CHAPTER 3 - NETWORKS Flashcards
Bus topology
computer network in which a “bus” connects all the devices together through a common cable
Data packet
portion of a message that is transmitted through a network; contains check digits and destination address
Hub
Network connection point for all devices using Ethernet cables; data arriving at a hub is copied and send to all the devices on the network
Local Area Network (LAN)
computer network where all connected computers are within a limited geographical area (e.g. home, school, etc); connection between the computers may be through cables or microwave transmission
Packet switching
network communication method that creates and transmits small units of data, called packets, through a network, independently of the overall message
Protocol
international rules that ensure the transfer of data between systems; e.g. TCP/IP standard protocol
TCP/IP (Transmission control protocol/Internet protocol)
communications protocols used to connect hosts on the Internet; models & represents all functionalities required for a successful communication between users
Wide Area Network (WAN)
computer network where all connected computers are in a larger geographical area than that served by a LAN or a MAN (metropolitan area network)
Switch
connection point for multiple devices on a single network; identifies which network device is connected to which port and transmit data to the exact port and network device for which it is intended
Router
used to join multiple networks and serve as an intermediary between these networks so that data can be exchanged efficiently between network devices of those networks; used to connect home network to the internet
Similarities and differences between LAN and WLAN
Similarities:
- both act on local level
- both allow communication
Differences:
- use a different transmission medium
- WLAN offer greater flexibility
Wireless Local Area Network (WLAN)
links 2 or more computer systems within a limited geographical area, similar to LAN; connects using wireless connection method so users can move around
Virtual Local Area Network (VLAN)
virtualized connection that connects multiple devices and network nodes from different LANs into one logical network
Similarities and differences between LAN and WAN
Similarities:
- both allow communication
- both allow sharing of resources
Differences:
- LAN is usually faster
- WAN is more expensive
Similarities and differences between LAN and VLAN
Similarities:
- act on a local level
- both allow communication
Differences:
- VLAN is safer and offers greater flexibility
- VLAN delivers better performance
Storage Area Network (SAN)
network that connects the servers to the storage devices so that they have enough storage space to complete their tasks; connects servers using a switch and Ethernet cabling
Intranet
a collection of private computer networks within a company, a school or an organization that utilizes standard network protocols to facilitate communication between individuals/work groups and to improve data sharing
Extranet
a computer network that utilizes the Internet to allow controlled access by specific users to a specific LAN or WAN
Internet
a global WAN connecting millions of computer systems together and provides an extensive number of services to users such as the World Wide Web (WWW), containing websites and webpages, file transfer etc
Virtual Private Network (VPN)
a tunnelled computer network that connects 2 or more computer systems, like LAN and WLAN, but allows clients from remote locations to connect to the network and appear to be inside the LAN as if they were physically present
Ways to access the Internet
- Broadband access via DSL or cable modem
- Wi-Fi access via Wi-Fi router
- Dial-up access via modem
Internet of Things (IOT)
network of individual “things” that are able to connect to the Internet, communicate and exchange data
Differences between VPN and Extranet
Similarities:
- both use the Internet
- both are considered inexpensive solutions
Differences:
- VPN provides more security
- VPN provides a secure connection to employees of the company while extranet limits access to the company network to selected outsiders
Personal Area Network (PAN)
a network that interconnects devices that are centered around an individual person’s workspace; a LAN that supports only one person and covers a maximum of 10 meters
Peer-To-Peer (P2P) network
a network that does not utilize the client/server model where clients request resources and servers provide them; it utilizes a distributed network architecture where all the computer systems in the network are decentralized and are both clients and servers at the same time
Similarities and differences between client-server model and P2P
Similarities:
- both serve a lot of devices and users
- both act on different scales (local/wide)
Differences:
- client server model offers a centralized control of services whereas a P2P model offers a control that is decentralized
- client server model offers better security
Advantages of Layers
- easy to manage
- makes protocol design easier
OSI (reference model)
Open Systems Interconnection model (OSI); networking standard established by the International Standards Organization and aims to facilitate communication across a variety of systems
7 layers of OSI
Please Don’t Nurture The Spiky Plant Alpi
(Physical, Data Link, Network, Transport, Session, Presentation, Application)
TCP/IP model
Never I Throw Art
(Network Access, Internet, Transport, Application)
VPN Benefits
- easier communication
- improves productivity of remote employees
- provides teleworker support
State which layer does IP belongs
Network Layer
Similarities and differences between TCP/IP and OSI
Similarities:
- used to describe network functionality
- include a number of different layers
Differences:
- OSI has more layers than TCP/IP
- OSI is a reference model while TCP/IP is a protocol model
Technologies used for VPN
Hardware:
- Internet access
- VPN software
- VPN routers
Site to Site VPN
type of VPN that connects entire networks and facilitates secure data interchange between different sites
Remote access VPN
type of VPN that connects individual hosts to private networks and facilitates teleworkers who need access to their company’s network securely using the Internet
Secure VPN
all traffic on the VPN must be encrypted, authenticated, and then sent along virtual tunnels; technologies: IPSec (Internet Protocol Security) and SSL 3.0 (Secure Sockets Layer)
Trusted VPN
all traffic on VPN relies on security of providers network to protect the network; technologies: Asynchronous Transfer Mode (ATM) circuits and MultiProtocol Label Switching (MPLS)
Discuss the importance of protocols in ensuring the successful preparation, transmission and delivery of data using packet switching
Internet protocols are responsible for controlling the transmission of data packets from one network/computer system to another within a network, ensuring that data integrity remains preserved during data transmission. Protocols also ensure that senders and receivers of data are authenticated and follow their digital certificates.
Factors affect speed of data transmission
- bandwidth of the network
- data transfer rate of storage devices
- malicious software
Data compression
reduces the size of files to be transmitted over a network; the reduction of bits by encoding data using fewer bits than the original representation
2 types of data compression
Lossy data compression:
- some loss of information is acceptable and there is no way to get the original file back; e.g. JPEG
Lossless data compression:
- this compression method reduces the number of bits by first identifying and then eliminating any statistical redundancy; e.g. compression decompression software
Wired communication
- copper cable
- fiber optic cable
Wireless communication
- satellite
- microwave radio
Mention 2 types of packet switching
- Datagram packet switching: each packet contains the receiver address; the path of datagrams take between the same source and destination can be different
- Virtual circuit packet switching: a route from source to destination is set up before any transmission takes place
Star network topology
A star network consists of one central node to which all other nodes are connected
Advantages and disadvantages of wireless network
Advantages:
- installing a cable can often be difficult
- easier to set up and allows higher flexibility
Disadvantages:
- gives relatively low speed
- affected by weather
Evaluate the use of trusted media access control (MAC) addresses as one method of network security
MAC addresses uniquely identify computers as it consists of a string of characters/digits that are contained in NIC. They can be used to enhance a network’s security as it permits access to only a set of allowed devices. However, lists of permitted MAC addresses are difficult to maintain, especially if the network has a lot of devices connected to it. In addition, there are cases where MAC addresses are falsified, meaning that the digits contained in the devices are not original and are designed to show a different set of figures.
Data Encryption
Data encryption is a method used to protect data from unauthorized access during Internet use or any other untrusted network. The process of encryption uses complex mathematical algorithms and encryption keys to alter a message into a form that is not recognizable to an unauthorized person
NIC
A NIC (Network Interface Card) is available in any computer/network device and is used to authenticate them into a wireless network. Every NIC has a unique MAC address given when it is manufactured and this can be used to uniquely identify a device and enhance wireless network protection
