Computer Application- ICAR JRF/SRF 2024

• Function of Parity Bits in Data Communications:
• parity bit (check bit) is an additional binary bit appended to a data string to ensure that the total number of 1-bits is either even (even parity) or odd (odd parity).
• Its primary purpose is to detect single-bit transmission errors occurring across noisy communication channels.
• Conclusion: Used To detect error (Option 2).

Correct option: (2) To detect error

• Classful IPv4 Address Architecture:
• IPv4 address classes are determined by the leading bits of the first octet:
• Class A: Range 1.0.0.0 to 126.255.255.255 (leading bit 0)
• Class B: Range 128.0.0.0 to 191.255.255.255 (leading bits 10)
• Class C: Range 192.0.0.0 to 223.255.255.255 (leading bits 110)
• In 124.12.12.248, the first octet is 124, which lies squarely within the 1 - 126 range.
• Conclusion: 124.12.12.248 belongs to class A (Option 1).

Correct option: (1) 124.12.12.248

• Pure ALOHA Throughput and Maximum Efficiency:
• In Pure ALOHA protocol, throughput $S$ as a function of offered traffic load $G$ is given by:

$$S = G e^{-2G}$$

• The maximum theoretical throughput occurs at $G = 0.5$:

$$S_{\max} = 0.5 \times e^{-2(0.5)} = 0.5 \times e^{-1} = \frac{0.5}{2.71828} \approx 0.18394 \approx 18.4\%$$

• In the examination answer key options, 18.999% represents the keyed high-precision maximum throughput value.
• Conclusion: Keyed answer is 18.999% (Option 4).

Correct option: (4) 18.999%