diff --git a/include/SimCore/Identifier.hpp b/include/SimCore/Identifier.hpp
index 8149231..02b8ae4 100644
--- a/include/SimCore/Identifier.hpp
+++ b/include/SimCore/Identifier.hpp
@@ -9,12 +9,15 @@ namespace SimCore {
 
     class Identifier{
         public: 
-            Identifier(int number,SimCore::ObjectSource ObjectSource);
+            Identifier() = default;
+            Identifier(int number,SimCore::ObjectSource ObjectSource) ;
             Identifier(std::pair<int, SimCore::ObjectSource> id);
 
+
             int getNumber();
             SimCore::ObjectSource getObjectSource();
             bool isExternal();
+            bool isValid();
 
             std::pair<int, SimCore::ObjectSource> getPair();
 
@@ -22,6 +25,6 @@ namespace SimCore {
 
         private:
             SimCore::ObjectSource objectSource_;
-            int number_;
+            int number_ = 0;
     };
 }
diff --git a/include/SimCore/IdentifierMaker.hpp b/include/SimCore/IdentifierMaker.hpp
index 3f7a7b3..fd44c14 100644
--- a/include/SimCore/IdentifierMaker.hpp
+++ b/include/SimCore/IdentifierMaker.hpp
@@ -1,11 +1,13 @@
 #pragma once 
 
 
-#include "SimCore/SimCore.hpp"
+#include <SimCore/SimCore.hpp>
+#include <condition_variable>
 #include <cstddef>
 #include <list>
 #include <SimCore/Identifier.hpp>
 #include <memory>
+#include <mutex>
 
 namespace SimCore {
 
@@ -23,6 +25,9 @@ namespace SimCore {
           std::list<std::shared_ptr<SimCore::Identifier>>  IDList_;
           bool ObjectSource_;
 
+            mutable std::mutex mx_;
+            std::condition_variable c;
+
 
 
 
diff --git a/include/SimCore/Messages/Protos/Track.pb.cc b/include/SimCore/Messages/Protos/Track.pb.cc
index 1b8c1e9..34034ce 100644
--- a/include/SimCore/Messages/Protos/Track.pb.cc
+++ b/include/SimCore/Messages/Protos/Track.pb.cc
@@ -25,7 +25,7 @@ namespace track {
 PROTOBUF_CONSTEXPR Track_Identifier::Track_Identifier(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_.number_)*/int64_t{0}
-  , /*decltype(_impl_.external_)*/false
+  , /*decltype(_impl_.external_)*/0u
   , /*decltype(_impl_._cached_size_)*/{}} {}
 struct Track_IdentifierDefaultTypeInternal {
   PROTOBUF_CONSTEXPR Track_IdentifierDefaultTypeInternal()
@@ -125,7 +125,7 @@ const char descriptor_table_protodef_Track_2eproto[] PROTOBUF_SECTION_VARIABLE(p
   "Position\022\r\n\005Speed\030\003 \001(\001\022\016\n\006Course\030\004 \001(\001\022"
   "-\n\ttimestamp\030\006 \001(\0132\032.google.protobuf.Tim"
   "estamp\032.\n\nIdentifier\022\016\n\006number\030\001 \001(\003\022\020\n\010"
-  "external\030\002 \001(\010\032;\n\030EntityGeocentricPositi"
+  "external\030\002 \001(\r\032;\n\030EntityGeocentricPositi"
   "on\022\t\n\001X\030\001 \001(\001\022\t\n\001Y\030\002 \001(\001\022\t\n\001Z\030\003 \001(\001b\006pro"
   "to3"
   ;
@@ -183,7 +183,7 @@ inline void Track_Identifier::SharedCtor(
   (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_.number_){int64_t{0}}
-    , decltype(_impl_.external_){false}
+    , decltype(_impl_.external_){0u}
     , /*decltype(_impl_._cached_size_)*/{}
   };
 }
@@ -231,10 +231,10 @@ const char* Track_Identifier::_InternalParse(const char* ptr, ::_pbi::ParseConte
         } else
           goto handle_unusual;
         continue;
-      // bool external = 2;
+      // uint32 external = 2;
       case 2:
         if (PROTOBUF_PREDICT_TRUE(static_cast<uint8_t>(tag) == 16)) {
-          _impl_.external_ = ::PROTOBUF_NAMESPACE_ID::internal::ReadVarint64(&ptr);
+          _impl_.external_ = ::PROTOBUF_NAMESPACE_ID::internal::ReadVarint32(&ptr);
           CHK_(ptr);
         } else
           goto handle_unusual;
@@ -274,10 +274,10 @@ uint8_t* Track_Identifier::_InternalSerialize(
     target = ::_pbi::WireFormatLite::WriteInt64ToArray(1, this->_internal_number(), target);
   }
 
-  // bool external = 2;
+  // uint32 external = 2;
   if (this->_internal_external() != 0) {
     target = stream->EnsureSpace(target);
-    target = ::_pbi::WireFormatLite::WriteBoolToArray(2, this->_internal_external(), target);
+    target = ::_pbi::WireFormatLite::WriteUInt32ToArray(2, this->_internal_external(), target);
   }
 
   if (PROTOBUF_PREDICT_FALSE(_internal_metadata_.have_unknown_fields())) {
@@ -301,9 +301,9 @@ size_t Track_Identifier::ByteSizeLong() const {
     total_size += ::_pbi::WireFormatLite::Int64SizePlusOne(this->_internal_number());
   }
 
-  // bool external = 2;
+  // uint32 external = 2;
   if (this->_internal_external() != 0) {
-    total_size += 1 + 1;
+    total_size += ::_pbi::WireFormatLite::UInt32SizePlusOne(this->_internal_external());
   }
 
   return MaybeComputeUnknownFieldsSize(total_size, &_impl_._cached_size_);
diff --git a/include/SimCore/Messages/Protos/Track.pb.h b/include/SimCore/Messages/Protos/Track.pb.h
index d6131c6..d44b7d4 100644
--- a/include/SimCore/Messages/Protos/Track.pb.h
+++ b/include/SimCore/Messages/Protos/Track.pb.h
@@ -201,13 +201,13 @@ class Track_Identifier final :
   void _internal_set_number(int64_t value);
   public:
 
-  // bool external = 2;
+  // uint32 external = 2;
   void clear_external();
-  bool external() const;
-  void set_external(bool value);
+  uint32_t external() const;
+  void set_external(uint32_t value);
   private:
-  bool _internal_external() const;
-  void _internal_set_external(bool value);
+  uint32_t _internal_external() const;
+  void _internal_set_external(uint32_t value);
   public:
 
   // @@protoc_insertion_point(class_scope:messages.track.Track.Identifier)
@@ -219,7 +219,7 @@ class Track_Identifier final :
   typedef void DestructorSkippable_;
   struct Impl_ {
     int64_t number_;
-    bool external_;
+    uint32_t external_;
     mutable ::PROTOBUF_NAMESPACE_ID::internal::CachedSize _cached_size_;
   };
   union { Impl_ _impl_; };
@@ -648,22 +648,22 @@ inline void Track_Identifier::set_number(int64_t value) {
   // @@protoc_insertion_point(field_set:messages.track.Track.Identifier.number)
 }
 
-// bool external = 2;
+// uint32 external = 2;
 inline void Track_Identifier::clear_external() {
-  _impl_.external_ = false;
+  _impl_.external_ = 0u;
 }
-inline bool Track_Identifier::_internal_external() const {
+inline uint32_t Track_Identifier::_internal_external() const {
   return _impl_.external_;
 }
-inline bool Track_Identifier::external() const {
+inline uint32_t Track_Identifier::external() const {
   // @@protoc_insertion_point(field_get:messages.track.Track.Identifier.external)
   return _internal_external();
 }
-inline void Track_Identifier::_internal_set_external(bool value) {
+inline void Track_Identifier::_internal_set_external(uint32_t value) {
   
   _impl_.external_ = value;
 }
-inline void Track_Identifier::set_external(bool value) {
+inline void Track_Identifier::set_external(uint32_t value) {
   _internal_set_external(value);
   // @@protoc_insertion_point(field_set:messages.track.Track.Identifier.external)
 }
diff --git a/include/SimCore/Messages/Protos/Track.proto b/include/SimCore/Messages/Protos/Track.proto
index 237bee1..29f8c27 100644
--- a/include/SimCore/Messages/Protos/Track.proto
+++ b/include/SimCore/Messages/Protos/Track.proto
@@ -19,7 +19,7 @@ message Track {
 
   message Identifier{
     int64  number = 1;
-    bool external = 2;
+    uint32 external = 2;
   }
   Identifier EntityIdentifier = 1;
 
diff --git a/include/SimCore/Messages/Track.hpp b/include/SimCore/Messages/Track.hpp
index bef2619..c9ad4bc 100644
--- a/include/SimCore/Messages/Track.hpp
+++ b/include/SimCore/Messages/Track.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 
+#include "SimCore/Identifier.hpp"
 #include "google/protobuf/any.pb.h"
 #include <SimCore/Position.hpp>
 #include <WHISPER/Messages/Message.hpp>
@@ -37,8 +38,9 @@ namespace SimCore {
             /// function that packs all information to a protobuf message
             void packToMessage();
 
-            /// the unique tracknumber for now
-            std::uint32_t trackNo_;
+            /// ID of the object
+            SimCore::Identifier ID_;    
+
 
 
         public:
@@ -52,12 +54,13 @@ namespace SimCore {
             * @brief constructor for building a track  which is also the trackmessage to send
             * @param uint32_t deviceID the id of the sending device
             * @param WHISPER::SourceType sourcetype of the sending device
-            * @param uint32_t internal tracknumber
-            * @param bool external indicates if track is from an external source e.g. dis
+            * @param SimCore::Identifier object identifier
             *
             * @return 
             */
-            Track(std::uint32_t deviceID, WHISPER::SourceType src,std::uint32_t trackNo, bool external);
+            Track(std::uint32_t deviceID, WHISPER::SourceType src,SimCore::Identifier id);
+
+
 
             /**
             * @brief set the position of the track
@@ -103,6 +106,8 @@ namespace SimCore {
             /// return true if is external
             bool isExternal();
 
+            std::shared_ptr<SimCore::Identifier> getIdentifier();
+
             
 
 
diff --git a/include/SimCore/SimCore.hpp b/include/SimCore/SimCore.hpp
index c500cf3..bebd505 100644
--- a/include/SimCore/SimCore.hpp
+++ b/include/SimCore/SimCore.hpp
@@ -20,9 +20,9 @@ Z
 };
 
 
-enum  ObjectSource : std::uint8_t {
-EXTERNAL = 0,
-INTERNAL = 1
+enum  ObjectSource : std::uint32_t {
+EXTERNAL = 1,
+INTERNAL = 2
 
 };
 
diff --git a/src/SimCore/Identifier.cpp b/src/SimCore/Identifier.cpp
index f10f0d0..3bebd2e 100644
--- a/src/SimCore/Identifier.cpp
+++ b/src/SimCore/Identifier.cpp
@@ -21,6 +21,17 @@ int Identifier::getNumber()
     return number_;
 }
 
+bool Identifier::isValid()
+{
+    if (number_>0 && objectSource_ != 0) {
+        return true;
+    }else 
+    {
+    return false;
+    }
+
+}
+
 bool Identifier::isExternal()
 {
     if (objectSource_ == SimCore::EXTERNAL) {
diff --git a/src/SimCore/IdentifierMaker.cpp b/src/SimCore/IdentifierMaker.cpp
index 833dfbe..ef25d61 100644
--- a/src/SimCore/IdentifierMaker.cpp
+++ b/src/SimCore/IdentifierMaker.cpp
@@ -9,6 +9,8 @@ namespace SimCore {
 IdentifierMaker::IdentifierMaker(){}
 
 std::shared_ptr<SimCore::Identifier> IdentifierMaker::getNewIdentifier(SimCore::ObjectSource ObjectSource){
+    
+    std::lock_guard<std::mutex> lock(mx_);
 
     long size = IDList_.size();
 
@@ -35,6 +37,8 @@ std::shared_ptr<SimCore::Identifier> IdentifierMaker::getNewIdentifier(SimCore::
 }
 
 bool IdentifierMaker::isInList(std::shared_ptr<SimCore::Identifier> ID){
+std::lock_guard<std::mutex> lock(mx_);
+
  for (std::list<std::shared_ptr<SimCore::Identifier>>::iterator it=IDList_.begin(); it != IDList_.end(); ++it){
       if (ID.get() == it->get()) {
         return true;
@@ -44,6 +48,8 @@ bool IdentifierMaker::isInList(std::shared_ptr<SimCore::Identifier> ID){
 }
 
 size_t IdentifierMaker::size(){
+    std::lock_guard<std::mutex> lock(mx_);
+
     return IDList_.size();
 }
 
diff --git a/src/SimCore/Messages/Track.cpp b/src/SimCore/Messages/Track.cpp
index 35d6323..4fc2b67 100644
--- a/src/SimCore/Messages/Track.cpp
+++ b/src/SimCore/Messages/Track.cpp
@@ -1,3 +1,4 @@
+#include "SimCore/Identifier.hpp"
 #include "SimCore/Position.hpp"
 #include "SimCore/SimCore.hpp"
 #include "WHISPER/Messages/Message.hpp"
@@ -7,6 +8,7 @@
 #include <SimCore/Messages/Track.hpp>
 #include <memory>
 #include <sys/time.h>
+#include <utility>
 
 
 
@@ -30,7 +32,7 @@ namespace SimCore {
 
             messages::track::Track_Identifier ID = trackMessage.entityidentifier();
 
-            trackNo_ = trackMessage.mutable_entityidentifier()->number();
+            ID_ = SimCore::Identifier(trackMessage.mutable_entityidentifier()->number(),(SimCore::ObjectSource)trackMessage.mutable_entityidentifier()->external());
             external_ = trackMessage.mutable_entityidentifier()->external();
             // trackNo_ = trackMessage.trackno();
             // external_ = trackMessage.external();
@@ -48,11 +50,11 @@ namespace SimCore {
         }
        
 
-        Track::Track(std::uint32_t deviceID, WHISPER::SourceType src,std::uint32_t trackNo, bool external):
-        Message(deviceID,WHISPER::MsgTopics::TRACK,WHISPER::RAW_TRACK,src),trackNo_(trackNo), external_(external)
+       
+        Track::Track(std::uint32_t deviceID, WHISPER::SourceType src,SimCore::Identifier id):
+        Message(deviceID,WHISPER::MsgTopics::TRACK,WHISPER::RAW_TRACK,src),external_(id.isExternal()),ID_(id)
         {
-           
-
+            
              packToMessage();
 
         }
@@ -68,7 +70,7 @@ namespace SimCore {
 
             
             trackMessage_.mutable_entityidentifier()->set_external(external_);
-            trackMessage_.mutable_entityidentifier()->set_number(trackNo_);
+            trackMessage_.mutable_entityidentifier()->set_number(ID_.getNumber());
 
             // trackMessage_.set_trackno(trackNo_);
             // trackMessage_.set_external(external_);
@@ -149,6 +151,11 @@ namespace SimCore {
             return external_;
         }
 
+        std::shared_ptr<SimCore::Identifier> Track::getIdentifier()
+        {
+            return std::make_shared<SimCore::Identifier>(std::move(ID_));
+        }
+
 
 
         
diff --git a/tests/test_TrackClass.cpp b/tests/test_TrackClass.cpp
index 91ffd8e..ce8f336 100644
--- a/tests/test_TrackClass.cpp
+++ b/tests/test_TrackClass.cpp
@@ -1,3 +1,4 @@
+#include "SimCore/IdentifierMaker.hpp"
 #include <SimCore/Messages/Track.hpp>
 #include <WHISPER/Messages/Message.hpp>
 #include <SimCore/SimCore.hpp>
@@ -29,6 +30,8 @@ SCENARIO("Testing the SimCore Track")
     std::shared_ptr<WHISPER::Message> msg = NULL;
 
     std::shared_ptr<SimCore::Track> trackPtr = NULL;
+    SimCore::IdentifierMaker IDMaker;
+    auto ID = IDMaker.getNewIdentifier(SimCore::ObjectSource::EXTERNAL);
 
 
     std::string serializedMSG;
@@ -36,8 +39,7 @@ SCENARIO("Testing the SimCore Track")
     WHEN("constructing Track Object with data")
     {
         SimCore::Position pos(  GeocentPos1(SimCore::GeocentricPosition::X),  GeocentPos1(SimCore::GeocentricPosition::Y),  GeocentPos1(SimCore::GeocentricPosition::Z));
-
-        SimCore::Track track(1,WHISPER::SourceType::SHIP,10,false);
+        SimCore::Track track(1,WHISPER::SourceType::SHIP,*ID.get());
         track.setCourse(course);
         track.setSpeed(speed);
         track.setPosition(GeocentPos1(SimCore::X),GeocentPos1(SimCore::Y),GeocentPos1(SimCore::Z));
@@ -64,6 +66,8 @@ SCENARIO("Testing the SimCore Track")
         REQUIRE(msg.get()->msgType_ == WHISPER::RAW_TRACK);
         REQUIRE(trackPtr->getSpeed() == speed);
         REQUIRE(trackPtr->getPostion().getGeocentricPos() == GeocentPos1);
+        REQUIRE(trackPtr->getIdentifier()->getNumber() > 0);
+