diff --git a/include/villas/nodes/rtp.h b/include/villas/nodes/rtp.h
index ac5c199d6..f21e74758 100644
--- a/include/villas/nodes/rtp.h
+++ b/include/villas/nodes/rtp.h
@@ -60,6 +60,8 @@ struct rtp {
 	struct format_type *format;
 	struct io io;
 
+	struct mbuf *mb;
+
 	double rate;			/**< Sample rate of source */
 
 	struct {
diff --git a/lib/nodes/rtp.c b/lib/nodes/rtp.c
index 4f261fc41..7a363108b 100644
--- a/lib/nodes/rtp.c
+++ b/lib/nodes/rtp.c
@@ -325,6 +325,15 @@ int rtp_start(struct node *n)
 	if (ret)
 		return ret;
 
+	/* Initialize memory buffer for sending */
+	r->mb = mbuf_alloc(RTP_INITIAL_BUFFER_LEN + 12);
+	if (!r->mb)
+		return -1;
+
+	ret = mbuf_fill(r->mb, 0, 12);
+	if (ret)
+		return -1;
+
 	ret = io_check(&r->io);
 	if (ret)
 		return ret;
@@ -390,6 +399,8 @@ int rtp_stop(struct node *n)
 	if (ret)
 		warning("Problem destroying queue");
 
+	mem_deref(r->mb);
+
 	return io_destroy(&r->io);
 }
 
@@ -500,71 +511,34 @@ int rtp_write(struct node *n, struct sample *smps[], unsigned cnt, unsigned *rel
 	int ret;
 	struct rtp *r = (struct rtp *) n->_vd;
 
-	char *buf;
-	char pad[] = "            ";
-	size_t buflen;
 	size_t wbytes;
+	size_t avail;
 
-	buflen = RTP_INITIAL_BUFFER_LEN;
-	buf = alloc(buflen);
-	if (!buf) {
-		warning("Error allocating buffer space");
-		cnt = -1;
-		goto out1;
-	}
+	uint32_t ts = (uint32_t) time(NULL);
 
-retry:	cnt = io_sprint(&r->io, buf, buflen, &wbytes, smps, cnt);
-	if (cnt < 0) {
-		warning("Error from io_sprint, reason: %d", cnt);
-		goto out1;
-	}
+retry:	mbuf_set_pos(r->mb, 12);
+	avail = mbuf_get_space(r->mb);
+	cnt = io_sprint(&r->io, (char *) r->mb->buf, avail, &wbytes, smps, cnt);
+	if (cnt < 0)
+		return -1;
 
-	if (wbytes <= 0) {
-		warning("Error written bytes = %ld <= 0", wbytes);
-		cnt = -1;
-		goto out1;
-	}
+	if (wbytes > avail) {
+		ret = mbuf_resize(r->mb, wbytes + 12);
+		if (!ret)
+			return -1;
 
-	if (wbytes > buflen) {
-		buflen = wbytes;
-		buf = realloc(buf, buflen);
 		goto retry;
 	}
-
-	/* Prepare mbuf */
-	struct mbuf *mb = mbuf_alloc(buflen + 12);
-	if (!mb) {
-		warning("Failed to allocate memory");
-		cnt = -1;
-		goto out2;
-	}
-
-	ret = mbuf_write_str(mb, pad);
-	if (ret) {
-		warning("Error writing padding to mbuf");
-		cnt = ret;
-		goto out2;
-	}
-
-	ret = mbuf_write_mem(mb, (uint8_t*)buf, buflen);
-	if (ret) {
-		warning("Error writing data to mbuf");
-		cnt = ret;
-		goto out2;
-	}
-
-	mbuf_set_pos(mb, 12);
+	else
+		mbuf_set_end(r->mb, r->mb->pos + wbytes);
 
 	/* Send dataset */
-	ret = rtp_send(r->rs, &r->out.saddr_rtp, false, false, 21, (uint32_t) time(NULL), mb);
+	ret = rtp_send(r->rs, &r->out.saddr_rtp, false, false, 21, ts, r->mb);
 	if (ret) {
 		warning("Error from rtp_send, reason: %d", ret);
 		cnt = ret;
 	}
 
-out2:	mem_deref(mb);
-out1:	free(buf);
-
 	return cnt;
 }