diff --git a/openbsc/include/openbsc/mgcp.h b/openbsc/include/openbsc/mgcp.h
index 4e22e0f..8ab52ce 100644
--- a/openbsc/include/openbsc/mgcp.h
+++ b/openbsc/include/openbsc/mgcp.h
@@ -118,6 +118,10 @@
 
 	int omit_rtcp;
 
+	/* RTP patching */
+	int force_constant_ssrc; /* 0: don't, 1: once */
+	int force_constant_timing;
+
 	/* spec handling */
 	int force_realloc;
 
diff --git a/openbsc/include/openbsc/mgcp_internal.h b/openbsc/include/openbsc/mgcp_internal.h
index 0b52c1c..02e193d 100644
--- a/openbsc/include/openbsc/mgcp_internal.h
+++ b/openbsc/include/openbsc/mgcp_internal.h
@@ -83,6 +83,10 @@
 	int  frames_per_packet;
 	char *fmtp_extra;
 
+	/* RTP patching */
+	int force_constant_ssrc;
+	int force_constant_timing;
+
 	/*
 	 * Each end has a socket...
 	 */
@@ -142,9 +146,6 @@
 	struct mgcp_rtp_state net_state;
 	struct mgcp_rtp_state bts_state;
 
-	/* SSRC/seq/ts patching for loop */
-	int allow_patch;
-
 	/* fields for re-transmission */
 	char *last_trans;
 	char *last_response;
@@ -176,6 +177,9 @@
 struct mgcp_trunk_config *mgcp_trunk_alloc(struct mgcp_config *cfg, int index);
 struct mgcp_trunk_config *mgcp_trunk_num(struct mgcp_config *cfg, int index);
 
+void mgcp_rtp_end_config(struct mgcp_endpoint *endp, int expect_ssrc_change,
+			 struct mgcp_rtp_end *rtp);
+
 void mgcp_state_calc_loss(struct mgcp_rtp_state *s, struct mgcp_rtp_end *,
 			uint32_t *expected, int *loss);
 uint32_t mgcp_state_calc_jitter(struct mgcp_rtp_state *);
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 53f1a20..367cebd 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -264,7 +264,7 @@
 		state->seq_offset = (state->out_stream.last_seq + 1) - seq;
 		state->timestamp_offset =
 			(state->out_stream.last_timestamp + tsdelta) - timestamp;
-		state->patch = endp->allow_patch;
+		state->patch = rtp_end->force_constant_ssrc;
 		LOGP(DMGCP, LOGL_NOTICE,
 			"The SSRC changed on 0x%x SSRC: %u offset: %d tsdelta: %d "
 			"from %s:%d in %d\n",
diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c
index a0b905d..c703bec 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -614,6 +614,21 @@
 	return found_media;
 }
 
+void mgcp_rtp_end_config(struct mgcp_endpoint *endp, int expect_ssrc_change,
+			 struct mgcp_rtp_end *rtp)
+{
+	struct mgcp_trunk_config *tcfg = endp->tcfg;
+
+	rtp->force_constant_timing = tcfg->force_constant_timing;
+	rtp->force_constant_ssrc = tcfg->force_constant_ssrc;
+
+	LOGP(DMGCP, LOGL_DEBUG,
+	     "Configuring RTP endpoint: local port %d%s%s\n",
+	     ntohs(rtp->rtp_port),
+	     rtp->force_constant_timing ? ", force constant timing" : "",
+	     rtp->force_constant_ssrc ? ", force constant ssrc" : "");
+}
+
 static struct msgb *handle_create_con(struct mgcp_parse_data *p)
 {
 	struct mgcp_trunk_config *tcfg;
@@ -688,6 +703,8 @@
 
 	/* initialize */
 	endp->net_end.rtp_port = endp->net_end.rtcp_port = endp->bts_end.rtp_port = endp->bts_end.rtcp_port = 0;
+	mgcp_rtp_end_config(endp, 0, &endp->net_end);
+	mgcp_rtp_end_config(endp, 0, &endp->bts_end);
 
 	/* set to zero until we get the info */
 	memset(&endp->net_end.addr, 0, sizeof(endp->net_end.addr));
@@ -825,6 +842,9 @@
 		}
 	}
 
+	mgcp_rtp_end_config(endp, 1, &endp->net_end);
+	mgcp_rtp_end_config(endp, 1, &endp->bts_end);
+
 	/* modify */
 	LOGP(DMGCP, LOGL_DEBUG, "Modified endpoint on: 0x%x Server: %s:%u\n",
 		ENDPOINT_NUMBER(endp), inet_ntoa(endp->net_end.addr), ntohs(endp->net_end.rtp_port));
@@ -1121,7 +1141,6 @@
 	memset(&endp->bts_state, 0, sizeof(endp->bts_state));
 
 	endp->conn_mode = endp->orig_mode = MGCP_CONN_NONE;
-	endp->allow_patch = 0;
 
 	memset(&endp->taps, 0, sizeof(endp->taps));
 }
diff --git a/openbsc/src/libmgcp/mgcp_vty.c b/openbsc/src/libmgcp/mgcp_vty.c
index 5aeb393..e48b050 100644
--- a/openbsc/src/libmgcp/mgcp_vty.c
+++ b/openbsc/src/libmgcp/mgcp_vty.c
@@ -31,6 +31,7 @@
 #include <string.h>
 
 #define RTCP_OMIT_STR "Drop RTCP packets in both directions\n"
+#define RTP_PATCH_STR "Modify RTP packet header in both directions\n"
 
 static struct mgcp_config *g_cfg = NULL;
 
@@ -88,6 +89,13 @@
 		vty_out(vty, "  rtcp-omit%s", VTY_NEWLINE);
 	else
 		vty_out(vty, "  no rtcp-omit%s", VTY_NEWLINE);
+	if (g_cfg->trunk.force_constant_ssrc || g_cfg->trunk.force_constant_timing) {
+		vty_out(vty, "  %srtp-patch ssrc%s",
+			g_cfg->trunk.force_constant_ssrc ? "" : "no ", VTY_NEWLINE);
+		vty_out(vty, "  %srtp-patch timestamp%s",
+			g_cfg->trunk.force_constant_timing ? "" : "no ", VTY_NEWLINE);
+	} else
+		vty_out(vty, "  no rtp-patch%s", VTY_NEWLINE);
 	if (g_cfg->trunk.audio_payload != -1)
 		vty_out(vty, "  sdp audio-payload number %d%s",
 			g_cfg->trunk.audio_payload, VTY_NEWLINE);
@@ -421,6 +429,61 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_mgcp_patch_rtp_ssrc,
+      cfg_mgcp_patch_rtp_ssrc_cmd,
+      "rtp-patch ssrc",
+      RTP_PATCH_STR
+      "Force a fixed SSRC\n"
+      )
+{
+	g_cfg->trunk.force_constant_ssrc = 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_no_patch_rtp_ssrc,
+      cfg_mgcp_no_patch_rtp_ssrc_cmd,
+      "no rtp-patch ssrc",
+      NO_STR RTP_PATCH_STR
+      "Force a fixed SSRC\n"
+      )
+{
+	g_cfg->trunk.force_constant_ssrc = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_patch_rtp_ts,
+      cfg_mgcp_patch_rtp_ts_cmd,
+      "rtp-patch timestamp",
+      RTP_PATCH_STR
+      "Adjust RTP timestamp\n"
+      )
+{
+	g_cfg->trunk.force_constant_timing = 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_no_patch_rtp_ts,
+      cfg_mgcp_no_patch_rtp_ts_cmd,
+      "no rtp-patch timestamp",
+      NO_STR RTP_PATCH_STR
+      "Adjust RTP timestamp\n"
+      )
+{
+	g_cfg->trunk.force_constant_timing = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_no_patch_rtp,
+      cfg_mgcp_no_patch_rtp_cmd,
+      "no rtp-patch",
+      NO_STR RTP_PATCH_STR)
+{
+	g_cfg->trunk.force_constant_ssrc = 0;
+	g_cfg->trunk.force_constant_timing = 0;
+	return CMD_SUCCESS;
+}
+
+
 #define CALL_AGENT_STR "Callagent information\n"
 DEFUN(cfg_mgcp_agent_addr,
       cfg_mgcp_agent_addr_cmd,
@@ -511,6 +574,13 @@
 			vty_out(vty, "  rtcp-omit%s", VTY_NEWLINE);
 		else
 			vty_out(vty, "  no rtcp-omit%s", VTY_NEWLINE);
+		if (trunk->force_constant_ssrc || trunk->force_constant_timing) {
+			vty_out(vty, "  %srtp-patch ssrc%s",
+				trunk->force_constant_ssrc ? "" : "no ", VTY_NEWLINE);
+			vty_out(vty, "  %srtp-patch timestamp%s",
+				trunk->force_constant_timing ? "" : "no ", VTY_NEWLINE);
+		} else
+			vty_out(vty, "  no rtp-patch%s", VTY_NEWLINE);
 		if (trunk->audio_fmtp_extra)
 			vty_out(vty, "   sdp audio fmtp-extra %s%s",
 				trunk->audio_fmtp_extra, VTY_NEWLINE);
@@ -599,6 +669,66 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_trunk_patch_rtp_ssrc,
+      cfg_trunk_patch_rtp_ssrc_cmd,
+      "rtp-patch ssrc",
+      RTP_PATCH_STR
+      "Force a fixed SSRC\n"
+      )
+{
+	struct mgcp_trunk_config *trunk = vty->index;
+	trunk->force_constant_ssrc = 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trunk_no_patch_rtp_ssrc,
+      cfg_trunk_no_patch_rtp_ssrc_cmd,
+      "no rtp-patch ssrc",
+      NO_STR RTP_PATCH_STR
+      "Force a fixed SSRC\n"
+      )
+{
+	struct mgcp_trunk_config *trunk = vty->index;
+	trunk->force_constant_ssrc = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trunk_patch_rtp_ts,
+      cfg_trunk_patch_rtp_ts_cmd,
+      "rtp-patch timestamp",
+      RTP_PATCH_STR
+      "Adjust RTP timestamp\n"
+      )
+{
+	struct mgcp_trunk_config *trunk = vty->index;
+	trunk->force_constant_timing = 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trunk_no_patch_rtp_ts,
+      cfg_trunk_no_patch_rtp_ts_cmd,
+      "no rtp-patch timestamp",
+      NO_STR RTP_PATCH_STR
+      "Adjust RTP timestamp\n"
+      )
+{
+	struct mgcp_trunk_config *trunk = vty->index;
+	trunk->force_constant_timing = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trunk_no_patch_rtp,
+      cfg_trunk_no_patch_rtp_cmd,
+      "no rtp-patch",
+      NO_STR RTP_PATCH_STR)
+{
+	struct mgcp_trunk_config *trunk = vty->index;
+	trunk->force_constant_ssrc = 0;
+	trunk->force_constant_timing = 0;
+	return CMD_SUCCESS;
+}
+
+
 DEFUN(loop_endp,
       loop_endp_cmd,
       "loop-endpoint <0-64> NAME (0|1)",
@@ -636,7 +766,10 @@
 		endp->conn_mode = MGCP_CONN_LOOPBACK;
 	else
 		endp->conn_mode = endp->orig_mode;
-	endp->allow_patch = 1;
+
+	/* Handle it like a MDCX, switch on SSRC patching if enabled */
+	mgcp_rtp_end_config(endp, 1, &endp->bts_end);
+	mgcp_rtp_end_config(endp, 1, &endp->net_end);
 
 	return CMD_SUCCESS;
 }
@@ -827,6 +960,11 @@
 	install_element(MGCP_NODE, &cfg_mgcp_number_endp_cmd);
 	install_element(MGCP_NODE, &cfg_mgcp_omit_rtcp_cmd);
 	install_element(MGCP_NODE, &cfg_mgcp_no_omit_rtcp_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_patch_rtp_ssrc_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_no_patch_rtp_ssrc_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_patch_rtp_ts_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_no_patch_rtp_ts_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_no_patch_rtp_cmd);
 	install_element(MGCP_NODE, &cfg_mgcp_sdp_fmtp_extra_cmd);
 
 	install_element(MGCP_NODE, &cfg_mgcp_trunk_cmd);
@@ -839,6 +977,11 @@
 	install_element(TRUNK_NODE, &cfg_trunk_loop_cmd);
 	install_element(TRUNK_NODE, &cfg_trunk_omit_rtcp_cmd);
 	install_element(TRUNK_NODE, &cfg_trunk_no_omit_rtcp_cmd);
+	install_element(TRUNK_NODE, &cfg_trunk_patch_rtp_ssrc_cmd);
+	install_element(TRUNK_NODE, &cfg_trunk_no_patch_rtp_ssrc_cmd);
+	install_element(TRUNK_NODE, &cfg_trunk_patch_rtp_ts_cmd);
+	install_element(TRUNK_NODE, &cfg_trunk_no_patch_rtp_ts_cmd);
+	install_element(TRUNK_NODE, &cfg_trunk_no_patch_rtp_cmd);
 	install_element(TRUNK_NODE, &cfg_trunk_sdp_fmtp_extra_cmd);
 
 	return 0;
diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index 8e130bb..908773a 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -558,6 +558,9 @@
 
 	trunk.number_endpoints = 1;
 	trunk.endpoints = &endp;
+	trunk.force_constant_ssrc = patch_ssrc;
+	trunk.force_constant_timing = patch_ts;
+
 	endp.tcfg = &trunk;
 
 	/* This doesn't free endp but resets/frees all fields of the structure
@@ -568,7 +571,6 @@
 	mgcp_free_endp(&endp);
 
 	rtp->payload_type = 98;
-	endp.allow_patch = patch_ssrc;
 
 	for (i = 0; i < ARRAY_SIZE(test_rtp_packets1); ++i) {
 		struct rtp_packet_info *info = test_rtp_packets1 + i;
@@ -577,6 +579,8 @@
 		OSMO_ASSERT(info->len >= 0);
 		memmove(buffer, info->data, info->len);
 
+		mgcp_rtp_end_config(&endp, 1, rtp);
+
 		mgcp_patch_and_count(&endp, &state, rtp, &addr,
 				     buffer, info->len);