--- a/src/internet-node/udp-header.cc	Wed Mar 19 10:30:59 2008 -0700
+++ b/src/internet-node/udp-header.cc	Wed Mar 19 10:31:50 2008 -0700
@@ -98,6 +98,7 @@
 {
   static TypeId tid = TypeId ("ns3::UdpHeader")
     .SetParent<Header> ()
+    .AddConstructor<UdpHeader> ()
     ;
   return tid;
 }