• Repeaters : amplify data signal thereby extending the physical coverage of a network. It can connect two LANs locally.
• Bridges: connect similar types of networks e.g a token ring to another token ring
• Routers: link networks of different types
• Gateway: allows computers in a network to connect regardless of their topology

• It refers to a computer that controls other computers in a network and monitors user's access to the shared resources.

• star - if one computer goes down the others can still be used
• ring - if one computer goes down the others can not be used

download speed :
– speed at which information/data is transferred FROM server/Internet
– speed at which information/data is transferred TO the user’s computer
upload speed :
– speed at which information/data is transferred FROM user’s computer
– speed at which information/data is transferred TO the Internet/server

• an use Internet connection and telephone at the same time
• much faster data transfer speed
• always “on”
• charged for number of bytes/flat rate per month rather than actual time on line
• more bandwidth

– when transferring large files/attachments with emails
– when streaming music/video files/bit streaming
– when using VoIP/video conferencing
– software updates
– online transactions
– Using VLE (Virtual Learning Environment)

– if one station/cable fails, others are not affected
– easier to identify faults when using star topologies
– it is easier to expand this type of network
– performance doesn’t deteriorate under load

RFID stands for radio frequency identification. There is an RFID reader and tag.RFID is used in contactless credit and debit cards as well as in some hotel room cards. Inside an RFID tag is a chip that contains a small amount of memory. The chip is attached to a coil of wire which acts as an antenna. When an RFID tag is scanned, the reader emits radio waves which are picked up by the tag’s antenna. The power induced in the tag’s antenna from these waves is enough to power the chip which then uses its antenna to emit its own radio wave, which contains the information held on the chip. This wave is picked up by the reader which decodes the information and returns the information to a computer.

It has a header

• consists of values between 0–255 / 0–FFF
• values are separated by full stops/colons
• it is a unique address
• can be static or dynamic
• can be public or private
• can be IPv4 / have four groups of digits
• can be IPv6 / have eight groups of digits
• in IPv6: can replace groups of zeros.

Shielded twisted pair cable:
A twisted pair cable is made up of four pairs of twisted copper wires, a shielded twisted pair cable applies a shield to each one of the pairs on a cable or to all of the pairs together. This shield can reduce EMI (electromagnetic interference), which would be emitted from heavy machinery. This increased data transmission quality in the workshop. STP can also reduce crosstalk.

• The different factors that can influence the performance of a network include: bandwidth, network design, data collisions, and excess broadcast traffic.
• The bandwidth can influence through the method of transmission and medium used

• A compiled program will only execute on a processor of specific type/family/with same instruction set
• A program run using an interpreter can execute on a computer with any type of processor;

Can share files/data Can share applications/software Can collaborate Can share peripherals (printers, speakers) Can share connectivity (Internet connection, hotspot) Can access files from any computer / hot desk Central control/management (security, software updates, backup, remote support, users, remote monitoring) Allows communication (email, social media, video conferencing, online meeting, collaborative games)

1. Enable resource sharing
2. Facilitate remote communication
3. Enable distributed processing
4. Provide better data security and management

1. Application
2. Presentation
3. Session
4. Transport
5. Network
6. Data link
7. Physical

Twisted pair cables

Coaxial cables

Fibre optic cables

• a repeater is a two-port device that amplifies a signal from one port to another
• a switch is a multiport device that uses a table of addresses to send a signal through the correct port

a repeater will amplify a signal and resend it to overcome reduction in signal strength (attenuation) because over a distance network signals diminish in size/amplitude (are attenuated) due to characteristics of the media.

Advantages