+#define DEFAULT_RCVBUFSIZE 0
+#define DEFAULT_MAXRCVBUFSIZE 131072
+
+#define DEFAULT_MTU 1000
+
+#define USEC_PER_SEC 1000000
+#define DEFAULT_USER_TIMEOUT 60 // sec
+#define CLOCK_GRANULARITY 1000 // usec
+#define START_RTO 1000000 // usec
+#define MAX_RTO 3000000 // usec