2. What is a network?
- A computer network is a system of interconnected computers and
peripheral devices
- For example, it may connect computers, printers, External Hard
Drives and cameras
3. How are networks classified?
- Topology :The geometric arrangement of devices on the network.
For example, devices can be arranged in a ring or in a straight
line.
- protocols :The rules and encoding specifications for sending
data. The protocols also determine whether the network uses a
peer-to-peer or client/server architecture.
- media :Devices can be connected by twisted-pair wire, coaxial
cables, or fiber optic cables. Some networks do without connecting
media altogether, communicating instead via radio waves.
4. What are the different types of networks?
- MAN (Metropolitan Area Network)
5. Local Area Network
- Smallest network compared to the others
- The simplest form of LAN is to connect two computers
together
- LAN is operated within a limited physical area, such as School
or Home
6. Metropolitan Area Network
- Metropolitan describes important cities such as Sydney,
Singapore, Hong Kong, Tokyo and London
- Companies that have several branches within a city such as
banks, use a MAN
- Often acts as a high speed network ( although not as fast as
LAN) to allow sharing of regional resources
7. Comparison of LAN, MAN Large SmallNumber of computers
Twisted-pair and fibre-optics cable Twisted-pair Transmission media
type Slow Fast Speed Large SmallNetwork Size High Low Cost MAN LAN
Criteria 8. Topography
- The shape of a local-area network (LAN) or other communications
system
9. bus topology
- All devices are connected to a central cable, called the bus or
backbone. Bus networks are relatively inexpensive and easy to
install for small networks. Ethernet systems use a bus
topology
10. ring topology
- All devices are connected to one another in the shape of a
closed loop, so that each device is connected directly to two other
devices, one on either side of it. Ring topologies are relatively
expensive and difficult to install, but they offer high bandwidth
and can span large distances.
11. startopology
- All devices are connected to a central hub. Star networks are
relatively easy to install and manage, but bottlenecks can occur
because all data must pass through the hub.
12. Basic Hardware Components
13. Network interface card
- Often abbreviated as NIC, an expansion board you insert into a
computer so the computer can be connected to a network. Most NICs
are designed for a particular type of network, protocol, and media,
although some can serve multiple networks.
14. Switch
- A network switch is a small hardware device that joins multiple
computers together within one local area network (LAN)
- A switch stores the MAC Address of every device which is
connected to it.
- MAC addresses are globally unique addressed that are written
into hardware at the time of manufacture
- A MAC address is 48 bits long. This means that there are
281,474,976,710,656 possible MAC addresses
- If the switch does not recognize the MAC Address, it will not
know which port to copy the frame to. When that happens, the switch
will broadcast the frame to all of its ports.
15. Hub
- A common connection point for devices in a network. Hubs are
commonly used to connect segments of a LAN. A hub contains multiple
ports. When a packet arrives at one port, it is copied to the other
ports so that all segments of the LAN can see all packets.
16. Router
- A network device that forwards packets from one network to
another. . Based on internal routing tables, routers read each
incoming packet and decide how to forward it. The destination
address in the packets determines which interface on the router
outgoing packets are directed to