5) Fundamentals of Computer Networks Flashcards
1
Q
What is a network?
A
A collection of connected computers
2
Q
Why might we set up a network?
A
Data exchange
Managing computers
Resource sharing
3
Q
What can a network manager manage over other computers in the network?
A
Updating software
Fixing problems
Help users (password resets)
4
Q
What resources are commonly shared within a network?
A
Printers
Scanners
Internet Connections
5
Q
What is a topology?
A
How the computers are laid out and connected together
6
Q
What factors affect the overall performance on a network?
A
Topology
Bandwidth
Wired vs Wireless
Choice of hardware
7
Q
What is bandwith?
A
The amount of data that can be transferred in a given time
8
Q
Why can increased bandwidth not increase performance?
A
Bandwidth is shared so there may be too many users
9
Q
What is transmission media?
A
Different ways of physcially transferring data along a network
10
Q
What are fibre-optic cables made out of?
A
Thin strands of glass which transmit binary data as pulses of light
11
Q
What are advantages of fibre-optic cables?
A
Do not suffer interference
Very high bandwidth (100Tbps)
12
Q
What is fibre-optic cabling appropriate or?
A
Long distance communcation such as undersea channeling
13
Q
What are the types of transmission media?
A
Fibre-optic cables
Radio waves
Coaxial cable
Twister-pair copper cable
14
Q
What are radio waves?
A
The transmission media of wireless networking
15
Q
What is a coaxial cable?
A
A wired transmission media where and insulated copper wire is surounded by a metal mesh to protect it from interference
16
Q
What are coaxial cables most often used for?
A
Cable television
17
Q
What is the twister-pair copper cable often referred to as?
A
An Ethernet cable
18
Q
What is inside a twister-pair copper cable?
A
8 wires twisted in pairs which reduces interfernce
19
Q
What do twisted cables ratings indictae?
A
How quickly data can be transferred
20
Q
What can Cat-5e transmit at?
A
1 Gbps
21
Q
What can Cat-6 transmit at?
A
10 Gbps
22
Q
What are the geographical classifications of networks?
A
Personal area network
Local area network
Wide area network
23
Q
What does PAN stand for?
A
Personal area network
24
Q
What does LAN stand for?
A
Local area network
25
What does WAN stand for?
Wide area network
26
What is a PAN used for?
Connecting a single user's devices
27
What is a WAN used for?
Connecting international offices for multionational companies
28
What is a WAN?
A collection of computers connected over a large geographical area
29
What is a LAN?
A collection of computers connected over a small geographical area?
30
What are examples for each geographical calssification of network?
PAN- Bluettoh headset to phone
LAN- Homes, Schools
WAN- The Internet
31
What is WiFi?
A set of protocls that define how network devices can communicate wirelessly over radio waves
32
What are WiFi standards?
802. g - 54Mb/s
802. 11n - 600Mb/s
802. 11ac - 3.2Gb/s
33
How can we ensure devices are comaptible?
By creating devices which uses the same WiFi standards
34
How do we try to avoid interference?
By splitting frequencies into bands and channels
35
What frequency bands fo most WiFi standards transit data using?
2.4 Ghz
| 5 Ghz
36
How many channels are in the 2.4 Ghz frequency band?
13
| 3 of these do not intefere with each other
37
How many channels are in the 5 Ghz frequency band?
24 non-overlapping channels
38
What are WiFi security methods?
Wired Equivalent Privacy (WEP)
WPA
WPA2
39
What does WEP stand for?
Wired Equivalent Privacy
40
What does WPA stand for?
WiFi protected access
41
What is WEP?
Nedding a password to join a network
| No data is encrypted so can be easily intercepted
42
What is WPA?
Uuses a password to join a network
| Uses encryption to scarmble data being sent
43
What is WPA2?
Successor of WPA
| Stronger encryption algorithm
44
Rank the WiFi secuirty measures from strongest to weakest
WPA2
WPA
WEP
45
What is the star toplogy?
Each device is connected to a central switch or server
46
Where are star topologies common?
LANs
47
What are features of star topologies?
Simultaneous access
Reliable
Scalable
Expensive
48
Why is a star topology reliable?
If a single client fails all the other clients can continue
| If the server fails the whole network is affected
49
What is the bus topology?
Each computer is connected to a main cable called the bus
50
What are features of bus topologies?
Little cabling
Unreliable
Easily expanadable
Difficulty troubleshooting
51
Why can problems within a bus topology network be hard to find?
A break in the main cable could have occured in any place
52
Why is a bus topology unreliable?
If the main cable is broken the network is shut down
53
What does IP stand for?
Internet Protocol
54
What are IP addresses used by routers to determine?
Whether a packet's destination is within the network or not
55
What happens if a packet's detinsation isn't within the current network?
The router will pass the packet onto the WAN
| Other routers can use IP address to figure out where to send the packet
56
What are IP addresses used for?
Identifying where data packets are from and where they need to go
57
Where must IP addresses be unique?
Within the same LAN
58
Why are there different types of IP address?
IP addresses are not universally unique
59
What are the types of IP address?
Static IP vs Dynamic IP
Private IP vs Public IP
IPv4 vs IPv6
60
What is a static IP address?
A device that has the same IP every time it connects to the network
61
What is a dynamic IP address?
A device that will be allocated a new IP address every time it connects to the network
62
What provides dynamic IPs?
Dynamic Host COnfiguration Protocl
| (DHCP) server
63
Describe a private IP
Devices within a LAN can have a private IP
| These can be used to exchange data between devices on the LAN
64
Describe a public IP
Routers which connect a LAN to a WAN have a public IP
| These are used when other networks on the WAN want to send data to the LAN of the router
65
What is the IPv4 format?
32-bit numbers
| 11.22.33.44
66
What is the IPv6 format?
128-bit numbers often 8 groups of 4 hex digits
| 111A.222B.333C.0000.0000.0000.0000.888D
67
What does NIC stand for?
Network Interface Controller
68
What does every NIC have?
A globally unique MAC address
69
What does MAC stand for?
Media Access Control
70
When are MAC addresses assigned?
When the device is manufactured and cannot be changed
71
How many MAC address do devices with multiple interfaces have?
Multiple MAC addresses
72
What are uses of MAC addressing?
Used to exchange data on the same LAN
| Used by swithces and NICs to send data to the intended recipient
73
What is the MAC address format?
48-bit numbers as pairs of hex digits
| 1A.2B.3C.4D
74
What does each half of a MAC address mean?
First half = manufacturer
| Second half = Individual device produced
75
What are netowkr protocols?
A set of rules that define how data is transmitted beween connected devices
76
What are the transmission protocols?
```
IP
Ethernet
WIFI
Transmission Control Protocol (TCP)
User Datagram Protocol (UDP)
```
77
What does the IP define?
How packets should be sent between networks
| IP header added to packets with source and destination
78
What does ethernet define?
How data should be physically transmitted
79
What does WiFi define?
How data should be transmitted using radio waves
80
What does TCP stand for?
Transmission Control Protocol
81
What does the TCP do?
Splits data into packets
| Each packet has a header and payload
82
What is the payload of a data packet?
The actual data
83
What does UDP stand for?
User Datagram Protocol
84
What does the UDP do?
Performs same functions as TCP but doesn't check packet has arrived
85
What are the differences between TCP and UDP?
UDP faster but less reliable than TCP
| UDP better for gaming
86
What are the web protocols?
HTTP
HTTPS
File Transfer Protocol (FTP)
87
What does HTTPS stand for?
Hypertext Transfer Protocol Secure
88
What is HTTP mainly used for?
Accessing websites from servewrs
89
What does HTTP define?
How data should be exchanged between web browsers and web servers
90
What does HTTPS use to encrypt data between the client and server?
Secure Socket Layer (SSL)
91
What does SSL stand for?
Secure Socket Layer
92
What does FTP define?
How binary and text data can be requested from a server and transmitted back to the client
93
What is FTP used to do?
Download or transfer files over a network
94
What does FTP stand for?
File Transfer Protocol
95
What are the email protocols?
SMTP
IMAP
POP
96
What does POP stand for?
Post Office Protocol
97
What does POP do?
Defines how emails can be retrieved from a mail server
| Once user has dowloaded mail from server, server deletes copy and only local copy remains
98
What does IMAP stand for?
Internet Message Access Protocol
99
Why is IMAP more popular than POP?
Ability to sync multiple devices
| Inboxes remain constant across multiple devices
100
What does SMTP stand for?
Simple Mail Transfer Protocol
101
What are almost all e-mails sent using?
SMTP
102
What does SMTP define?
How emails are sent from an e-mail client to a mail server
103
What is a protocol layer in a protocol layer model?
A group or collection of network protocols that work at a similar level within the networking process
104
What are properties of netwrok layers?
Layers of protocol layer model should be inedpendent
| Layers should only interact with each other by considering inputs and outputs of that layer
105
What are layers an example of?
Abstration
106
What are the 4 layers of the TCP model?
Application
Transport
Internet
Network Access
107
What does the application layer do?
Creates and interprets data (HTTP, IMAP, FTP)
108
What does the transport layer do?
Splits/joins data (TCP)
109
What does the internet layer do?
Adds addresses to data (IP)
110
What does the network access layer do?
Converts data into electrical signal, hardware (Ethernet, WiFi)
111
What are the 7 layers of the OSI model?
```
Application
Presentation
Session
Transport
Network
Data Link
Physical
```
112
What are the first three layers of the OSI model grouped into in the TCP model?
The application layer
113
What layer is the same in both the TCP and OSI model?
The transport layer
114
What is the OSI's network layer called in the TCP model?
Internet
115
What are the bottom two layers of the OSI model grouped into in the TCP model?
The network access layer
116
What are advantages of layering?
Application developers create apps without network knowledge
Specialists can work on one layer
Layers can be changed without affecting others
Individual layers can be debugged
117
What are the 2 common layering models?
TCP
| OSI
118
What does TCP stand for?
Transmission Control Protocol
119
What does OSI stand for?
Open Systems Interconnection
120
What are the first 3 sections of a URL?
Protocol
Path
Domain
