Communication #3 Flashcards
Define network
- Consists of a number of computer systems connected together
3 advantages of a network
(look in page 35 for more)
- Share data/files
- Central backup
- Access data from any pc
3 disadvantages of a network
(look in page 35 for more)
- Hackers can gain access to data easily
- Server down = all workstations affected
- Cost of servers expensive af
What are the 2 main types of network?
LAN
WAN
What is LAN?
- Local Area Network
- All computer systems located close to each other
What is WAN?
- Wide Area Network
- All computer systems located far from each other
What are network topologies?
Theoretical layout of computer systems on a network
What are the 4 types of network topologies?
- Bus network
- Ring network
• Star network - Mesh network
Another word for computer systems?
(topology)
Nodes
Explain bus network
(topology)
- All nodes connected to a single cable
where data can be sent - Has terminators on each end
to ensure networks functions correctly
Explain more about bus network
(topology)
• Bus carries data packets along cable
as packet arrives at each computer system
* Authenticates the destination address contained in packet
to see if it matches own address
* Doesn’t match = packet ignored
* Matches = data is processed
3 Advantages of bus network
(topology)
+ Easy to implement
+ Quick to set up
+ Cost-effective - less cabling
3 Disadvantages of bus network
(topology)
- Difficult to troubleshoot bus
- Limited cable length & stations
- Problem with main cable = whole network down
Explain ring network
(topology)
- Computer systems connected in a ring/loop
- Data packets sent around ring
- Passes from pc to next until arrive to destination
3 Advantages of ring network
(topology)
+ Data quickly transferred without a bottleneck
+ Prevents network collisions
+ Transmission of data relatively simple, one direction
3 Disadvantages of ring network
(topology)
- 1 pc fails = ring is broken
- Problem with main cable = whole network down
- Difficult to troubleshoot ring
Explain Star network
(topology)
- Each computer system connected to central node aka hub
3 Advantages of star network
(topology)
+ Fast network speed
+ Easy to set up
+ Better security
2 Disadvantages of star network
(topology)
- Expensive to install - more cabling req.
- Extra hardware req. (hub)
Explain mesh network
(topology)
- Each pc directly connected to as many other pc’s as possible
- Look at page 38 for a full mesh network diagram
*** most common topology on wireless networks
What is partial mesh network?
(topology)
- Same as mesh network, but only some affected, and rest connected to 1/2 devices
3 Advantages of mesh network
(topology)
+ 1 node fails, always alternative present, data transfer isn’t affected
+ Provides high levels of security & privacy
+ Fault can be diagnosed easily
3 Disadvantages of mesh network
(topology)
- Cabling costs are high
- Set-up is very difficult
- Administration of network is difficult
How does a pc connect to a network
Must have NIC (Network Interface Card)
2 methods of connecting to network
1) physical hardware port (use of cable <– ethernet???)
2) wireless connection (wi-fi)
How is a physical connection made?
Whats the typical data transfer speed?
(connectivity)
- Copper cable - between 100 Mb & 1 Gb per second
- Fibre-optic connection - between 1 & 10 Gb
Typical data transfer speed for Wi-Fi?
54 - 108 Mb or higher
What 2 things can affect transfer speed of wi-fi?
1) Distance between device and router
2) Atmospheric conditions - weather
What is circuit switching?
An example?
Type of networking technology, provides temporary but dedicated link between 2 stations/nodes.
e.g. Landline telephone system
