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Add Retransmission for Unacknowledged Segments

hard4/8

Implement TCP Data Transfer with Sequence Numbers and ACKs Implement TCP Sliding Window Flow Control

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2.0s Limit 256MB

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Implementation

Implement a simulation of TCP retransmission on packet loss.

Requirements:

Simulate sending multiple segments with one lost segment
Show RTO timer and timeout detection
Implement exponential backoff on retransmission
Show fast retransmit triggered by 3 duplicate ACKs
Retransmit lost segment with same sequence number
Display Karn's algorithm concept (skip RTT sample after retransmit)
Print timer values, timeout events, and retransmitted segments
Show the difference between timeout-based and fast retransmit recovery

Why This Matters

RFC 6298's RTO formula and Karn's 1987 algorithm (skip RTT samples from retransmitted segments) are implemented nearly verbatim in the Linux kernel's tcp_rtt_estimator(). Fast retransmit on three duplicate ACKs is the mechanism that keeps a video call or SSH session usable during transient packet loss instead of stalling for a full timeout.

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Validation Suite

main.c

Workspace 1.0

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