diff --git a/include/libipc/def.h b/include/libipc/def.h
index d9cfdc0..9be5206 100755
--- a/include/libipc/def.h
+++ b/include/libipc/def.h
@@ -29,6 +29,7 @@ enum : std::size_t {
     invalid_value   = (std::numeric_limits<std::size_t>::max)(),
     data_length     = 64,
     large_msg_limit = data_length,
+    large_msg_align = 512,
     large_msg_cache = 32,
     default_timeout = 100 // ms
 };