diff --git a/src/libosmo-mgcp-client/mgcp_client_fsm.c b/src/libosmo-mgcp-client/mgcp_client_fsm.c
index ab7af10..e83a119 100644
--- a/src/libosmo-mgcp-client/mgcp_client_fsm.c
+++ b/src/libosmo-mgcp-client/mgcp_client_fsm.c
@@ -404,6 +404,12 @@
 	}
 	LOGPFSML(fi, LOGL_DEBUG, "MGW/MDCX: MGW responded with address %s:%u\n", r->audio_ip, r->audio_port);
 
+	if (r->head.x_osmo_osmux_use) {
+		LOGPFSML(fi, LOGL_DEBUG, "MGW/CRCX: MGW responded using Osmux %u\n", r->head.x_osmo_osmux_cid);
+		mgcp_ctx->conn_peer_remote.x_osmo_osmux_use = true;
+		mgcp_ctx->conn_peer_remote.x_osmo_osmux_cid = r->head.x_osmo_osmux_cid;
+	}
+
 	osmo_strlcpy(mgcp_ctx->conn_peer_remote.addr, r->audio_ip, sizeof(mgcp_ctx->conn_peer_remote.addr));
 	mgcp_ctx->conn_peer_remote.port = r->audio_port;
 
diff --git a/src/libosmo-mgcp/mgcp_protocol.c b/src/libosmo-mgcp/mgcp_protocol.c
index 35141f8..555d6c6 100644
--- a/src/libosmo-mgcp/mgcp_protocol.c
+++ b/src/libosmo-mgcp/mgcp_protocol.c
@@ -323,7 +323,7 @@
 	}
 
 	/* Attach optional OSMUX parameters */
-	if (conn->osmux.state == OSMUX_STATE_NEGOTIATING) {
+	if (mgcp_conn_rtp_is_osmux(conn)) {
 		rc = msgb_printf(sdp, "X-Osmux: %u\r\n", conn->osmux.cid);
 		if (rc < 0)
 			goto error;