DCNSA Level II
Computer Networking cheat sheet
Every chapter's key points, formulas and definitions on one page, for the last week before the exam. Each heading links to the chapter that explains it.
Computing skills
- Data is raw, unprocessed facts with no context; information is data processed into a meaningful, useful form.
- A standalone computer processes data for one user; a networked computer processes and shares it for many, which is the whole reason networks exist.
- Networked computers give faster communication, shared files and hardware, centralised data management and backup, remote access, and cost savings from shared resources.
- Networking equipment is often live and shared, so power down, discharge static, label cables and ports, and schedule disruptive work with notice: a mistake is felt by every connected user.
- A NIC is the hardware that connects a computer to the network and carries its MAC address; a driver is the software that lets the operating system use it, and a business need is met by pairing hardware with software.
Key terms
- Processing
- A computer executing instructions on data to produce a result, the core activity every device on a network performs on the data it sends and receives.
- Computer
- An electronic device that accepts data, processes it, and produces information as output.
- Information
- Data that has been processed into a meaningful, useful form.
- Data
- Raw, unprocessed facts and figures with no context on their own.
- Sharing
- Making data or resources accessible to other users or systems, the whole reason networks exist. A standalone computer processes data for one user; a networked computer processes and shares it for many.
- Ports
- Physical connection points on a device: Ethernet (RJ45), USB, and the specialised console port on network equipment used for initial configuration. A device's number and type of ports decide what it can physically connect to.
- Cables
- The physical medium carrying signals between devices, covered fully in the chapter on network features: twisted pair, fibre optic and, rarely now, coaxial.
- Network card (NIC)
- The hardware component that connects a computer to a network, converting the computer's internal data into signals suitable for the cable or radio medium, and carrying the device's own MAC address.
- Peripheral devices
- Input/output devices connected to a computer, some of which, a network printer or a network-attached scanner, are themselves network resources reachable by other devices rather than only by the one they are plugged into.
- Operating system
- Manages the computer and, in a network operating system, additionally coordinates network resources, user accounts and security policy across many machines (the subject of Network Operating Systems).
- Networking software
- Applications and services specifically for managing and using network connections: a VPN client, network monitoring software, remote-desktop tools.
- Drivers
- Software that lets the operating system communicate with a specific hardware device, including the NIC; without the correct driver a network card is physically present but unusable.
The rest of the sheet covers
- Features of a computer network
- Functions of a computer network
- Network protocols
- Network design
- Worked examples
- Exam technique and revision
- Glossary