Network Intelligence Research Center (NIRC)

Jul 27, 2025 · Operations

Implementing the Classic DCQCN Congestion Control Algorithm in NS‑3

This article explains the DCQCN end‑to‑end congestion control algorithm for RoCEv2, describes its three roles (RP, CP, NP), and provides detailed NS‑3 code implementations for ECN marking, CNP generation, and rate‑adjustment logic, including scheduling and parameter calculations.