catchunks: Improve CUBIC performance for lossy networks

Change-Id: I4baea5dcbc02d5c4a989330603e059daa55e767f
refs: #5036
diff --git a/tools/chunks/catchunks/options.hpp b/tools/chunks/catchunks/options.hpp
index 0f432b3..fbca964 100644
--- a/tools/chunks/catchunks/options.hpp
+++ b/tools/chunks/catchunks/options.hpp
@@ -46,7 +46,7 @@
   size_t maxPipelineSize = 1;
 
   // Adaptive pipeline common options
-  double initCwnd = 1.0;        ///< initial congestion window size
+  double initCwnd = 2.0;        ///< initial congestion window size
   double initSsthresh = std::numeric_limits<double>::max(); ///< initial slow start threshold
   time::milliseconds rtoCheckInterval{10}; ///< interval for checking retransmission timer
   bool ignoreCongMarks = false; ///< disable window decrease after receiving congestion mark