diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 2142264..408fea4 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -120,6 +120,7 @@
 	timestamp = ntohl(rtp_hdr->timestamp);
 
 	if (!state->initialized) {
+		state->first_seq_no = seq;
 		state->seq_no = seq - 1;
 		state->ssrc = state->orig_ssrc = rtp_hdr->ssrc;
 		state->initialized = 1;