diff --git a/src/iperf.h b/src/iperf.h
index 3fc91d0c0..2abd4bb93 100644
--- a/src/iperf.h
+++ b/src/iperf.h
@@ -272,6 +272,8 @@ struct iperf_test
     TAILQ_HEAD(xbind_addrhead, xbind_entry) xbind_addrs; /* all -X opts */
     int       bind_port;                        /* --cport option */
     int       server_port;
+    int       num_of_server_ports;              /* second value of --port option */
+    int       server_udp_streams_accepted;          /* offset of last server port used - 0 means none used (max `num_of_server_ports`) */
     int       omit;                             /* duration of omit period (-O flag) */
     int       duration;                         /* total duration of test (-t flag) */
     char     *diskfile_name;			/* -F option */
@@ -397,6 +399,9 @@ struct iperf_test
 #define OMIT 0 /* seconds */
 #define DURATION 10 /* seconds */
 
+#define UDP_STREAM_INIT_REQ_DATAGRAM 123456789
+#define UDP_STREAM_INIT_RESP_DATAGRAM 987654321
+
 #define SEC_TO_NS 1000000000LL	/* too big for enum/const on some platforms */
 #define MAX_RESULT_STRING 4096
 
diff --git a/src/iperf_api.c b/src/iperf_api.c
index f8f2321ec..c290e8d6c 100644
--- a/src/iperf_api.c
+++ b/src/iperf_api.c
@@ -1033,6 +1033,21 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
     while ((flag = getopt_long(argc, argv, "p:f:i:D1VJvsc:ub:t:n:k:l:P:Rw:B:M:N46S:L:ZO:F:A:T:C:dI:hX:", longopts, NULL)) != -1) {
         switch (flag) {
             case 'p':
+            	slash = strchr(optarg, '/');
+		if (slash) {
+		    *slash = '\0';
+		    ++slash;
+                    if (*slash != '\0') {
+                        test->num_of_server_ports = atoi(slash);
+                        if (test->num_of_server_ports < 1 || test->num_of_server_ports > MAX_STREAMS) {
+                            i_errno = IENUMPORTS;
+                            return -1;
+                        }
+                        if (test->num_of_server_ports > 1) {
+                            server_flag = 1;
+                        }
+                    }
+		}
 		portno = atoi(optarg);
 		if (portno < 1 || portno > 65535) {
 		    i_errno = IEBADPORT;
@@ -1898,6 +1913,26 @@ iperf_exchange_parameters(struct iperf_test *test)
         if (get_parameters(test) < 0)
             return -1;
 
+        // Check spcific conditions required for UDP under Cygwin as it does not support parallel stream using same port
+        if (test->protocol->id == Pudp) {
+            // Ensure UDP ports pool size if large enough for the required number of streams
+            if (test->num_of_server_ports > 1) {
+                if (test->num_of_server_ports < test->num_streams) {
+                    i_errno = IEPORTNUM;
+                    return -1;
+                }
+            }
+#if defined(__CYGWIN__)
+            else {
+                // Parallel UDP streams under Cygwin must use different port number per stream
+                if (test->num_streams > 1) {
+                    i_errno = IECYGWINPORTSUDP;
+                    return -1;
+                }
+            }
+#endif /* __CYGWIN__ */
+        }
+
 #if defined(HAVE_SSL)
         if (test_is_authorized(test) < 0){
             if (iperf_set_send_state(test, SERVER_ERROR) != 0)
@@ -1913,7 +1948,7 @@ iperf_exchange_parameters(struct iperf_test *test)
 #endif //HAVE_SSL
 
         if ((s = test->protocol->listen(test)) < 0) {
-	        if (iperf_set_send_state(test, SERVER_ERROR) != 0)
+	    if (iperf_set_send_state(test, SERVER_ERROR) != 0)
                 return -1;
             err = htonl(i_errno);
             if (Nwrite(test->ctrl_sck, (char*) &err, sizeof(err), Ptcp) < 0) {
@@ -2631,6 +2666,8 @@ iperf_defaults(struct iperf_test *testp)
     testp->congestion_used = NULL;
     testp->remote_congestion_used = NULL;
     testp->server_port = PORT;
+    testp->num_of_server_ports = 0;
+    testp->server_udp_streams_accepted = 0;
     testp->ctrl_sck = -1;
     testp->prot_listener = -1;
     testp->other_side_has_retransmits = 0;
@@ -2904,6 +2941,7 @@ iperf_reset_test(struct iperf_test *test)
     test->mode = RECEIVER;
     test->sender_has_retransmits = 0;
     set_protocol(test, Ptcp);
+    test->server_udp_streams_accepted = 0;
     test->omit = OMIT;
     test->duration = DURATION;
     test->server_affinity = -1;
diff --git a/src/iperf_api.h b/src/iperf_api.h
index cb4a86d76..0cfc7a0bc 100644
--- a/src/iperf_api.h
+++ b/src/iperf_api.h
@@ -379,6 +379,9 @@ enum {
     IEIDLETIMEOUT = 30,     // Invalid value specified as idle state timeout
     IERCVTIMEOUT = 31,      // Illegal message receive timeout
     IERVRSONLYRCVTIMEOUT = 32,  // Client receive timeout is valid only in reverse mode
+    IENUMPORTS = 33,        // number of ports is less than 1 or larger than server limit
+    IEPORTNUM = 34,         // requested number of parallel streams is larger than the number of ports set for the server
+    IECYGWINPORTSUDP = 35,  // different port (parameter `-p #/<num of ports>`) should be available for parallel UDP streams under Cygwin
     /* Test errors */
     IENEWTEST = 100,        // Unable to create a new test (check perror)
     IEINITTEST = 101,       // Test initialization failed (check perror)
diff --git a/src/iperf_error.c b/src/iperf_error.c
index 1bcf8a83e..380951a2d 100644
--- a/src/iperf_error.c
+++ b/src/iperf_error.c
@@ -432,7 +432,7 @@ iperf_strerror(int int_errno)
 	case IETOTALRATE:
 	    snprintf(errstr, len, "total required bandwidth is larger than server limit");
             break;
-    case IESKEWTHRESHOLD:
+        case IESKEWTHRESHOLD:
 	    snprintf(errstr, len, "skew threshold must be a positive number");
             break;
 	case IEIDLETIMEOUT:
@@ -441,9 +441,18 @@ iperf_strerror(int int_errno)
 	case IENOMSG:
 	    snprintf(errstr, len, "idle timeout for receiving data");
             break;
-    case IESETDONTFRAGMENT:
+        case IESETDONTFRAGMENT:
 	    snprintf(errstr, len, "unable to set IP Do-Not-Fragment flag");
             break;
+        case IENUMPORTS:
+	    snprintf(errstr, len, "number of ports is less than 1 or larger than server limit");
+            break;
+        case IEPORTNUM:
+	    snprintf(errstr, len, "requested number of parallel streams is larger than the number of ports set for the server");
+            break;
+        case IECYGWINPORTSUDP:
+	    snprintf(errstr, len, "different port (parameter `-p #/<num of ports>`) should be available for parallel UDP streams under Cygwin");
+            break;
 	default:
 	    snprintf(errstr, len, "int_errno=%d", int_errno);
 	    perr = 1;
diff --git a/src/iperf_locale.c b/src/iperf_locale.c
index e1e9dc5b6..fe9a1793c 100644
--- a/src/iperf_locale.c
+++ b/src/iperf_locale.c
@@ -97,7 +97,9 @@ const char usage_shortstr[] = "Usage: iperf3 [-s|-c host] [options]\n"
 const char usage_longstr[] = "Usage: iperf3 [-s|-c host] [options]\n"
                            "       iperf3 [-h|--help] [-v|--version]\n\n"
                            "Server or Client:\n"
-                           "  -p, --port      #         server port to listen on/connect to\n"
+                           "  -p, --port      #[/#]     server port to listen on/connect to\n"
+                           "                            (optional for server UDP: pool size of ports starting with\n"
+                           "                            port # - required for parallel UDP sterams under cygwin)\n"
                            "  -f, --format   [kmgtKMGT] format to report: Kbits, Mbits, Gbits, Tbits\n"
                            "  -i, --interval  #         seconds between periodic throughput reports\n"
                            "  -I, --pidfile file        write PID file\n"
diff --git a/src/iperf_server_api.c b/src/iperf_server_api.c
index 500ff73da..92bf40789 100644
--- a/src/iperf_server_api.c
+++ b/src/iperf_server_api.c
@@ -371,6 +371,7 @@ static void
 cleanup_server(struct iperf_test *test)
 {
     struct iperf_stream *sp;
+    int i;
 
     /* Close open streams */
     SLIST_FOREACH(sp, &test->streams, streams) {
@@ -390,6 +391,12 @@ cleanup_server(struct iperf_test *test)
 	close(test->prot_listener);
     }
 
+    /* Close all listening ports in case pool of listening ports is used */
+    for (i = 0; i <= test->server_udp_streams_accepted; i++) {
+        printf("***** Closing UDP port %d;\n", test->server_port + i);
+        close(test->server_port + i);
+    }
+
     /* Cancel any remaining timers. */
     if (test->stats_timer != NULL) {
 	tmr_cancel(test->stats_timer);
diff --git a/src/iperf_udp.c b/src/iperf_udp.c
index 126cd639f..91e9b6db6 100644
--- a/src/iperf_udp.c
+++ b/src/iperf_udp.c
@@ -369,6 +369,7 @@ iperf_udp_accept(struct iperf_test *test)
     socklen_t len;
     int       sz, s;
     int	      rc;
+    int       port;
 
     /*
      * Get the current outstanding socket.  This socket will be used to handle
@@ -437,10 +438,28 @@ iperf_udp_accept(struct iperf_test *test)
 	}
     }
 
+
+    /*
+     * Set  listening por for accepting next parallel stream request.
+     * Use differet port per stream when pool of ports was defined.
+     * (required to support parallel stream under Windows cygwin.)
+     */
+    buf = UDP_STREAM_INIT_RESP_DATAGRAM;
+    port = test->server_port;
+    if (test->num_of_server_ports > 1) {
+        if (test->server_udp_streams_accepted >= test->num_of_server_ports) {
+            i_errno = IEPORTNUM;
+            return -1;
+        }
+        test->server_udp_streams_accepted++;
+        port += test->server_udp_streams_accepted;
+        buf = port;
+    }
+
     /*
      * Create a new "listening" socket to replace the one we were using before.
      */
-    test->prot_listener = netannounce(test->settings->domain, Pudp, test->bind_address, test->bind_dev, test->server_port);
+    test->prot_listener = netannounce(test->settings->domain, Pudp, test->bind_address, test->bind_dev, port);
     if (test->prot_listener < 0) {
         i_errno = IESTREAMLISTEN;
         return -1;
@@ -449,8 +468,10 @@ iperf_udp_accept(struct iperf_test *test)
     FD_SET(test->prot_listener, &test->read_set);
     test->max_fd = (test->max_fd < test->prot_listener) ? test->prot_listener : test->max_fd;
 
-    /* Let the client know we're ready "accept" another UDP "stream" */
-    buf = 987654321;		/* any content will work here */
+    /* 
+     * Let the client know we're ready "accept" another UDP "stream",
+     * and send the listening port when applicable.
+     */
     if (write(s, &buf, sizeof(buf)) < 0) {
         i_errno = IESTREAMWRITE;
         return -1;
@@ -560,7 +581,7 @@ iperf_udp_connect(struct iperf_test *test)
      * Write a datagram to the UDP stream to let the server know we're here.
      * The server learns our address by obtaining its peer's address.
      */
-    buf = 123456789;		/* this can be pretty much anything */
+    buf = UDP_STREAM_INIT_REQ_DATAGRAM;		/* this can be pretty much anything */
     if (write(s, &buf, sizeof(buf)) < 0) {
         // XXX: Should this be changed to IESTREAMCONNECT? 
         i_errno = IESTREAMWRITE;
@@ -575,6 +596,13 @@ iperf_udp_connect(struct iperf_test *test)
         return -1;
     }
 
+    /*
+    * If the recived value is a port number, use it as the next connection port
+    */
+    if (buf != UDP_STREAM_INIT_RESP_DATAGRAM) {
+        test->server_port = buf;
+    } 
+
     return s;
 }