Ochieng manages a network for an organisation.
(a) Two computers are assigned the same IP address.
Explain why Ochieng must change the IP address of one of the computers.

• Network operating systems
• Protocols

Physical topology - the physical arrangement of nodes of a computer network

• their small wavelength allows conveniently sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna

• Radiowaves are omnidirectional while microwaves propagate in one direction at a time(unidirectional)
• Radiowaves can be propagated over long distances through sky mode while microwaves require a relay satellite to amplify and retransmit the microwaves signals to the receiver earth station

State the characteristics of each of the following network topologies (KCSE COMPUTER STUDIES 2021 )

• Physical topology deals with the placement of nodes
• Logical topology deals with the data flow  in the network

• Guided media uses cables to connect to computers whereas unguided media uses waves.

• Bus topology is characterised by common transmission media shared by all the connected nodes
• Star topology is characterised by a central switching node connected directly to each of the multiple nodes in the network

Any one of:
• To allow connected machines to communicate
• To provide the rules of communication between two networked devices

Network Failure - when the network becomes faulty or the network is down, users may not access network resources hence operations of an organization may be brought to a standstill

• Security
• Installation cost
• bandwidth the medium can support
• Flexibility e.g wireless media
• Distance

A PAN exist around a single person whereas a LAN covers a larger area

• connecting wireless headphone to a phone
• Using a wireless mouse, keyboard etc
•  

• In a client-server network, every device is either a client or a server whereas in a peer-to-peer network each computer has equal responsibility and each has the ability to work as both a server and a client

• Single-mode fibre consists of a narrow core in which all light pulses travel at the same speed and arrive roughly at the same time at the destination.
• Supports higher bandwidth with less signal loss over a greater distance
• Multi-mode Multi-mode fibre consists of a larger core in which multiple light pulses can travel down the core.
• Supports a smaller bandwidth and signals attenuate at a shorter distance than single mode fibre.

• All nodes ‘listen’ for traffic to sense when the network is idle.
• When a node wishes to transmit, it transmits a ‘request to send’ frame’ (RTS)
• The intended receiving device will transmit a ‘clear to send’ (CTS) frame if it is available.
• All other nodes ‘sense’ the network is busy and wait a random amount of time before trying to transmit

• Standards specify a set of rules for hardware and/or software used in network communications. Because all manufacturers must adhere to the standards when manufacturing network hardware or software, it means that all devices should be able to communicate, regardless of manufacturer.

• Fibre optic cable would be used because it has a higher bandwidth, allowing faster communication in the main part of the network. It is also more secure as it cannot be tapped.
• Firewalls filter the data in and out of a network. Each packet is examined against the filter rules and if a packet is flagged, it is dropped. Only data packets that satisfy the filter rules are allowed through the firewall, thus providing a layer of security for the network.
• A satellite system would be better as it does not rely on wifi, cellular etc. It is not subject to interference and is reliable in remote conditions
• Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to track inventory goods..

• Radio waves
• Microwaves
• Infrared waves