diff --git a/src/common/protocol.h b/src/common/protocol.h
--- a/src/common/protocol.h
+++ b/src/common/protocol.h
@@ -47,6 +47,11 @@ enum distren_request_type
     DISTREN_REQUEST_VERSION = 1,
     DISTREN_REQUEST_PING = 2,
     DISTREN_REQUEST_PONG = 3,
+    /**
+       The data is the a reason describing why the one end is
+       disconnecting. The other end should respectfully close()
+       the socket or the sender will timeout shortly.
+     */
     DISTREN_REQUEST_DISCONNECT = 4,
 
     /**