diff --git a/src/internal.h b/src/internal.h
index 68f0135..1754e3b 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -17,9 +17,17 @@
 	uint32_t	ifidx;
 	struct in_addr	ms_addr;
 	struct in_addr	sgsn_addr;
-	uint64_t	tid;
-	uint16_t	flowid;
 	int		gtp_version;
+	union {
+		struct {
+			uint64_t tid;
+			uint16_t flowid;
+		} v0;
+		struct {
+			uint32_t i_tei;
+			uint32_t o_tei;
+		} v1;
+	} u;
 };
 
 #endif