diff --git a/examples/ndn-simple-for-nrt-helper.cpp b/examples/ndn-simple-for-nrt-helper.cpp
index eb320a9..a43ab13 100644
--- a/examples/ndn-simple-for-nrt-helper.cpp
+++ b/examples/ndn-simple-for-nrt-helper.cpp
@@ -61,7 +61,7 @@
   // setting default parameters for PointToPoint links and channels
   Config::SetDefault("ns3::PointToPointNetDevice::DataRate", StringValue("1Mbps"));
   Config::SetDefault("ns3::PointToPointChannel::Delay", StringValue("10ms"));
-  Config::SetDefault("ns3::QueueBase::MaxPackets", UintegerValue(20));
+  Config::SetDefault("ns3::QueueBase::MaxSize", StringValue("20p"));
 
   // Read optional command-line parameters (e.g., enable visualizer with ./waf --run=<> --visualize
   CommandLine cmd;