diff --git a/src/iperf.h b/src/iperf.h
index 6b55559..b1ff1e8 100644
--- a/src/iperf.h
+++ b/src/iperf.h
@@ -77,6 +77,7 @@ struct iperf_interval_results
     int snd_cwnd;
     TAILQ_ENTRY(iperf_interval_results) irlistentries;
     void     *custom_data;
+    int rtt;
 };
 
 struct iperf_stream_result
@@ -89,6 +90,8 @@ struct iperf_stream_result
     int stream_retrans;
     int stream_prev_total_sacks;
     int stream_sacks;
+    int stream_max_rtt;
+    int stream_max_snd_cwnd;
     struct timeval start_time;
     struct timeval end_time;
     TAILQ_HEAD(irlisthead, iperf_interval_results) interval_results;
diff --git a/src/iperf_api.c b/src/iperf_api.c
index d9b3983..b8f7891 100644
--- a/src/iperf_api.c
+++ b/src/iperf_api.c
@@ -2015,6 +2015,13 @@ iperf_stats_callback(struct iperf_test *test)
 		    rp->stream_prev_total_retrans = total_retrans;
 
 		    temp.snd_cwnd = get_snd_cwnd(&temp);
+		    if (temp.snd_cwnd > rp->stream_max_snd_cwnd) {
+			rp->stream_max_snd_cwnd = temp.snd_cwnd;
+		    }
+		    temp.rtt = get_rtt(&temp);
+		    if (temp.rtt > rp->stream_max_rtt) {
+			rp->stream_max_rtt = temp.rtt;
+		    }
 		}
 	    }
 	} else {
@@ -2211,7 +2218,7 @@ iperf_print_results(struct iperf_test *test)
 	    if (test->sender_has_retransmits) {
 		/* Summary, TCP with retransmits. */
 		if (test->json_output)
-		    cJSON_AddItemToObject(json_summary_stream, "sender", iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d", (int64_t) sp->socket, (double) start_time, (double) end_time, (double) end_time, (int64_t) bytes_sent, bandwidth * 8, (int64_t) sp->result->stream_retrans));
+		    cJSON_AddItemToObject(json_summary_stream, "sender", iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d  max_snd_cwnd:  %d  max_rtt:  %d", (int64_t) sp->socket, (double) start_time, (double) end_time, (double) end_time, (int64_t) bytes_sent, bandwidth * 8, (int64_t) sp->result->stream_retrans, (int64_t) sp->result->stream_max_snd_cwnd, (int64_t) sp->result->stream_max_rtt));
 		else
 		    iprintf(test, report_bw_retrans_format, sp->socket, start_time, end_time, ubuf, nbuf, sp->result->stream_retrans, report_sender);
 	    } else {
@@ -2395,7 +2402,7 @@ print_interval_results(struct iperf_test *test, struct iperf_stream *sp, cJSON *
 	if (test->sender && test->sender_has_retransmits) {
 	    /* Interval, TCP with retransmits. */
 	    if (test->json_output)
-		cJSON_AddItemToArray(json_interval_streams, iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d  snd_cwnd:  %d  omitted: %b", (int64_t) sp->socket, (double) st, (double) et, (double) irp->interval_duration, (int64_t) irp->bytes_transferred, bandwidth * 8, (int64_t) irp->interval_retrans, (int64_t) irp->snd_cwnd, irp->omitted));
+		cJSON_AddItemToArray(json_interval_streams, iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d  snd_cwnd:  %d  rtt:  %d  omitted: %b", (int64_t) sp->socket, (double) st, (double) et, (double) irp->interval_duration, (int64_t) irp->bytes_transferred, bandwidth * 8, (int64_t) irp->interval_retrans, (int64_t) irp->snd_cwnd, (int64_t) irp->rtt, irp->omitted));
 	    else {
 		unit_snprintf(cbuf, UNIT_LEN, irp->snd_cwnd, 'A');
 		iprintf(test, report_bw_retrans_cwnd_format, sp->socket, st, et, ubuf, nbuf, irp->interval_retrans, cbuf, irp->omitted?report_omitted:"");
diff --git a/src/iperf_api.h b/src/iperf_api.h
index 368f498..0fe85b8 100644
--- a/src/iperf_api.h
+++ b/src/iperf_api.h
@@ -197,6 +197,7 @@ int has_tcpinfo_retransmits(void);
 void save_tcpinfo(struct iperf_stream *sp, struct iperf_interval_results *irp);
 long get_total_retransmits(struct iperf_interval_results *irp);
 long get_snd_cwnd(struct iperf_interval_results *irp);
+long get_rtt(struct iperf_interval_results *irp);
 void print_tcpinfo(struct iperf_test *test);
 void build_tcpinfo_message(struct iperf_interval_results *r, char *message);
 
diff --git a/src/tcp_info.c b/src/tcp_info.c
index cd3154c..ebf44e9 100644
--- a/src/tcp_info.c
+++ b/src/tcp_info.c
@@ -100,8 +100,9 @@ save_tcpinfo(struct iperf_stream *sp, struct iperf_interval_results *irp)
 	iperf_err(sp->test, "getsockopt - %s", strerror(errno));
 
     if (sp->test->debug) {
-	printf("tcpi_snd_cwnd %u tcpi_snd_mss %u\n",
-	       irp->tcpInfo.tcpi_snd_cwnd, irp->tcpInfo.tcpi_snd_mss);
+	printf("tcpi_snd_cwnd %u tcpi_snd_mss %u tcpi_rtt %u\n",
+	       irp->tcpInfo.tcpi_snd_cwnd, irp->tcpInfo.tcpi_snd_mss,
+	       irp->tcpInfo.tcpi_rtt);
     }
 
 #endif
@@ -140,6 +141,24 @@ get_snd_cwnd(struct iperf_interval_results *irp)
 #endif
 }
 
+/*************************************************************/
+/*
+ * Return rtt in usec.
+ */
+long
+get_rtt(struct iperf_interval_results *irp)
+{
+#if defined(linux) && defined(TCP_MD5SIG)
+    return irp->tcpInfo.tcpi_rtt;
+#else
+#if defined(__FreeBSD__) && __FreeBSD_version >= 600000
+    return irp->tcpInfo.tcpi_rtt;
+#else
+    return -1;
+#endif
+#endif
+}
+
 /*************************************************************/
 void
 build_tcpinfo_message(struct iperf_interval_results *r, char *message)