diff --git a/sjrpc/core/protocols/__init__.py b/sjrpc/core/protocols/__init__.py
index 27d9f30c9ce6bf516bb2194cbda71f48b60c690e..25a1bdcfd22ec859ba36f5a6fbe0fe088a5f7432 100644
--- a/sjrpc/core/protocols/__init__.py
+++ b/sjrpc/core/protocols/__init__.py
@@ -34,10 +34,18 @@ class Protocol(object):
 
     @property
     def connection(self):
+        '''
+        The :class:`~sjrpc.core.RpcConnection` instance which handle
+        this protocol.
+        '''
         return self._connection
 
     @property
     def label(self):
+        '''
+        The label binded to this protocol in the
+        :class:`~sjrpc.core.RpcConnection` instance.
+        '''
         return self._label
 
     def send(self, payload):