diff --git a/openbsc/src/rtp_proxy.c b/openbsc/src/rtp_proxy.c
index 5513497..0293812 100644
--- a/openbsc/src/rtp_proxy.c
+++ b/openbsc/src/rtp_proxy.c
@@ -176,6 +176,21 @@
 	return 0;
 }
 
+/* "to - from" */
+static void tv_difference(struct timeval *diff, const struct timeval *from,
+			  const struct timeval *__to)
+{
+	struct timeval _to = *__to, *to = &_to;
+
+	if (to->tv_usec < from->tv_usec) {
+		to->tv_sec -= 1;
+		to->tv_usec += 1000000;
+	}
+
+	diff->tv_usec = to->tv_usec - from->tv_usec;
+	diff->tv_sec = to->tv_sec - from->tv_sec;
+}
+
 /* encode and send a rtp frame */
 int rtp_send_frame(struct rtp_socket *rs, struct gsm_data_frame *frame)
 {
@@ -211,6 +226,26 @@
 		return -EINVAL;
 	}
 
+	{
+		struct timeval tv, tv_diff;
+		long int usec_diff, frame_diff;
+
+		gettimeofday(&tv, NULL);
+		tv_difference(&tv_diff, &rs->transmit.last_tv, &tv);
+		rs->transmit.last_tv = tv;
+
+		usec_diff = tv_diff.tv_sec * 1000000 + tv_diff.tv_usec;
+		frame_diff = (usec_diff / 20000);
+
+		if (abs(frame_diff) > 1) {
+			long int frame_diff_excess = frame_diff - 1;
+
+			DEBUGP(DMUX, "Correcting frame difference of %ld frames\n", frame_diff_excess);
+			rs->transmit.sequence += frame_diff_excess;
+			rs->transmit.timestamp += frame_diff_excess * duration;
+		}
+	}
+
 	msg = msgb_alloc(sizeof(struct rtp_hdr) + payload_len, "RTP-GSM-FULL");
 	if (!msg)
 		return -ENOMEM;