Question 7 of 7: Networking and Communications Terminology

Question 7: Networking and Communications Terminology (20 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

1. IEEE. The Institute of Electrical and Electronics Engineers — a professional association that develops and maintains many of the standards networking equipment relies on, most notably the IEEE 802 family (802.3 Ethernet, 802.11 Wi-Fi, 802.15 Bluetooth/personal-area networks).
2. Bit Error Rate (BER). The ratio of the number of bit errors received to the total number of bits transmitted over a link in a given period; it is the standard measure of a digital transmission link's quality, driven by noise, interference, and attenuation on the physical channel.
3. Piconet / scatternet (Bluetooth). A piconet is a small ad hoc network of up to eight active Bluetooth devices — one master and up to seven slaves — sharing a common frequency-hopping pattern set by the master. A scatternet is formed when multiple overlapping piconets are linked by a device that participates in more than one piconet (acting as a bridge between them), extending coverage and connectivity beyond a single piconet's eight-device limit.
4. Codec. Short for coder/decoder (or compressor/decompressor): a device or algorithm that converts an analog signal to a digital representation and back (e.g. a PCM voice codec), or that compresses and decompresses digital media (e.g. an audio/video codec), trading data rate against fidelity.
5. Crosstalk. Unwanted coupling of signal energy from one communication circuit into an adjacent one, caused by electromagnetic coupling between nearby conductors (or channels); it is heard/seen as interference superimposed on the wanted signal and is one of the physical-layer impairments (alongside attenuation and noise) that limits achievable data rate.
6. CSMA/CD. Carrier Sense Multiple Access with Collision Detection — the medium-access-control protocol used by classic (shared-medium) Ethernet. A station listens before transmitting (carrier sense); if two stations transmit at nearly the same time and their signals collide, both detect the collision, stop transmitting, and each retransmits after a randomized backoff interval (binary exponential backoff) to reduce the chance of an immediate repeat collision.
7. CDMA. Code-Division Multiple Access — a spread-spectrum-based multiple-access technique in which every user's signal is spread with a distinct, (near-)orthogonal code, allowing many users to transmit simultaneously in the same frequency band and time slot; the receiver separates a given user's signal from all the others by correlating with that user's own code.
8. B-ISDN. Broadband Integrated Services Digital Network — a set of ITU-T standards extending narrowband ISDN to support high-bandwidth, integrated voice/video/data services over a single network, using Asynchronous Transfer Mode (ATM) as its underlying transport and switching technology.
9. TCP/IP. Transmission Control Protocol/Internet Protocol — the foundational protocol suite of the Internet. IP provides best-effort logical addressing and routing of packets (network layer); TCP, layered above it, provides reliable, ordered, connection-oriented byte-stream delivery between processes (transport layer), including retransmission and flow/congestion control.
10. Packet. A formatted unit of data transmitted over a packet-switched network, comprising a header (source/destination addressing and control information) and a payload (the actual data being carried); it is the basic unit the network layer forwards, switches, and routes.