Networks

• Protocol


  A set of rules governing the exchange or transmission of data between devices.
• Hypertext Transfer Protocol (HTTP)


  protocol that defines how messages are formatted and transmitted over the World Wide Web
• File Transfer Protocol (FTP)


  a simple network protocol that allows the transfer of files between two computers on the internet
• Transmission Control Protocol (TCP)

  provides reliable, ordered, and error-checked delivery of a stream of packets on the internet.
• Internet Protocol (IP)


  A communication standard that enables computers to route communications traffic from one network to another as needed.
• Post Office Protocol (POP)

  An application layer over the internet standard protocol used by local email clients to retrieve email from a remote server over TCP/IP connection.
• Internet Message Access Protocol (IMAP)

  A protocol that resides on an incoming mail server. Similar to POP, but is more powerful. Allows sharing of mailboxes and multiple mail server access.
• Simple Message Transfer Protocol (SMTP)


  the basic communications protocol used to send e-mail
• UDP (User Datagram Protocol)


  Protocol that operates instead of TCP in applications where delivery speed is important and quality can be sacrificed.
• Application Layer


  provides services to ensure that effective communication between computer programs on a network is possible.
• Transport Layer


  A set of protocols that ensure that data are transferred from point A to point B reliably and without errors. This layer services include flow control, acknowledgment, error correction, segmentation, reassembly, and sequencing.
• Internet Layer


  A layer responsible for addressing, packaging, and routing messages on the Internet
• Link Layer


  handles all the physical details of interfacing with the cable, including the network interface card and a device driver
• Local Area Network (LAN)


  Connects a group of computers in close proximity, such as in an office building, school, or home
• Wide Area Network (WAN)


  A network that connects devices in geographically separated areas.
• Domain Name System (DNS)


  The system administered by the Internet Corporation for Assigned Names (ICANN) that assigns names to each site on the Internet.
• Uniform Resource Locator (URL)


  The set of letters that identifies the address of a specific resource on the Web.
• IP Address


  A number that uniquely identifies each computer or device connected to the Internet.
• Packet Switching


  Occurs when the sending computer divides a message into a number of efficiently sized units called packets, each of which contains the address of the destination computer
• Circuit Switching


  a dedicated connection is formed between two points and the connection remains active for the duration of the transmission
• Spyware


  software that enables a user to obtain covert information about another's computer activities by transmitting data covertly from their hard drive.
• Denial of Service (DoS)

  attack floods a network or server with service requests to prevent legitimate users' access to the system
• SQL Injection


  An attacker issues a command to a web server as part of the URL or as input to a form on a company's website; web server might pass the command onto the database which then allows potentially anything to be done to the database
• Phishing


  An attack that sends an email or displays a Web announcement that falsely claims to be from a legitimate enterprise in an attempt to trick the user into surrendering private information
• Pharming


  An online scam that attacks the browser's address bar. Users type in what they think is a valid website address and are unknowingly redirected to an illegitimate site that steals their personal information.
• Firewall


  a part of a computer system or network that is designed to block unauthorized access while permitting outward communication.
• Modem


  A device that allows computers to communicate over telephone lines
• Router


  A device that transfers data from one network to another in an intelligent way
• Network Switch


  More functional than a hub; records and recognizes the local network addresses (MAC or IP) or all computers connected to it
• Network Interface Card


  An interface fitted inside a personal computer or network terminal which allows it to communicate with other machines over a network.
• Fibre Optic Cable


  A connection that uses light to transmit information.
• Ethernet Cable


  cable that connects computers to the LAN that allows the computers to communicate with each other and other peripherals.
• Client Server Network


  A network that uses centrally administered computers, known as servers, to enable resource sharing for and to facilitate communication between the other computers on the network.
• Peer-to-peer network


  any network without a central file server and in which all computers in the network have access to the public files located on all other workstations
• Ring Topology


  A LAN configuration in which all nodes are connected in a closed loop
• Star Topology


  A topology with one central node that has each computer or network device attached to the central node. All data first goes into the central node and then is sent out to its destination. (Think of it like a bicycle wheel with spokes.)
• Mesh Topology


  Devices are connected with many redundant interconnections between network nodes.