WHAT IS NETWORKING NETWORKING SIMPLY MEANS THE CONNECTION

WHAT IS NETWORKING? NETWORKING SIMPLY MEANS THE CONNECTION BETWEEN TWO OR MORE COMPUTERS. A NETWORK PROVIDES THE SHARING OF HARDWARE. WE NEED NETWORK IN ADDITION TO THE SPEED AND RELIABILITY OF DATA TRANFER COMPUTERS. IT ALLOWS A FLEXIBLE WORK ENVIRONMENT MAINLY BECAUSE THEY ALLOW REMOTE ACCESS TO RESOURSE AT WORKPLACE.

TYPES OF NETWORKING. #LAN : -LOCAL AREA NETWORK A LAN CONTAINS A LIMITED NUMBERS OF A SMALL DISTANCE. EX: -DEPARTMENTAL STORE. COMPUTERS AND CAN COVER #MAN: -METRPOLITAN AREA NETWORK IT COVERS A MUCH AREA THAN LAN IN A EX: -CAMPUS NETWORK METROPOLITAN CITY. #WAN: -WIDE AREA NETWORK A WAN SPREAD OVER DIFFERENT CITIES & TOWNS EX: -INTERNET

COMPUTER NETORKING DEVICES. COMPUTER NETWORKING DEVICE ARE UNITS THAT ARE MEDIATE DATA IN A COMPUTER NETWORK. THIS DEVICES ARE ALSO CALLED NETWORK EQUIPMENTS. MAIN NETWORKING DEVICES #HUB #BRIDGES #REPEATER #ROUTER #SWITCH #NETWORK INTERFACE CARD(NIC) #CABLES #FIREWALLS

HUB *A CENTRAL POINT OF A *CAN BE MORE THAN A ADDITIONAL SERVICES STAR TOPOLOGIES BASIC HUB –PROVIDING *ALLOWS THE MULTIPLE CONNECTION OF DEVICE *IN REALITY A HUB IS A REAPETER WITH MULTIPLE PORTS *FUNCTION IN SIMILAR MANNER TO A REPEATER *WORKS AT THE PHYSICAL LAYER OF OSI MODEL *USE LARGE HUBS OF 24 PORTS OR STACKING THEM IS A NEGATIVE FEATURE.

HUB THERE ARE MAINLY FOUR COMPONANTS OF HUB • ETHERNET WIRE • NETWORK INTERFACE CARDS • NETWORKING HUBS • NETWORKING SOFTWARE

BRIDGE A BRIDGE IS A DEVICE THAT HELPS TO INTERCONNECT WIRED LANS WITH EACH OTHER. BRIDGES ARE PART OF A SECOND LAYER OF OSI MODEL. IT GENERATES A SIGNALS AND PASSES IT ON. FOR EX: - IF A DATA SIGNAL GETS CORRUPTED BEFORE REACHIING A BRIDGE , THE BRIDGE PASSES ON THE CORRUPTED DATA

TO THE NETWORK SEGMENTS ATTACHED TO IT. TRANSPERENT BRIDGES (IEEE 802. 1 D) MAKE ALL ROUTING DECISION THE BRIDGES IS SAID TO BE TRANPARENT TO THE WORKSTATION. THE BRIDGE WILL AUTOMATICALY INITIALISED ITSELF AND CONFIGURE ITS OWN ROUTING INFORMATION AFTER IT HAS BEEN ENABLED. IF WORKSTATION ON NETWORK SEGMENT A NEEDED ACCESS TO A SERVER, THE BEST PLACE TO LOCATE THAT SERVER IS ON THE SAME SEGMENT AS WORKSTATION, AS THIS MINIMISES TRAFFIC ON THE OTHER SEGMENT, AND AVOID THE DELAY INCURRED BY THE BRIDGE.

REPEATER *REPEATER CONNECT MULTIPLE NETWORK SEGMENTS TOGETHER. *THEY AMPLIFY THE INCOMING SIGNAL RECEIVED FROM ONE SEGMENT AND SEND IT ON TO ALL OTHER ATTACHED SEGMENT *THIS ALLOWS THE DISTANCE LIMITATIONS OF NETWORK CABLING TO BE EXTENDED. THERE ARE NUMBER LIMITS ON THE NUMBER OF REPEATERS WHICH CAN BE USED. *REPEATERS ALSO ALLOW ISOLATION OF SEGMENTS IN THE EVENT OF FAILURES OR FUALT CONDITIONS.

*THE NETWORK NUMBER ASSIGNED TO THE MAIN NETWORK SEGMENT AND THE NETWORK NUMBER ASIGNED TO THE OTHER SIDES OF THE REPEATER ARE THE SAME *THE TRAFFIC GENERATED ON ONE SEGMENT IS PROPAGATED ONTO THE OTHER SEGMENT. THIS CAUSE A RISE IN THE TOTAL AMOUNT OF TRAFFIC , SO IF THE NETWORK SEGMENTS ARE ALREADY LOADED , ITS NOT A GOOD IDEA TO USE A REPEATER.

ROUTER *ROUTER WORKS ON A NETWORK LAYER IN AN INTELLIGENT MANNER. *IT CAN CONNECT DIFFERENT NETWORK SEGMENTS , IF THEY ARE IN SAME BUILDING. *WORKS IN LAN, MAN & WAN. USING DIFFERENT PROTOCOLS. *ALLOWS ACCESS TO RESOURCE BY SELECTING THE BEST PATH • IT CAN FUNCTION AS BOTH A BRIDGE & A ROUTER.

ROUTER STATIC ROUTING DYNAMIC ROUTING *ROUTING TABLE: -- A DATABASE WHICH KEEPS TRACK OF THE ROUTES TO NETWORK AND THE ASSOCIATED COSTS. *STATIC ROUTING: -- ROUTES ARE MANUALLY CONFIGURED BY A NETWORK ADMINISTRATOR. *DYNAMIC ROUTING: -- ADJUST IN NETWORK TOPOLOGIES. AUTOMATIC TO THE CHANGES

SWITCH *SWITCHES : -- A MULTIPLE BRIDGE , FUNCTIONING AT THE DATA LINK LAYER. *EACH PORT OF THE BRIDGE DECIDES DATA WHETHER TO FORWARD PACKETS TO THE ATTACHED NETWORK. *ACTS LIKE A HUB, BUT FILTER LIKE A BRIDGE *EACH PORT ON A SWITCHES IS A COLLISION DOMAIN.

Switch CROSS-BAR SWITCH CELL-BACKPLANE SWITCH STORE-FORWARD SWITCH *CROSS-BAR SWITCHES: -~READ THE DESTINATION ADDRESS THEN IMMEDIATELY FORWARD ~ ACTS AS A SIMPLE REPEATER ONCE THE PATH IS ESTABLISH. *CELL-BACKPLANE SWITCH: -~ BREAK THE FRAME INTO SMALL FIXED CELL LENGTHS. ~ THE CELLS ARE BUFFERED AT THE DESTINATION PORT. *STORE-FORWARD SWITCH: -~THEY EXAMINE ~DETECT MORE THE ENTIRE PACKETS. ERRORS THAN THE CUT-THROUGH VARIETY.

CABLES Cables are used to transfer the data from one place to another place. There are three types of cables. Ø Coaxial cable Ø Fiber-optical cable Ø Twisted-pair cable

CO-OXIAL CABLES Coaxial cable carries signals of higher frequency ranges. Applications In telephone networks ØCable TV networks Ø In traditional Ethernet LANs Ø

FIBER-OPTICAL CABLE A Fiber optical cable is made of glass or plastic and transmits signals in the form of light Advantages ØHigher bandwidth ØLess signal attenuation ØImmunity to electromagnetic interference ØResistance to corrosive materials ØLight weight

TWISTED-PAIR CABLE A twisted pair consists of two conductors each with its own plastic insulation twisted together. One of the wires is used to carry signals to the receiver and the other is used only as a ground reference. Application Ø In telephone lines Ø In local area networks

COMPARISION HUB & SWITCH THE ROLE PLAYED BY A HUB OR SWITCH CAN BE SIMPLE AS BUYING A HUB & CABLE AND PLUGGING THEM IN. HUB MAY THE REQIRES ALMOST NO INSTALLATION. EACH OF COMPUTER STILL NEED TO BE CONFIGURED TO TALK TO THE INTERNET DEVICES USING THEM ALL SHARE SAME BANDWIDTH. WHILE SWITCHES DON’T FOR ALL NETWORK DEVICE TO SHARE THE SAME BANDWIDTH.

WHAT IS THE DIFFERENCE? ROUTERS -- SWITCHES – HUB IN A HUB , FRAME IS PASSED ALONG OR “BROADCAST “ TO EVERY ONE OF ITS PORT , NO MATTER THAT THE FRAME IS ON ONLY DESTINATED TO ONE PORT. IN CASE OF SWITCH IT KEEPS A RECORD OF THE MAC ADDRESS OF ALL THE DEVICES CONNECTED TO IT. SO WHEN A FRAME IS RECEIVED IT KNOWS EXATLY WHICH PORT TO SEND IT. IN CASE OF ROUTER IT’S JOB IS TO ROUTE PACKETS TO OTHER NETWORKS UNTIL THAT PACKET ULTIMATELY REACHES ITS DESTINATION.

ADVANTAGES & DISADVANTAGES HUB: ADVANTAGES— ~ HUB MAY BE CASCADED TO ADDITIONAL PORTS. ~BECOMING A LOW COST SOLUTION ~ UTILIZE EXISTING CABLING & OTHER NETWORK COMPOSITES. DISADVANTAGE— ~CAN NOT FILTER INFORMATION ~EXTENDS COLLISION DOMAIN.

BRIDGE: ADVANTAGES: -~INCREASE THE NUMBER OF ATTACHED WORKSTATION & NETWORK SEGMENTS. ~THEY ARE TRANSPARENT TO HIGHER LEVEL PROTOCOLS DUE TO MAC LAYER DISADVANTAGES: -~IT MAY OVERLOADED DURING PERIOD OF HIGH TRAFFIC. ~THE BUFFERING OF FRAMES INTRODUCE NETWORK DELAY.

ROUTER: ADVANTAGES: -~LIMITS THE COLLISION DOMAIN ~CAN FUNCTION IN LAN & WAN ~CAN FILTER BROADCAST, DETERMINE BEST PATH. DISADVANTAGES: -~EXPENSIVE, MUST USE ROUTABLE PROTOCOL ~SLOWER THAN BRIDGE ~CAN BE DIFFICULT TO CONFIGURE.

SWITCH: -ADVANTAGES: ~LIMITS THE COLISION DOMAIN ~CAN IMPROVE BRIDGING ~CAN BE CONFIGURED TO LIMIT BROADCAST DOMAIN DISADVANTAGES: -~MORE EXPENSIVE THAN A HUB OR BRIDGE ~CONFIGURATION OF ADDITIONAL FUNCTION CAN BE VERY COMPLEX.

REPEATER: -ADVANTAGES: -~CAN CONNECT DIFFERENT TYPES OF MEDIA ~CAN EXTEND A NETWORK IN TERM OF DISTANCES ~DOES NOT INCREASE NETWORK TRAFFIC DISADVANTAGES: ~EXTENDS THE COLLISION DOMAIN ~CAN NOT FILTER DATA ~LIMITED NUMBERS ONLY CAN BE USED IN NETWORK

BIBLOGRAPHY BOOK REFFERED: -COMPUTER NETWORKS ( ANDREW S. TANENBAUM ) COMPUTER NETWORKS (NIIT) DATA COMMUNICATION & NETWORK ( BY FOROUZAN ) RELATED URL’S: NETGEAR. NET BRASSCANNON. NET