diff --git a/openflow_input/bsn_log b/openflow_input/bsn_log
index 4f7fbce..b2a9758 100644
--- a/openflow_input/bsn_log
+++ b/openflow_input/bsn_log
@@ -47,5 +47,5 @@
     uint32_t experimenter == 0x5c16c7;
     uint32_t subtype == 63;
     enum ofp_bsn_loglevel loglevel;
-    of_octets_t data;
+    of_octets_t data; /* US-ASCII string, no null terminator */
 };