Mock 2 – Networking & Internet + Mixed Practice

A protocol is an agreed set of rules (format, timing, error handling) that two parties follow to communicate — e.g. TCP, HTTP, FTP. Routing chooses a path, a layer is one level of a network model, and switching forwards data between links.

MAN = Metropolitan Area Network: it covers a city or campus, bigger than a LAN and smaller than a WAN (e.g. a city cable-TV network).

NIC = Network Interface Card, the hardware that connects a computer to a network and holds its MAC address. It is sometimes also called a network interface controller, but 'card' is the standard expansion.

Circuit switching sets up a dedicated end-to-end path before any data flows and keeps it for the whole session, as in the old telephone network. Packet and message switching share links instead.

Network topologies include bus, star, ring, mesh, tree and hybrid. Stack is a data structure, not a topology.

TCP sets up a connection (three-way handshake) before sending data and gives reliable, ordered delivery — a connection-oriented protocol. UDP is the connectionless one.

The IP header checksum detects corruption in the header (such as a damaged destination address) so the packet is not delivered to the wrong host.

The internet grew out of ARPANET (1969), funded by the US Department of Defense for military research and communication.

Elastic traffic (e-mail, file transfer, web) adjusts to changes in delay and throughput and still works.

An Internet Service Provider (ISP) is the gateway through which users connect to the internet.

A socket address is the pair (IP address, port number). The IP address finds the host and the port finds the process on that host.

In a datagram (packet-switched) network every packet is routed independently and no connection is set up first, so it is a connectionless network.

Nyquist: the sampling rate must be at least twice the highest frequency in the signal (fs ≥ 2·fmax).

Netiquette (net + etiquette) is the code of polite behaviour for writing messages and posts on the internet.

Bits per page = 24 × 80 × 8 = 15,360; for 100 pages = 1,536,000 bits. This is the textbook (Forouzan) example, which takes 100 pages per second and prints the answer as 1.636 Mbps — so option 4 is the intended key. Strictly, 100 pages per minute is only about 25.6 kbps, which is not among the options.

IEEE 802.11 is the Wireless LAN (Wi-Fi) standard. 802.3 = Ethernet, 802.4 = Token Bus, 802.15 = Bluetooth/WPAN.

Physical → bit synchronisation, Data link → framing and error control, Session → dialog control and synchronisation, Presentation → translation and compression: i-b, ii-d, iii-a, iv-c.

In a full mesh every device links to every other: n(n − 1)/2 cables and n − 1 ports per device — the most of any topology.

SMTP (Simple Mail Transfer Protocol) sends e-mail. FTP transfers files; TELNET gives remote login.

cellpadding sets the space inside a cell, between its border and its content. cellspacing sets the gap between neighbouring cells.

Guided (wired) media carry signals along a physical path: twisted pair, coaxial cable and optical fibre. Radio, microwave and infrared are unguided (wireless).

The cloud service models are IaaS, PaaS and SaaS. 'System as a Service' is not a standard model.