.
Signal re generators :-- strip out the original signal which has weakened.




















                                         HUB

A hub joins multiple computers (or other network devices) together to form a single network segment.
A hub includes a series of ports that each accept a network cable.
Larger hubs contain 8, 12, 16 and even 24 ports.








                                                          NETWORK INTERFACE CARD 


Amplifies electronic signals
Packages data for transmission
Physically connects computer to transmission media (cable)









                                                                                 
                                    BRIDGES 

Bridges have all the features of a repeater.
They function at the Data Link layer of the OSI model.












                                         SWITCHES 

A switch is a small device that joins multiple computers together.
They function at the Data Link layer of the OSI model.













                                           ROUTERS


Routers is used in wide area networks which often connect networks using different communication protocols and different addressing schemes.
They function at the Network layer of the OSI model.








Routing Protocols

Routing protocols are used between routers to determine paths and maintain routing tables.
Eg: RIP, IGRP, EIGRP, OSPF.


                    Routing Protocol Evolution


RIP
Distance vector                                           
Most common IGP                                        
Uses hop count

IGRP
                                                           •Distance vector
                                                           •Developed by Cisco       
                                                                          


EIGRP
Hybrid protocol
Developed by Cisco
Merges benefits of link state & distance vector


  OSPF
            •Link state
            •Successor to RIP
            •Uses least-cost routing, multipath routing, and load balancing 

                                                                                                             Distance Vector
                                                                                            Hybrid
                                                                                                  Link State






No comments:

Post a Comment