Chapter 5 Flashcards
PAN
Personal area network; Connects personal devices in a very short range with or without cables (Ex. Phone to headset)
LAN
Local area network; Connects personal computers within a limited area (Ex. School computer lab)
MAN
Metropolitan area network; Public high-speed network capable of transmission within 50 mile range (Ex. Local internet service providers)
WAN
Wide area network; Covers a large geographical area and several smaller networks (Ex. The Internet)
Shared resources
Hardware, software, and data made available for authorized network users to access
Node
Each connection point on a network containing a computer, peripheral, or other device
NIC
Network interface card; Special circuitry in a system board required to connect to a LAN
Networked peripheral
Device that contains network circuitry to directly connect to a network
NAS
Network attached storage; Storage device that directly connects to a network
Network device
Any electronic device that broadcasts network data, boosts signals, or routes data to its destination
Router
A type of network device that acts as a central distribution point for getting data to its destination
Communications channel
Physical path or a frequency for signal transmissions
RJ45 connector
At the end of a network cable
Optical fiber cable
Composed of many strands of thin glass tubes that send data at the speed of light
Bandwidth
Transmission capacity of a communications channel
Broadband
High-bandwidth communications systems (Ex. Cable TV & DSL)
Narrowband
Communications systems with less capacity (Ex. Dial-up)
Communications protocol
A set of rules for efficiently transmitting data from one network node to another
Handshaking
The process by which two computers on a network negotiate their communications protocols
Packet
Parcel of data that is sent across a computer network
Circuit switching
Establishes a dedicated, private link between two devices, such as a telephone
Packet switching
Divides a message into several packets that can be routed independently to their destination
MAC address
A unique number assigned to a network interface card when it is manufactured
IP address
Series of numbers used to identify a network device
DHCP
Dynamic Host Configuration Protocol; Protocol designed to automatically distribute IP addresses
Advantages of LAN
- LANs enable people to work together
- Sharing networked software can reduce costs
- Sharing data on a LAN can increase productivity
- Sharing networked hardware can reduce costs
- Sharing an Internet connection can be cost-effective and convenient
- Sharing networked hardware can provide access to a wide range of services and specialized peripheral devices
Disadvantages of LANs
- Malfunctions limit access to data
- LANs are vulnerable to unauthorized access
- LANs are vulnerable to malicious code
What can communications protocols do?
- Divide messages into packets
- Affix addresses to packets
- Initiate transmission
- Regulate the flow of data
- Check for transmission errors
- Acknowledge receipt of transmitted data
How does data travel over a network?
- Source –> (Encoded data) –> 2. Transmitter –> (Signal) –> 3. Communications channel –> 4. Receiver –> (Decoded data) –> 5. Destination
What kind of signals can travel over computer networks?
Electromagnetic signals
- Digital signals: limited set of frequencies
- Analog signals: any value in a range of frequencies
How can a network detect if a signal has been corrupted?
Detects and reestablishes voltages that have errors
Ex. +3 volts corrected to +5 volts when the only options are -5 volts and +5 volts
Ethernet
A wired network technology that is defined by IEEE 802.3 standards; standard for wired connections in local area networks
Ethernet adapter
Can be installed if a computer has no Ethernet port
RF signals
Radio waves
Transceiver
A combination of a transmitter and a receiver that sends and receives radio waves
Microwaves
Electromagnetic signals that behave differently than radio waves
- Can be aimed in a single direction
- More carrying capacity
- Cannot penetrate metal objects
Infrared light
Carry data signals for short distances with a clear line of sight
Bluetooth
A short-range wireless network technology that is designed to make connections between two devices
Pairing
Creates a persistent link between two devices, usually through the exchange of an authentication code called a passkey
Discovery mode
Allows devices with Bluetooth capability to be open for pairing
Wi-Fi
Refers to a set of wireless networking technologies defined by IEEE 802.11 standards that transmits data as radio waves and is compatible with Ethernet
Wireless ad-hoc protocol
Devices broadcast directly to each other
Wireless infrastructure protocol
Centralized broadcasting device coordinates communication among network devices (more security than ad-hoc)
Wi-Fi adapter
Plugs into a USB port of an internal expansion slot to allow equipment to be Wi-Fi compatible
Dual-band
When a router uses two frequencies
MIMO
(Multiple-input multiple-output) Technology to boost signals and spread them more evenly over the signal range
What is wired technology?
Uses cables to connect network devices
What are the advantages of wired technology?
- Fast
- Secure
- Simple to configure
What are the disadvantages of wired technology?
- Limited mobility
- Unsightly
- Cables get tangled and collect dust
Why is Ethernet so popular?
- Easy to understand, implement, manage, and maintain
- Available from many vendors for low prices
- Flexibility in network design
- Compatible with Wi-Fi technology
How does Ethernet work?
Simultaneously broadcasts data packets to all network devices, but is only accepted to the one it is addressed to
What is wireless technology?
Transports data from one device to another without the use of cables or wires
What are the advantages of wireless connections?
-Mobility
What are the disadvantages of wireless connections?
- Speed
- Range
- Licensing
- Security
What is wireless slower than wired?
Susceptibility to interference, which takes extra time
What limits the range of a wireless network?
- Type of signal
- Transmitter strength
- Physical environment
What are the issues with wireless security?
Signals float through the air and penetrate walls, so that anyone can surreptitiously join your network
SSID
(Service set identifier) The name of a wireless network
Wireless encryption
Scrambles the data transmitted between wireless devices and then unscrambles the data only one devices that have a valid encryption key
WEP
(Wired Equivalent Privacy) Original wireless encryption protocol that had a level of confidentiality similar to that of a wired network
WPA
(Wi-Fi Protected Access) Offer stronger protection that WEP by making sure that packets have not been intercepted or tampered in any way
PSK
(Pre-shared key) A personal type of WPA used on most home networks
Wireless encryption key
Basis for scrambling and unscrambling the data transmitted between wireless devices
Hub
Extends a wired network by adding additional ports
Switch
Intelligently facilitates communication among multiple devices on a network
Gateway
Joins two different types of networks, such as your home network and the Internet
Bridge
Connects two similar networks
Repeater
Extends the range of a network by restoring signals to maximum strength and retransmitting them
Wireless access point (WAP)
Allows wireless devices to connect to a wired network
File sharing
Allows files containing documents, photos, music, and other data to be accessed from computers other than the one on which they are stored
Network discovery
Setting that affects whether your computer can see other computers on a network, and whether your computer can be seen by others
Public folder
Designed to hold files and folders that you want to share with other people on your network
Homegroup
Collection of trusted Windows computers that automatically share files and folders
File server
Computer whose primary purpose is to be a repository for files that can be accessed by network workstations
Are there restrictions on file sharing?
- Which devices your computer can discover
- Which files you allow others to access
- What others are allowed to do with the files they can access
Specific files
Can be designated as shared, which is versatile, but not secure. Public folders are a better option.
Read and write permission
Allows access for opening, viewing, modifying, or deleting files
Read permission
Allows authorized people to open a file and view it, but they cannot modify or delete it
Write only permission
Works like a drop box, allowing people to put files in one of your folders, but not open, copy, or change any files that you have stored there
Encryption
Transforms a message in such a way that its contents are hidden from unauthorized readers. Plaintext to ciphertext.
Paintext
An original message that has not yet been encrypted
Ciphertext
Encrypted message
Decryption
Ciphertext to plaintext. The reverse process of encryption.
Cryptographic algorithm
Procedure for encrypting or decrypting a message
Cryptographic key
Word, number, or phrase that must be known to encrypt or decrypt a message
Weak encryption
Easy to decrypt without the algorithm and key
Strong encryption
Very difficult to break
AES
Advanced Encryption Standard; technology used for WPA2; One of the strongest cryptographic algorithms
Symmetric key encryption
Key used to encrypt a message is also used to decrypt the message
PKE
Public key encryption; eliminate the key-distribution process by using one key to encrypt a message, but another key to decrypt the message
