Role of a front-end processor (FEP): In data communications architectures, a front-end processor dedicated to communications typically performs which of the following functions?

Introduction / Context:
A front-end processor (FEP) is a specialized communications computer that offloads network I/O tasks from a host system. It manages line control, session handling, and message integrity, improving throughput and responsiveness for enterprise hosts.

Given Data / Assumptions:

• The FEP sits between network lines and the main host.
• It handles real-time line discipline and protocol details.
• Functions include polling terminals, synchronization, and error control.

Concept / Approach:
Polling enables the FEP to query attached devices/terminals in sequence. Synchronization aligns sender and receiver so frames are recognized correctly. Error checking detects transmission errors using parity, checksums, or CRC so corrupted frames are retransmitted or discarded.

Step-by-Step Solution:
Identify standard FEP responsibilities: line control and protocol services.Map examples: polling, synchronization, error checking are all canonical.Therefore, select “All of the above.”

Verification / Alternative check:
Classic systems (for example, IBM 370/VTAM environments) illustrate FEPs handling line scanning, framing, and integrity checks.

Why Other Options Are Wrong:
Each single function is correct but incomplete; only the combined option reflects the FEP’s scope.

Common Pitfalls:
Assuming hosts should handle low-level line control directly; offloading to FEPs historically improved efficiency.

Final Answer:
All of the above