Technical Vocabulary: Definitions, Terms & Industry Applications

Key Concepts and Definitions

1. Data vs. Information

• Data: Raw, unprocessed facts (e.g., numbers, symbols, text). Example: 1010101 (binary), 2023-10-15 (date), KTM-2345 (vehicle number).
• Information: Processed data that has meaning. Example: Your order #12345 is dispatched (processed from raw order data).

Real-world example:

• eSewa stores your data (account number, transaction ID) but provides information (balance, transaction status) after processing.

2. Communication Channels

Communication occurs over physical (cables, air) or logical (protocols) channels.

How data travels as light pulses in NTC’s internet backbone (Image: J.P.Lon at English Wikipedia, CC BY 2.5, via Openverse)

3. Bandwidth vs. Latency

• Bandwidth: Maximum data transfer rate (measured in bits per second, e.g., Mbps, Gbps). Example: A 100 Mbps connection downloads a 500 MB file in ~40 seconds.
• Latency: Time delay between sending and receiving data (measured in milliseconds, ms). Example: 50 ms latency means a 0.05-second delay in a video call.

Real-world example:

• Ncell’s 4G has ~30 Mbps bandwidth but ~50 ms latency—good for calls but not ultra-low-latency gaming.

4. Network Topologies

How devices are connected in a network. Common types:

5. Protocols and Standards

Rules governing data exchange. Key examples:

Real-world trace: Loading a Daraz page

1. You type daraz.com.ne.
2. DNS resolves it to an IP (e.g., 103.245.222.77).
3. TCP/IP establishes a connection.
4. HTTP requests the homepage.
5. Server sends HTML/CSS (via bandwidth).
6. Your browser renders the page (low latency ensures speed).

sequenceDiagram
    You->>DNS Server: daraz.com.ne?
    DNS Server-->>You: 103.245.222.77
    You->>Daraz Server: HTTP GET /homepage
    Daraz Server-->>You: HTML (200 OK)

6. Error Detection and Correction

Methods to ensure data integrity:

• Parity Bit: Simple error check (even/odd).
• Checksum: Sum of data blocks (e.g., used in FTP).
• CRC (Cyclic Redundancy Check): Advanced error detection (used in Ethernet, Wi-Fi).

Example: If you send 1010 with a parity bit of 1 (odd parity), the receiver checks:

• Received 10101 → Sum = 3 (odd) → No error.
• If 10111 is received → Sum = 4 (even) → Error detected.

7. Modulation Techniques

Converting digital data into signals for transmission:

• ASK (Amplitude Shift Keying): Varies signal amplitude.
• FSK (Frequency Shift Keying): Varies frequency (used in old modems).
• PSK (Phase Shift Keying): Varies phase (used in Wi-Fi, 4G/5G).

Real-world example:

• Ncell’s 4G uses QAM (Quadrature Amplitude Modulation), a mix of ASK and PSK, to send data efficiently.

In the Real World

1. eSewa Transactions

   • Uses HTTPS (protocol) for secure data transfer.
   • Latency must be low (<100 ms) to avoid timeouts during payments.
   • Bandwidth ensures quick processing of transaction data.

2. Daraz Order Fulfillment

   • TCP/IP ensures orders reach warehouses reliably.
   • Mesh networks in delivery hubs improve route efficiency (like Pathao’s dynamic routing).
   • Error detection (CRC) prevents corrupted order data.

3. NTC Internet Service

   • Fiber optic cables provide high bandwidth (up to 1 Gbps).
   • Star topology connects users to central NTC servers.
   • Modulation (DWDM) allows multiple data streams on one fiber.

Worked Example: Calculating Bandwidth and Latency

Scenario: A user in Kathmandu uploads a 2 GB file to Google Drive.

• Bandwidth: 50 Mbps (megabits per second).
• Latency: 80 ms.

Steps:

1. Convert file size to bits: $2\text{ GB}=2\times 1024\times 1024\times 1024\times 8=16,777,216,000\text{ bits}$.
2. Calculate time (ignoring latency for simplicity): $\text{Time}=\frac{\text{Data}}{\text{Bandwidth}}=\frac{16,777,216,000}{50\times 10^6}=335.54\text{ seconds}\approx 5.6\text{ minutes}$.
3. With latency: Each packet adds 80 ms delay. For 100 packets: $100\times 0.08\text{ s}=8\text{ seconds}$ extra.

Real-world tie-in:

• Ncell’s 4G (100 Mbps) would halve the upload time (~2.8 minutes).
• NTC’s fiber (1 Gbps) would reduce it to ~1.6 minutes.

Comparison Table: Common Technical Terms

Exam Tip

1. Memorize definitions with examples:
   • "Bandwidth is the maximum capacity of a channel, while throughput is the actual achieved rate."
2. Relate to real systems:
   • "Ncell’s 4G uses OFDM (a modulation technique) to divide signals into multiple carriers."
3. Diagrams are worth marks:
   • Draw topologies, protocol stacks, or modulation waveforms in exams.
4. Common mistakes to avoid:
   • Confusing bandwidth (capacity) with throughput (real speed).
   • Mixing latency (delay) with jitter (delay variation).
5. Application-based questions:
   • "How does eSewa ensure secure communication?" → HTTPS + encryption.
   • "Why does Pathao use low-latency servers?" → Faster ride confirmations.