Networks Flashcards
LAN and VLAN
A Local Area Network (LAN) is a network of computers and other devices that are connected within a limited geographic area, such as a building or campus. The purpose of a LAN is to allow devices to communicate and share resources, such as printers, files, and internet connections.
A Virtual Local Area Network (VLAN) is a network technology that allows you to create logical subnetworks within a physical network. VLANs are used to improve network performance and security by separating traffic into different virtual networks.
So basically A Virtual Local Area Network (VLAN) is like a virtual network that separates devices into different groups based on their function or location. It allows network administrators to create separate logical networks within a physical network infrastructure.
Instead of having to set up switches and cabling in order to create separate LANs for every department, a VLAN can be used to partition the initial LAN, where every department is connected, into logical separate networks. Each logical separate network cannot see the computer systems or the shared resources of other such logical separate networks, without specific set up that allows it to see them.
Definiton of network, client and server
A network is a collection of computers, servers, and other devices that are interconnected and can communicate with each other. The purpose of a network is to share resources, such as files, printers, and internet connections, and to enable communication between devices.
When we say that computers, servers, and other devices are “interconnected”, we mean that they are physically or logically connected to each other through a network.
A server is a computer or device that provides resources or services to other devices on the network. Servers can provide a wide range of services, such as file storage, email, web hosting, database management, and more. Servers are typically more powerful and have more storage and processing capacity than client devices.
A client, on the other hand, is a computer or device that requests and uses services or resources provided by servers. Clients can be desktop computers, laptops, tablets, smartphones, or other devices that are connected to the network. Clients typically have less processing power and storage capacity than servers and rely on servers for resources and services.
In summary, a network is a collection of devices that communicate with each other, a server is a device that provides resources or services to other devices, and a client is a device that requests and uses resources or services from servers.
Wirless Local area network and Wide area network
Wireless Local Area Network – A Wireless local area network functions exactly the same as a LAN without the wires. The advantage being people can connect to the network with tablets and mobile phones.
Wide Area Network – A wide area network is a network that spans larger geographical areas for example they may span countries or continents. The purpose of the network is to share information and store data. It is likely that a WAN makes use of both private hardware within buildings but public hardware to connect across countries. An example of this would be if a company has offices across several locations and they are all connected together.
definiton of interent
The Internet is a global network of computers and servers that are connected to each other through the use of standard communication protocols. It allows people and devices all over the world to communicate with each other, share information, and access a vast array of online services and resources.
Storage area network
A Storage Area Network (SAN) is a network of storage devices that can be accessed by multiple servers or computers, providing a shared pool of storage space.
A Storage Area Network (SAN) is a network of storage devices that are connected to multiple servers, enabling them to access shared storage resources.
Extranet, Intranet
An extranet is a computer network that utilizes the internet to allow controlled access by its specific users to a specific LAN or WAN.
An intranet is a private network that is used by an organization to facilitate communication and collaboration between its employees, departments, and other stakeholders. It is typically accessed using internal network connections and is not accessible from outside the organization
An “intranet” is the broad term for a collection of private computer networks that utilizes standard network protocols like TCP/IP,
In summary, an intranet is a private network that is used for internal communication and collaboration, while an extranet is a network that allows external users to access specific resources or services provided by an organization.
extranet is a network that allows external users controlled access to an organizations resources or services
PAN and Peer to peer
A Personal Area Network (PAN) is a type of network that connects devices in close proximity to an individual person, typically within a range of a few meters. A PAN may include devices such as smartphones, laptops, tablets, wearable devices, and other personal electronics.
A Personal Area Network (PAN) is a type of network used for communication between devices that are located within a person’s personal space, typically within a range of 10 meters or less.
Peer-to-Peer (P2P) network is a type of network that allows devices to connect directly with each other, without the need for a centralized server or network infrastructure. In a P2P network, all devices are considered equal and can act as both clients and servers, sharing resources and data with each other as needed.
VPN, Defintion + Advantages and disadvantges
A VPN is a computer network that connects two or more systems, similar to LAN or a WLAN, but also allows clients from remote locations to connect to the network and appear to be inside the LAN as if they were physically present. A VPN has all the benefits of a plan, allowing users to share data and resources without comprising security
furthermore a VPN can securely and cost efficiently connect geographically disparte offices of a business within a network with all the functionalties of a single LAN
VPN stands for Virtual Private Network, which is a technology that creates a secure and encrypted connection over a public network such as the Internet. A VPN allows users to connect to a private network remotely, as if they were directly connected to that network, even if they are geographically located elsewhere.
When a user connects to a VPN, their device creates a secure and encrypted “tunnel” through the public network to the VPN server. All data sent between the user’s device and the VPN server is encrypted, making it difficult for anyone to intercept or access the data.
Virtual Private Network (VPN)
Allows clients from distant locations to connect, that otherwise wouldn’t be able to connect with LAN (too far for cables) or WAN (too far for signal to be picked up). e.g. if worker goes abroad but still needs access to the network.
Technologies needed…
Can use hardware for public networks like the internet through tunnelling, which allows the network to send data via other network’s connections as if connected to LAN Hardware/ software requirements like internet access, VPN software, routers Protocols to encrypt and authenticate traffic to ensure secure transfer over virtual tunnel, e.g. IPSec (Internet Protocol Security)
Advantages:
Info can be accessed in remote places
No need for long-distance leased lines = lower cost
Enhanced security through encryption, can hide your IP address
Disadvantages:
Needs a professional with detailed understanding of security issues and configuration to ensure sufficient security and protection
Reliability of VPN is not directly under the organisation’s control, but under ISP Not all VPN products are compatible across different vendors
VPN can change working patterns, e.g. changes in costs, flexibility to employees and remote offices, global networking opportunities, less time travelling for remote users
VPN vs Extranet
VPN authenticates sender before establishing tunnel
VPN access and transmission are always encrypted, whereas extranet has limited encryption
VPN users have access to everything whereas extranet users only have access to specific services
Importance of standards in c
Data Tranmission. Standards define
Standards: Standards have helped to allow communication over a network. By developing standards that are common across systems we have allowed communication between systems developed in different ways. This means that even if the machines do not understand each other, they understand how to send each other information to be read.
Open System interconnection (Name all 7)
The OSI model is a conceptual model that shows how the data is transferred across a network. The OSI model has seven layers each responsible for a different action relating to sending information
The top levels are the levels that deal with the user and the bottom levels deal with actual physical transmission.
Protocols and data integrity
Protocols are the list of instructions devices agree on to determine how to communicate. It is an agreed behavior between devices. Without them devices would not be able to communicate as: data integrity could be compromised, the flow of data could be interrupted, deadlocks could occur, congestion may happen and error may occur.
data integrity is concerned with the validity of the data, data can be changed in transmission in a number of ways but data integrity checking aims to ensure the data received is the same as the data sent.
It ensures that the data is not altered or modified in an unauthorized or unintended manner and that the data is reliable and trustworthy.
data packet defintion, and whats the three thigngs packets have
a data packet is a unit of data that is transmitted over a network.
Header - Sender IP Address, Reciver IP Adress, procotcol and packet number
Data - Which is the data
Footer - Data to show end of packet, error checkign
The header located within a data packet is a block of information that appears at the beginning of the packet and contains important information about the packet, such as Sender IP Address, Reciver IP Adress, procotcol and packet number
A footer located within a data packet is a block of information that appears at the end of the packet and contains data about the packet itself, such as the packet’s length, error-checking code, and other metadata.
Packet switching and circuit switching
Data is split into packets and sent along different paths around the network to get to its destination. The advantage of this is they are harder to intercept as they are all following different routes. More efficient use of network resources. However, they can arrive in non sequential order at different times so it could take longer to receive the data and the data could get corrupted.
Circuit Switching
Data is sent along the same route. The advantage to this is the packets are sent in order and will arrive in order so they are easier to piece together and less likely to get lost. The issue is they are easier to eavesdrop upon and could be intercepted.
In packet switching, data is broken up into small packets and transmitted over a shared network. Each packet is sent individually and can take different paths to reach its destination. When a packet arrives at a network device, such as a router, it is inspected and forwarded to its next destination based on the destination address contained in the packet header. This process continues until all packets have reached their destination. Packet switching is commonly used on the Internet and other packet-switched networks.
In circuit switching, a dedicated communication path, or circuit, is established between two devices before data transmission begins. Once the circuit is established, data is transmitted over the dedicated path until the transmission is complete. During this time, the circuit is reserved exclusively for the use of the two devices. Circuit switching is commonly used in traditional telephone networks.
The main advantage of packet switching is that it allows multiple users to share the same network resources, making it more efficient and cost-effective. However, it may result in higher latency or delays, as packets may be delayed or lost due to congestion on the network. Circuit switching, on the other hand, provides a dedicated, reliable connection between two devices, but may be more expensive and less efficient for transmitting data between multiple devices.
Overall, both packet switching and circuit switching have their own advantages and disadvantages and are used in different types of networks and communication systems depending on the specific needs and requirements.
Hub, switch, router
A hub is the connection point for devices on a single network. Network devices and computer systems connect to a hub using Ethernet cables that attach to a port.
A switch is also the connection point for multiple devices on a singie network. However, unlike a hub, the switch can identify which network device is connected to which port. This allows the switch to transmit data to the exact port and network device for which it is intended.
A router connects multiple networks and serve as an intermediary between these networks so that data can be exchanged effectively and efficiently between network devices of those networks.
Importance of standards in construction of networks
Importance of standards in construction of networks
We need common rules/ standards when forming a network, otherwise some computer systems may not be able to connect due to incompatibilities, especially when trying to connect internationally. e.g. if there’s no standards, could have a system developed to only support USB and a switch developed that only has Ethernet ports.
