diff --git a/src/iperf_api.c b/src/iperf_api.c
index 05f881e..df6f3b2 100644
--- a/src/iperf_api.c
+++ b/src/iperf_api.c
@@ -595,19 +595,33 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
 int
 iperf_send(struct iperf_test *test, fd_set *write_setP)
 {
-    iperf_size_t bytes_sent;
-    struct iperf_stream *sp;
+    int burst, r;
+    register struct iperf_stream *sp;
 
-    SLIST_FOREACH(sp, &test->streams, streams) {
-	if (FD_ISSET(sp->socket, write_setP)) {
-	    if ((bytes_sent = sp->snd(sp)) < 0) {
-		i_errno = IESTREAMWRITE;
-		return -1;
+    /* Can we do burst mode? */
+    if (test->protocol->id == Pudp && test->settings->rate != 0)
+        burst = 1;	/* nope */
+    else
+        burst = 20;	/* arbitrary */
+
+    for (; burst > 0; --burst) {
+	SLIST_FOREACH(sp, &test->streams, streams) {
+	    if (FD_ISSET(sp->socket, write_setP)) {
+		if ((r = sp->snd(sp)) < 0) {
+		    if (r == NET_SOFTERROR)
+			break;
+		    i_errno = IESTREAMWRITE;
+		    return r;
+		}
+		test->bytes_sent += r;
+		if (burst > 1 && test->settings->bytes != 0 && test->bytes_sent >= test->settings->bytes)
+		    break;
 	    }
-	    test->bytes_sent += bytes_sent;
-	    FD_CLR(sp->socket, write_setP);
 	}
     }
+    SLIST_FOREACH(sp, &test->streams, streams)
+	if (FD_ISSET(sp->socket, write_setP))
+	    FD_CLR(sp->socket, write_setP);
 
     return 0;
 }
@@ -615,16 +629,16 @@ iperf_send(struct iperf_test *test, fd_set *write_setP)
 int
 iperf_recv(struct iperf_test *test, fd_set *read_setP)
 {
-    iperf_size_t bytes_sent;
+    int r;
     struct iperf_stream *sp;
 
     SLIST_FOREACH(sp, &test->streams, streams) {
 	if (FD_ISSET(sp->socket, read_setP)) {
-	    if ((bytes_sent = sp->rcv(sp)) < 0) {
+	    if ((r = sp->rcv(sp)) < 0) {
 		i_errno = IESTREAMREAD;
-		return -1;
+		return r;
 	    }
-	    test->bytes_sent += bytes_sent;
+	    test->bytes_sent += r;
 	    FD_CLR(sp->socket, read_setP);
 	}
     }
diff --git a/src/iperf_tcp.c b/src/iperf_tcp.c
index a14ee32..39d8713 100644
--- a/src/iperf_tcp.c
+++ b/src/iperf_tcp.c
@@ -33,19 +33,17 @@
 int
 iperf_tcp_recv(struct iperf_stream *sp)
 {
-    int result = 0;
-    int size = sp->settings->blksize;
+    int r;
 
-    result = Nread(sp->socket, sp->buffer, size, Ptcp);
+    r = Nread(sp->socket, sp->buffer, sp->settings->blksize, Ptcp);
 
-    if (result < 0) {
-        return -1;
-    }
+    if (r < 0)
+        return r;
 
-    sp->result->bytes_received += result;
-    sp->result->bytes_received_this_interval += result;
+    sp->result->bytes_received += r;
+    sp->result->bytes_received_this_interval += r;
 
-    return result;
+    return r;
 }
 
 
@@ -56,19 +54,17 @@ iperf_tcp_recv(struct iperf_stream *sp)
 int
 iperf_tcp_send(struct iperf_stream *sp)
 {
-    int result;
-    int size = sp->settings->blksize;
+    int r;
 
-    result = Nwrite(sp->socket, sp->buffer, size, Ptcp);
+    r = Nwrite(sp->socket, sp->buffer, sp->settings->blksize, Ptcp);
 
-    if (result < 0) {
-        return -1;
-    }
+    if (r < 0)
+        return r;
 
-    sp->result->bytes_sent += result;
-    sp->result->bytes_sent_this_interval += result;
+    sp->result->bytes_sent += r;
+    sp->result->bytes_sent_this_interval += r;
 
-    return result;
+    return r;
 }
 
 
diff --git a/src/iperf_udp.c b/src/iperf_udp.c
index 538b790..768992a 100644
--- a/src/iperf_udp.c
+++ b/src/iperf_udp.c
@@ -35,20 +35,19 @@
 int
 iperf_udp_recv(struct iperf_stream *sp)
 {
-    int       result;
+    int       r;
     int       size = sp->settings->blksize;
     int       sec, usec, pcount;
     double    transit = 0, d = 0;
     struct timeval sent_time, arrival_time;
 
-    result = Nread(sp->socket, sp->buffer, size, Pudp);
+    r = Nread(sp->socket, sp->buffer, size, Pudp);
 
-    if (result < 0) {
-        return -1;
-    }
+    if (r < 0)
+        return r;
 
-    sp->result->bytes_received += result;
-    sp->result->bytes_received_this_interval += result;
+    sp->result->bytes_received += r;
+    sp->result->bytes_received_this_interval += r;
 
     memcpy(&sec, sp->buffer, sizeof(sec));
     memcpy(&usec, sp->buffer+4, sizeof(usec));
@@ -82,7 +81,7 @@ iperf_udp_recv(struct iperf_stream *sp)
     //      J = |(R1 - S1) - (R0 - S0)| [/ number of packets, for average]
     sp->jitter += (d - sp->jitter) / 16.0;
 
-    return result;
+    return r;
 }
 
 
@@ -107,7 +106,7 @@ send_timer_proc(TimerClientData client_data, struct timeval* nowP)
 int
 iperf_udp_send(struct iperf_stream *sp)
 {
-    ssize_t   result = 0;
+    int r;
     int64_t   dtargus;
     int64_t   adjustus;
     uint64_t  sec, usec, pcount;
@@ -115,46 +114,47 @@ iperf_udp_send(struct iperf_stream *sp)
     struct timeval before, after;
     TimerClientData cd;
 
-    if (sp->udp_green_light) {
-        gettimeofday(&before, 0);
+    if (! sp->udp_green_light)
+        return 0;
 
-        ++sp->packet_count;
-        sec = htonl(before.tv_sec);
-        usec = htonl(before.tv_usec);
-        pcount = htonl(sp->packet_count);
+    gettimeofday(&before, 0);
 
-        memcpy(sp->buffer, &sec, sizeof(sec));
-        memcpy(sp->buffer+4, &usec, sizeof(usec));
-        memcpy(sp->buffer+8, &pcount, sizeof(pcount));
+    ++sp->packet_count;
+    sec = htonl(before.tv_sec);
+    usec = htonl(before.tv_usec);
+    pcount = htonl(sp->packet_count);
 
-        result = Nwrite(sp->socket, sp->buffer, size, Pudp);
+    memcpy(sp->buffer, &sec, sizeof(sec));
+    memcpy(sp->buffer+4, &usec, sizeof(usec));
+    memcpy(sp->buffer+8, &pcount, sizeof(pcount));
 
-        if (result < 0)
-            return -1;
+    r = Nwrite(sp->socket, sp->buffer, size, Pudp);
 
-        sp->result->bytes_sent += result;
-        sp->result->bytes_sent_this_interval += result;
+    if (r < 0)
+	return r;
 
-	if (sp->settings->rate != 0) {
-	    gettimeofday(&after, 0);
-	    dtargus = (int64_t) (sp->settings->blksize) * SEC_TO_US * 8;
-	    dtargus /= sp->settings->rate;
-	    assert(dtargus != 0);
-	    adjustus = dtargus;
-	    adjustus += (before.tv_sec - after.tv_sec) * SEC_TO_US;
-	    adjustus += (before.tv_usec - after.tv_usec);
-	    if (adjustus > 0) {
-		dtargus = adjustus;
-	    }
-	    cd.p = sp;
-	    sp->udp_green_light = 0;
-	    sp->send_timer = tmr_create((struct timeval*) 0, send_timer_proc, cd, dtargus, 0);
-	    if (sp->send_timer == NULL)
-		return -1;
+    sp->result->bytes_sent += r;
+    sp->result->bytes_sent_this_interval += r;
+
+    if (sp->settings->rate != 0) {
+	gettimeofday(&after, 0);
+	dtargus = (int64_t) (sp->settings->blksize) * SEC_TO_US * 8;
+	dtargus /= sp->settings->rate;
+	assert(dtargus != 0);
+	adjustus = dtargus;
+	adjustus += (before.tv_sec - after.tv_sec) * SEC_TO_US;
+	adjustus += (before.tv_usec - after.tv_usec);
+	if (adjustus > 0) {
+	    dtargus = adjustus;
 	}
+	cd.p = sp;
+	sp->udp_green_light = 0;
+	sp->send_timer = tmr_create((struct timeval*) 0, send_timer_proc, cd, dtargus, 0);
+	if (sp->send_timer == NULL)
+	    return -1;
     }
 
-    return result;
+    return r;
 }
 
 
diff --git a/src/net.c b/src/net.c
index 03ca9f8..0dd6d82 100644
--- a/src/net.c
+++ b/src/net.c
@@ -131,7 +131,7 @@ Nread(int fd, void *buf, int count, int prot)
             if (errno == EINTR)
                 n = 0;
             else
-                return -1;
+                return NET_HARDERROR;
         } else if (n == 0)
             break;
 
@@ -144,9 +144,6 @@ Nread(int fd, void *buf, int count, int prot)
 
 /*
  *                      N W R I T E
- *
- * XXX: After updating this function to use read/write, the only difference between
- *      TCP and UDP is that udp handles ENOBUFS. Should we merge the two?
  */
 
 int
@@ -155,34 +152,22 @@ Nwrite(int fd, void *buf, int count, int prot)
     register int n;
     register int nleft = count;
 
-    if (prot == SOCK_DGRAM) { /* UDP mode */
-        while (nleft > 0) {
-            if ((n = write(fd, buf, nleft)) < 0) {
-                if (errno == EINTR) {
-                    n = 0;
-                } else if (errno == ENOBUFS) {
-                    /* wait if run out of buffers */
-                    /* XXX: but how long to wait? Start shorter and increase delay each time?? */
-                    delay(18000);   // XXX: Fixme!
-                    n = 0;
-                } else {
-                    return -1;
-                }
-            }
-            nleft -= n;
-            buf += n;
-        }
-    } else {
-        while (nleft > 0) {
-            if ((n = write(fd, buf, nleft)) < 0) {
-                if (errno == EINTR)
-                    n = 0;
-                else
-                    return -1;
-            }
-            nleft -= n;
-            buf += n;
-        }
+    while (nleft > 0) {
+	if ((n = write(fd, buf, nleft)) < 0) {
+	    switch (errno) {
+		case EINTR:
+		return count - nleft;
+
+		case EAGAIN:
+		case ENOBUFS:
+		return NET_SOFTERROR;
+
+		default:
+		return NET_HARDERROR;
+	    }
+	}
+	nleft -= n;
+	buf += n;
     }
     return count;
 }
diff --git a/src/net.h b/src/net.h
index cb14fc6..4a6129c 100644
--- a/src/net.h
+++ b/src/net.h
@@ -18,6 +18,9 @@ int getsock_tcp_mss(int);
 int set_tcp_options(int, int, int);
 int setnonblocking(int);
 
+#define NET_SOFTERROR -1
+#define NET_HARDERROR -2
+
 unsigned long long htonll(unsigned long long);
 unsigned long long ntohll(unsigned long long);