Chapter 2 - Networking Flashcards

1
Q

ARPAnet

A

Advanced Research Projects Agency network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

WAN

A

Wide Area Network (network covering a very large geographical area)
Typically consists of LANs connected via public communications networks
This means it may be a private network and passwords/user IDs are required to access it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

LAN

A

Local Area Network (network covering a small area such as a single building)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

MAN

A

Metropolitan Area Network
Larger than LAN smaller than WAN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

File server

A

Server on a network where central files and other data are stored and can be accessed by a user logged onto the network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Hub

A

Hardware used to connect together a number of devices to form a LAN that directs incoming data packets to all devices on the network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Switch

A

Hardware connecting a number of devices to form a LAN that directs incoming data packets to a specific destination address only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Router

A

Devices which enables data packets to be routed between different networks (eg. can join LANs to form a WAN)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Modem

A

Modulator demodulator
Device that converts digital data to analogue data (to be sent down a telephone wire), also converts analogue data to digital data. Allows several simultaneous wireless connections to take place without interfering with each other. Connects to public infrastructure (cable optic fibre etc.) and supplies a standard Ethernet output which allows connection to a router and internet connection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

WLAN

A

Wireless LAN (local area network)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

(W)AP

A

(Wireless) Access Point
Access point which allows a device to access a LAN without a wired connection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

PAN

A

Network that is centred around a person/their workspace

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Client server

A

Network that uses separate dedicated servers and specific client workstations, all client computers are connected to the dedicated servers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Spread spectrum technology

A

Wide and radio frequency with a range of 30 to 50 metres
Resistant to blocking/tracking as the frequencies change constantly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Node

A

Device connected to a network (can be computer, storage device or peripheral device)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Peer-to-peer

A

Network in which each node can share its files with all the other nodes. Each node has its own data and there is no central server

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Thin client

A

Device that needs access to the internet for it to work + depends a more powerful computer for processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Thin client

A

Device that needs access to the internet for it work + depends on a more powerful computer for processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Thick client

A

Device which can work both offline and online + is able to do some processing even if not connected to a network/internet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Bus network topology

A

Network using single central cable in which all devices are connected to this cable so data can only travel in one direction and only one device is allowed to transmit at a time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Packet

A

Message/data sent over a network from node to node (includes the address of the node sending the packet, address of recipient and actual data)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Star network topology

A

Network that uses a central hub/switch with all devices connected to it so that all data packets are directed through the hub/switch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Mesh network topology

A

Interlinked computers/devices which use routing logic so data packets are sent from sending stations to receiving stations via the shortest route

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Hybrid network

A

Network made up of a combination of other network topologies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Cloud storage
Method of data storage where data is stored on off-site servers
26
Data redundancy
Situation in which the same data is stored on several devices in case of maintenance or repair
27
Wi-Fi
Wireless connectivity that uses radio waves, microwaves. Implements IEEE 802.11 protocols
28
Bluetooth
Wireless connectivity that uses radio waves in the 2.45GHz frequency band
29
Spread spectrum frequency hopping
Method of transmitting radio signals in which a device picks one of 79 channels at random, if in use it randomly picks another. Has a range up to 100 metres
30
WPAN
Wireless Personal Area Network Local wireless network which connects devices in very close proximity (laptop, phone, home devices etc)
31
Twisted pair cable
Cable in which 2 wires of a single circuit are twisted together, several of these pairs make up a single cable, most common cable type in LANs. Lowest data transfer rate and suffers from external interference but is the cheapest option
32
Coaxial cable
Cable made up of central copper core, insulation, copper mesh and outer insulation. Most commonly used in MANs + by television companies. Higher cost but better data transfer rate (80x better capacity than twisted pair) and less affected by external interference. Greatest signal attenuation. Best anti-jamming capabilities
33
Fibre optic cable
Cable made up of glass fibre wires which uses pulses of light rather than electricity to transmit data. Most commonly used over long distances. Best data transfer rate, smallest signal attenuation, highest cost. 26 000 times the transmission capacity of twisted pair cables
34
Gateway
Device that connects LANs which use different protocols
35
Repeater
Device used to boost a signal on both wired(analogue/copper and digital/fibre optic) and wireless networks (prevents dead spots in WiFi zone and are termed non-logical devices because they boost ALL detected signals)
36
Repeating Hubs
Network devices which are a hybrid of hub and repeater unit
37
Bridge
Device that connect LANs using the same protocols can be wired or wireless
38
Softmodem
Software modem Software based modem that uses minimal hardware
39
NIC
Network Interface Card Allow devices to connect to the internet (associated with a MAC address set at the factory)
40
WNIC
Wireless Network Interface Cards
41
Ethernet
Protocol IEEE.802.3 used by many wired LANs
42
Conflict
Situation in which 2 devices have the same IP address
43
Broadcast
Communication where pieces of data are sent from sender to receiver
44
Collision
Situation where 2 messages/data from different sources are trying to transmit along the same data channel
45
CSMA/CD
Carrier Sense Multiple Access with Collision Detection Method used to detect collisions and resolve the issue When a frame is sent it causes a voltage change on the Ethernet cable, when a collision is detected a node stops transmitting a frame and transmits a ‘jam’ signal and waits for a random time interval before resending the frame
46
Bit streaming
Contiguous sequence of digital bits sent over a network/internet
47
Buffering
Store which temporarily holds data
48
Bit rate
Number of buts per second that can be transmitted over a network. Measure of the data transfer rate over a digital telecoms network
49
On demand (bit streaming)
System that allows users to stream video or music files from a central server as + when required without having to save the files on their own computer/tablet/phone
50
Real time (bit streaming)
System in which an event is captured by camera + microphone connected to a computer and sent to a server where the data is encoded. User can access data live
51
WAN vs the internet
Internet is a vast number of decentralised networks+computers which have a common point of access so any one with internet access can connect to computers on these networks WAN required passwords or user IDs to access it
52
Benefits of networking computers and devices (7)
Devices can be shared (reducing costs) Licences to run software on networks are often far cheaper than for an equivalent no. Of stand alone computers Users can share files and data Access to reliable data that comes from a central source eg. file server Data files can be backed up centrally at the end of each day Users can communicate using email and instant messaging A network manager can oversee the network and apply access rights to certain files/restrict access to external networks
53
Drawbacks of networking computers and devices (4)
Cabling + services are expensive Managing a large network is complex and difficult Breakdown of devices can affect the whole network Malware + hacking can affect entire networks (firewalls help)
54
Hardware infrastructure of networked computers (5)
LAN cards Routers Switches Wireless routers Cabling
55
Software infrastructure of networked computers (3)
Operation + management of the network Operation of firewalls Security applications/utilities
56
Services of networked computers (4)
DSL (optic fibre) Satellite communication channels Wireless protocols IP addressing
57
Categories of networks (2)
Public Private
58
Private networks
Networks owned by a single company or organisation. Often LANs/intranets with restricted user access. Companies responsible for purchase of own equipment and software, maintenance of network + hiring and training of staff
59
Public networks
Networks Owned by a communications carrier company used by many orginisations, there are no specific password requirements but sub-networks may be under security management
60
Describe function of LANs
Consists of a number of computers + devices connected to hubs/switches, one of which is connected to a router and/or modem to allow the LAN to connect to the internet/become part of a WAN
61
Function of WAPs
Wireless access points Connected to the wired network at fixed locations, commercial LANs (because of limited range) need several WAPs to permit uninterrupted wireless communications. Use spread spectrum technology(Wideband radio frequency) or infrared (short range+easily blocked) Receives and transmits data between the WLAN and the wired network structure
62
How end users access the WLAN
Through wireless LAN adapters which are built into the devices/as a plug in module
63
Function of WANs (3)
Wide Area Networks Used when computers/networks are situated far from each other. Formed by joining a number of LANs using a router or a modem. Make use of public communications network or dedicated/leased lines (less expensive and more secure) Consists of several end systems and intermediate systems
64
Guide to decide the size of a network (4)
PAN - 1m to 10m (home system) LAN - 10m to 1000m MAN - 1km to 100km WAN - 100km to 1000+km
65
Types of networking models (2)
Client server Peer to peer
66
Client server models (10)
Uses separate dedicated servers + specific client workstations Users able to access most of the files stored on dedicated servers Server dictates which users are able to access which files Allows installation of software onto a clients computer Uses central security databases (control access to shared resources) Logged in users will only have access to resources assigned to them by the network administrator Can be as large as you want and easy to scale up Central server looks after storing, delivery and sending of emails Offers the most stable system (nightly backup restores deleted resources) Can become bottlenecked if there are several client requests simultaneously
67
Most important part of client-server vs peer-to-peer model
Client server: sharing of data Peerto-peer: connectivity
68
Responsibilities of a file server in client-server model (3)
Central storage + management of files Allowing users to share info without the need for offline devices (memory sticks) Allowing any computer to be configured as the host machine and act as the file server
69
Why would you use a client-server model (4)
Company/user has a large user-base Access to network needs to be properly controlled Need for good network security Company requires data to be free from accidental loss (needs to be backed up at a central location)
70
Example of client server model Example of peer-to-peer model
Amazon Small business where there is frequent user interaction
71
What each node joining the peer-to-peer network allows (5)
Provision of services to all other network users Other users on the network to simply access data from another node Communication with peers connected to the network Peers to be both consumers and suppliers (client server keeps them separate) Peers to participate as equals on the network
72
Function of peer-to-peer
Does not have a central server(thus meaning there is no requirement to authenticate users), each of the nodes on the network can share its files with all the other nodes and each of the nodes will have its own data. Used where no more than 10 nodes are required (leads to performance + management issues)
73
Security of peer-to-peer
Little since there is no central security system, so it is impossible to know who is authorised to share certain data. Users can create their own network node share point as the only real security aspect, but there are no real authentication procedures
74
When would peer-to-peer be used (3)
Network of users is fairly small No need for robust security Require workstation-based applications rather than server-based
75
What client server model offers (2)
Thin clients and thick clients
76
Pros of thick clients (2)
More robust (device can carry out processing even when not connected to server) Clients have more control (can store their own programs + data/files
77
Cons of thick clients (3)
Less secure (relies on clients to keep their data secure) Each client needs to update data+software individually Data integrity issues, many clients access the same data leading to inconsistencies
78
Pros of thin clients (3)
Less expensive to expand All devices linked to a server (data updates + new software installation done centrally) Server can offer protection against hacking + malware
79
Cons of thin clients (2)
High reliance on the server (if it goes down/there is a link break devices cannot work) Start up costs are generally higher than for thick clients
80
Ways to connect computers to make complex networks (4)
Bus networks Star networks Mesh networks Hybrid networks
81
Thin client vs thick clients software (4 for each)
Always reliefs on connection to remote server/computer - can run some features when not connected Requires few local resources (eg. SSD,RAM) - Relies heavily on local resources Relies on a fast, stable network connection - more tolerant of a slow network connection Data stored on a remote server/computer - can store data on local resources (HDD/SDD)
82
Disadvantages of bus network topology (3)
If main cable fails the whole network goes down The performance of the network deteriorates under heavy loading Network is not secure since each packet passes through every node
83
Advantages of bus network topology (2)
Network continues to function if a node fails Easy to increase size of the network by adding additional nodes
84
Suitability of bus networks
Situations with a small number of devices with light traffic occurring (small company/office environment)
85
Function of bus networks
PEER TO PEER Uses single cable to connect all computers + devices. Data can only travel in 1 direction so if data is being sent between devices other devices cannot. Requires terminators at each end to prevent signal reflection. Each node looks at each packet, determines if the address of recipient matches the node address, if not it is ignored.
86
Disadvantages of a star network (2)
High installation costs Of central hub/switch fails, whole network goes down
87
Advantages of star network (4)
Reduced data collisions More secure network (security methods can be applied to central node, packets only travel to nodes with correct address) Easy to improve by installing an upgraded hub If one of the connections is broken it only affects one of the nodes
88
Suitability of star networks
Evolving networks where devices are frequently added or removed/apllication where there is heavy data traffic
89
Function of star networks
CLIENT SERVER Each device is connected to the central hub/switch, through with data is directed. Each device has its own dedicated connection and any type of network cable can be used. If hub: packets sent to every device on network (accepted/ignored depending on address) If switch: packets only sent to nodes where address matches the recipient address in the packet
90
Examples of mesh network topology (4)
Internet and WANs/MANs Medical monitoring of patients in a hospital Electronics interconnectivity Modern vehicles
91
Function of mesh networks
PEER TO PEER 2 types: routing and flooding Routing: works by giving nodes routing logic (act as routers) so data is directed via the shortest route to its destination and can be rerouted Flooding: sends data via all nodes using no routing logic (leads to unnecessary loading on the network)
92
Disadvantages of mesh networks (2)
Large amount of cabling needed (expensive+time consuming) Set up + maintenance is difficult + complex
93
Advantages of mesh networks (4)
Easy to identify where faults on the network have occurred Broken links do not affect other nodules Good privacy + security (packets travel along dedicated routes) Relatively easy to expand
94
Disadvantage of hybrid networks
Can be very complex to install, configure and maintain
95
Advantages of hybrid networks (3)
Can handle large volumes of traffic Easy to identify where a network fault has occurred Very well suited to the creation of larger networks
96
Systems of cloud computing (3)
Public Private Hybrid
97
Public cloud
Storage environment where the customers/client and cloud storage provider are different companies
98
Private cloud
Storage provided by a dedicated environment behind a company firewall. Customer/client and cloud storage provider are integrated + operate as a single entity
99
Hybrid cloud
Combination of private and public clouds, some data resides in the private cloud, less sensitive/less commercial data can be accessed from a public cloud storage provider
100
Pros of cloud storage (5)
Files can be accessed anytime from any device anywhere is internet access is available No need to carry an external storage device/use the same computer to store information Provides a remote back-up of data (aids data loss and disaster recovery) Recovers data if a customer/client has a hard disk/back-up device failure Offers almost unlimited storage capacity
101
Cons of cloud storage (4)
Problems accessing/downloading files with a slow/unstable internet connection Costs high if large storage capacity is required Expensive to pay for high down/upload data transfer limits with internet service provider Potential failure of cloud storage company (loss of all back-up data)
102
Data security concerns with cloud storage (3)
Physical security by the building where the data is housed Service providers resistance to natural disasters/powercuts Safeguards regarding personnel who work for the cloud service company
103
Areas covered by cloud (5)
Storage Databases Networking Software Analytical services using the internet
104
Cloud software
105
Cloud software
Allows software applications to be delivered on demand. The provider will manage and maintain the applications for a monthly fee. The software is fully tested and does not need to reside on the users device, but the user can still use the software if the internet is lost, the data will then be stored in the local device and uploaded when the connection returns
106
When is Bluetooth useful (3)
Transferring data between 2 devices which are less than 30 metres apart The speed of data transmission is not critical Using low bandwidth applications
107
Bandwidth of radio waves, microwaves and infrared
Infrared>microwaves>radio waves
108
Penetration of radio waves, microwaves and infrared
Radio waves>microwaves>infrared
109
Attenuation of radio waves, microwaves and infrared
Radio>microwaves>infrared
110
Penetration
Ability of the electromagnetic radiation to pass through different media
111
Attenuation
Reduction in amplitude of a signal (infrared is low because it can be affected by rain)
112
Satellite technology
Curvature of the earth prevents electromagnetic waves from carrying signals globally, so signals are beamed from antenna A to a satellite orbiting earth, the signal is then boosted by the satellite and is beamed back to earth and picked up by antenna B
113
Communication between satellite and antennae
Carried out by radio waves / micro frequencies. Different bands are used to prevent signal interference + allow networks across the earth to communicate
114
Types of cables in wired networks (3)
Twisted pair cables Coaxial cables Fibre optic cables
115
Types of twisted pair cables (2)
Shielded (commercial, contains thin metal foil jacket to cancel out external interference) Unshielded (residential)
116
Types of fibre-optic cables (2)
-Single mode (single mode light source, smaller central core, less reflection along the cable so faster and further data travel so best for telecommunications and CATV) -Multi-mode (multi-mode light source, construction causes higher light reflections in core, so work best over short distances, best for LAN)
117
Pros of bitcoin streaming (5)
No need to wait for a whole video/music file to download before watching/listening No need to store large files on your device Allows video + music files to be played on demand No need for any specialist hardware Affords piracy protection (more difficult to copy streamed files)
118
Cons of bit-streaming (5)
Can’t stream video/music files if broadband connection is lost Video/music files paused streaming to catch up (insufficient buffer capacity/slow broadband connection) Uses a lot of bandwidth Security risks of downloading from the internet Copyright issues
119
How on demand bit streaming works (5)
Digital files stored on server converted to a bit streaming format Link to encoded to video/music file is placed on the web server to be downloaded User clicks on the link and the file is downloaded in a contiguous bit stream Streamed video/music is broadcast to the user as and when required Possible to pause rewind and fast forward if required
120
How real time bit streaming works
Event is captured by camera and microphone and is sent to a computer Video signal is converted to a streaming media file Encoded file is uploaded from the computer to the dedicated video streaming server Server sends the encoded live video to the users device Not possible to pause, rewind or fast forward since it is live
121
Drawbacks of repeating hubs (repeaters) (2)
Only have 1 collision domain, so need jamming signals to manage collisions, but reduces network performance since it involves repeated broadcasts Devices are referred to as unmanaged since they are unable to manage delivery paths + security in the network
122
Role of routers (5)
Restricts broadcasts to a LAN Act as a default gateway Can perform protocol translation (lets wired communicate with WiFi by protocol conversion) Can move data between networks Can calculate best route to destination address
123
Internet
Massive network of networks, made up of computers and other electronic devices; uses TCP/Ip communication protocols
124
WWW
World Wide Web Collection of multimedia web-pages stored on a website which uses the internet to access information from servers and other computers. Http(s) protocols are written using HTML, URLs specify the location of all web pages, web resources are accessed by web browsers.
125
HTML
Hypertext Mark-up Language Used to design web-pages + to write http(s) protocols
126
URL
Uniform Resource Locator Specifies location of a web page
127
Web browser
Software that connects to DNS to locate IP addresses; interprets web pages sent to a users computer so that documents and multimedia can be read or watched/listened to
128
ISP
Internet Service provider Company which allows a user to connect to the internet, usually charge a monthly fee for the service they provide
129
PSTN
Public Switched Telephone Network Network used by traditional telephones when making calls/sending faxes
130
VoIP
Converts voice and webcam images into digital packages to be sent over the internet Carries out file compression to reduce the amount of data being transmitted
131
IP
Internet protocol Uses IPv4 or IPv6 to give addresses to devices connected to the Internet
132
IPv4
IP address format which uses 32 bits giving 2*32 possible addresses 32 bits are split into 4 bits of 8 (range of 0-255)
133
CIDR
Classless internet-domain routing Increases IPv4 flexibility by adding a suffix to the IP address eg. 200.21.100.6/18
134
IPv6
Newer IP address format which uses 128 bits (hex)
135
Zero compression
Way of reducing the length of an IPv6 address by replacing groups of zeroes by a double colon (::); can only be applied once to avoid ambiguity
136
Sub-netting
Practice of dividing networks into 2 or more sub-networks, reduces network traffic and hides the complexity of the overall network. Splits the HostID
137
Private IP address
IP address reserved for internal network use behind a router
138
Public IP address
IP address allocated by the user’s ISP to identify the location of their device on the Internet
139
DNS
Domain Name Server/System Gives domain names for Internet hosts and is a system for finding IP addresses of a domain name Eliminates the need for the user to memorise IP addresses
140
JavaScript
Object-oriented programming language used mainly on the web to enhance HTML pages
141
PHP
Hypertext processor HTML embedded scripting language used to write web-pages
142
Differences between the internet and the worldwide web (8)
Internet: -massive network of networks made up of various electronic devices -stands for interconnected network -makes use of transmission control protocol(TCP)/Internet protocols (IP) Www: -collection of multimedia web pages and other documents stored on websites -http(s) protocols written using HTML -URLs specify location of all web pages -www uses internet to access information from servers and other computers
143
Requirements for connecting to the internet (5)
Device Telephone line/mobile phone network connection (may be wireless) Router ISP Web browser
144
What happens when using the internet to make a phone call
Users voice is converted to digital packages using Voice over Internet Protocol (VoIP)
145
Phone calls using PSTN
Public switched telephone network Uses a standard telephone connected to a phone line which is always open and not terminated until the receivers are replaced by both parties. It even remains active during power cuts as they have their own power source. Modern digitised systems use fibre optic cables meanwhile existing phone lines use circuit switching
146
Phone calls using the Internet
Use either an Internet phone or microphone and speakers (and webcam for video calls) Connection is only live while data is being transmitted VoIP converts sound to digital packages which can be sent over the internet using packet switching, data is routed through thousands of possible pathways. The data is split into packages with each packet containing the sender and receivers address and order number. The sending computer sends data to router which sends packets to another router and so on until they arrive and are reassembled
147
Phone calls using cellular networks and satellites
Done by mobile phones which act as the ISPs since they contain communication software which allows the, to access the telephone network and make an internet connection Satellites are used for network communications that cover large distances, due to the curve of the earth, the higher the satellite orbit the more coverage it can give
148
GEO
Geostationary orbit Provides long distance telephone and computer network communications 35800 km 24 hour orbital period
149
GEO
Geostationary orbit 35800 km 24 hours
150
MEO
Medium Earth Orbit GPS systems 5000-12000km 2-12 hour orbital period
151
LEO
Low Earth Orbit Mobile phone networks 500-1200km 80 minutes-2 hour orbital period
152
Advantages of satellites
Always give complete coverage Don’t suffer from signal attenuation to the same extent as underground/sea cables Easier to isolate and resolve faults that undersea cables
153
Operation of broadband routers
Sit behind a firewall which protects the computers on the network. Main function is to transmit the Internet and transmission protocols between 2 networks and allow private networks to be connected. Inspects data package sent to it, sends the packet to the appropriate switch (inspect IP) from which it will be delivered using the MAC address
154
Routers features (4)
Forward packets of data from one network to another Route traffic between networks Join LANs to form WANs or connect LANs to the internet Offer additional features such as dynamic routing (ability to forward data by different routes)
155
WNIC modes (2)
Infrastructure mode - uses WAP (and hub/switch) to transfer all the data, all wireless devices must use the same security and authentication techniques Ad hoc mode - does not have access to WAPs, possible for devices to interface with each other directly
156
Parts of a network using Ethernet (3)
Node (any device on the LAN) Medium (path used by LAN devices such as Ethernet cable) Frame (data is transmitted in frames made up of source and destination address (often MAC))
157
What public IP addresses are used by (3)
DNS servers Network routers Directly-controlled computers
158
Web browsers
Software that allow users to access using URLs and display web pages on their screens by interpreting HTML sent from websites and displaying the results.
159
Web browsers
Software that allow users to access using URLs and display web pages on their screens by interpreting HTML sent from websites and displaying the results.
160
Format of URL
protocol://website address/path/filename Protocol is usually http/https
161
Content of website address (4)
Domain host (www) Domain name (name of website) Domain type (.com, .org etc.) Country code (.uk, .za etc.)
162
DNS process (5)
-User opens browser, types in URL and the browser asks the DNS server(1) for the IP address of the website -DNS server(1) can’t find it in its database or it’s cache and sends request to DNS server(2) -DNS server(2) finds the URL and can map it to an IP address which is then sent back to the DNS server(1) which puts the IP address and associated URL into its cache/database -IP address is then sent back to the user’s computer -Computer sets up a communication with the server and downloads required pages, the browser interprets HTML and displays the information on the Users screen
163
Network class A Give IPv4 range, no. of netID bits, no. of hostID bits, types of network
0.0.0.0 to 127.255.255.255 8 24 Very large
164
Network class B Give IPv4 range, no. of netID bits, no. of hostID bits, types of network
128.0.0.0 to 191.255.255.255 16 16 Medium size
165
Network class D Give IPv4 range, no. of netID bits, no. of hostID bits, types of network
224.0.0.0 to 239.255.255.255 - - Multi-cast
166
Network class E Give IPv4 range, no. of netID bits, no. of hostID bits, types of network
240.0.0.0 to 255.255.255.255 - - Experimental
167
Network class C Give IPv4 range, no. of netID bits, no. of hostID bits, types of network
192.0.0.0 to 223.255.255.255 24 8 Small networks
168
Benefits of IPv6 (4)
No need for NATs (Network Address Translations) Removes risk of private IP address collisions Has built in authentication Allows for more efficient routing