Module flow 

VCL Flow Control & Congestion Control

FlowController implements sliding window flow control with AIMD (Additive Increase Multiplicative Decrease) congestion control and retransmission support.

How it works

window_size = 4

Sent but unacked:  [0] [1] [2] [3]   <- window full, must wait
Acked:             [0]               <- window slides, can send [4]
Sent but unacked:      [1] [2] [3] [4]

Congestion Control (AIMD)

No loss:  cwnd += 1 per RTT    (additive increase)
Loss:     cwnd *= 0.5          (multiplicative decrease)
Min cwnd: 1
Max cwnd: bounded by window_size

Example

use vcl_protocol::flow::FlowController;

let mut fc = FlowController::new(4);

// Send packets
assert!(fc.can_send());
fc.on_send(0, vec![0]);
assert!(!fc.can_send()); // window full

// Acknowledge packets
fc.on_ack(0);
assert!(fc.can_send()); // window has space again

Structs

FlowController

Sliding window flow controller with AIMD congestion control and retransmission support.

InFlightPacket

A packet that has been sent but not yet acknowledged.

RetransmitRequest

A packet that needs to be retransmitted.