diff --git a/library/OSMUX_Emulation.ttcn b/library/OSMUX_Emulation.ttcn
new file mode 100644
index 0000000..e1275b9
--- /dev/null
+++ b/library/OSMUX_Emulation.ttcn
@@ -0,0 +1,575 @@
+module OSMUX_Emulation {
+
+/* Functionalities that we want this module to implement:
+ *  * act as a Osmux source that generates a Osmux Stream
+ *  * act as a Osmux sink that consumes a Osmux Stream
+ *
+ * for all of the above, we want to be able to
+ *  * specify the payload type
+ *  * specify the interval / sample rate
+ *  * create drop-outs in the stream
+ *  * detect reordered or lost frames
+ *  * validate if the size of the frames matches epectations
+ *  * play back real audio (at least some tones?)
+ *  * enable/disable generation/verification of RTCP
+ */
+
+/* Ideas:
+
+* each component consists of transmitter and receiver
+* transmitters and receivers can be operated as tuple?
+* high-level operation
+** set-up config at transmitter + receiver
+** transmit sequence of payloads
+** verify receiption of those payloads
+* can operate full-duplex/bi-directional as needed
+
+* transmitter
+** trigger transmission of n number of packets
+** transmit them at normal ptime interval
+** payload size configurable
+** payload contents PRBS or the like
+
+* receiver
+** count number of related packets at receiver
+** check received payload type
+** check received timestamp increments
+** check received seq_nr increments
+** (optionally) check for SSRC
+** (optionally) check for payload size
+** (optionally) check for payload contents
+
+* later
+** how to test transcoding?
+** how to test pure play-out endpoints (rx only)?
+** how to test "Rx from wrong IP/port" scenarios?
+** how to test RTCP?
+** maybe keep ports un-connected to show wrong src -lrt
+
+*/
+
+
+
+
+import from General_Types all;
+import from Osmocom_Types all;
+import from IPL4asp_Types all;
+import from OSMUX_Types all;
+import from OSMUX_CodecPort all;
+import from OSMUX_CodecPort_CtrlFunct all;
+
+type component OSMUX_Emulation_CT {
+	/* down-facing ports for Osmux on top of IPL4asp */
+	port OSMUX_CODEC_PT OSMUX;
+	var integer g_osmux_conn_id := -1;
+
+	/* user-facing port for controlling the binding */
+	port OsmuxEM_CTRL_PT CTRL;
+
+	/* configurable by user, should be fixed */
+	var OsmuxemConfig g_cfg := c_OsmuxemDefaultCfg;
+
+	/* statistics */
+	var OsmuxemStats g_stat := c_OsmuxemStatsReset;
+
+	var HostName g_remote_host;
+	var PortNumber g_remote_port;
+	var HostName g_local_host;
+	var PortNumber g_local_port;
+
+	/* state variables, change over time */
+	var boolean g_rx_enabled := false;
+	var boolean g_tx_connected := false; /* Set to true after connect() */
+
+	var INT7b g_rx_payload_type := 0;
+	var LIN2_BO_LAST g_rx_last_seq;
+	var uint32_t g_rx_last_ts;
+
+	var RxHandleTableRec RxHandleTable[16];
+	var OsmuxTxHandle TxHandleList[16];
+}
+
+type record RxHandleTableRec {
+	OsmuxCID cid,
+	OsmuxRxHandle vc_conn
+};
+
+type record OsmuxRxHandle {
+	OsmuxCID cid,
+	boolean first_seq_seen,
+	INT1 last_seq_ack
+};
+
+const OsmuxRxHandle c_OsmuxemDefaultRxHandle := {
+	cid := 0,
+	first_seq_seen := false,
+	last_seq_ack := 0
+}
+
+type record OsmuxTxHandle {
+	INT2b ft,
+	BIT1 amr_f,
+	BIT1 amr_q,
+	INT1 seq,
+	OsmuxCID cid,
+	INT4b amr_ft,
+	INT4b amr_cmr
+};
+
+template OsmuxTxHandle t_TxHandleAMR590(OsmuxCID cid) := {
+	ft := 1,//enum2int(OsmuxFT:OSMUX_FT_AMR)
+	amr_f := '0'B, /* this frame is the last frame in this payload */
+	amr_q := '1'B, /* frame not damaged */
+	seq := 12,
+	cid := cid,
+	amr_ft := 2, /* AMR 5.90 */
+	amr_cmr := 0
+};
+
+type enumerated OsmuxemMode {
+	OSMUXEM_MODE_NONE,
+	OSMUXEM_MODE_TXONLY,
+	OSMUXEM_MODE_RXONLY,
+	OSMUXEM_MODE_BIDIR
+};
+
+type record OsmuxemStats {
+	/* number of packets transmitted */
+	integer num_pkts_tx,
+	/* number of Osmux payload bytes transmitted */
+	integer bytes_payload_tx,
+
+	/* number of packets received */
+	integer num_pkts_rx,
+	/* number of Osmux payload bytes received */
+	integer bytes_payload_rx,
+	/* number of packets received out-of-sequence */
+	integer num_pkts_rx_err_seq,
+	/* number of packets received during Rx disable */
+	integer num_pkts_rx_err_disabled,
+	/* number of packets received with mismatching payload */
+	integer num_pkts_rx_err_payload
+}
+
+const OsmuxemStats c_OsmuxemStatsReset := {
+	num_pkts_tx := 0,
+	bytes_payload_tx := 0,
+	num_pkts_rx := 0,
+	bytes_payload_rx := 0,
+	num_pkts_rx_err_seq := 0,
+	num_pkts_rx_err_disabled := 0,
+	num_pkts_rx_err_payload := 0
+}
+
+type record OsmuxemConfig {
+	INT3b batch_size,
+	integer tx_duration_ms,
+	octetstring tx_fixed_payload optional,
+	octetstring rx_fixed_payload optional
+};
+
+const OsmuxemConfig c_OsmuxemDefaultCfg := {
+	batch_size := 4,
+	tx_duration_ms := 20 * 4, /* 4 is batch_size */
+	tx_fixed_payload := '010203040102030401020304010203040102030401020304'O,
+	rx_fixed_payload := '010203040102030401020304010203040102030401020304'O
+}
+
+signature OsmuxEM_bind(in HostName local_host, inout PortNumber local_port);
+signature OsmuxEM_connect(in HostName remote_host, in PortNumber remote_port);
+signature OsmuxEM_mode(in OsmuxemMode mode);
+signature OsmuxEM_configure(in OsmuxemConfig cfg);
+signature OsmuxEM_stats_get(out OsmuxemStats stats);
+signature OsmuxEM_register_rxhandle(in OsmuxRxHandle hdl);
+signature OsmuxEM_register_txhandle(in OsmuxTxHandle hdl);
+
+type port OsmuxEM_CTRL_PT procedure {
+	inout OsmuxEM_bind, OsmuxEM_connect, OsmuxEM_mode, OsmuxEM_configure,
+	      OsmuxEM_stats_get, OsmuxEM_register_rxhandle, OsmuxEM_register_txhandle;
+} with { extension "internal" };
+
+function f_osmuxem_bind(OsmuxEM_CTRL_PT pt, in HostName local_host, inout PortNumber local_port) {
+	pt.call(OsmuxEM_bind:{local_host, local_port}) {
+		[] pt.getreply(OsmuxEM_bind:{local_host, ?}) -> param (local_port) {};
+	}
+}
+function f_osmuxem_connect(OsmuxEM_CTRL_PT pt, in HostName remote_host, in PortNumber remote_port) {
+	pt.call(OsmuxEM_connect:{remote_host, remote_port}) {
+		[] pt.getreply(OsmuxEM_connect:{remote_host, remote_port}) {};
+	}
+}
+function f_osmuxem_mode(OsmuxEM_CTRL_PT pt, in OsmuxemMode mode) {
+	pt.call(OsmuxEM_mode:{mode}) {
+		[] pt.getreply(OsmuxEM_mode:{mode}) {};
+	}
+}
+function f_osmuxem_configure(OsmuxEM_CTRL_PT pt, in OsmuxemConfig cfg) {
+	pt.call(OsmuxEM_configure:{cfg}) {
+		[] pt.getreply(OsmuxEM_configure:{cfg}) {};
+	}
+}
+function f_osmuxem_stats_get(OsmuxEM_CTRL_PT pt) return OsmuxemStats {
+	var OsmuxemStats stats;
+	pt.call(OsmuxEM_stats_get:{-}) {
+		[] pt.getreply(OsmuxEM_stats_get:{?}) -> param(stats) {};
+	}
+	return stats;
+}
+
+function f_osmuxem_register_rxhandle(OsmuxEM_CTRL_PT pt, OsmuxRxHandle hdl) {
+	pt.call(OsmuxEM_register_rxhandle:{hdl}) {
+		[] pt.getreply(OsmuxEM_register_rxhandle:{hdl}) {};
+	}
+}
+
+function f_osmuxem_register_txhandle(OsmuxEM_CTRL_PT pt, OsmuxTxHandle hdl) {
+	pt.call(OsmuxEM_register_txhandle:{hdl}) {
+		[] pt.getreply(OsmuxEM_register_txhandle:{hdl}) {};
+	}
+}
+
+
+function f_osmuxem_stats_compare_value(integer a, integer b, integer tolerance := 0) return boolean {
+	var integer temp;
+
+	temp := (a - b)
+	if (temp < 0) {
+		temp := -temp;
+	}
+
+	if (temp > tolerance) {
+		return false;
+	}
+
+	return true;
+}
+
+/* Cross-compare two osmuxem-statistics. The transmission statistics on the a side
+ * must match the reception statistics on the other side and vice versa. The
+ * user may also supply a tolerance value (number of packets) when deviations
+ * are acceptable */
+function f_osmuxem_stats_compare(OsmuxemStats a, OsmuxemStats b, integer tolerance := 0) return boolean {
+	var integer plen;
+
+	log("stats A: ", a);
+	log("stats B: ", b);
+	log("tolerance: ", tolerance, " packets");
+
+	if (f_osmuxem_stats_compare_value(a.num_pkts_tx, b.num_pkts_rx, tolerance) == false) {
+		return false;
+	}
+
+	if (f_osmuxem_stats_compare_value(a.num_pkts_rx, b.num_pkts_tx, tolerance) == false) {
+		return false;
+	}
+
+	if(a.num_pkts_tx > 0) {
+		plen := a.bytes_payload_tx / a.num_pkts_tx;
+	} else {
+		plen := 0;
+	}
+
+	if (f_osmuxem_stats_compare_value(a.bytes_payload_tx, b.bytes_payload_rx, tolerance * plen) == false) {
+		return false;
+	}
+
+	if (f_osmuxem_stats_compare_value(a.bytes_payload_rx, b.bytes_payload_tx, tolerance * plen) == false) {
+		return false;
+	}
+
+	return true;
+}
+
+/* Check the statistics for general signs of errors. This is a basic general
+ * check that will fit most situations and  is intended to be executed by
+ * the testcases as as needed. */
+function f_osmuxem_stats_err_check(OsmuxemStats s) {
+	log("stats: ", s);
+
+	/* Check if there was some activity at either on the RX or on the
+	 * TX side, but complete silence would indicate some problem */
+	if (s.num_pkts_tx < 1 and s.num_pkts_rx < 1) {
+		setverdict(fail, "no Osmux packet activity detected (packets)");
+		mtc.stop;
+	}
+	if (s.bytes_payload_tx < 1 and s.bytes_payload_rx < 1) {
+		setverdict(fail, "no Osmux packet activity detected (bytes)");
+		mtc.stop;
+	}
+
+	/* Check error counters */
+	if (s.num_pkts_rx_err_seq != 0) {
+		setverdict(fail, "Osmux packet sequence number errors occurred");
+		mtc.stop;
+	}
+	if (s.num_pkts_rx_err_disabled != 0) {
+		setverdict(fail, "Osmux packets received while RX was disabled");
+		mtc.stop;
+	}
+	if (s.num_pkts_rx_err_payload != 0) {
+		setverdict(fail, "Osmux packets with mismatching payload received");
+		mtc.stop;
+	}
+}
+
+template PDU_Osmux_AMR ts_OsmuxAMR(BIT1 marker, INT3b ctr, BIT1 amr_f, BIT1 amr_q, INT1 seq,
+				   OsmuxCID cid, INT4b amr_ft, INT4b amr_cmr,
+				   octetstring payload) := {
+	header := {
+		marker := marker,
+		ft := 1,
+		ctr := ctr,
+		amr_f := amr_f,
+		amr_q := amr_q,
+		seq := seq,
+		cid := cid,
+		amr_ft := amr_ft,
+		amr_cmr := amr_cmr
+	},
+	data := payload
+}
+
+private function f_rxhandle_get_by_cid(OsmuxCID cid) runs on OSMUX_Emulation_CT return OsmuxRxHandle {
+	var integer i;
+	for (i := 0; i < sizeof(RxHandleTable); i := i+1) {
+		if (isbound(RxHandleTable[i].cid) and RxHandleTable[i].cid == cid) {
+			return RxHandleTable[i].vc_conn;
+		}
+	}
+	setverdict(fail, "No Component for CID ", cid);
+	mtc.stop;
+}
+
+private function f_rxhandle_cid_add(OsmuxRxHandle hdl) runs on OSMUX_Emulation_CT {
+	var integer i;
+	for (i := 0; i < sizeof(RxHandleTable); i := i+1) {
+		if (not isbound(RxHandleTable[i].cid)) {
+			RxHandleTable[i].cid := hdl.cid;
+			RxHandleTable[i].vc_conn := hdl;
+			return;
+		}
+	}
+	testcase.stop("No Space in RxHandleTable for ", hdl.cid);
+	mtc.stop;
+}
+
+private function f_txhandle_cid_add(OsmuxTxHandle hdl) runs on OSMUX_Emulation_CT {
+	var integer i;
+	for (i := 0; i < sizeof(TxHandleList); i := i+1) {
+		if (not isbound(TxHandleList[i])) {
+			TxHandleList[i] := hdl;
+			return;
+		}
+	}
+	testcase.stop("No Space in TxHandleList for ", hdl.cid);
+	mtc.stop;
+}
+
+function f_osmux_gen_expected_rx_rtp_payload(INT4b amr_ft, octetstring tx_fixed_payload) return octetstring {
+	var integer payload_len;
+	var octetstring payload_truncated;
+	var integer i;
+	payload_len := f_amrft_payload_len(amr_ft);
+	payload_truncated := substr(tx_fixed_payload, 0, payload_len);
+	return payload_truncated;
+}
+
+private function f_osmux_gen_payload(INT3b ctr, INT4b amr_ft) runs on OSMUX_Emulation_CT return octetstring {
+	var octetstring payload_truncated := ''O;
+	var integer i;
+
+	for (i := 0; i < ctr + 1; i := i+1) {
+		payload_truncated := payload_truncated & f_osmux_gen_expected_rx_rtp_payload(amr_ft, g_cfg.tx_fixed_payload);
+	}
+	return payload_truncated;
+}
+
+private function f_tx_osmux(integer i, INT3b ctr, octetstring payload, BIT1 marker := '0'B) runs on OSMUX_Emulation_CT {
+	var OsmuxTxHandle hdl := TxHandleList[i];
+	var PDU_Osmux_AMR osmux_amr := valueof(ts_OsmuxAMR(marker, ctr, hdl.amr_f,
+					  hdl.amr_q, hdl.seq, hdl.cid, hdl.amr_ft,
+					  hdl.amr_cmr, payload));
+	OSMUX.send(t_Osmux_Send(g_osmux_conn_id, OSMUX_PDU:{osmux_amr:=osmux_amr}));
+	/* increment sequence + timestamp for next transmit */
+	TxHandleList[i].seq := TxHandleList[i].seq + 1;
+
+	/* update counters */
+	g_stat.num_pkts_tx := g_stat.num_pkts_tx+1;
+	g_stat.bytes_payload_tx := g_stat.bytes_payload_tx +
+						lengthof(payload);
+}
+
+private function f_tx_osmux_all_cid(BIT1 marker := '0'B) runs on OSMUX_Emulation_CT {
+	/* TODO: append all in one UDP packet and send together */
+	var integer i;
+	var octetstring payload_truncated;
+	var INT3b ctr := g_cfg.batch_size - 1;
+
+	for (i := 0; i < sizeof(TxHandleList); i := i+1) {
+		if (isbound(TxHandleList[i])) {
+			payload_truncated := f_osmux_gen_payload(ctr, TxHandleList[i].amr_ft);
+			f_tx_osmux(i, ctr, payload_truncated, marker);
+
+		}
+	}
+}
+
+function f_main() runs on OSMUX_Emulation_CT
+{
+	var Result res;
+	var OsmuxRxHandle rx_hdl;
+	var OsmuxTxHandle tx_hdl;
+	var octetstring payload_truncated;
+
+	timer T_transmit := int2float(g_cfg.tx_duration_ms)/1000.0;
+	var Osmux_RecvFrom rx_osmux;
+	var PDU_Osmux_AMR  rx_amr;
+	var PDU_Osmux_DUMMY osmux_dummy;
+	var OsmuxemConfig cfg;
+	var template Osmux_RecvFrom tr_osmux_amr := {
+		connId := ?,
+		remName := ?,
+		remPort := ?,
+		locName := ?,
+		locPort := ?,
+		msg := ?
+	};
+	tr_osmux_amr.msg := { osmux_amr := ? };
+	var template Osmux_RecvFrom tr_osmux_dummy := {
+		connId := ?,
+		remName := ?,
+		remPort := ?,
+		locName := ?,
+		locPort := ?,
+		msg := ?
+	};
+	tr_osmux_dummy.msg := { osmux_dummy := ? };
+
+	while (true) {
+	alt {
+		/* control procedures (calls) from the user */
+		[] CTRL.getcall(OsmuxEM_bind:{?,?}) -> param(g_local_host, g_local_port) {
+
+			g_tx_connected := false; /* will set it back to true upon next connect() call */
+			res := OSMUX_CodecPort_CtrlFunct.f_IPL4_listen(OSMUX, g_local_host,
+								g_local_port, {udp:={}});
+			if (not ispresent(res.connId)) {
+				setverdict(fail, "Could not listen on Osmux socket, check your configuration");
+				mtc.stop;
+			}
+			g_osmux_conn_id := res.connId;
+			tr_osmux_amr.connId := g_osmux_conn_id;
+			tr_osmux_dummy.connId := g_osmux_conn_id;
+
+			CTRL.reply(OsmuxEM_bind:{g_local_host, g_local_port});
+		}
+		[] CTRL.getcall(OsmuxEM_connect:{?,?}) -> param (g_remote_host, g_remote_port) {
+			res := OSMUX_CodecPort_CtrlFunct.f_IPL4_connect(OSMUX, g_remote_host,
+								g_remote_port,
+								g_local_host, g_local_port,
+								g_osmux_conn_id, {udp:={}});
+			if (not ispresent(res.connId)) {
+				setverdict(fail, "Could not connect to Osmux socket, check your configuration");
+				mtc.stop;
+			}
+			g_tx_connected := true;
+			CTRL.reply(OsmuxEM_connect:{g_remote_host, g_remote_port});
+		}
+		[] CTRL.getcall(OsmuxEM_mode:{OSMUXEM_MODE_NONE}) {
+			T_transmit.stop;
+			g_rx_enabled := false;
+			CTRL.reply(OsmuxEM_mode:{OSMUXEM_MODE_NONE});
+		}
+		[] CTRL.getcall(OsmuxEM_mode:{OSMUXEM_MODE_TXONLY}) {
+			/* start transmit timer */
+			T_transmit.start;
+			g_rx_enabled := false;
+			CTRL.reply(OsmuxEM_mode:{OSMUXEM_MODE_TXONLY});
+		}
+		[] CTRL.getcall(OsmuxEM_mode:{OSMUXEM_MODE_RXONLY}) {
+
+			T_transmit.stop;
+			if (g_rx_enabled == false) {
+				/* flush queues */
+				OSMUX.clear;
+				g_rx_enabled := true;
+			}
+			CTRL.reply(OsmuxEM_mode:{OSMUXEM_MODE_RXONLY});
+		}
+		[] CTRL.getcall(OsmuxEM_mode:{OSMUXEM_MODE_BIDIR}) {
+			T_transmit.start;
+			if (g_rx_enabled == false) {
+				/* flush queues */
+				OSMUX.clear;
+				g_rx_enabled := true;
+			}
+			CTRL.reply(OsmuxEM_mode:{OSMUXEM_MODE_BIDIR});
+		}
+		[] CTRL.getcall(OsmuxEM_configure:{?}) -> param (cfg) {
+			g_cfg := cfg;
+			CTRL.reply(OsmuxEM_configure:{cfg});
+		}
+		[] CTRL.getcall(OsmuxEM_register_txhandle:{?}) -> param (tx_hdl) {
+			f_txhandle_cid_add(tx_hdl);
+			CTRL.reply(OsmuxEM_register_txhandle:{tx_hdl});
+		}
+		[] CTRL.getcall(OsmuxEM_register_rxhandle:{?}) -> param (rx_hdl) {
+			f_rxhandle_cid_add(rx_hdl);
+			CTRL.reply(OsmuxEM_register_rxhandle:{rx_hdl});
+		}
+		[] CTRL.getcall(OsmuxEM_stats_get:{?}) {
+				CTRL.reply(OsmuxEM_stats_get:{g_stat});
+		}
+
+		/* simply ignore any Osmux AMR if receiver not enabled */
+		[g_rx_enabled==false] OSMUX.receive(tr_osmux_amr) {
+			g_stat.num_pkts_rx_err_disabled := g_stat.num_pkts_rx_err_disabled+1;
+		}
+		/* simply ignore any Osmux Dummy if receiver not enabled */
+		[g_rx_enabled==false] OSMUX.receive(tr_osmux_dummy) -> value rx_osmux {
+			log("Osmux Dummy received on CID ", rx_osmux.msg.osmux_dummy.header.cid, " (rx_disabled)");
+		}
+
+		/* process received Osmux AMR if receiver enabled */
+		[g_rx_enabled] OSMUX.receive(tr_osmux_amr) -> value rx_osmux {
+			/* increment counters */
+			g_stat.num_pkts_rx := g_stat.num_pkts_rx+1;
+			g_stat.bytes_payload_rx := g_stat.bytes_payload_rx +
+								lengthof(rx_osmux.msg.osmux_amr.data);
+			rx_hdl := f_rxhandle_get_by_cid(rx_osmux.msg.osmux_amr.header.cid);
+
+			if (rx_hdl.first_seq_seen and rx_hdl.last_seq_ack != rx_osmux.msg.osmux_amr.header.seq - 1 ) {
+				g_stat.num_pkts_rx_err_seq := g_stat.num_pkts_rx_err_seq + 1;
+			}
+			rx_hdl.first_seq_seen := true;
+			rx_hdl.last_seq_ack := rx_osmux.msg.osmux_amr.header.seq;
+
+			payload_truncated := f_osmux_gen_payload(rx_osmux.msg.osmux_amr.header.ctr, rx_osmux.msg.osmux_amr.header.amr_ft);
+			if (ispresent(g_cfg.rx_fixed_payload) and rx_osmux.msg.osmux_amr.data != payload_truncated) {
+				g_stat.num_pkts_rx_err_payload := g_stat.num_pkts_rx_err_payload + 1;
+			}
+		}
+		/* process received Osmux Dummy if receiver enabled */
+		[g_rx_enabled] OSMUX.receive(tr_osmux_dummy) -> value rx_osmux {
+			log("Osmux Dummy received on CID", rx_osmux.msg.osmux_dummy.header.cid);
+			rx_hdl := f_rxhandle_get_by_cid(rx_osmux.msg.osmux_dummy.header.cid);
+		}
+
+		/* transmit if timer has expired */
+		[g_tx_connected] T_transmit.timeout {
+			/* send one Osmux frame, re-start timer */
+			f_tx_osmux_all_cid();
+			T_transmit.start;
+		}
+
+		/* fail on any unexpected messages */
+		[] OSMUX.receive {
+			setverdict(fail, "Received unexpected type from Osmux");
+			mtc.stop;
+		}
+	}
+	}
+}
+
+
+}