SYLLABUS NETWORKING BASICS / IP ADDRESSING SUBNETTING / VLSM VLSM / LAN AND WAN DEVICES OSI LAYER / ENCAPCULATION AND DENCAPSULATION TCP/IP / IP HEADER ROUTER IOS / BASIC CONFIG / ROUTING BASIC DYNAMIC ROUTING DYNAMIC ROUTING SWITCH BASIC SWITCH ADVANCED ACL / FRAME RELAY NAT / IPV6 VPN / WI-FI SOME ADVANCED TOPIC

COMPUTER NETWORK

NETWORK IS A COLLECTION OR GROUP OF DEVICES THAT CAN COMMUNICATE WITH EACH

OTHER.

BENEFITS OF COMPUTER NETWORK

USING NETWORK WE CAN SHARE EXPENSIVE RESOURCES AND ALLOW USERS IN THE NETWORK TO ACCESS THEM SIMULTANEOUSLY.

DATA SHARING

COMPUTER NETWORKS ENABLE DATA SHARING THAT IS FASTER AND MORE EFFICIENT THAN USING DEVICES SUCH AS FLOOPIES AND COMPACT DISC.

COMMUNICATION

GIVES THE FACILITY OF SITTING IN A PLACE AND FLASHING MESSAGE ON THE SCREEN OF OTHER COMPUTERS IN THE OFFICE.

EXPANDED PC USAGE

A NETWORK IS VERY ACCOMODATING AND FLEXIBLE. NEW MACHINES CAN BE ADDED AND EXISTING ONES REMOVED.

DATA : IT REFERS TO THE INFORMATION PRESENTED IN WHATEVER FORM IS AGREED UPON BY THE PARTIES.

DEPENDING UPON DIRECTION OF FLOW OF DATA IT CAN BE :

A. SIMPLEX : COMMUNICATION IS UNIDIRECTIONAL.

B. HALF DUPLEX : EACH STATION CAN TRANSMIT AND RECEIVE BUT NOT AT THE SAME TIME.

C. FULL DUPLEX : BOTH STATIONS CAN TRANSMIT AND RECEIVE SIMULTANEOUSLY.

NETWORK TERMS TO REMEMBER

COST: Indicates the general cost of components, installation and maintenance of the network.

SPEED: Is a measure of how fast a data can be transmitted over a network, i.e. the data rate.

SECURITY: Indicates how secure the network is including the data that is transmitted.

AVAILAIBILITY: Is a measure of the probability that the network will be available for use when required.

PERCENTAGE AVAILABILITY=([NO OF MIN IN A YEAR-DOWNTIME]/[NO OF MIN IN A YEAR]*100).

THINGS TO REMEMBER WHEN DESIGNING A NETWORK

SCALABILITY : Indicates how well a network can accommodate new users an data transmission requirements.

RELIABILITY : Indicates the dependability of the components that make up the network.

TOPOLOGY : Are of two types – a. Physical b. Logical.

PERSONAL COMPUTERS : The PCs serve as a end point in the network, sending and receiving data.

INTERCONNECTIONS: They provide a means for data to travel from one point to another point in the network. They consists of components like:

NETWORK INTERFACE CARDS: That translates the data produced by the computer into a format that can be transmitted over the local network.

NETWORK MEDIA: May be wired or wireless and provides a means by which signals can be transmitted from on network device to another.

CONNECTORS: It provides the connection points for the media. SWITCHES: Devices that provide attachment to the end systems and

intelligent switching of data within the local network. ROUTERS: They interconnect network and chooses the best path

between networks.

COMPONENTS OF A NETWORK

UNICAST : ONE TO ONE COMMUNICATION.

MULTICAST : ONE TO A GROUP COMMUNICATION.

BROADCAST : ONE TO ALL COMMUNICATION.

TYPES OF COMMUNICATION

LOCAL AREA NETWORK (LAN).

METROPOLITIAN AREA NETWORK(MAN).

WIDE AREA NETWORK (WAN).

TYPES OF NETWORK BASED ON DISTANCE COVERED

LAN

A LAN IS A GROUP OF COMPUTERS IN A LOCALIZED AREA. IT IS A NETWORK CONFINED TO A SMALL ROOM, A BUILDING OR A CLUSTER OF BUILDINGS AND IS INSTALLED FOR THE EXCLUSIVE USE OF A PARTICULAR OFFICE OR A FACTORY OF AN ORGANISATION.

MAN

LAN COVERS AN AREA LARGER THAN LAN. IT COVERS AN AREA OF A STATE

OR A CITY AND INCLUDES TWO OR MORE LANS.

WAN

IN WAN, COMPUTER NETWORK LOCATED IN DIFFERENT COUNTRIES AND

CONTINENTS CAN BE CONNECTED TO SHARE INFORMATION. A WAN USES

TELEPHONE CABLES AND SATELLITES FOR COMMUNICATION. EG: INTERNET.

PHYSICAL TOPOLOGIES

BUS TOPOLOGY

IN PHYSICAL BUS TOPOLOGY A SINGLE CABLE CONNECTS ALL DEVICES.

IN BUS TOPOLOGY ONLY ONE MACHINE IS ALLOWED TO TRANSMIT AT A TIME.

IT USES THE CSMA/CD.

SPEED RATE IS 10 Mbps TO 10 Gbps.

STAR TOPOLOGY

HERE EACH HOST IS CONNECTED TO A CENTRAL DEVICE

RING TOPOLOGY

ALL HOSTS ARE CONNECTED IN THE FORM OF A RING.

IT USES A SPECIAL FRAME CALLED TOKEN WHICH ROTATES AROUND THE RING.

AND WHICHEVER DEVICE HAS THE TOKEN AT THAT TIME WILL BE SENDER.

MESH TOPOLOGY

EACH AND EVERY DEVICE IN THIS TOPOLOGY HAS A POINT TO POINT CONNECTION WITH THE OTHER DEVICES.THIS RESULTS IN A COSTLIEST DESIGN.

UNDERSTANDING DECIMAL, BINARY AND HEXADECIMAL