diff --git a/model/ccnx-content-object-header.cc b/model/ccnx-content-object-header.cc
index e567207..d1ad0cf 100644
--- a/model/ccnx-content-object-header.cc
+++ b/model/ccnx-content-object-header.cc
@@ -37,6 +37,7 @@
 CcnxContentObjectHeader::GetTypeId (void)
 {
   static TypeId tid = TypeId ("ns3::CcnxContentObjectHeader")
+    .SetGroupName ("Ccnx")
     .SetParent<Header> ()
     .AddConstructor<CcnxContentObjectHeader> ()
     ;