Section 4: Computer Networks Flashcards
1
Q
VoIP
A
Voice over internet protocol
2
Q
Define Networking
A
sharing information and resources through linked computer systems
3
Q
PAN
A
personal area network
4
Q
LAN
A
local area network
5
Q
WAN
A
wide area network
6
Q
What are the 3 major categories of networks?
A
- PAN
- LAN
- WAN
7
Q
What are PAN networks used for?
A
short-range communications, within a few feet.
8
Q
Name 2 examples of technology that may utilize PAN networks?
A
- wireless headphones to a smartphone
- Wireless mouse to a PC
9
Q
What are LANs (not acronym)
A
a collection of computers in a single building or building complex.
10
Q
What is a WAN (not acronym)
A
link systems over a greater distance including machines across the world
11
Q
Name one type of open network?
A
the internet
12
Q
Communication over the internet is governed by what?
A
a collection of standards known as the TCP/IP protocol.
13
Q
What is topology
A
another classification of networks, designated by the pattern in which the machines are connected.
14
Q
What are the 4 common topologies of networks?
A
- bus
- star
(1 and 2 most common) - ring.
- mesh
15
Q
How are the machines connected to a bus network?
A
machines are connected to a common communication line called a bus.
16
Q
How are machines connected in a star network?
A
star networks have a single machine serving as a single point to which all others are connected
17
Q
How are machines connected in a ring network?
A
ring topologies connect directly to each other as a peer.
18
Q
How are machines connected in a mesh network?
A
Mesh connects every device in a network to every other device.
Mesh networks enable redundancy while also introducing significantly more network traffic.
19
Q
How is the star topology used today? (Example)
A
wireless networks where communication is carried out via radio broadcast to a central machine called the AP (Access point)
20
Q
AP
A
Access point.
21
Q
Which network topology best handles downed links without losing connectivity between devices?
A. Bus
B. Ring
C. Mesh
D. Star
A
C. Mesh
22
Q
What function do protocols serve in a computer?
A
Networks rely on protocols to govern communication.
Using protocols, vendors are able to build products for network applications that are compatible with products from other vendors.
23
Q
What is interprocess communication (what does it do?)
A
allows the activities or processes on different computers within a network to coordinate actions and a complete tasks.
24
Q
What is client/server & what are the basic roles?
A
A popular convention for interprocess communication.
Processes are categorized as either a client making requests or a server satisfying client requests.
25
P2P
peer-to-peer
26
How does P2P work?
processes both request and provide service to each other.
27
Name 2 examples of the P2P model
1. Instant Messaging
2. Interactive games played by users on multiple machines.
28
What is the Gnutella Protocol?
Operates without any centralized server and allows for numerous software clients to be used for access.
29
What are distributed systems?
execute software processes on more than one computer.
30
Name 3 types of distributed systems.
1. Cluster computing
2. Grid Computing
3. Cloud Computing
31
How does Cluster Computing work?
Uses many independent computers to provide computation or services comparable to a larger machine. Can use several individual machines similarly to a larger supercomputer.
32
What are two benefits to Cluster Computing?
1. Provides high availability as it’s likely at least one computer in a cluster will be available.
2. Can balance loads by automatically shifting requests among the cluster members.
3. (Cost—can be more affordable than other options eg supercomputer.)
33
What is Grid Computing?
A type of distributed system that’s more loosely coupled than clusters but still works together as a system to complete large tasks.
Typically includes specialized software to make it easier to distribute workload and data among machines in the grid.
34
What is Cloud Computing?
provides large pools of shared computers that can be allocated to clients as needed.
35
What is a benefit of cloud computing?
reasonably guarantees for reliability and scalability.
36
What is the downside to Cloud Computing?
it raises concerns about security and privacy.
37
What is transmission medium?
a component that carries data from one network device to another.
38
What are the two types of transmission medium?
1. Wired
2. Wireless
39
Name 3 common network media used in wired networks.
1. Twisted pair cables
2. coaxial cable
3. optical fiber cable.
40
Name 3 common network media used in wireless networks
1. radio waves
2. microwaves
3. infrared waves.
41
UTP
Unshielded twisted pair (twisted pair cables)
42
STP
shielded twisted pair (twisted pair cables)
43
What are the two most common types of twisted pair cables?
1. UTP
2. STP
44
What is the difference between STP and UTP twisted pair cables?
STP consist of two separately insulated copper wires wound around each other, making them more expensive than UTP
45
What is the benefit of SPT
the insulating sheath protects the wires from things like neighboring unshielded cables and electromagnetic interference from fluorescent lights.
46
What is the maximum segment length of Twisted pair cables?
328 feet.
47
How is network bandwidth usually measured?
megabits per second (Mbps) and gigabits per second (Gbps)
48
Which has more bandwidth, Twisted pair cables or coaxial cables?
coaxial cables.
49
What is baseband
a signal at a very narrow frequency range on which data or information is superimposed and then transmitted.
50
Name 2 examples of baseband
1. EthernetLANs
2. Serial Cables
51
What is broadband?
high-capacity transmission technologies used to transmit data, voice, and video across long distances at high speeds.
52
Name 3 examples of broadband
1. Coaxial cable
2. fiber optic cable
3. radio waves.
53
How do fiber optic cables work?
use the concept of reflection of light through a core made up of glass or plastic. The core is surrounded by a less dense glass or plastic covering called the cladding.
54
What is a server?
a server is a computer that provides services, such as website hosting and routing for other devices
55
What is a switch?
a network switch extends the network by using a packet switching to forward data to the intended hard-wired devices.
56
What are routers?
special-purpose computers that forward messages from the machines on their network.
57
How do routers work?
they use their forwarding table to match up the privacy IP addresses with the internet IP address and send the message to the correct machine.
58
What is a firewall
monitors network traffic and blocks traffic that triggers its safety rules, providing a barrier between a trusted private network and an untrusted network like the internet.
59
What does a modem do?
bridges the gap between the customer and the ISP converting the incoming analog data into digital and the outgoing digital data into analog. Provides the access point to the internet.
60
What 4 devices can be used to connect networks?
1. Repeaters
2. Bridges
3. Switches
4. Routers
61
What are repeaters?
extend the range of cabling types so connections can be made by increasing the strength of the network signal.
62
What are bridges?
used to connect different types of network and provide management of the message.
ex. a bridge can be used to connect a twisted pair and coaxial network.
63
What are switches?
used on LANs to reduce network traffic by management of network messages.
64
What is a Gateway?
a device on your LAN.
65
How do routers manage traffic?
Having a routing table of known devices. If a destination address is unknown to the router, it will forward the message to another router. This analyze and forward process continues until the message reaches the correct address.
66
Which type of transmission media can broadcast in baseband mode?
A. Twisted Pair Cable
B. Optical Wire
C. Wireless Transmission
D. Coax Cable
D. Coax Cable
67
Who constructs and maintains the individual networks comprising the internet?
ISPs
68
How are ISPs classified?
classified in theirs depending on the role they play in the overall internet structure.
69
What is Tier 1 ISP hierarchy
The backbone of the internet. Tier 1’s consist of high-speed, high-capacity, international WAN’s that are typically operated by large communication companies.
70
What is Tier 2 ISP hierarchy
More common than Tier 1 and more regional in scope. Essentially networks of routers that collectively provide the internet’s communication infrastructure.
71
What is Tier 3 ISP hierarchy
Access ISPs, typicall independent internets sometimes called intranets operated by a single organization that supplies internet access to homes and businesses.
72
What are end systems or hosts?
Common internet devices used to connect to the access ISP. Include common devices such as PC’s, laptops, and smartphones but also includes cameras, cars, and home appliances.
73
What are some examples (3) of technologies used to connect end systems to larger networks?
1. Satellites
2. Telephone lines
3. Cables
74
IP
Internet Protocol
75
What kind of IP addresses are in use today?
IPv6 (IP version 6) with126-bit addresses in addition to legacy IPv4 addresses.
76
How are ISP’s assigned?
ICANN coordinates internet operations and awards blocks of consecutively numbered IP addresses to ISPs. ISP’s then assign a unique IP address to each machine within their region of authority.
77
How are IPv4 addresses written?
Written in dotted decimal notation with the bytes of the address separated by periods.
Example: 192.207.177.103
78
How are IPv6 addresses written?
In hexadecimal
Example: 2001:DB8:12:34::1111
79
ICANN
Internet Corporation for Assigned Names and Numbers
80
Where must every domain be registered?
With ICANN
81
What are network protocols?
Rules, procedures and formats that govern the communication of multiple devices over a network.
82
HTTP
Hypertext Transfer Protocol
83
SMTP
Simple Mail Transfer Protocol.
84
How does SMTP work?
Uses Domain Name System (DNS) lookups to identify the recipient of the email and send the message over the internet to a mail server where it can be retrieved using protocol such as POP3 and IMAP
85
DNS
Domain Name System
86
POP3
Post Office Protocol version 3
87
IMAP
Internet Message Access Protocol
88
How does VOIP work?
It establishes a connection between two devices and then performing real-time two-way transmission of audio data.
89
What is a softphone?
Allow two or more computers to share a call without any additional hardware.
90
CDNs
Content Delivery Networks
91
What are CDNs
Content delivery networks which are groups of servers distributed strategically over the internet that stream copies of content to nearby end users.
92
Anycast
Enables an end user to connect to the closest server automatically.
93
URL
Uniform Resource Locator.
94
What do URL’s include?
The protocol, domain, and all subdomains as well as the resource path ID and name of the document.
95
HTML
HyperText Markup Language
96
What is HTML
HTML is a way of encoding a document.
97
XML
Extensible Markup Language
98
What is XML
A standardized style for designing notational systems for representing data as text files.
99
What is the difference between XML and HTML?
XML emphasizes semantics while HTML focuses on appearances.
100
What is Malware?
Any software intentionally designed to cause damage to a computer, server, client, or computer network.
101
Name 4 types of Malware?
1. Computer Viruses
2. Worms
3. Spyware
4. Phishing
102
What is a virus?
A software program that infects a computer by inserting itself into programs that already reside in the machine.
When the “host” program is executed, the virus is also executed, possibly performing degradations of portions of the OS, erasing large amounts of data, or corrupting data and other programs.
103
What is a worm?
An autonomous program that forwards copies of itself to other machines in a network and could result in detriment of individual machines or the operations of the network.
104
What is spyware?
Resides on the computer collecting information about the computers activities and reporting back to the spyware’s instigator. Passwords and credit card numbers can be exposed using spyware.
105
DoS
Denial of Services attack
106
What is a DoS attack?
It’s the process of overloading a computer with messages and results in suffocating the network resources.
107
MITM
Man in the middle
108
What is Packet Sniffing?
MITM attack. The attacker intercepts the data as it’s traveling to or from the victim’s device, including authentication credentials.
109
Rainbow table attack and dictionary attack are two forms of what kind of attack?
Brute force.
110
What is a brute force attack?
The attacker uses all possible combinations of characters to learn the user’s password.
111
What is a dictionary attack?
Attacks are performed by the attacker using an application and a large dictionary text file with just words. When the attacker runs the application, it tries identifying the password by trying hundreds or thousands of words per minute from that dictionary file.
112
How are passwords usually stored in most applications?
Scrambled text or hash values similar to “298cde70c32a57b84d0a546fedbb2596”
113
What is a Rainbow Tables attack?
Rainbow tables try to identify the hash value of the password and then convert it back to plain text.
114
What is a firewall?
A filter traffic passes through. A program. Block outgoing messages with certain destination addresses and blocking incoming messages from untrustworthy sources.
115
What is Network Auditing Software?
It monitors network behaviors such as the origin and volume of traffic, looking for anomalies to proactively or reactively mitigate unwanted occurences.
116
BEC
Business email compromise. A type of social engineering attack/scam.
117
What are the two most common classifications of software?
1. System software
2. Application Software
