diff --git a/src/steam/engine/buffer-provider.hpp b/src/steam/engine/buffer-provider.hpp
index 622f24f3b..02bdc2ba8 100644
--- a/src/steam/engine/buffer-provider.hpp
+++ b/src/steam/engine/buffer-provider.hpp
@@ -181,23 +181,30 @@ namespace engine {
     protected:
       bool was_created_by_this_provider (BuffDescr const&)  const;
       
+      using Buff = StreamType::ImplFacade::DataBuffer;  ///< marker type for an actual data buffer
+      
       
       class BufferStage
         : public BufferMetadata         /////////////////////////////////////////////////////////////////////TICKET #1410 : mix-in exiting old implementation -- for sake of refactoring only!
         {
         protected:
-          using Key = metadata::Key;
+          using ID = metadata::Key const&;
         public:
           virtual ~BufferStage() { } ///< this is an interface
-          
           using BufferMetadata::BufferMetadata;   ///////////////////////////////////////////////////////////TICKET #1410 : actual implementation structures should move down into this classes implementation
+          
+          virtual ID lookup (HashVal)                          =0;
+          virtual ID mark_locked (ID typeKey, Buff*, LocalTag) =0;
+          virtual ID mark_emitted (HashVal stateKey)           =0;
+          virtual ID mark_released (HashVal stateKey)          =0;
+          virtual ID abandon (HashVal, bool destroy=false)     =0;
+          virtual void discard (HashVal stateKey)              =0;
         };
       
       class BufferStore
         : util::NonCopyable
         {
         protected:
-          using Buff = StreamType::ImplFacade::DataBuffer;  ///< marker type for an actual data buffer
           using Slot = std::tuple<Buff*,LocalTag>;
         public:
           virtual ~BufferStore() { } ///< this is an interface
diff --git a/src/steam/engine/simple-buffer-state-registry.hpp b/src/steam/engine/simple-buffer-state-registry.hpp
index fdd2b41ae..24259c1b6 100644
--- a/src/steam/engine/simple-buffer-state-registry.hpp
+++ b/src/steam/engine/simple-buffer-state-registry.hpp
@@ -37,6 +37,7 @@ namespace engine {
   
   namespace error = lumiera::error;
   
+  using metadata::Buff;
 //  using std::unique_ptr;
 //  using lib::HashVal;
   
@@ -49,9 +50,51 @@ namespace engine {
     : public BufferProviderSetup::Stage
     {
       ///////////////////////////////////////////////////////////////////////////////////////////////////////TICKET 1410 : rather hold BufferMetatdata object here
-    public:
+
       /* === BufferStage interface === */
       
+      ID
+      lookup (HashVal key)  override
+        {
+          return this->get (key);
+        }
+      
+      ID
+      mark_locked (ID typeKey, Buff* storage, LocalTag implMark)  override
+        {
+          return this->markLocked (typeKey, storage, implMark);
+        }
+      
+      ID
+      mark_emitted (HashVal stateKey)  override
+        {
+          metadata::Entry& metaEntry = this->get (stateKey);
+          metaEntry.mark(EMITTED);
+          return metaEntry;   // contains also the key
+        }
+      
+      ID
+      mark_released (HashVal stateKey)  override
+        {
+          metadata::Entry& metaEntry = this->get (stateKey);
+          metaEntry.mark(FREE);   // might invoke embedded dtor function
+          return metaEntry;
+        }
+      
+      ID
+      abandon (HashVal stateKey, bool invokeDtor)  override
+        {
+          metadata::Entry& metaEntry = this->get (stateKey);
+          metaEntry.invalidate (invokeDtor);
+          return metaEntry;
+        }
+      
+      void
+      discard (HashVal stateKey)  override
+        {
+          this->release (stateKey);
+        }
+      
       
     public:
       SimpleBufferStateRegistry (Literal implementationID)