ISYS111 Lecture Notes - Lecture 5: Network Interface Controller, Coaxial Cable
17 Jun 2018
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• In modern organisations, computers do not work in isolations
• There is a constant exchange data with one another
• Data exchange is facilitated by telecommunication technologies
• Provide companies with significant advantages
• Data exchange can take place over any distance and over networks of any size
WHAT IS A COMPUTER NETWORK?
A. What are the primary business reasons for using networks?
• Allow computers to communicate with other computers within and outside
the organisation
• Make organisations more flexible by enabling them to change with the
business environment
• Hardware, computer applications and data can be shared
• Documents can be shared over distant geographical locations over a network
• Networks link the organisation to other businesses, partners and customers
B. Local area networks (LAN) and Wide area networks (WAN)
• LAN connects networks in a limited geographical location (in a building)
• LAN is generally owned by the business that uses it
• WAN connects networks in a wide geographical location (internet)
• WAN is made up of lines owned by telephone companies and global
communication companies and have a much larger data transmission capacity
than a LAN
C. Enterprise network
• Combination of LANs and WANs that make up a network used by an
organisation
• Networks are interconnected so that anyone on the various components of
the network can communicate with others on the same network
• Has a single backbone network to which all other LANs and WANs are
connected
D. Network devices
• Network Interface Card (NIC): Computers and devices need the NIC to be
able to physically connect to a network
• Hub: Simple network device to broadcast data packets it receives to all other
devices connected to it
• Switch: Network device to transmit data packet it receives to the destination
device or computer connected to it within a local network
• Router: Similar to a switch, but can also send data packets to the internet, to
be sent to the destination device or computer
• Modem: Network device to convert between digital and analog signals
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