Network fundamentals, Types of networks, VPN Flashcards
Network, node, server, hub, Router
Network: Set of computers or computer systems that are interconnected and share resources and data
Node: Device on network
Server: Computer system or software package that provides service to other devices in network, e.g. ability to file share. Fulfils requests from client programs or computers. Client: Device that requests service from server in the same network, e.g. email software client requesting email server software to fetch new emails
Hub: Connection point for all devices on network, devices connected through Ethernet cables. Data from device goes to the hub, then sent to all devices. Target device receives, others ignore Switch: Connection point but can identify which device is connected to which port, so can send data to target device
Router: Device that connects network to another e.g. home network to internet.
Types of networks (Lan, WLAN, SAN, PAN, Interent and extranet and extranet)
Local Area Network (LAN): Network devices are connected within limited geographical area, e.g. a room, a home, a school, office building etc. Data and peripherals can be shared. Usually client-server, connected with hub/ switch and Ethernet cabling
Virtual Local Area Network (VLAN): Devices or LANs from different segments in a LAN connected logically, e.g. splitting a hospital LAN into VLANs according to department so each department can only access certain data. Usually via software, not hardware
Wireless Local Area Network (WLAN): Connects nodes in limited geographical area but with no wires. Allows for mobile devices and easier connection/ removal, although less secure
Wide Area Network (WAN): Connects different computer systems or LANs from different geographical areas, can span over a city, country or the world, e.g. internet, different sites of organisations connected
Storage Area Network (SAN): Type of LAN designed to handle large data transfers. Each client is connected to a server that provides access to storage devices
Personal Area Network (PAN): Network covering individual’s working area, very small space. e.g. PC, phone, tablet sharing data. Can be wired (e.g. USB) or not (e.g. Bluetooth) Peer-to-Peer Network (P2P): Different to client-server, no centralised server. All nodes have equal privileges and responsibility for processing and sending data. All are client and server at same time, consuming and supplying resources from and to other peers
Internet: A WAN. Connect to it through internet service provider (ISP) for monthly fee. Not owned by single entity, no central server. All computer systems are independent to share resources. Internet provides services such as support for email, file transfer, and the WWW, which consists of webpages
Extranet: External extension to a LAN- Part of a network that uses internet protocols to allow
controlled access by specific users to LAN or WAN. e.g. business wants to share some data/ information with clients or partners but not all, so extends part of network (extranet) available for access but with security/ privacy measures (e.g. firewall) so outsiders cannot access secure data
VPN
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.
