200-901 Network Fundamentals Practice Question
A developer is designing a system that requires high reliability and ordered data delivery. The developer chooses TCP. Which THREE features are provided by TCP?
⚠ Common exam trap
200-901 often tests the features of TCP vs. UDP, and candidates might incorrectly attribute multicast or low overhead to TCP, which are UDP characteristics.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Flow control using window size
TCP provides flow control using a sliding window mechanism (Option A), where the receiver advertises a window size in each segment to prevent the sender from overwhelming its buffer. TCP is connection-oriented (Option D): it establishes a session via the three-way handshake (SYN, SYN-ACK, ACK) before data transfer, which underpins its reliability guarantees. TCP also performs sequencing and retransmission (Option E): each byte is numbered with a sequence number, and unacknowledged segments are retransmitted after a timeout or duplicate ACKs, ensuring ordered, loss-free delivery. Option B is incorrect because multicast is not a TCP feature; TCP is strictly unicast, and multicast delivery is handled by UDP-based or specialized protocols. Option C is incorrect because TCP uses a relatively large 20-byte (minimum) header with many fields, whereas UDP has the simple 8-byte header with minimal overhead.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Flow control using window size
Why this is correct
TCP's sliding window mechanism lets the receiver advertise how much data it can buffer, so a fast sender cannot overwhelm a slower receiver. This directly satisfies the high-reliability requirement in the stem by preventing buffer overflow and packet loss during transmission.
- ✗
Multicast support
Why it's wrong here
TCP is connection-oriented unicast; multicast delivery is handled by UDP, which supports one-to-many transmission without per-connection state. Multicast tempts because TCP guarantees delivery, but that guarantee applies only to a single established connection between two endpoints, not group addressing.
- ✗
Simple header with minimal overhead
Why it's wrong here
TCP's 20-byte minimum header carries sequence numbers, acknowledgement numbers, window size and flags, so overhead is substantial rather than minimal. The option tempts because UDP's eight-byte header is genuinely minimal, but that simplicity is exactly what TCP sacrifices to provide reliability and ordering.
- ✓
Connection-oriented communication using a three-way handshake
Why this is correct
TCP establishes a session via the SYN, SYN-ACK, ACK exchange before data flows, guaranteeing both endpoints are reachable and ready. This connection-oriented handshake underpins the reliability and ordered delivery the stem demands, since sequence numbers and acknowledgements can only be tracked within an established session.
- ✓
Sequencing and retransmission of lost packets
Why this is correct
TCP numbers every byte so the receiver reassembles segments in the original order, and unacknowledged segments are retransmitted after a timeout. This directly satisfies the stem's ordered-delivery and high-reliability constraints, which UDP cannot guarantee since it offers neither sequencing nor retransmission.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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