Topic 3

Protocol

A set of predetermined rules on how information is sent and received.

Virtual Private Network (VPN)

A paid (but sometimes free) service that allows the user to create an encrypted link between the user and a remote server. Once connected, the user can anonymously access the information, data, or the internet using the remote server instead of his own machine.

Computer network

Allows different computers to communicate with one another.

Local Area Network (LAN)

A computer network that spans a relatively small area (a single room, house, building, etc.)

Wide Area Network (WAN)

A system of LANs that spans a relatively large geographical area.

Wireless Local Area Network (WLAN)

A wireless distribution method for a local area network that use high-frequency radio waves and often include an access point to the Internet.

Access Point

A hardware device or a computer's software that acts as a communication hub for users of a wireless device to connect to a wired LAN.

Node

A single computer or device on a computer network.

Peer to Peer (P2P)

Computer systems that communicate to each other through a network without passing through a central server.

Internet

A WAN that spans the entire world.

Extranet

An intranet that can be partially accessed by authorized outside users, enabling businesses to exchange information over the Internet securely.

Intranet

A private network that is contained within an enterprise. It may consist of many interlinked local area networks and also use leased lines in the wide area network. Typically, an intranet includes connections through one or more gateway computers to the outside Internet.

Storage Area Network (SAN)

A high-speed network of storage devices that also connects those storage devices with servers.

Direct attached storage (DAS)

Digital storage that is attached directly to a computer or a server. In other words, this isn't part of a storage network. The most familiar example of this is the internal hard drive in a laptop/desktop.

Personal Area Network (PAN)

The interconnection of devices within the range of an individual person, typically within a range of 10 meters. For example, a person traveling with a laptop and a portable printer could interconnect them.

Wireless Personal Area Network (WPAN)

A personal area network that is wireless. Most common example is Bluetooth.

Physical, Data Link, Network, Transport, Session, Presentation, and Application

These are the 7 layers of the Open Systems Interconnection (OSI) Model.

Tunneling

The transmission of data intended for use only within a private, usually corporate, network through a public network in such a way that the routing nodes in the public network are unaware that the transmission is part of a private network. VPNs use this.

VPN Gateway

A type of networking device that connects two or more devices or networks together in a VPN infrastructure.

Data packet

Large digital files are divided up into these smaller messages to be sent individually.

Packet switching

Data packets for a single message are all sent at different times to different locations. When all the data packets arrive at their destination, they are reassembled into their original larger message.

Deadlock

A situation where two or more competing actions are waiting on each other to finish. As a result, neither of them ever finish.

Network congestion

An increase in data transmissions results in a proportionately smaller increase, or even a reduction, in throughput.

Throughput

The amount of data that passes through the network per unit of time (such as the number of packets per second).

Denial of Service (DoS)

The attacker (usually some computer science nerd with no life) sends excessive messages that causes so much network congestion that the network crashes.

Distributed Denial of Service (DDoS)

Multiple computers all attack a single target to create a large DoS attack. If the attacker has no friends, he/she can still do this by taking control over other computer(s).

Error checking

The process of detecting errors during the transmission of data or storage of data.

Broadband

A high-capacity transmission technique using a wide range of frequencies, which enables a large number of messages to be communicated simultaneously.

Wi-Fi

A piece of technology that your grandmother can never get right. Allows devices to connect to the internet.

Firewall

Determines what information can go inside and outside a computer network. Without this, anything would be able to pass through.

Media Access Control Address (MAC Address)

A unique identifier hardwired or hard-coded onto your computer's network interface card.

Trusted MAC Address Filtering

Only allowing computers with specific MAC Addresses to connect to a private network.

Bandwidth

The speed of how long it takes for data to be moved from one place to another on a network.

Ring topology

LAN topology that connects all nodes in a closed loop on which messages travel in one direction. The nodes of this topology pass along messages until they reach their destination.

Star topology

LAN topology that centers on one central node that allows communication. All the other nodes are connected to this central node. This topology puts a huge burden on the central node.

Bus topology

LAN topology that connects nodes to a single communication line that carries messages in both directions. Each node checks any messages that are sent on the network and ignore messages that are not addressed to them.

Metropolitan Area Network (MAN)

Similar to a WAN, but unlike a WAN, this network is more narrowly focused on a single campus, city, or other population.

Internet Service Provider (ISP)

An organization providing access to the internet. Ex. Comcast, Verizon, etc.

Phone modem

A device that converts computer data into an analog audio signal for transfer over a telephone line and back again when the message is received.

Open system

A system that is based on a common model of network architecture and an accompanying suite of protocols.

Repeater

If communication lines span a long distance (ex. over the ocean), these devices are installed periodically along the line to strengthen and propagate the signals across the lines.

Transmission Control Protocol (TCP)

The network protocol that breaks messages into packets, reassembles them at the destination, and takes care of errors.

Internet Protocol (IP)

The network protocol that deals with the routing of packets through interconnected networks to the final destination.

Transmission Control Protocol and Internet Protocol (TCP/IP)

A suite of protocols and utilities that support network communication. Breaks down packets, routes them, and rebuilds packets.

Access Control

The ability to determine who can send and receive messages. Usually used by firewalls.

Wireless Network Information Card (NIC)

This is needed for a single computer to connect to a wireless router. Most, if not all, computers are built with this hardware.

Cloud computing

The practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer.

NBC

Not Backward Compatibile

extranet

Intranet that is partially accessible to outside users. Provides various levels of accessibility to outsiders

OSI Seven layer model

Please Do Not Throw Sausage Pizza Away.

Physical (OSI layer 1)

conveys bit stream (electrical impulse, light, or radio signal) through the network.

Data Link (Layer 2)

data packs are encoded and decoded into bits. Furnishes transmission protocol knowledge and management and handles errors in layer 1

Network (Layer 3)

Provides switching and routing technologies, creating logical paths, known as virtual circuits.

Transport(Layer 4)

Transparent transfer of data between systems.

Session(Layer 5)

Establishes, manages, and terminates connections between applications.

Presentation(Layer 6)

Provides independence from differences in data representation by translating from application to network format or vice versa. Turns data into form application can accept.

Application (Layer 7)

Supports application and end-user processes.

Requirements needed to create VPN

Server, client, tunnel, protocols, encryption, tunneled data, and transit internetwork.

Data integrity

overall completeness, accuracy, and consistency of data and is achieved by error checking and correction protocols.

Flow control

control packet flow so sender doesn't transmit more packets than a receiver can process

deadlock

two computer programs prevent each other from using the resource because they both are using it.

Congestion

source sends more packets than receiver can handle

error checking

based on accuracy, speed, and efficiency

packet switching

breaking data files into small packets in order to send them across a network.

Network

when two or more computers are connected with one another for the purposes of communicating data

Data Encryption

the act of changing electronic information into an unreadable state through the use of algorithms or ciphers so that it is readable by the communicating parties. A strong encryption is very hard to break Computer are fast enough to encrypt data on-the-fly. Often, users are lazy and take a password that is easy to guess

The password needs to be transmitted over the network to receiver to allow them to read the message

Some encryptions are designed to have backdoors built in

User ID

A userid and password are used to identify the specific communicating user.

Access rights to the network can be set for each user User groups can be created to manage user rights in batches. A userID can be stolen

system can be bypassed

Does not protect against intercepting messages in the network

Permissions

As well as passwords to enable users to login, each user also has a set of permissions associated with their logon name or group. Some users, administrators or super-users, can look in any data file, change user passwords and delete any file on the system. Ordinary users can only access their own files and use specified resources such as printers and CD burners

Data packet

is when pieces of information on the file are broken down into chunks of data in order to be transmitted over a network.

Explain why the speed of data transmission across a network can vary

Trafficking -

Many users may want to transmit data through the network at the same time

Interference - to the network from the outside can corrupt many data packages, causing them to have been retransmitted

Router

accepts packets on at least two network interfaces, and forwards packets from one interface to another.

Switch

is used in hybrid networks to connect the different segments and pass packets of data between them.

Gateway

device that is used to connect users of a LAN to another network, which uses different protocols.