From 8783e5992ba8b3e38310c4eea26e427b2c1b7fd8 Mon Sep 17 00:00:00 2001
From: Parikshit Gune <parikshitgune@gmail.com>
Date: Wed, 13 May 2020 19:18:44 +0530
Subject: [PATCH] tcp: Fix an issue with fast convergence in Cubic

---
 src/internet/model/tcp-cubic.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/internet/model/tcp-cubic.cc b/src/internet/model/tcp-cubic.cc
index a0281da46..e98af4c1f 100644
--- a/src/internet/model/tcp-cubic.cc
+++ b/src/internet/model/tcp-cubic.cc
@@ -397,7 +397,7 @@ TcpCubic::GetSsThresh (Ptr<const TcpSocketState> tcb, uint32_t bytesInFlight)
   /* Wmax and fast convergence */
   if (segCwnd < m_lastMaxCwnd && m_fastConvergence)
     {
-      m_lastMaxCwnd = m_beta * segCwnd;
+      m_lastMaxCwnd = (segCwnd * (1 + m_beta)) / 2; // Section 4.6 in RFC 8312
     }
   else
     {