diff --git a/bin/nfreplay.c b/bin/nfreplay.c
index 76a29fb..0aaf2e6 100644
--- a/bin/nfreplay.c
+++ b/bin/nfreplay.c
@@ -108,7 +108,7 @@ static void usage(char *name);
 static void send_blast(unsigned int delay );
 
 static void send_data(char *rfile, time_t twin_start, time_t twin_end, uint32_t count, 
-				unsigned int delay,  int confirm, int netflow_version);
+				unsigned int delay,  int confirm, int netflow_version, int distribution);
 
 static int FlushBuffer(int confirm);
 
@@ -133,6 +133,7 @@ static void usage(char *name) {
 					"-r <input>\tread from file. default: stdin\n"
 					"-f <filter>\tfilter syntaxfile\n"
 					"-v <version>\tUse netflow version to send flows. Either 5 or 9\n"
+					"-z <distribution>\tSimulate real time distribution with coefficient\n"
 					"-t <time>\ttime window for sending packets\n"
 					"\t\tyyyy/MM/dd.hh:mm:ss[-yyyy/MM/dd.hh:mm:ss]\n"
 					, name);
@@ -204,13 +205,18 @@ double 					fps;
 } // End of send_blast
 
 static void send_data(char *rfile, time_t twin_start, 
-			time_t twin_end, uint32_t count, unsigned int delay, int confirm, int netflow_version) {
+			time_t twin_end, uint32_t count, unsigned int delay, int confirm, int netflow_version, int distribution) {
 master_record_t	master_record;
 common_record_t	*flow_record;
 nffile_t		*nffile;
 int 			i, done, ret, again;
 uint32_t		numflows, cnt;
 
+	// z-parameter variables
+	struct timeval todayTime, currentTime;
+	double first, last, now, today = 0, reftime = 0;
+	int reducer = 0;
+
 #ifdef COMPAT15
 int	v1_map_done = 0;
 #endif
@@ -407,6 +413,31 @@ int	v1_map_done = 0;
 					LogError("Skip unknown record type %i\n", flow_record->type);
 				}
 			}
+
+			// z-parameter
+			//first and last are line (tstart and tend) timestamp with milliseconds
+			first = (double) flow_record->first + ((double)flow_record->msec_first / 1000);
+			last = (double) flow_record->last + ((double)flow_record->msec_last / 1000);
+
+			gettimeofday(&currentTime, NULL);
+			now =  (double)currentTime.tv_sec + (double)currentTime.tv_usec / 1000000;
+
+			// remove incoherent values
+			if (reftime == 0 && last > 1000000000 && last < 2000000000){
+				reftime = last;
+				gettimeofday(&todayTime, NULL);
+	 			today =  (double)todayTime.tv_sec + (double)todayTime.tv_usec / 1000000;
+			}
+
+			// Reducer avoid to have too much computation: It takes 1 over 3 line to regulate sending time
+			if (reducer % 3 == 0 && distribution != 0 && reftime != 0 && last > 1000000000){
+				while (last - reftime > distribution * (now - today)){
+					gettimeofday(&currentTime, NULL);
+					now =  (double)currentTime.tv_sec + (double)currentTime.tv_usec / 1000000;
+				}
+			}
+			reducer++;
+
 			// Advance pointer by number of bytes for netflow record
 			flow_record = (common_record_t *)((pointer_addr_t)flow_record + flow_record->size);	
 
@@ -438,7 +469,7 @@ int	v1_map_done = 0;
 int main( int argc, char **argv ) {
 struct stat stat_buff;
 char *rfile, *ffile, *filter, *tstring;
-int c, confirm, ffd, ret, blast, netflow_version;
+int c, confirm, ffd, ret, blast, netflow_version, distribution;
 unsigned int delay, count, sockbuff_size;
 time_t t_start, t_end;
 
@@ -458,7 +489,8 @@ time_t t_start, t_end;
 	blast			= 0;
 	verbose			= 0;
 	confirm			= 0;
-	while ((c = getopt(argc, argv, "46BhH:i:K:L:p:d:c:b:j:r:f:t:v:VY")) != EOF) {
+	distribution	= 0;
+	while ((c = getopt(argc, argv, "46BhH:i:K:L:p:d:c:b:j:r:f:t:v:z:VY")) != EOF) {
 		switch (c) {
 			case 'h':
 				usage(argv[0]);
@@ -524,6 +556,9 @@ time_t t_start, t_end;
 			case 'r':
 				rfile = optarg;
 				break;
+			case 'z':
+				distribution = atoi(optarg);
+				break;
 			case '4':
 				if ( peer.family == AF_UNSPEC )
 					peer.family = AF_INET;
@@ -611,7 +646,7 @@ time_t t_start, t_end;
 			exit(255);
 	}
 
-	send_data(rfile, t_start, t_end, count, delay, confirm, netflow_version);
+	send_data(rfile, t_start, t_end, count, delay, confirm, netflow_version,distribution);
 
 	FreeExtensionMaps(extension_map_list);