26. What is the main idea behind Go-Back-N ARQ?
a) Transmitting multiple frames and waiting for individualacknowledgments
b) Transmitting one frame at a time and waiting for acknowledgment
c) Transmitting frames without any acknowledgment
d) Transmitting frames in reverse order

27. What is the main advantage of Selective Repeat ARQ over Go-Back-N ARQ?
a) Transmitting frames in reverse order
b) Only retransmitting erroneous frames
c) Transmitting multiple frames without acknowledgment
d) Encrypting data during transmission

28. What are block coding and linear block codes used for in data transmission?
a) Encryption
b) Error detection and correction
c) Data compression
d) Modulation

29. What does HDLC stand for in networking?
a) High-level Data Link Control
b) High-level Digital Link Control
c) High-level Data Layer Control
d) High-level Digital Layer Control

30. What does PPP stand for in networking?
a) Point-to-Point Protocol
b) Peer-to-Peer Protocol
c) Packet-to-Packet Protocol
d) Path-to-Path Protocol