diff --git a/src/libdebug/debug.c b/src/libdebug/debug.c
index 67ba00c..f7b91e0 100644
--- a/src/libdebug/debug.c
+++ b/src/libdebug/debug.c
@@ -57,6 +57,8 @@ struct debug_cat {
 	{ "jollycom", "\033[1;34m" },
 	{ "eurosignal", "\033[1;34m" },
 	{ "pocsag", "\033[1;34m" },
+	{ "golay", "\033[1;34m" },
+	{ "5-ton-folge", "\033[1;34m" },
 	{ "frame", "\033[0;36m" },
 	{ "call", "\033[0;37m" },
 	{ "cc", "\033[1;32m" },
@@ -89,12 +91,16 @@ struct debug_cat {
 	{ "dss1", "\033[1;34m" },
 	{ "sip", "\033[1;35m" },
 	{ "telephone", "\033[1;34m" },
+	{ "uk0", "\033[1;34m" },
+	{ "ph", "\033[0;33m" },
+	{ "dcf77", "\033[1;34m" },
+	{ "jitter", "\033[0;36m" },
 	{ NULL, NULL }
 };
 
 int debuglevel = DEBUG_INFO;
 int debug_date = 0;
-uint64_t debug_mask = ~0;
+uint64_t debug_mask[2] = { ~0, ~0 };
 extern int num_kanal;
 
 void (*clear_console_text)(void) = NULL;
@@ -105,6 +111,25 @@ int debug_limit_scroll = 0;
 static int lock_initialized = 0;
 static pthread_mutex_t debug_mutex;
 
+void lock_debug(void)
+{
+	int rc;
+
+	if (!lock_initialized) {
+		rc = pthread_mutex_init(&debug_mutex, NULL);
+		if (rc == 0)
+			lock_initialized = 1;
+	}
+	if (lock_initialized)
+		pthread_mutex_lock(&debug_mutex);
+}
+
+void unlock_debug(void)
+{
+	if (lock_initialized)
+		pthread_mutex_unlock(&debug_mutex);
+}
+
 void get_win_size(int *w, int *h)
 {
 	struct winsize win;
@@ -127,22 +152,15 @@ void _printdebug(const char *file, const char __attribute__((unused)) *function,
 	int s = sizeof(buffer) - 1;
 	const char *p;
 	va_list args;
-	int w, h;
-	int rc;
+	int w, h = 0; // make GCC happy
 
 	if (debuglevel > level)
 		return;
 
-	if (!(debug_mask & ((uint64_t)1 << cat)))
+	if (!(debug_mask[cat >> 6] & ((uint64_t)1 << (cat & 63))))
 		return;
 
-	if (!lock_initialized) {
-		rc = pthread_mutex_init(&debug_mutex, NULL);
-		if (rc == 0)
-			lock_initialized = 1;
-	}
-	if (lock_initialized)
-		pthread_mutex_lock(&debug_mutex);
+	lock_debug();
 
 	buffer[sizeof(buffer) - 1] = '\0';
 
@@ -174,15 +192,14 @@ void _printdebug(const char *file, const char __attribute__((unused)) *function,
 
 		printf("%04d-%02d-%02d %02d:%02d:%02d.%03d ", tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, (int)(tv.tv_usec / 10000.0));
 	}
-	printf("%s%s:%4d %s: %s\033[0;39m", debug_cat[cat].color, file, line, debug_level[level], buffer);
+	printf("%s%s %4d %s-%s: %s\033[0;39m", debug_cat[cat].color, file, line, debug_cat[cat].name, debug_level[level], buffer);
 	if (debug_limit_scroll)
 		printf("\0337\033[%d;%dr\0338", 1, h);
 	if (print_console_text)
 		print_console_text();
 	fflush(stdout);
 
-	if (lock_initialized)
-		pthread_mutex_unlock(&debug_mutex);
+	unlock_debug();
 }
 
 const char *debug_amplitude(double level)
@@ -274,7 +291,7 @@ int parse_debug_opt(const char *optarg)
 		return -EINVAL;
 	}
 	if (dstring)
-		debug_mask = 0;
+		memset(debug_mask, 0, sizeof(debug_mask));
 	while((p = strsep(&dstring, ","))) {
 		for (i = 0; debug_cat[i].name; i++) {
 			if (!strcasecmp(p, debug_cat[i].name))
@@ -285,7 +302,7 @@ int parse_debug_opt(const char *optarg)
 			free(dup);
 			return -EINVAL;
 		}
-		debug_mask |= ((uint64_t)1 << i);
+		debug_mask[i >> 6] |= ((uint64_t)1 << (i & 63));
 	}
 
 	free(dup);
diff --git a/src/libdebug/debug.h b/src/libdebug/debug.h
index ae16857..5942651 100644
--- a/src/libdebug/debug.h
+++ b/src/libdebug/debug.h
@@ -19,38 +19,48 @@
 #define DJOLLY		12
 #define DEURO		13
 #define DPOCSAG		14
-#define DFRAME		15
-#define DCALL		16
-#define DCC		17
-#define DDB		18
-#define DTRANS		19
-#define DDMS		20
-#define DSMS		21
-#define DSDR		22
-#define DUHD		23
-#define DSOAPY		24
-#define DWAVE		25
-#define DRADIO		26
-#define DAM791X		27
-#define DUART		28
-#define DDEVICE		29
-#define DDATENKLO	30
-#define DZEIT		31
-#define DSIM1		32
-#define DSIM2		33
-#define DSIMI		34
-#define DSIM7		35
-#define DMTP2		36
-#define DMTP3		37
-#define DMUP		38
-#define DROUTER		39
-#define DSTDERR		40
-#define DSS5		41
-#define DISDN		42
-#define DMISDN		43
-#define DDSS1		44
-#define DSIP		45
-#define DTEL		46
+#define DGOLAY		15
+#define DFUENF		16
+#define DFRAME		17
+#define DCALL		18
+#define DCC		19
+#define DDB		20
+#define DTRANS		21
+#define DDMS		22
+#define DSMS		23
+#define DSDR		24
+#define DUHD		25
+#define DSOAPY		26
+#define DWAVE		27
+#define DRADIO		28
+#define DAM791X		29
+#define DUART		30
+#define DDEVICE		31
+#define DDATENKLO	32
+#define DZEIT		33
+#define DSIM1		34
+#define DSIM2		35
+#define DSIMI		36
+#define DSIM7		37
+#define DMTP2		38
+#define DMTP3		39
+#define DMUP		40
+#define DROUTER		41
+#define DSTDERR		42
+#define DSS5		43
+#define DISDN		44
+#define DMISDN		45
+#define DDSS1		46
+#define DSIP		47
+#define DTEL		48
+#define DUK0		49
+#define DPH		50
+#define DDCF77		51
+#define DJITTER		52
+//NOTE: increment mask array, if 127 is exceeded
+
+void lock_debug(void);
+void unlock_debug(void);
 
 void get_win_size(int *w, int *h);
 
diff --git a/src/libosmocc/cause.c b/src/libosmocc/cause.c
index 4a3a41e..df2b07b 100644
--- a/src/libosmocc/cause.c
+++ b/src/libosmocc/cause.c
@@ -22,7 +22,7 @@
 #include "message.h"
 #include "cause.h"
 
-/* stolen from freeswitch */
+/* stolen from freeswitch, did some corrections */
 /* map sip responses to QSIG cause codes ala RFC4497 section 8.4.4 */
 static uint8_t status2isdn_cause(uint16_t status)
 {
@@ -36,10 +36,9 @@ static uint8_t status2isdn_cause(uint16_t status)
 	case 603:
 		return 21; //SWITCH_CAUSE_CALL_REJECTED;
 	case 404:
-		return 1; //SWITCH_CAUSE_UNALLOCATED_NUMBER;
 	case 485:
 	case 604:
-		return 3; //SWITCH_CAUSE_NO_ROUTE_DESTINATION;
+		return 1; //SWITCH_CAUSE_UNALLOCATED_NUMBER;
 	case 408:
 	case 504:
 		return 102; //SWITCH_CAUSE_RECOVERY_ON_TIMER_EXPIRE;
@@ -55,7 +54,7 @@ static uint8_t status2isdn_cause(uint16_t status)
 	case 513:
 		return 127; //SWITCH_CAUSE_INTERWORKING;
 	case 480:
-		return 180; //SWITCH_CAUSE_NO_USER_RESPONSE;
+		return 18; //SWITCH_CAUSE_NO_USER_RESPONSE;
 	case 400:
 	case 481:
 	case 500:
@@ -68,7 +67,7 @@ static uint8_t status2isdn_cause(uint16_t status)
 		return 28; //SWITCH_CAUSE_INVALID_NUMBER_FORMAT;
 	case 488:
 	case 606:
-		return 88; //SWITCH_CAUSE_INCOMPATIBLE_DESTINATION;
+		return 65; //SWITCH_CAUSE_BERER_CAPABILITY_NOT_IMPLEMENTED;
 	case 502:
 		return 38; //SWITCH_CAUSE_NETWORK_OUT_OF_ORDER;
 	case 405:
@@ -81,7 +80,7 @@ static uint8_t status2isdn_cause(uint16_t status)
 	case 483:
 		return 25; //SWITCH_CAUSE_EXCHANGE_ROUTING_ERROR;
 	case 487:
-		return 31; //??? SWITCH_CAUSE_ORIGINATOR_CANCEL;
+		return 31; //??? SWITCH_CAUSE_ORIGINATOR_CANCEL; (not specified)
 	default:
 		return 31; //SWITCH_CAUSE_NORMAL_UNSPECIFIED;
 	}
diff --git a/src/libosmocc/endpoint.c b/src/libosmocc/endpoint.c
index 120b53c..cb591b8 100644
--- a/src/libosmocc/endpoint.c
+++ b/src/libosmocc/endpoint.c
@@ -568,6 +568,18 @@ static void notify_ind(osmo_cc_call_t *call, osmo_cc_msg_t *msg)
 	forward_to_ul(call, msg);
 }
 
+static void update_req(osmo_cc_call_t *call, osmo_cc_msg_t *msg)
+{
+	/* to lower layer */
+	forward_to_ll(call, msg);
+}
+
+static void update_cnf(osmo_cc_call_t *call, osmo_cc_msg_t *msg)
+{
+	/* to upper layer */
+	forward_to_ul(call, msg);
+}
+
 static void disc_req(osmo_cc_call_t *call, osmo_cc_msg_t *msg)
 {
 	/* change state */
@@ -853,6 +865,10 @@ static struct statemachine {
 	 OSMO_CC_MSG_INFO_IND, info_ind},
 	{SBIT(OSMO_CC_STATE_ACTIVE),
 	 OSMO_CC_MSG_INFO_REQ, info_req},
+	{SBIT(OSMO_CC_STATE_ACTIVE),
+	 OSMO_CC_MSG_UPDATE_REQ, update_req},
+	{SBIT(OSMO_CC_STATE_ACTIVE),
+	 OSMO_CC_MSG_UPDATE_CNF, update_cnf},
 
 	/* call release */
 	{SBIT(OSMO_CC_STATE_INIT_OUT) | SBIT(OSMO_CC_STATE_INIT_IN) |
@@ -1072,6 +1088,36 @@ void osmo_cc_ul_msg(void *priv, uint32_t callref, osmo_cc_msg_t *msg)
 	osmo_cc_msg_list_enqueue(&call->sock_queue, msg, call->callref);
 }
 
+static void osmo_cc_help_name(void)
+{
+	printf("Name options:\n\n");
+
+	printf("name <name>\n");
+
+	printf("Allows to override endpoint name given by application.\n");
+}
+
+static int osmo_cc_set_name(osmo_cc_endpoint_t *ep, const char *text)
+{
+	if (!strncasecmp(text, "name", 4)) {
+		text += 4;
+		/* remove spaces after keyword */
+		while (*text) {
+			if (*text > 32)
+				break;
+			text++;
+		}
+	} else {
+		PDEBUG(DCC, DEBUG_ERROR, "Invalid name definition '%s'\n", text);
+		return -EINVAL;
+	}
+
+	free((char *)ep->local_name);
+	ep->local_name = strdup(text);
+
+	return 0;
+}
+
 static void osmo_cc_help_address(void)
 {
 	printf("Address options:\n\n");
@@ -1080,6 +1126,8 @@ static void osmo_cc_help_address(void)
 	printf("local [<IPv6 address>]:<port>\n");
 	printf("remote <IPv4 address>:<port>\n");
 	printf("remote [<IPv6 address>]:<port>\n\n");
+	printf("remote auto\n\n");
+	printf("remote none\n\n");
 
 	printf("These options can be used to define local and remote IP and port for the socket\n");
 	printf("interface. Note that IPv6 addresses must be enclosed by '[' and ']'.\n\n");
@@ -1090,6 +1138,9 @@ static void osmo_cc_help_address(void)
 	printf("If no remote address is given, the local IP is used. If the local port is %d,\n", OSMO_CC_DEFAULT_PORT);
 	printf("the remote port will be %d. If not, the remote port will be %d. This way it is\n", OSMO_CC_DEFAULT_PORT + 1, OSMO_CC_DEFAULT_PORT);
 	printf("possible to link two interfaces without any IP configuration required.\n\n");
+
+	printf("Use 'remote auto' to enable and 'remote none' to disable. This can be useful to\n");
+	printf("override application default.\n\n");
 }
 
 static int osmo_cc_set_address(osmo_cc_endpoint_t *ep, const char *text)
@@ -1124,6 +1175,11 @@ static int osmo_cc_set_address(osmo_cc_endpoint_t *ep, const char *text)
 			ep->remote_auto = 1;
 			return 0;
 		}
+		if (!strcasecmp(text, "none")) {
+			PDEBUG(DCC, DEBUG_DEBUG, "disable automatic remote peer selection\n");
+			ep->remote_auto = 0;
+			return 0;
+		}
 		ep->remote_auto = 0;
 		address_p = &ep->remote_address;
 		host_p = &ep->remote_host;
@@ -1220,6 +1276,7 @@ static int osmo_cc_set_rtp(osmo_cc_endpoint_t *ep, const char *text)
 				return -EINVAL;
 			}
 			from = from * 10 + *text - '0';
+			text++;
 		}
 
 		/* remove spaces after keyword */
@@ -1235,7 +1292,8 @@ static int osmo_cc_set_rtp(osmo_cc_endpoint_t *ep, const char *text)
 				PDEBUG(DCC, DEBUG_ERROR, "Given 'to' port in '%s' is invalid.\n", text);
 				return -EINVAL;
 			}
-			from = from * 10 + *text - '0';
+			to = to * 10 + *text - '0';
+			text++;
 		}
 
 		osmo_cc_set_rtp_ports(&ep->session_config, from, to);
@@ -1247,9 +1305,10 @@ static int osmo_cc_set_rtp(osmo_cc_endpoint_t *ep, const char *text)
 
 void osmo_cc_help(void)
 {
-	osmo_cc_help_screen();
+	osmo_cc_help_name();
 	osmo_cc_help_address();
 	osmo_cc_help_rtp();
+	osmo_cc_help_screen();
 }
 
 /* create a new endpoint instance */
@@ -1286,6 +1345,12 @@ int osmo_cc_new(osmo_cc_endpoint_t *ep, const char *version, const char *name, u
 
 	/* apply args */
 	for (i = 0; i < argc; i++) {
+		if (!strncasecmp(argv[i], "name", 4)) {
+			rc = osmo_cc_set_name(ep, argv[i]);
+			if (rc < 0) {
+				return rc;
+			}
+		} else
 		if (!strncasecmp(argv[i], "local", 5)) {
 			rc = osmo_cc_set_address(ep, argv[i]);
 			if (rc < 0) {
diff --git a/src/libosmocc/helper.c b/src/libosmocc/helper.c
index 807542e..4eeee92 100644
--- a/src/libosmocc/helper.c
+++ b/src/libosmocc/helper.c
@@ -29,7 +29,7 @@
 #include "endpoint.h"
 #include "helper.h"
 
-osmo_cc_session_t *osmo_cc_helper_audio_offer(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len), osmo_cc_msg_t *msg, int debug)
+osmo_cc_session_t *osmo_cc_helper_audio_offer(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len), osmo_cc_msg_t *msg, int debug)
 {
 	osmo_cc_session_t *session;
 	osmo_cc_session_media_t *media;
@@ -52,7 +52,7 @@ osmo_cc_session_t *osmo_cc_helper_audio_offer(osmo_cc_session_config_t *conf, vo
 	return session;
 }
 
-const char *osmo_cc_helper_audio_accept(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len), osmo_cc_msg_t *msg, osmo_cc_session_t **session_p, osmo_cc_session_codec_t **codec_p, int force_our_codec)
+const char *osmo_cc_helper_audio_accept(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len), osmo_cc_msg_t *msg, osmo_cc_session_t **session_p, osmo_cc_session_codec_t **codec_p, int force_our_codec)
 {
 	char offer_sdp[65536];
 	const char *accept_sdp;
diff --git a/src/libosmocc/helper.h b/src/libosmocc/helper.h
index c12a50a..0d3585e 100644
--- a/src/libosmocc/helper.h
+++ b/src/libosmocc/helper.h
@@ -7,7 +7,7 @@ struct osmo_cc_helper_audio_codecs {
 	void (*decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len);
 };
 
-osmo_cc_session_t *osmo_cc_helper_audio_offer(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len), osmo_cc_msg_t *msg, int debug);
-const char *osmo_cc_helper_audio_accept(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len), osmo_cc_msg_t *msg, osmo_cc_session_t **session_p, osmo_cc_session_codec_t **codec_p, int force_our_codec);
+osmo_cc_session_t *osmo_cc_helper_audio_offer(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len), osmo_cc_msg_t *msg, int debug);
+const char *osmo_cc_helper_audio_accept(osmo_cc_session_config_t *conf, void *priv, struct osmo_cc_helper_audio_codecs *codecs, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len), osmo_cc_msg_t *msg, osmo_cc_session_t **session_p, osmo_cc_session_codec_t **codec_p, int force_our_codec);
 int osmo_cc_helper_audio_negotiate(osmo_cc_msg_t *msg, osmo_cc_session_t **session_p, osmo_cc_session_codec_t **codec_p);
 
diff --git a/src/libosmocc/message.c b/src/libosmocc/message.c
index 5b069dd..ab66a9f 100644
--- a/src/libosmocc/message.c
+++ b/src/libosmocc/message.c
@@ -33,7 +33,8 @@
 }
 
 #define _OSMO_CC_NAME2VALUE(array) { \
-	for (int value = 0; (size_t)value < (sizeof(array) / sizeof(array[0])); value++) { \
+	int value; \
+	for (value = 0; (size_t)value < (sizeof(array) / sizeof(array[0])); value++) { \
 		if (!strcasecmp(array[value], name)) \
 			return value; \
 	} \
diff --git a/src/libosmocc/message.h b/src/libosmocc/message.h
index 2bb299a..8f4d487 100644
--- a/src/libosmocc/message.h
+++ b/src/libosmocc/message.h
@@ -30,6 +30,8 @@ enum osmo_cc_msg_type {
 	OSMO_CC_MSG_NOTIFY_IND =	0x85,
 	OSMO_CC_MSG_INFO_REQ =		0x88,
 	OSMO_CC_MSG_INFO_IND =		0x89,
+	OSMO_CC_MSG_UPDATE_REQ =	0x91,
+	OSMO_CC_MSG_UPDATE_CNF =	0x93,
 	OSMO_CC_MSG_ATTACH_REQ =	0xf8,
 	OSMO_CC_MSG_ATTACH_IND =	0xf9,
 	OSMO_CC_MSG_ATTACH_RSP =	0xfa,
diff --git a/src/libosmocc/rtp.c b/src/libosmocc/rtp.c
index afaf22d..b118833 100644
--- a/src/libosmocc/rtp.c
+++ b/src/libosmocc/rtp.c
@@ -52,7 +52,7 @@ struct rtp_x_hdr {
 	uint16_t length;
 } __attribute__((packed));
 
-static int rtp_receive(int sock, uint8_t **payload_p, int *payload_len_p, uint8_t *marker_p, uint8_t *pt_p, uint16_t *sequence_p, uint32_t *timestamp_p)
+static int rtp_receive(int sock, uint8_t **payload_p, int *payload_len_p, uint8_t *marker_p, uint8_t *pt_p, uint16_t *sequence_p, uint32_t *timestamp_p, uint32_t *ssrc_p)
 {
 	static uint8_t data[2048];
 	int len;
@@ -83,6 +83,7 @@ static int rtp_receive(int sock, uint8_t **payload_p, int *payload_len_p, uint8_
 	payload_type = rtph->byte1 & 0x7f;
 	*sequence_p = ntohs(rtph->sequence);
 	*timestamp_p = ntohl(rtph->timestamp);
+	*ssrc_p = ntohl(rtph->ssrc);
 
 	if (version != RTP_VERSION) {
 		PDEBUG(DCC, DEBUG_NOTICE, "Received RTP version %d not supported.\n", version);
@@ -131,7 +132,7 @@ static int rtp_receive(int sock, uint8_t **payload_p, int *payload_len_p, uint8_
 	return 0;
 }
 
-static void rtp_send(int sock, uint8_t *payload, int payload_len, uint8_t pt, uint16_t sequence, uint32_t timestamp, uint32_t ssrc)
+static void rtp_send(int sock, uint8_t *payload, int payload_len, uint8_t marker, uint8_t pt, uint16_t sequence, uint32_t timestamp, uint32_t ssrc)
 {
 	struct rtp_hdr *rtph;
 	char data[sizeof(*rtph) + payload_len];
@@ -140,7 +141,7 @@ static void rtp_send(int sock, uint8_t *payload, int payload_len, uint8_t pt, ui
 	rtph = (struct rtp_hdr *)data;
 	len = sizeof(*rtph);
 	rtph->byte0 = RTP_VERSION << 6;
-	rtph->byte1 = pt;
+	rtph->byte1 = pt | (marker << 7);
 	rtph->sequence = htons(sequence);
 	rtph->timestamp = htonl(timestamp);
 	rtph->ssrc = htonl(ssrc);
@@ -172,7 +173,7 @@ int osmo_cc_rtp_open(osmo_cc_session_media_t *media)
 	int flags;
 	int rc;
 
-	media->rtp_ssrc = rand();
+	media->tx_ssrc = rand();
 
 	osmo_cc_rtp_close(media);
 
@@ -182,7 +183,12 @@ int osmo_cc_rtp_open(osmo_cc_session_media_t *media)
 		memset(&sa, 0, sizeof(sa));
 		sa4 = (struct sockaddr_in *)&sa;
 		sa4->sin_family = domain;
-		sa4->sin_addr.s_addr = INADDR_ANY;
+		rc = inet_pton(AF_INET, media->connection_data_local.address, &sa4->sin_addr);
+		if (rc < 1) {
+pton_error:
+			PDEBUG(DCC, DEBUG_NOTICE, "Cannot bind to address '%s'.\n", media->connection_data_local.address);
+			return -EINVAL;
+		}
 		sport = &sa4->sin_port;
 		slen = sizeof(*sa4);
 		break;
@@ -191,7 +197,9 @@ int osmo_cc_rtp_open(osmo_cc_session_media_t *media)
 		memset(&sa, 0, sizeof(sa));
 		sa6 = (struct sockaddr_in6 *)&sa;
 		sa6->sin6_family = domain;
-		sa6->sin6_addr = in6addr_any;
+		rc = inet_pton(AF_INET6, media->connection_data_local.address, &sa6->sin6_addr);
+		if (rc < 1)
+			goto pton_error;
 		sport = &sa6->sin6_port;
 		slen = sizeof(*sa6);
 		break;
@@ -313,7 +321,7 @@ connect_error:
 }
 
 /* send rtp data with given codec */
-void osmo_cc_rtp_send(osmo_cc_session_codec_t *codec, uint8_t *data, int len, int inc_sequence, int inc_timestamp)
+void osmo_cc_rtp_send(osmo_cc_session_codec_t *codec, uint8_t *data, int len, uint8_t marker, int inc_sequence, int inc_timestamp)
 {
 	uint8_t *payload = NULL;
 	int payload_len = 0;
@@ -328,7 +336,7 @@ void osmo_cc_rtp_send(osmo_cc_session_codec_t *codec, uint8_t *data, int len, in
 		payload_len = len;
 	}
 
-	rtp_send(codec->media->rtp_socket, payload, payload_len, codec->payload_type_remote, codec->media->tx_sequence, codec->media->tx_timestamp, codec->media->rtp_ssrc);
+	rtp_send(codec->media->rtp_socket, payload, payload_len, marker, codec->payload_type_remote, codec->media->tx_sequence, codec->media->tx_timestamp, codec->media->tx_ssrc);
 	codec->media->tx_sequence += inc_sequence;
 	codec->media->tx_timestamp += inc_timestamp;
 
@@ -351,7 +359,7 @@ int osmo_cc_rtp_receive(osmo_cc_session_media_t *media)
 	if (!media || media->rtp_socket <= 0)
 		return -EIO;
 
-	rc = rtp_receive(media->rtp_socket, &payload, &payload_len, &marker, &payload_type, &media->rx_sequence, &media->rx_timestamp);
+	rc = rtp_receive(media->rtp_socket, &payload, &payload_len, &marker, &payload_type, &media->rx_sequence, &media->rx_timestamp, &media->rx_ssrc);
 	if (rc < 0)
 		return rc;
 
@@ -374,7 +382,7 @@ int osmo_cc_rtp_receive(osmo_cc_session_media_t *media)
 	}
 
 	if (codec->media->receive)
-		codec->media->receiver(codec, media->rx_sequence, media->rx_timestamp, data, len);
+		codec->media->receiver(codec, marker, media->rx_sequence, media->rx_timestamp, media->rx_ssrc, data, len);
 
 	if (codec->decoder)
 		free(data);
diff --git a/src/libosmocc/rtp.h b/src/libosmocc/rtp.h
index e309f56..eb74f73 100644
--- a/src/libosmocc/rtp.h
+++ b/src/libosmocc/rtp.h
@@ -2,7 +2,7 @@
 void osmo_cc_set_rtp_ports(osmo_cc_session_config_t *conf, uint16_t from, uint16_t to);
 int osmo_cc_rtp_open(osmo_cc_session_media_t *media);
 int osmo_cc_rtp_connect(osmo_cc_session_media_t *media);
-void osmo_cc_rtp_send(osmo_cc_session_codec_t *codec, uint8_t *data, int len, int inc_sequence, int inc_timestamp);
+void osmo_cc_rtp_send(osmo_cc_session_codec_t *codec, uint8_t *data, int len, uint8_t marker, int inc_sequence, int inc_timestamp);
 int osmo_cc_rtp_receive(osmo_cc_session_media_t *media);
 void osmo_cc_rtp_close(osmo_cc_session_media_t *media);
 
diff --git a/src/libosmocc/screen.c b/src/libosmocc/screen.c
index 5040ce6..5558f42 100644
--- a/src/libosmocc/screen.c
+++ b/src/libosmocc/screen.c
@@ -58,6 +58,10 @@ void osmo_cc_help_screen(void)
 	printf("to allow any suffix to match from now on. The new caller ID or dialed number\n");
 	printf("may contain a '*', to append the suffix from the current caller ID or dialed\n");
 	printf("number.\n\n");
+
+	printf("When screening an incoming caller ID or dialed number, the '@' can be appended\n");
+	printf("to the 'new caller ID', followed by a 'host:port', to route call to a special\n");
+	printf("Osmo-CC endpoint. This way it is possible to do simple routing.\n\n");
 }
 
 char *osmo_cc_strtok_quotes(const char **text_p)
@@ -139,6 +143,7 @@ int osmo_cc_add_screen(osmo_cc_endpoint_t *ep, const char *text)
 	} else if (!strncasecmp(text, "screen-called-in", 16)) {
 		text += 16;
 		list_p = &ep->screen_called_in;
+		calling_in = 1;
 	} else if (!strncasecmp(text, "screen-calling-out", 18)) {
 		text += 18;
 		list_p = &ep->screen_calling_out;
@@ -218,6 +223,7 @@ no_present_error:
 		list->from_present = OSMO_CC_PRESENT_RESTRICTED;
 		goto next_from;
 	} else {
+		star_used = 0;
 		for (i = j = 0; token[i] && j < (int)sizeof(list->from) - 1; i++, j++) {
 			if (token[i] == '?')
 				list->from[j] = SCREEN_QUESTIONMARK;
@@ -240,7 +246,6 @@ no_present_error:
 		list->from[j] = '\0';
 	}
 
-	star_used = 0;
 next_to:
 	token = osmo_cc_strtok_quotes(&text);
 	if (!token) {
@@ -293,6 +298,7 @@ next_to:
 		list->to_present = OSMO_CC_PRESENT_RESTRICTED;
 		goto next_to;
 	} else {
+		at_used = star_used = 0;
 		for (i = j = 0; token[i] && j < (int)sizeof(list->to) - 1; i++, j++) {
 			if (token[i] == '*') {
 				if (star_used) {
@@ -506,7 +512,8 @@ static int osmo_cc_screen(const char *what, osmo_cc_screen_list_t *list, uint8_t
 			continue;
 		/* '@' means to stop and return routing also */
 		} else if (list->to[i] == SCREEN_AT) {
-			*routing_p = &list->to[i];
+			if (routing_p)
+				*routing_p = &list->to[i + 1];
 			break;
 		}
 		/* copy output digit */
@@ -543,6 +550,8 @@ static int osmo_cc_screen(const char *what, osmo_cc_screen_list_t *list, uint8_t
 		PDEBUG(DCC, DEBUG_INFO, " -> present = restricted\n");
 		break;
 	}
+	if (routing_p && *routing_p)
+		PDEBUG(DCC, DEBUG_INFO, " -> remote = %s\n", *routing_p);
 
 	return 0;
 }
@@ -586,13 +595,13 @@ osmo_cc_msg_t *osmo_cc_screen_msg(osmo_cc_endpoint_t *ep, osmo_cc_msg_t *old_msg
 	if (in && ep->screen_called_in) {
 		rc = osmo_cc_get_ie_called(old_msg, 0, &called_type, &called_plan, id, sizeof(id));
 		if (rc >= 0) {
-			rc = osmo_cc_screen("incoming dialed number", ep->screen_called_in, &called_type, NULL, called, sizeof(called), id, NULL);
+			rc = osmo_cc_screen("incoming dialed number", ep->screen_called_in, &called_type, NULL, called, sizeof(called), id, routing_p);
 			if (rc >= 0)
 				called_status = 1;
 		} else {
 			called_type = OSMO_CC_TYPE_UNKNOWN;
 			called_plan = OSMO_CC_PLAN_TELEPHONY;
-			rc = osmo_cc_screen("incoming dialed number", ep->screen_called_in, &called_type, NULL, called, sizeof(called), "", NULL);
+			rc = osmo_cc_screen("incoming dialed number", ep->screen_called_in, &called_type, NULL, called, sizeof(called), "", routing_p);
 			if (rc >= 0)
 				called_status = 1;
 		}
diff --git a/src/libosmocc/sdp.c b/src/libosmocc/sdp.c
index 8e44117..849bfb9 100644
--- a/src/libosmocc/sdp.c
+++ b/src/libosmocc/sdp.c
@@ -260,7 +260,7 @@ struct osmo_cc_session *osmo_cc_session_parsesdp(osmo_cc_session_config_t *conf,
 	memset(&ccd, 0, sizeof(ccd));
 
 	/* create SDP session description */
-	session = osmo_cc_new_session(conf, priv, NULL, NULL, NULL, osmo_cc_session_nettype_inet, osmo_cc_session_addrtype_ipv4, "127.0.0.1", NULL, 0); // values will be replaced by local definitions during negotiation
+	session = osmo_cc_new_session(conf, priv, NULL, NULL, NULL, 0, 0, NULL, NULL, 0);
 
 	/* check every line of SDP and parse its data */
 	while(*sdp) {
diff --git a/src/libosmocc/session.c b/src/libosmocc/session.c
index 50a4a92..8216c05 100644
--- a/src/libosmocc/session.c
+++ b/src/libosmocc/session.c
@@ -29,7 +29,7 @@
 #include "../liboptions/options.h"
 #include "endpoint.h"
 
-#define NTP_OFFSET      2208988800
+#define NTP_OFFSET      2208988800U
 
 void osmo_cc_set_local_peer(osmo_cc_session_config_t *conf, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address)
 {
@@ -127,7 +127,7 @@ void osmo_cc_free_session(osmo_cc_session_t *session)
 	free(session);
 }
 
-osmo_cc_session_media_t *osmo_cc_add_media(osmo_cc_session_t *session, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, enum osmo_cc_session_media_type type, uint16_t port, enum osmo_cc_session_media_proto proto, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len), int debug)
+osmo_cc_session_media_t *osmo_cc_add_media(osmo_cc_session_t *session, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, enum osmo_cc_session_media_type type, uint16_t port, enum osmo_cc_session_media_proto proto, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len), int debug)
 {
 	osmo_cc_session_config_t *conf = session->config;
 	osmo_cc_session_media_t *media, **mediap;
@@ -374,7 +374,7 @@ osmo_cc_session_t *osmo_cc_session_receive_offer(osmo_cc_session_config_t *conf,
 	return session;
 }
 
-void osmo_cc_session_accept_media(osmo_cc_session_media_t *media, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len))
+void osmo_cc_session_accept_media(osmo_cc_session_media_t *media, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len))
 {
 	osmo_cc_session_config_t *conf = media->session->config;
 
diff --git a/src/libosmocc/session.h b/src/libosmocc/session.h
index c0717c0..791bcb4 100644
--- a/src/libosmocc/session.h
+++ b/src/libosmocc/session.h
@@ -79,10 +79,10 @@ typedef struct osmo_cc_session_media {
 	osmo_cc_session_connection_data_t connection_data_local, connection_data_remote;
 	struct osmo_cc_session_codec *codec_list;
 	int send, receive;
-	void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len);
+	void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len);
 	int rtp_socket;
 	int rtcp_socket;
-	uint32_t rtp_ssrc;
+	uint32_t tx_ssrc, rx_ssrc;
 	uint16_t tx_sequence, rx_sequence;
 	uint32_t tx_timestamp, rx_timestamp;
 	int accepted;
@@ -110,14 +110,14 @@ typedef struct osmo_cc_session_codec {
 void osmo_cc_set_local_peer(osmo_cc_session_config_t *conf, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address);
 osmo_cc_session_t *osmo_cc_new_session(osmo_cc_session_config_t *conf, void *priv, const char *username, const char *sess_id, const char *sess_version, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *unicast_address, const char *session_name, int debug);
 void osmo_cc_free_session(osmo_cc_session_t *session);
-osmo_cc_session_media_t *osmo_cc_add_media(osmo_cc_session_t *session, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, enum osmo_cc_session_media_type type, uint16_t port, enum osmo_cc_session_media_proto proto, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len), int debug);
+osmo_cc_session_media_t *osmo_cc_add_media(osmo_cc_session_t *session, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, enum osmo_cc_session_media_type type, uint16_t port, enum osmo_cc_session_media_proto proto, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len), int debug);
 void osmo_cc_free_media(osmo_cc_session_media_t *media);
 osmo_cc_session_codec_t *osmo_cc_add_codec(osmo_cc_session_media_t *media, const char *playload_name, uint32_t playload_rate, int playload_channels, void (*encoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len), void (*decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len), int debug);
 void osmo_cc_free_codec(osmo_cc_session_codec_t *codec);
 int osmo_cc_session_check(struct osmo_cc_session *session, int remote);
 const char *osmo_cc_session_send_offer(osmo_cc_session_t *session);
 osmo_cc_session_t *osmo_cc_session_receive_offer(osmo_cc_session_config_t *conf, void *priv, const char *sdp);
-void osmo_cc_session_accept_media(osmo_cc_session_media_t *media, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len));
+void osmo_cc_session_accept_media(osmo_cc_session_media_t *media, enum osmo_cc_session_nettype nettype, enum osmo_cc_session_addrtype addrtype, const char *address, int send, int receive, void (*receiver)(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence_number, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len));
 void osmo_cc_session_accept_codec(osmo_cc_session_codec_t *codec, void (*encoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len), void (*decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len));
 const char *osmo_cc_session_send_answer(osmo_cc_session_t *session);
 int osmo_cc_session_receive_answer(osmo_cc_session_t *session, const char *sdp);