diff --git a/hbs2-core/lib/HBS2/Net/Proto/Sessions.hs b/hbs2-core/lib/HBS2/Net/Proto/Sessions.hs
new file mode 100644
index 00000000..681cdcc9
--- /dev/null
+++ b/hbs2-core/lib/HBS2/Net/Proto/Sessions.hs
@@ -0,0 +1,81 @@
+{-# Language FunctionalDependencies #-}
+module HBS2.Net.Proto.Sessions where
+
+import HBS2.Net.Proto.Types
+
+import Data.Typeable
+import Data.Dynamic
+import Data.Hashable
+import Data.Kind
+
+data SKey = forall a . (Unkey a, Eq a, Hashable a) => SKey (Proxy a) Dynamic
+
+class Typeable a => Unkey a where
+  unKey :: Proxy a -> Dynamic -> Maybe a
+
+instance Typeable a => Unkey a where
+  unKey _ = fromDynamic @a
+
+newSKey :: forall a . (Eq a, Typeable a, Unkey a, Hashable a) => a -> SKey
+newSKey s = SKey (Proxy @a) (toDyn s)
+
+
+instance Hashable SKey where
+  hashWithSalt s (SKey p d) = hashWithSalt s (unKey p d)
+
+
+instance Eq SKey where
+  (==) (SKey p1 a) (SKey p2 b) = unKey p1 a == unKey p1 b
+
+
+-- we probably can not separate sessions
+-- by sub-protocol types without
+-- really crazy types.
+--
+-- And if we really need this, it may be done
+-- by injecting a protocol type into 'e' or
+-- introducing a common ADT for all session types
+-- for common 'e' i.e. 'engine' or 'transport'
+--
+-- So it is that it is.
+
+data family SessionKey  e p :: Type
+type family SessionData e p :: Type
+
+
+class ( Monad m
+      , HasProtocol e p
+      , Eq (SessionKey e p)
+      , Hashable (SessionKey e p)
+      , Typeable (SessionData e p)
+      ) => Sessions e p m  | p -> e where
+
+
+
+  -- | Session fetch function.
+  -- | It will insert a new session, if default value is Just something.
+
+  find :: SessionKey e p           -- ^ session key
+       -> (SessionData e p -> a)  -- ^ modification function, i.e. lens
+       -> m (Maybe a)
+
+  -- | Session fetch function.
+  -- | It will insert a new session, if default value is Just something.
+
+  fetch  :: Bool                     -- ^ do add new session if not exists
+         -> SessionData e p          -- ^ default value in case it's not found
+         -> SessionKey e p           -- ^ session key
+         -> (SessionData e p -> a )  -- ^ modification function, i.e. lens
+         -> m a
+
+  -- | Session update function
+  -- | If will create a new session if it does not exist.
+  -- | A modified value (or default) value will we saved.
+
+  update :: SessionData e p                      -- ^ default value in case it's not found
+         -> SessionKey e p                       -- ^ session key
+         -> (SessionData e p -> SessionData e p) -- ^ modification function, i.e. lens
+         -> m ()
+
+  expire :: SessionKey e p -> m ()
+
diff --git a/hbs2-tests/test/Peer2Main.hs b/hbs2-tests/test/Peer2Main.hs
index a1fffcff..879d56eb 100644
--- a/hbs2-tests/test/Peer2Main.hs
+++ b/hbs2-tests/test/Peer2Main.hs
@@ -122,7 +122,7 @@ instance (IsKey HbSync, Key HbSync ~ Hash HbSync) => Storage AnyStorage HbSync B
 class HasStorage m where
   getStorage :: m AnyStorage
 
-data Fabriq e = forall bus . Messaging bus e ByteString => Fabriq bus
+data Fabriq e = forall bus . (Serialise (Encoded e), Messaging bus e ByteString) => Fabriq bus
 
 class HasFabriq e m where
   getFabriq :: m (Fabriq e)
@@ -253,8 +253,17 @@ instance ( MonadIO m
     liftIO $ Cache.delete se (newSKey @(SessionKey e p) k)
 
 
-
-
+instance ( MonadIO m
+         , HasProtocol e p
+         , HasFabriq e (PeerM e m)
+         , Serialise (Encoded e)
+         ) => Request e p (PeerM e m) where
+  request p msg = do
+    let proto = protoId @e @p (Proxy @p)
+    pipe <- getFabriq @e
+    me <- ownPeer @e
+    let bs = serialise (AnyMessage @e proto (encode msg))
+    sendTo pipe (To p) (From me) bs
 
 runPeerM :: MonadIO m => AnyStorage -> Fabriq e -> Peer e  -> PeerM e m a -> m ()
 runPeerM s bus p f  = do
@@ -268,6 +277,9 @@ runPeerM s bus p f  = do
   void $ liftIO $ stopPipeline de
   liftIO $ cancel as
 
+withPeerM :: MonadIO m => PeerEnv e -> PeerM e m a -> m ()
+withPeerM env action = void $ runReaderT (fromPeerM action) env
+
 runProto :: forall e m  . ( MonadIO m
                           , HasOwnPeer e m
                           , HasFabriq e m
@@ -376,10 +388,11 @@ runTestPeer p zu = do
   mapM_ cancel [sw,cw]
 
 
-handleBlockInfo :: forall e m . ( Monad m
+handleBlockInfo :: forall e m . ( MonadIO m
                                 , Sessions e (BlockSize e) m
                                 , Default (SessionData e (BlockSize e))
                                 , Ord (Peer e)
+                                , Pretty (Peer e)
                                 )
 
                 => (Peer e, Hash HbSync, Maybe Integer)
@@ -389,9 +402,28 @@ handleBlockInfo (p, h, sz') = do
    maybe1 sz' (pure ()) $ \sz -> do
     let bsz = fromIntegral sz
     update @e def (BlockSizeKey h) (over bsBlockSizes (Map.insert p bsz))
+    liftIO $ debug $ "got block:" <+> pretty (p, h, sz)
     -- FIXME: turn back on event notification
     -- lift $ runEngineM env $ emitBlockSizeEvent ev h (p, h, Just sz) -- TODO: fix this crazy shit
 
+
+blockDownloadLoop :: forall e . ( HasProtocol e (BlockSize e)
+                                , Request e (BlockSize e) (PeerM e IO)
+                                , Num (Peer e)
+                                ) =>  PeerM e IO ()
+blockDownloadLoop = do
+
+  -- w <- subscribe ???
+
+  request 1 (GetBlockSize @e "5KP4vM6RuEX6RA1ywthBMqZV5UJDLANC17UrF6zuWdRt")
+  request 1 (GetBlockSize @e "81JeD7LNR6Q7RYfyWBxfjJn1RsWzvegkUXae6FUNgrMZ")
+
+  fix \next -> do
+    liftIO $ print "piu!"
+
+    pause ( 0.85 :: Timeout 'Seconds )
+    next
+
 main :: IO ()
 main = do
   hSetBuffering stderr LineBuffering
@@ -425,11 +457,17 @@ main = do
     our <- async $ runTestPeer p0 $ \s  -> do
                 let blk = hasBlock s
                 runPeerM (AnyStorage s) fake p0 $ do
+                  env <- ask
+
+                  as <- liftIO $ async $ withPeerM env blockDownloadLoop
+
                   runProto @Fake
                     [ makeResponse (blockSizeProto blk handleBlockInfo)
                     -- , makeResponse (blockChunksProto undefined)
                     ]
 
+                  liftIO $ cancel as
+
     pause ( 5 :: Timeout 'Seconds)
 
     mapM_ cancel (our:others)