diff --git a/include/openbsc/abis_nm.h b/include/openbsc/abis_nm.h
index 1108aa4..ca4de85 100644
--- a/include/openbsc/abis_nm.h
+++ b/include/openbsc/abis_nm.h
@@ -275,7 +275,7 @@
 };
 
 /* Section 9.4.1 */
-struct abis_nm_abis_channel {
+struct abis_nm_channel {
 	u_int8_t	attrib;
 	u_int8_t	bts_port;
 	u_int8_t	timeslot;
@@ -294,7 +294,7 @@
 	int (*sw_act_req)(struct msgb *);
 };
 
-extern int abis_nm_rx(struct msgb *msg);
+extern int abis_nm_rcvmsg(struct msgb *msg);
 //extern struct abis_nm_h *abis_nm_init(struct abis_nm_cfg *cfg);
 //extern void abis_nm_fini(struct abis_nm_h *nmh);
 
diff --git a/include/openbsc/abis_rsl.h b/include/openbsc/abis_rsl.h
index 9413f65..cbbb797 100644
--- a/include/openbsc/abis_rsl.h
+++ b/include/openbsc/abis_rsl.h
@@ -105,7 +105,7 @@
 	RSL_MT_PHY_CONTEXT_CONF,
 	RSL_MT_RF_CHAN_REL,
 	RSL_MT_MS_POWER_CONTROL,
-	RSL_MT_BS_POWER_CONTROL,
+	RSL_MT_BS_POWER_CONTROL,		/* 0x30 */
 	RSL_MT_PREPROC_CONFIG,
 	RSL_MT_PREPROC_MEAS_RES,
 	RSL_MT_RF_CHAN_REL_ACK,
@@ -290,14 +290,18 @@
 		      u_int8_t ta);
 int rsl_chan_activate_tch_f(struct gsm_bts_trx_ts *ts);
 int rsl_chan_activate_sdcch(struct gsm_bts_trx_ts *ts);
-int rsl_chan_release(struct gsm_bts_trx_ts *ts, u_int8_t chan_nr);
+int rsl_chan_release(struct gsm_lchan *lchan);
 int rsl_paging_cmd(struct gsm_bts *bts, u_int8_t paging_group, u_int8_t len,
 		   u_int8_t *ms_ident, u_int8_t chan_needed);
 int rsl_paging_cmd_imsi(struct gsm_bts *bts, u_int8_t chan_needed, const char *imsi_str);
 int rsl_imm_assign_cmd(struct gsm_bts *bts, u_int8_t len, u_int8_t *val);
-int rsl_data_request(struct gsm_bts *bts, struct msgb *msg);
 
-int abis_rsl_rx(struct msgb *msg);
+int rsl_data_request(struct msgb *msg, u_int8_t link_id);
+
+int abis_rsl_rcvmsg(struct msgb *msg);
+
+/* to be provided by external code */
+int abis_rsl_sendmsg(struct msgb *msg);
 
 #endif /* RSL_MT_H */
 
diff --git a/include/openbsc/chan_alloc.h b/include/openbsc/chan_alloc.h
new file mode 100644
index 0000000..0cbd03e
--- /dev/null
+++ b/include/openbsc/chan_alloc.h
@@ -0,0 +1,22 @@
+#ifndef _CHAN_ALLOC_H
+#define _CHAN_ALLOC_H
+
+/* Special allocator for C0 of BTS */
+struct gsm_bts_trx_ts *ts_c0_alloc(struct gsm_bts *bts,
+				   enum gsm_phys_chan_config pchan);
+
+/* Regular physical channel allocator */
+struct gsm_bts_trx_ts *ts_alloc(struct gsm_bts *bts,
+				enum gsm_phys_chan_config pchan);
+
+/* Regular physical channel (TS) */
+void ts_free(struct gsm_bts_trx_ts *ts);
+
+
+/* Allocate a logical channel (SDCCH, TCH, ...) */
+struct gsm_lchan *lchan_alloc(struct gsm_bts *bts, enum gsm_chan_t type);
+
+/* Free a logical channel (SDCCH, TCH, ...) */
+void lchan_free(struct gsm_lchan *lchan);
+
+#endif /* _CHAN_ALLOC_H */
diff --git a/include/openbsc/gsm_04_08.h b/include/openbsc/gsm_04_08.h
index 7c51969..dc5eba9 100644
--- a/include/openbsc/gsm_04_08.h
+++ b/include/openbsc/gsm_04_08.h
@@ -235,4 +235,11 @@
 #define GSM_MI_TYPE_TMSI	0x04
 #define GSM_MI_ODD		0x08
 
+struct msgb;
+struct gsm_bts;
+
+int gsm0408_rcvmsg(struct msgb *msg);
+enum gsm_chan_t get_ctype_by_chreq(struct gsm_bts *bts, u_int8_t ra);
+
+
 #endif
diff --git a/include/openbsc/gsm_data.h b/include/openbsc/gsm_data.h
index 51e246c..8bb219a 100644
--- a/include/openbsc/gsm_data.h
+++ b/include/openbsc/gsm_data.h
@@ -3,8 +3,11 @@
 
 #include <sys/types.h>
 
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
 #define GSM_MAX_BTS	8
 #define BTS_MAX_TRX	8
+#define TS_MAX_LCHAN	8
 
 #define HARDCODED_ARFCN 123
 
@@ -13,6 +16,35 @@
 	struct gsm_bts *bts;
 };
 
+enum gsm_phys_chan_config {
+	GSM_PCHAN_NONE,
+	GSM_PCHAN_CCCH,
+	GSM_PCHAN_CCCH_SDCCH4,
+	GSM_PCHAN_TCH_F,
+	GSM_PCHAN_TCH_H,
+	GSM_PCHAN_SDCCH8_SACCH8C,
+	GSM_PCHAN_UNKNOWN,
+};
+
+enum gsm_chan_t {
+	GSM_LCHAN_NONE,
+	GSM_LCHAN_SDCCH,
+	GSM_LCHAN_TCH_F,
+	GSM_LCHAN_TCH_H,
+	GSM_LCHAN_UNKNOWN,
+};
+
+struct gsm_lchan {
+	/* The TS that we're part of */
+	struct gsm_bts_trx_ts *ts;
+	/* The logical subslot number in the TS */
+	u_int8_t nr;
+	/* The lotical channel type */
+	enum gsm_chan_t type;
+	/* To whom we are allocated at the moment */
+	struct gsm_subscriber *subscr;
+};
+
 #define BTS_TRX_F_ACTIVATED	0x0001
 /* One Timeslot in a TRX */
 struct gsm_bts_trx_ts {
@@ -20,7 +52,11 @@
 	/* number of this timeslot at the TRX */
 	u_int8_t nr;
 
+	enum gsm_phys_chan_config pchan;
+
 	unsigned int flags;
+
+	struct gsm_lchan lchan[TS_MAX_LCHAN];
 };
 
 /* One TRX in a BTS */
@@ -71,4 +107,24 @@
 
 struct gsm_network *gsm_network_init(unsigned int num_bts, u_int8_t country_code,
 				     u_int8_t network_code);
+
+enum gsm_call_type {
+	GSM_CT_NONE,
+	GSM_CT_MO,
+	GSM_CT_MT,
+};
+
+enum gsm_call_state {
+	GSM_CSTATE_NONE,
+};
+
+/* One end of a call */
+struct gsm_call {
+	enum gsm_call_type type;
+	enum gsm_call_state state;
+
+	/* the 'local' subscriber */
+	struct gsm_subscriber *subscr;
+};
+	
 #endif
diff --git a/include/openbsc/gsm_subscriber.h b/include/openbsc/gsm_subscriber.h
index d5c6eff..5bdf579 100644
--- a/include/openbsc/gsm_subscriber.h
+++ b/include/openbsc/gsm_subscriber.h
@@ -5,7 +5,7 @@
 #include "gsm_data.h"
 
 struct gsm_subscriber {
-	u_int8_t *name;
+	char *name;
 	u_int8_t tmsi[4];
 };
 
diff --git a/include/openbsc/msgb.h b/include/openbsc/msgb.h
index b0740ed..13631e7 100644
--- a/include/openbsc/msgb.h
+++ b/include/openbsc/msgb.h
@@ -20,12 +20,20 @@
  *
  */
 
+#include <openbsc/linuxlist.h>
+
 struct bts_link;
 
 struct msgb {
-	/* ptr to the incoming (RX) or outgoing (TX) BTS link */
+	struct llist_head list;
+
+	/* ptr to the physical E1 link to the BTS(s) */
 	struct gsm_bts_link *bts_link;
 
+	/* Part of which TRX logical channel we were received / transmitted */
+	struct gsm_bts_trx *trx;
+	struct gsm_lchan *lchan;
+
 	u_int8_t l2_off;
 	u_int8_t l3_off;
 
@@ -40,6 +48,8 @@
 
 extern struct msgb *msgb_alloc(u_int16_t size);
 extern void msgb_free(struct msgb *m);
+extern void msgb_enqueue(struct llist_head *queue, struct msgb *msg);
+extern struct msgb *msgb_dequeue(struct llist_head *queue);
 
 #define msgb_l2(m)	((void *)(m->data + m->l2_off))
 #define msgb_l3(m)	((void *)(m->data + m->l3_off))
@@ -71,4 +81,19 @@
 	return (msgb->data + msgb->data_len) - msgb->tail;
 }
 
+/* increase the headroom of an empty msgb, reducing the tailroom */
+static inline void msgb_reserve(struct msgb *msg, int len)
+{
+	msg->data += len;
+	msg->tail += len;
+}
+
+static inline struct msgb *msgb_alloc_headroom(int size, int headroom)
+{
+	struct msgb *msg = msgb_alloc(size);
+	if (msg)
+		msgb_reserve(msg, headroom);
+	return msg;
+}
+
 #endif /* _MSGB_H */
diff --git a/include/openbsc/select.h b/include/openbsc/select.h
index f98f72c..b677162 100644
--- a/include/openbsc/select.h
+++ b/include/openbsc/select.h
@@ -1,6 +1,8 @@
 #ifndef _BSC_SELECT_H
 #define _BSC_SELECT_H
 
+#include <openbsc/linuxlist.h>
+
 #define BSC_FD_READ	0x0001
 #define BSC_FD_WRITE	0x0002
 #define BSC_FD_EXCEPT	0x0004
@@ -14,4 +16,7 @@
 	unsigned int priv_nr;
 };
 
+int bsc_register_fd(struct bsc_fd *fd);
+void bsc_unregister_fd(struct bsc_fd *fd);
+int bsc_select_main(void);
 #endif /* _BSC_SELECT_H */
diff --git a/src/abis_nm.c b/src/abis_nm.c
index c873b95..bf442fa 100644
--- a/src/abis_nm.c
+++ b/src/abis_nm.c
@@ -2,6 +2,7 @@
  * 3GPP TS 12.21 version 8.0.0 Release 1999 / ETSI TS 100 623 V8.0.0 */
 
 /* (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ *
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -24,13 +25,16 @@
 #include <errno.h>
 #include <stdio.h>
 #include <sys/types.h>
+#include <netinet/in.h>
 
-#include "gsm_data.h"
-#include "debug.h"
-#include "msgb.h"
-#include "abis_nm.h"
+#include <openbsc/gsm_data.h>
+#include <openbsc/debug.h>
+#include <openbsc/msgb.h>
+#include <openbsc/tlv.h>
+#include <openbsc/abis_nm.h>
 
-#define OM_ALLOC_SIZE	1024
+#define OM_ALLOC_SIZE		1024
+#define OM_HEADROOM_SIZE	128
 
 /* unidirectional messages from BTS to BSC */
 static const enum abis_nm_msgtype reports[] = {
@@ -97,7 +101,7 @@
 /* is this msgtype a report ? */
 static int is_report(enum abis_nm_msgtype mt)
 {
-	return is_in_arr(mt, reports, ARRA_YSIZE(reports));
+	return is_in_arr(mt, reports, ARRAY_SIZE(reports));
 }
 
 #define MT_ACK(x)	(x+1)
@@ -126,6 +130,11 @@
 	foh->obj_inst.ts_nr = ts_nr;
 }
 
+static struct msgb *nm_msgb_alloc(void)
+{
+	return msgb_alloc_headroom(OM_ALLOC_SIZE, OM_HEADROOM_SIZE);
+}
+
 /* Send a OML NM Message from BSC to BTS */
 int abis_nm_sendmsg(struct gsm_bts *bts, struct msgb *msg)
 {
@@ -133,7 +142,7 @@
 }
 
 /* Receive a OML NM Message from BTS */
-static int abis_nm_rcvmsg(struct msgb *mb)
+static int abis_nm_rcvmsg_fom(struct msgb *mb)
 {
 	struct abis_om_fom_hdr *foh = msgb_l3(mb);
 	u_int8_t mt = foh->msg_type;
@@ -164,11 +173,11 @@
 
 /* High-Level API */
 /* Entry-point where L2 OML from BTS enters the NM code */
-int abis_nm_rx(struct msgb *msg)
+int abis_nm_rcvmsg(struct msgb *msg)
 {
 	int rc;
 	struct abis_om_hdr *oh = msgb_l2(msg);
-	unsigned int l2_len = msg->tail - msg_l2(msg);
+	unsigned int l2_len = msg->tail - (u_int8_t *)msgb_l2(msg);
 
 	/* Various consistency checks */
 	if (oh->placement != ABIS_OM_PLACEMENT_ONLY) {
@@ -193,7 +202,7 @@
 
 	switch (oh->mdisc) {
 	case ABIS_OM_MDISC_FOM:
-		rc = abis_nm_rcvmsg(msg);
+		rc = abis_nm_rcvmsg_fom(msg);
 		break;
 	case ABIS_OM_MDISC_MMI:
 	case ABIS_OM_MDISC_TRAU:
@@ -264,7 +273,7 @@
 }
 #endif
 
-static fill_nm_channel(struct abis_nm_channel *ch, u_int8_t bts_port,
+static void fill_nm_channel(struct abis_nm_channel *ch, u_int8_t bts_port,
 		       u_int8_t ts_nr, u_int8_t subslot_nr)
 {
 	ch->attrib = NM_ATT_CHANNEL;
@@ -281,13 +290,13 @@
 	struct abis_nm_channel *ch;
 	u_int8_t *tei_attr;
 	u_int8_t len = 2 + sizeof(*ch);
-	struct mgsb *msg = msgb_alloc(OM_ALLOC_SIZE);
+	struct msgb *msg = nm_msgb_alloc();
 
 	oh = (struct abis_om_hdr *) msgb_put(msg, ABIS_OM_FOM_HDR_SIZE);
 	fill_om_fom_hdr(oh, len, NM_MT_ESTABLISH_TEI, NM_OC_RADIO_CARRIER,
 			bts->bts_nr, trx_nr, 0xff);
 	
-	msgb_tv_put(msgb, NM_ATT_TEI, tei);
+	msgb_tv_put(msg, NM_ATT_TEI, tei);
 
 	ch = (struct abis_nm_channel *) msgb_put(msg, sizeof(*ch));
 	fill_nm_channel(ch, e1_port, e1_timeslot, e1_subslot);
@@ -299,10 +308,10 @@
 int abis_nm_conn_terr_sign(struct gsm_bts_trx *trx,
 			   u_int8_t e1_port, u_int8_t e1_timeslot, u_int8_t e1_subslot)
 {
-	struct gsm_bts *bts = ts->trx->bts;
+	struct gsm_bts *bts = trx->bts;
 	struct abis_om_hdr *oh;
 	struct abis_nm_channel *ch;
-	struct mgsb *msg = msgb_alloc(OM_ALLOC_SIZE);
+	struct msgb *msg = nm_msgb_alloc();
 
 	oh = (struct abis_om_hdr *) msgb_put(msg, ABIS_OM_FOM_HDR_SIZE);
 	fill_om_fom_hdr(oh, sizeof(*ch), NM_MT_CONN_TERR_SIGN,
@@ -328,7 +337,7 @@
 	struct gsm_bts *bts = ts->trx->bts;
 	struct abis_om_hdr *oh;
 	struct abis_nm_channel *ch;
-	struct msgb *msg = msgb_alloc(OM_ALLOC_SIZE);
+	struct msgb *msg = nm_msgb_alloc();
 
 	oh = (struct abis_om_hdr *) msgb_put(msg, ABIS_OM_FOM_HDR_SIZE);
 	fill_om_fom_hdr(oh, sizeof(*ch), NM_MT_CONN_TERR_TRAF,
@@ -352,12 +361,12 @@
 {
 	struct gsm_bts *bts = ts->trx->bts;
 	struct abis_om_hdr *oh;
-	u_int8_t arfcn = htons(ts->trx->arfcn);
+	u_int16_t arfcn = htons(ts->trx->arfcn);
 	u_int8_t zero = 0x00;
-	struct msgb *msg = msgb_alloc(OM_ALLOC_SIZE);
+	struct msgb *msg = nm_msgb_alloc();
 
 	oh = (struct abis_om_hdr *) msgb_put(msg, ABIS_OM_FOM_HDR_SIZE);
-	fill_om_fom_hdr(oh, sizeof(*ch), NM_MT_SET_CHAN_ATTR,
+	fill_om_fom_hdr(oh, sizeof(*oh), NM_MT_SET_CHAN_ATTR,
 			NM_OC_BASEB_TRANSC, bts->bts_nr,
 			ts->trx->nr, ts->nr);
 	/* FIXME: don't send ARFCN list, hopping sequence, mAIO, ...*/
@@ -371,15 +380,16 @@
 	return abis_nm_sendmsg(bts, msg);
 }
 
-int abis_nm_raw_msg(struct gsm_bts *bts, int len, u_int8_t *msg)
+int abis_nm_raw_msg(struct gsm_bts *bts, int len, u_int8_t *rawmsg)
 {
-	struct msgb *msg = msgb_alloc(OM_ALLOC_SIZE);
+	struct msgb *msg = nm_msgb_alloc();
+	struct abis_om_hdr *oh;
 	u_int8_t *data;
 
 	oh = (struct abis_om_hdr *) msgb_put(msg, sizeof(*oh));
 	fill_om_hdr(oh, len);
 	data = msgb_put(msg, len);
-	memcpy(msgb->data, msg, len);
+	memcpy(msg->data, rawmsg, len);
 
 	return abis_nm_sendmsg(bts, msg);
 }
@@ -388,10 +398,10 @@
 static int __simple_cmd(struct gsm_bts *bts, u_int8_t msg_type)
 {
 	struct abis_om_hdr *oh;
-	struct msg = msgb_alloc(OM_ALLOC_SIZE);
+	struct msgb *msg = nm_msgb_alloc();
 
 	oh = (struct abis_om_hdr *) msgb_put(msg, ABIS_OM_FOM_HDR_SIZE);
-	fill_om_fom_hdr(oh, sizeof(*ch), msg_type, NM_OC_SITE_MANAGER,
+	fill_om_fom_hdr(oh, sizeof(*oh), msg_type, NM_OC_SITE_MANAGER,
 			0xff, 0xff, 0xff);
 
 	return abis_nm_sendmsg(bts, msg);
diff --git a/src/abis_rsl.c b/src/abis_rsl.c
index f503684..79f83ab 100644
--- a/src/abis_rsl.c
+++ b/src/abis_rsl.c
@@ -2,6 +2,7 @@
  * 3GPP TS 08.58 version 8.6.0 Release 1999 / ETSI TS 100 596 V8.6.0 */
 
 /* (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ *
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -21,31 +22,34 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <errno.h>
 #include <sys/types.h>
 
-#include "gsm_data.h"
-#include "gsm_04_08.h"
-#include "abis_rsl.h"
-#include "debug.h"
-#include "tlv.h"
+#include <openbsc/gsm_data.h>
+#include <openbsc/gsm_04_08.h>
+#include <openbsc/abis_rsl.h>
+#include <openbsc/chan_alloc.h>
+#include <openbsc/debug.h>
+#include <openbsc/tlv.h>
 
-#define RSL_ALLOC_SIZE	1024
+#define RSL_ALLOC_SIZE		1024
+#define RSL_ALLOC_HEADROOM	128
 
 static u_int8_t mdisc_by_msgtype(u_int8_t msg_type)
 {
 	/* mask off the transparent bit ? */
 	msg_type &= 0xfe;
 
-	if (msg_type & 0xf0 == 0x00)
+	if ((msg_type & 0xf0) == 0x00)
 		return ABIS_RSL_MDISC_RLL;
-	if (msg_type & 0xf0 == 0x10) {
+	if ((msg_type & 0xf0) == 0x10) {
 		if (msg_type >= 0x19 && msg_type <= 0x22)
 			return ABIS_RSL_MDISC_TRX;
 		else
 			return ABIS_RSL_MDISC_COM_CHAN;
 	}
-	if (msg_type & 0xc == 0x00)
+	if ((msg_type & 0xc) == 0x00)
 		return ABIS_RSL_MDISC_DED_CHAN;
 	
 	return ABIS_RSL_MDISC_LOC;
@@ -97,6 +101,84 @@
 	return ret;
 }
 
+/* determine logical channel based on TRX and channel number IE */
+struct gsm_lchan *lchan_lookup(struct gsm_bts_trx *trx, u_int8_t chan_nr)
+{
+	struct gsm_lchan *lchan;
+	u_int8_t ts_nr = chan_nr & 0x07;
+	u_int8_t cbits = chan_nr >> 3;
+	u_int8_t lch_idx;
+	struct gsm_bts_trx_ts *ts = &trx->ts[ts_nr];
+
+	if (cbits == 0x01) {
+		lch_idx = 0;	/* TCH/F */	
+		if (ts->pchan != GSM_PCHAN_TCH_F)
+			fprintf(stderr, "chan_nr=0x%02x but pchan=%u\n",
+				chan_nr, ts->pchan);
+	} else if ((cbits & 0x1e) == 0x02) {
+		lch_idx = cbits & 0x1;	/* TCH/H */
+		if (ts->pchan != GSM_PCHAN_TCH_H)
+			fprintf(stderr, "chan_nr=0x%02x but pchan=%u\n",
+				chan_nr, ts->pchan);
+	} else if ((cbits & 0x1c) == 0x04) {
+		lch_idx = cbits & 0x3;	/* SDCCH/4 */
+		if (ts->pchan != GSM_PCHAN_CCCH_SDCCH4)
+			fprintf(stderr, "chan_nr=0x%02x but pchan=%u\n",
+				chan_nr, ts->pchan);
+	} else if ((cbits & 0x18) == 0x08) {
+		lch_idx = cbits & 0x7;	/* SDCCH/8 */
+		if (ts->pchan != GSM_PCHAN_SDCCH8_SACCH8C)
+			fprintf(stderr, "chan_nr=0x%02x but pchan=%u\n",
+				chan_nr, ts->pchan);
+	} else if (cbits == 0x10 || cbits == 0x11 || cbits == 0x12) {
+		lch_idx = 0;
+		if (ts->pchan != GSM_PCHAN_CCCH &&
+		    ts->pchan != GSM_PCHAN_CCCH_SDCCH4)
+			fprintf(stderr, "chan_nr=0x%02x but pchan=%u\n",
+				chan_nr, ts->pchan);
+		/* FIXME: we should not return first sdcch4 !!! */
+	} else {
+		fprintf(stderr, "unknown chan_nr=0x%02x\n", chan_nr);
+		return NULL;
+	}
+
+	lchan = &ts->lchan[lch_idx];
+
+	return lchan;
+}
+
+u_int8_t lchan2chan_nr(struct gsm_lchan *lchan)
+{
+	struct gsm_bts_trx_ts *ts = lchan->ts;
+	u_int8_t cbits, chan_nr;
+
+	switch (ts->pchan) {
+	case GSM_PCHAN_TCH_F:
+		cbits = 0x01;
+		break;
+	case GSM_PCHAN_TCH_H:
+		cbits = 0x02;
+		cbits += lchan->nr;
+		break;
+	case GSM_PCHAN_CCCH_SDCCH4:
+		cbits = 0x04;
+		cbits += lchan->nr;
+		break;
+	case GSM_PCHAN_SDCCH8_SACCH8C:
+		cbits = 0x08;
+		cbits += lchan->nr;
+		break;
+	default:
+	case GSM_PCHAN_CCCH:
+		cbits = 0x10;
+		break;
+	}
+
+	chan_nr = (cbits << 3) | (ts->nr & 0x7);
+
+	return chan_nr;
+}
+
 /* As per TS 03.03 Section 2.2, the IMSI has 'not more than 15 digits' */
 u_int64_t str_to_imsi(const char *imsi_str)
 {
@@ -130,12 +212,17 @@
 	return (imsi % 1000) % (bs_cc_chans * n_pag_blocks) % n_pag_blocks;
 }
 
+static struct msgb *rsl_msgb_alloc(void)
+{
+	return msgb_alloc_headroom(RSL_ALLOC_SIZE, RSL_ALLOC_HEADROOM);
+}
+
 /* Send a BCCH_INFO message as per Chapter 8.5.1 */
 int rsl_bcch_info(struct gsm_bts *bts, u_int8_t type,
 		  const u_int8_t *data, int len)
 {
 	struct abis_rsl_dchan_hdr *dh;
-	struct msgb *msg = msgb_alloc(RSL_ALLOC_SIZE);
+	struct msgb *msg = rsl_msgb_alloc();
 
 	dh = (struct abis_rsl_dchan_hdr *) msgb_put(msg, sizeof*dh);
 	init_dchan_hdr(dh, RSL_MT_BCCH_INFO);
@@ -144,14 +231,16 @@
 	msgb_tv_put(msg, RSL_IE_SYSINFO_TYPE, type);
 	msgb_tlv_put(msg, RSL_IE_FULL_BCCH_INFO, len, data);
 
-	return abis_rsl_sendmsg(bts, msg);
+	msg->trx = bts->c0;
+
+	return abis_rsl_sendmsg(msg);
 }
 
 int rsl_sacch_filling(struct gsm_bts *bts, u_int8_t type, 
 		      const u_int8_t *data, int len)
 {
 	struct abis_rsl_common_hdr *ch;
-	struct msgb *msg = msgb_alloc(RSL_ALLOC_SIZE);
+	struct msgb *msg = rsl_msgb_alloc();
 
 	ch = (struct abis_rsl_common_hdr *) msgb_put(msg, sizeof(*ch));
 	ch->msg_discr = ABIS_RSL_MDISC_TRX;
@@ -160,7 +249,9 @@
 	msgb_tv_put(msg, RSL_IE_SYSINFO_TYPE, type);
 	msgb_tlv_put(msg, RSL_IE_L3_INFO, len, data);
 
-	return abis_rsl_sendmsg(bts, msg);
+	msg->trx = bts->c0;
+
+	return abis_rsl_sendmsg(msg);
 }
 
 /* Chapter 8.4.1 */
@@ -172,7 +263,7 @@
 		      u_int8_t ta)
 {
 	struct abis_rsl_dchan_hdr *dh;
-	struct msgb *msg = msgb_alloc(RSL_ALLOC_SIZE);
+	struct msgb *msg = rsl_msgb_alloc();
 	u_int8_t encr_info = 0x01;
 
 	dh = (struct abis_rsl_dchan_hdr *) msgb_put(msg, sizeof(*dh));
@@ -192,7 +283,7 @@
 	msgb_tv_put(msg, RSL_IE_MS_POWER, ms_power);
 	msgb_tv_put(msg, RSL_IE_TIMING_ADVANCE, ta);
 
-	return abis_rsl_sendmsg(bts, msg);
+	return abis_rsl_sendmsg(msg);
 }
 
 #define TSC	7
@@ -243,23 +334,26 @@
 	return rsl_chan_activate(ts->trx->bts, chan_nr, 0x00, &cm, &ci, 0x01, 0x0f, 0x00);
 }
 
-int rsl_chan_release(struct gsm_bts_trx_ts *ts, u_int8_t chan_nr)
+int rsl_chan_release(struct gsm_lchan *lchan)
 {
 	struct abis_rsl_dchan_hdr *dh;
-	struct msgb *msg = msgb_alloc(RSL_ALLOC_SIZE);
+	struct msgb *msg = rsl_msgb_alloc();
 
 	dh = (struct abis_rsl_dchan_hdr *) msgb_put(msg, sizeof(*dh));
 	init_dchan_hdr(dh, RSL_MT_RF_CHAN_REL);
-	dh->chan_nr = chan_nr;
+	dh->chan_nr = lchan2chan_nr(lchan);
 
-	return abis_rsl_sendmsg(ts->trx->bts, msg);
+	msg->lchan = lchan;
+	msg->trx = lchan->ts->trx;
+
+	return abis_rsl_sendmsg(msg);
 }
 
 int rsl_paging_cmd(struct gsm_bts *bts, u_int8_t paging_group, u_int8_t len,
 		   u_int8_t *ms_ident, u_int8_t chan_needed)
 {
 	struct abis_rsl_dchan_hdr *dh;
-	struct msgb *msg = msgb_alloc(RSL_ALLOC_SIZE);
+	struct msgb *msg = rsl_msgb_alloc();
 
 	dh = (struct abis_rsl_dchan_hdr *) msgb_put(msg, sizeof(*dh));
 	init_dchan_hdr(dh, RSL_MT_PAGING_CMD);
@@ -269,7 +363,9 @@
 	msgb_tlv_put(msg, RSL_IE_MS_IDENTITY, len, ms_ident);
 	msgb_tv_put(msg, RSL_IE_CHAN_NEEDED, chan_needed);
 
-	return abis_rsl_sendmsg(bts, msg);
+	msg->trx = bts->c0;
+
+	return abis_rsl_sendmsg(msg);
 }
 
 int imsi_str2bcd(u_int8_t *bcd_out, const char *str_in)
@@ -299,7 +395,7 @@
 
 int rsl_imm_assign_cmd(struct gsm_bts *bts, u_int8_t len, u_int8_t *val)
 {
-	struct msgb *msg = msgb_alloc(RSL_ALLOC_SIZE);
+	struct msgb *msg = rsl_msgb_alloc();
 	struct abis_rsl_dchan_hdr *dh;
 
 	dh = (struct abis_rsl_dchan_hdr *) msgb_put(msg, sizeof(*dh));
@@ -310,34 +406,57 @@
 
 	msgb_tlv_put(msg, RSL_IE_IMM_ASS_INFO, len, val);
 
-	return abis_rsl_sendmsg(bts, msg);
+	msg->trx = bts->c0;
+
+	return abis_rsl_sendmsg(msg);
 }
 
+/* Send "DATA REQUEST" message with given L3 Info payload */
 /* Chapter 8.3.1 */
-int rsl_data_request(struct gsm_bts *bts, struct msgb *msg)
+int rsl_data_request(struct msgb *msg, u_int8_t link_id)
 {
-	/* FIXME: prepend RSL header to layer 3 message */
-	u_int8_t len = msg->len;
+	u_int8_t l3_len = msg->tail - (u_int8_t *)msgb_l3(msg);
 	struct abis_rsl_rll_hdr *rh;
 
-	msgb_tv_push(msg, RSL_IE_L3_INFO, len);
+	if (msg->lchan == NULL) {
+		fprintf(stderr, "cannot send DATA REQUEST to unknown lchan\n");
+		return -EINVAL;
+	}
 
+	/* First push the L3 IE tag and length */
+	msgb_tv_push(msg, RSL_IE_L3_INFO, l3_len);
+
+	/* Then push the RSL header */
 	rh = (struct abis_rsl_rll_hdr *) msgb_push(msg, sizeof(*rh));
 	init_llm_hdr(rh, RSL_MT_DATA_REQ);
-	rh->chan_nr = RSL_CHAN_SDCCH4_ACCH;	/* FIXME: don't harcode */
+	rh->chan_nr = lchan2chan_nr(msg->lchan);
+	rh->link_id = link_id;
 
-	return abis_rsl_sendmsg(bts, msg);
+	msg->trx = msg->lchan->ts->trx;
+
+	return abis_rsl_sendmsg(msg);
 }
 
 static int abis_rsl_rx_dchan(struct msgb *msg)
 {
-	struct abis_rsl_common_hdr *rslh = msgb_l2(msg)	;
+	struct abis_rsl_dchan_hdr *rslh = msgb_l2(msg);
+	int rc = 0;
 
-	switch (rslh->msg_type) {
+	msg->lchan = lchan_lookup(msg->trx, rslh->chan_nr);
+
+	switch (rslh->c.msg_type) {
 	case RSL_MT_CHAN_ACTIV_ACK:
+		DEBUGP(DRSL, "rsl_rx_dchan: Channel Activate ACK\n");
+		break;
 	case RSL_MT_CHAN_ACTIV_NACK:
+		DEBUGP(DRSL, "rsl_rx_dchan: Channel Activate NACK\n");
+		break;
 	case RSL_MT_CONN_FAIL:
+		DEBUGP(DRSL, "rsl_rx_dchan: Connection Fail\n");
+		break;
 	case RSL_MT_MEAS_RES:
+		DEBUGP(DRSL, "rsl_rx_dchan: Measurement Result\n");
+		break;
 	case RSL_MT_MODE_MODIFY_ACK:
 	case RSL_MT_MODE_MODIFY_NACK:
 	case RSL_MT_PHY_CONTEXT_CONF:
@@ -350,18 +469,20 @@
 	case RSL_MT_MR_CODEC_MOD_NACK:
 	case RSL_MT_MR_CODEC_MOD_PER:
 		fprintf(stderr, "Unimplemented Abis RSL DChan msg 0x%02x\n",
-			rslh->msg_type);
+			rslh->c.msg_type);
 		break;
 	default:
 		fprintf(stderr, "unknown Abis RSL DChan msg 0x%02x\n",
-			rslh->msg_type);
+			rslh->c.msg_type);
 		return -EINVAL;
 	}
+	return rc;
 }
 
 static int abis_rsl_rx_trx(struct msgb *msg)
 {
 	struct abis_rsl_common_hdr *rslh = msgb_l2(msg)	;
+	int rc = 0;
 
 	switch (rslh->msg_type) {
 	case RSL_MT_RF_RES_IND:
@@ -377,25 +498,58 @@
 			rslh->msg_type);
 		return -EINVAL;
 	}
-
+	return rc;
 }
 
+/* MS has requested a channel on the RACH */
 static int rsl_rx_chan_rqd(struct msgb *msg)
 {
 	struct gsm_bts *bts = msg->bts_link->bts;
+	struct abis_rsl_dchan_hdr *rqd_hdr = msgb_l2(msg);
+	struct gsm48_req_ref *rqd_ref;
 	struct gsm48_imm_ass ia;
+	enum gsm_chan_t lctype;
+	struct gsm_lchan *lchan;
+	u_int8_t rqd_ta;
+
 	u_int16_t arfcn;
 	u_int8_t ts_number, subch;
 
-	/* MS has requested a channel on the RACH */
-	/* parse channel number, request reference, access delay */
-	/* FIXME: check permission/availability */
-	ts_number = 0;
-	arfcn = HARDCODED_ARFCN;
-	subch = 0;
+	/* parse request reference to be used in immediate assign */
+	if (rqd_hdr->data[0] != RSL_IE_REQ_REFERENCE)
+		return -EINVAL;
+
+	rqd_ref = (struct gsm48_req_ref *) &rqd_hdr->data[1];
+
+	/* parse access delay and use as TA */
+	if (rqd_hdr->data[sizeof(struct gsm48_req_ref)+1] != RSL_IE_ACCESS_DELAY)
+		return -EINVAL;
+	rqd_ta = rqd_hdr->data[sizeof(struct gsm48_req_ref)+2];
+
+	/* determine channel type (SDCCH/TCH_F/TCH_H) based on
+	 * request reference RA */
+	lctype = get_ctype_by_chreq(bts, rqd_ref->ra);
+
+	/* check availability / allocate channel */
+	lchan = lchan_alloc(bts, lctype);
+	if (!lchan) {
+		fprintf(stderr, "CHAN RQD: no resources\n");
+		/* FIXME: send some kind of reject ?!? */
+		return -ENOMEM;
+	}
+
+	ts_number = lchan->ts->nr;
+	arfcn = lchan->ts->trx->arfcn;
+	subch = lchan->nr;
 	
+	DEBUGP(DRSL, "Activating ARFCN(%u) TS(%u) SS(%u) lctype %u\n",
+		arfcn, ts_number, subch, lchan->type);
+
 	/* send CHANNEL ACTIVATION on RSL to BTS */
-	rsl_chan_activate_sdcch(&bts->trx[0].ts[ts_number]);
+	if (lchan->ts->pchan == GSM_PCHAN_SDCCH8_SACCH8C)
+		rsl_chan_activate_sdcch(lchan->ts);
+	else
+		rsl_chan_activate_tch_f(lchan->ts);
 
 	/* create IMMEDIATE ASSIGN 04.08 messge */
 	memset(&ia, 0, sizeof(ia));
@@ -403,18 +557,14 @@
 	ia.proto_discr = GSM48_PDISC_RR;
 	ia.msg_type = GSM48_MT_RR_IMM_ASS;
 	ia.page_mode = GSM48_PM_NORMAL;
-	ia.chan_desc.chan_nr = rsl_enc_chan_nr(RSL_CHAN_SDCCH4_ACCH, subch, ts_number);
+	ia.chan_desc.chan_nr = rsl_enc_chan_nr(lchan->ts->pchan, subch, ts_number);
 	ia.chan_desc.h0.h = 0;
 	ia.chan_desc.h0.arfcn_high = arfcn >> 8;
 	ia.chan_desc.h0.arfcn_low = arfcn & 0xff;
 	ia.chan_desc.h0.tsc = 7;
-	/* FIXME: use real request reference extracted from CHAN_RQD */
-	ia.req_ref.ra = 0x80 | 0x1e;
-	ia.req_ref.t2 = 0x0c;
-	ia.req_ref.t1_ = 0x12;
-	ia.req_ref.t3_low = 0x19 & 3;
-	ia.req_ref.t3_high = 0x19 >> 3;
-	ia.timing_advance = 0;
+	/* use request reference extracted from CHAN_RQD */
+	memcpy(&ia.req_ref, rqd_ref, sizeof(ia.req_ref));
+	ia.timing_advance = rqd_ta;
 	ia.mob_alloc_len = 0;
 
 	/* send IMMEDIATE ASSIGN CMD on RSL to BTS (to send on CCCH to MS) */
@@ -423,10 +573,12 @@
 
 static int abis_rsl_rx_cchan(struct msgb *msg)
 {
-	struct abis_rsl_common_hdr *rslh = msgb_l2(msg)	;
-	int rc;
+	struct abis_rsl_dchan_hdr *rslh = msgb_l2(msg)	;
+	int rc = 0;
 
-	switch (rslh->msg_type) {
+	msg->lchan = lchan_lookup(msg->trx, rslh->chan_nr);
+
+	switch (rslh->c.msg_type) {
 	case RSL_MT_CHAN_RQD:
 		/* MS has requested a channel on the RACH */
 		rc = rsl_rx_chan_rqd(msg);
@@ -438,13 +590,15 @@
 	case RSL_MT_CCCH_LOAD_IND:
 		/* current load on the CCCH */
 		fprintf(stderr, "Unimplemented Abis RSL TRX message type 0x%02x\n",
-			rslh->msg_type);
+			rslh->c.msg_type);
 		break;
 	default:
 		fprintf(stderr, "Unknown Abis RSL TRX message type 0x%02x\n",
-			rslh->msg_type);
+			rslh->c.msg_type);
 		return -EINVAL;
 	}
+
+	return rc;
 }
 
 /*	ESTABLISH INDICATION, LOCATION AREA UPDATE REQUEST 
@@ -457,16 +611,20 @@
 {
 	struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
 	int rc;
+
+	msg->lchan = lchan_lookup(msg->trx, rllh->chan_nr);
 	
 	switch (rllh->c.msg_type) {
 	case RSL_MT_DATA_IND:
 		DEBUGP(DRLL, "DATA INDICATION\n");
-		/* FIXME: parse L3 info element */
+		/* FIXME: Verify L3 info element */
+		msg->l3_off = &rllh->data[2] - msg->data;
 		rc = gsm0408_rcvmsg(msg);
 		break;
 	case RSL_MT_EST_IND:
 		DEBUGP(DRLL, "ESTABLISH INDICATION\n");
-		/* FIXME: parse L3 info element */
+		/* FIXME: Verify L3 info element */
+		msg->l3_off = &rllh->data[2] - msg->data;
 		rc = gsm0408_rcvmsg(msg);
 		break;
 	case RSL_MT_ERROR_IND:
@@ -479,10 +637,11 @@
 		fprintf(stderr, "unknown Abis RLL message type 0x%02x\n",
 			rllh->c.msg_type);
 	}
+	return rc;
 }
 
 /* Entry-point where L2 RSL from BTS enters */
-int abis_rsl_rx(struct msgb *msg)
+int abis_rsl_rcvmsg(struct msgb *msg)
 {
 	struct abis_rsl_common_hdr *rslh = msgb_l2(msg)	;
 	unsigned int l2_len = (void *)msg->tail - msgb_l2(msg);
@@ -496,13 +655,16 @@
 		rc = abis_rsl_rx_dchan(msg);
 		break;
 	case ABIS_RSL_MDISC_COM_CHAN:
-	case ABIS_RSL_MDISC_TRX:
 		rc = abis_rsl_rx_cchan(msg);
 		break;
+	case ABIS_RSL_MDISC_TRX:
+		rc = abis_rsl_rx_trx(msg);
+		break;
 	case ABIS_RSL_MDISC_LOC:
 	default:
 		fprintf(stderr, "unknown RSL message discriminator 0x%02x\n",
 			rslh->msg_discr);
 		return -EINVAL;
 	}
+	return rc;
 }
diff --git a/src/bsc_hack.c b/src/bsc_hack.c
index 0f237cc..9bec0b4 100644
--- a/src/bsc_hack.c
+++ b/src/bsc_hack.c
@@ -21,9 +21,9 @@
 
 
 
-#include "gsm_data.h"
-#include "abis_rsl.h"
-#include "abis_nm.h"
+#include <openbsc/gsm_data.h>
+#include <openbsc/abis_rsl.h>
+#include <openbsc/abis_nm.h>
 
 /* global pointer to the gsm network data structure */
 static struct gsm_network *gsmnet;
@@ -536,8 +536,8 @@
 	bts->location_area_code = 1;
 	bts->trx[0].arfcn = HARDCODED_ARFCN;
 
+	mi_setup();
+
 	/* initialize the BTS */
 	bootstrap_bts(&gsmnet->bts[0]);
-
-
 }
diff --git a/src/chan_alloc.c b/src/chan_alloc.c
new file mode 100644
index 0000000..ca86908
--- /dev/null
+++ b/src/chan_alloc.c
@@ -0,0 +1,150 @@
+/* GSM Channel allocation routines
+ *
+ * (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/chan_alloc.h>
+
+struct gsm_bts_trx_ts *ts_c0_alloc(struct gsm_bts *bts,
+				   enum gsm_phys_chan_config pchan)
+{
+	struct gsm_bts_trx *trx = &bts->trx[0];	
+	struct gsm_bts_trx_ts *ts = &trx->ts[0];
+
+	if (pchan != GSM_PCHAN_CCCH &&
+	    pchan != GSM_PCHAN_CCCH_SDCCH4)
+		return NULL;
+
+	if (ts->pchan != GSM_PCHAN_NONE)
+		return NULL;
+
+	ts->pchan = pchan;
+
+	return ts;
+}
+
+
+/* Allocate a logical channel (TS) */
+struct gsm_bts_trx_ts *ts_alloc(struct gsm_bts *bts,
+				enum gsm_phys_chan_config pchan)
+{
+	int i, j;
+	for (i = 0; i < bts->num_trx; i++) {
+		struct gsm_bts_trx *trx = &bts->trx[i];
+		for (j = 0; j < 8; j++) {
+			struct gsm_bts_trx_ts *ts = &trx->ts[j];
+			if (ts->pchan == GSM_PCHAN_NONE) {
+				ts->pchan = pchan;
+				return ts;
+			}
+		}
+	}
+	return NULL;
+}
+
+/* Free a physical channel (TS) */
+void ts_free(struct gsm_bts_trx_ts *ts)
+{
+	ts->pchan = GSM_PCHAN_NONE;
+}
+
+static const u_int8_t subslots_per_pchan[] = {
+	[GSM_PCHAN_NONE] = 0,
+	[GSM_PCHAN_CCCH] = 0,
+	[GSM_PCHAN_CCCH_SDCCH4] = 4,
+	[GSM_PCHAN_TCH_F] = 1,
+	[GSM_PCHAN_TCH_H] = 2,
+	[GSM_PCHAN_SDCCH8_SACCH8C] = 8.
+};
+
+static struct gsm_lchan *
+_lc_find(struct gsm_bts *bts, enum gsm_phys_chan_config pchan)
+{
+	struct gsm_bts_trx *trx;
+	struct gsm_bts_trx_ts *ts;
+	int i, j, ss;
+	for (i = 0; i < bts->num_trx; i++) {
+		trx = &bts->trx[i];
+		for (j = 0; j < 8; j++) {
+			ts = &trx->ts[j];
+			if (ts->pchan != pchan)
+				continue;
+			/* check if all sub-slots are allocated yet */
+			for (ss = 0; ss < subslots_per_pchan[pchan]; ss++) {
+				struct gsm_lchan *lc = &ts->lchan[ss];
+				if (lc->type == GSM_LCHAN_NONE)
+					return lc;
+			}
+		}
+	}
+	/* we cannot allocate more of these */
+	if (pchan == GSM_PCHAN_CCCH_SDCCH4)
+		return NULL;
+
+	/* if we've reached here, we need to allocate a new physical
+	 * channel for the logical channel type requested */
+	ts = ts_alloc(bts, pchan);
+	if (!ts) {
+		/* no more radio resources */
+		return NULL;
+	}
+	return &ts->lchan[0];
+}
+
+/* Allocate a logical channel */
+struct gsm_lchan *lchan_alloc(struct gsm_bts *bts, enum gsm_chan_t type)
+{
+	struct gsm_lchan *lchan = NULL;
+
+	switch (type) {
+	case GSM_LCHAN_SDCCH:
+		lchan = _lc_find(bts, GSM_PCHAN_CCCH_SDCCH4);
+		if (lchan == NULL)
+			lchan = _lc_find(bts, GSM_PCHAN_SDCCH8_SACCH8C);
+		break;
+	case GSM_LCHAN_TCH_F:
+		lchan = _lc_find(bts, GSM_PCHAN_TCH_F);
+		break;
+	case GSM_LCHAN_TCH_H:
+		lchan =_lc_find(bts, GSM_PCHAN_TCH_H);
+		break;
+	default:
+		fprintf(stderr, "Unknown gsm_chan_t %u\n", type);
+	}
+
+	if (lchan)
+		lchan->type = type;
+
+	return lchan;
+}
+
+/* Free a logical channel */
+void lchan_free(struct gsm_lchan *lchan)
+{
+	lchan->type = GSM_LCHAN_NONE;
+	/* FIXME: ts_free() the timeslot, if we're the last logical
+	 * channel using it */
+}
diff --git a/src/gsm_04_08.c b/src/gsm_04_08.c
index 4165b78..397f131 100644
--- a/src/gsm_04_08.c
+++ b/src/gsm_04_08.c
@@ -2,6 +2,7 @@
  * 3GPP TS 04.08 version 7.21.0 Release 1998 / ETSI TS 100 940 V7.21.0 */
 
 /* (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ *
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -26,13 +27,15 @@
 #include <string.h>
 #include <errno.h>
 
-#include "msgb.h"
-#include "debug.h"
-#include "gsm_data.h"
-#include "gsm_subscriber.h"
-#include "gsm_04_08.h"
+#include <openbsc/msgb.h>
+#include <openbsc/debug.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/gsm_04_08.h>
+#include <openbsc/abis_rsl.h>
 
-#define GSM0408_ALLOC_SIZE	1024
+#define GSM48_ALLOC_SIZE	1024
+#define GSM48_ALLOC_HEADROOM	128
 
 struct gsm_lai {
 	u_int16_t mcc;
@@ -79,8 +82,8 @@
 	lai48->digits[1] = bcd[2];
 
 	to_bcd(bcd, mnc);
-	lai48->digits[2] |= bcd[2] << 4;
-	lai48->digits[3] = bcd[0] | (bcd[1] << 4);
+	lai48->digits[1] |= bcd[2] << 4;
+	lai48->digits[2] = bcd[0] | (bcd[1] << 4);
 	
 	lai48->lac = lac;
 }
@@ -98,11 +101,17 @@
 	buf[5] = tmsi_bcd[3];
 }
 
+static struct msgb *gsm48_msgb_alloc(void)
+{
+	return msgb_alloc_headroom(GSM48_ALLOC_SIZE, GSM48_ALLOC_HEADROOM);
+}
+
 static int gsm0408_sendmsg(struct msgb *msg)
 {
-	/* FIXME: set data pointer to beginning of L3 data object */
+	if (msg->lchan)
+		msg->trx = msg->lchan->ts->trx;
 
-	return rsl_data_request(msg);
+	return rsl_data_request(msg, 0);
 }
 
 static int gsm0408_rcv_cc(struct msgb *msg)
@@ -138,15 +147,17 @@
 			gh->msg_type);
 		break;
 	}
+
+	return 0;
 }
 
 /* Chapter 9.2.14 : Send LOCATION UPDATE REJECT */
-int gsm0408_loc_upd_rej(struct gsm_bts_link *bts_link, u_int8_t cause)
+int gsm0408_loc_upd_rej(struct gsm_lchan *lchan, u_int8_t cause)
 {
-	struct msgb *msg = msgb_alloc(GSM0408_ALLOC_SIZE);
+	struct msgb *msg = gsm48_msgb_alloc();
 	struct gsm48_hdr *gh;
 	
-	msg->bts_link = bts_link;
+	msg->lchan = lchan;
 
 	gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh) + 1);
 	gh->proto_discr = GSM48_PDISC_MM;
@@ -159,15 +170,15 @@
 }
 
 /* Chapter 9.2.13 : Send LOCATION UPDATE ACCEPT */
-int gsm0408_loc_upd_acc(struct gsm_bts_link *bts_link, u_int8_t *tmsi)
+int gsm0408_loc_upd_acc(struct gsm_lchan *lchan, u_int8_t *tmsi)
 {
-	struct gsm_bts *bts = bts_link->bts;
-	struct msgb *msg = msgb_alloc(GSM0408_ALLOC_SIZE);
+	struct gsm_bts *bts = lchan->ts->trx->bts;
+	struct msgb *msg = gsm48_msgb_alloc();
 	struct gsm48_hdr *gh;
 	struct gsm48_loc_area_id *lai;
 	u_int8_t *mid;
 	
-	msg->bts_link = bts_link;
+	msg->lchan = lchan;
 
 	gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh));
 	gh->proto_discr = GSM48_PDISC_MM;
@@ -185,15 +196,18 @@
 	return gsm0408_sendmsg(msg);
 }
 
-
 /* Chapter 9.2.15 */
 static int mm_loc_upd_req(struct msgb *msg)
 {
+	struct gsm48_hdr *gh = msgb_l3(msg);
 	struct gsm_bts *bts = msg->bts_link->bts;
 	struct gsm48_loc_upd_req *lu;
 	struct gsm_subscriber *subscr;
+	u_int8_t mi_type;
 
-	u_int8_t mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
+ 	lu = (struct gsm48_loc_upd_req *) gh->data;
+
+	mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
 
 	switch (mi_type) {
 	case GSM_MI_TYPE_IMSI:
@@ -220,12 +234,14 @@
 
 	if (!subscr) {
 		/* 0x16 is congestion */
-		gsm0408_loc_upd_rej(msg->bts_link, 0x16);
+		gsm0408_loc_upd_rej(msg->lchan, 0x16);
 		return -EINVAL;
 	}
 
+	msg->lchan->subscr = subscr;
 	subscr_update(subscr, bts);
-	return gsm0408_loc_upd_acc(msg->bts_link, subscr->tmsi);
+
+	return gsm0408_loc_upd_acc(msg->lchan, subscr->tmsi);
 }
 
 static int gsm0408_rcv_mm(struct msgb *msg)
@@ -279,7 +295,7 @@
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
 	u_int8_t pdisc = gh->proto_discr & 0x0f;
-	int rc;
+	int rc = 0;
 	
 	switch (pdisc) {
 	case GSM48_PDISC_CC:
@@ -304,3 +320,82 @@
 
 	return rc;
 }
+
+enum chreq_type {
+	CHREQ_T_EMERG_CALL,
+	CHREQ_T_CALL_REEST_TCH_F,
+	CHREQ_T_CALL_REEST_TCH_H,
+	CHREQ_T_CALL_REEST_TCH_H_DBL,
+	CHREQ_T_SDCCH,
+	CHREQ_T_TCH_F,
+	CHREQ_T_VOICE_CALL_TCH_H,
+	CHREQ_T_DATA_CALL_TCH_H,
+	CHREQ_T_LOCATION_UPD,
+	CHREQ_T_PAG_R_ANY,
+	CHREQ_T_PAG_R_TCH_F,
+	CHREQ_T_PAG_R_TCH_FH,
+};
+
+/* Section 9.1.8 / Table 9.9 */
+struct chreq {
+	u_int8_t val;
+	u_int8_t mask;
+	enum chreq_type type;
+};
+
+/* If SYSTEM INFORMATION TYPE 4 NECI bit == 1 */
+static const struct chreq chreq_type_neci1[] = {
+	{ 0xa0, 0xe0, CHREQ_T_EMERG_CALL },
+	{ 0xc0, 0xe0, CHREQ_T_CALL_REEST_TCH_F },
+	{ 0x68, 0xfc, CHREQ_T_CALL_REEST_TCH_H },
+	{ 0x6c, 0xfc, CHREQ_T_CALL_REEST_TCH_H_DBL },
+	{ 0xe0, 0xe0, CHREQ_T_SDCCH },
+	{ 0x40, 0xf0, CHREQ_T_VOICE_CALL_TCH_H },
+	{ 0x50, 0xf0, CHREQ_T_DATA_CALL_TCH_H },
+	{ 0x00, 0xf0, CHREQ_T_LOCATION_UPD },
+	{ 0x10, 0xf0, CHREQ_T_SDCCH },
+	{ 0x80, 0xe0, CHREQ_T_PAG_R_ANY },
+	{ 0x20, 0xf0, CHREQ_T_PAG_R_TCH_F },
+	{ 0x30, 0xf0, CHREQ_T_PAG_R_TCH_FH },
+};
+
+/* If SYSTEM INFORMATION TYPE 4 NECI bit == 0 */
+static const struct chreq chreq_type_neci0[] = {
+	{ 0xa0, 0xe0, CHREQ_T_EMERG_CALL },
+	{ 0xc0, 0xe0, CHREQ_T_CALL_REEST_TCH_H },
+	{ 0xe0, 0xe0, CHREQ_T_TCH_F },
+	{ 0x50, 0xf0, CHREQ_T_DATA_CALL_TCH_H },
+	{ 0x00, 0xe0, CHREQ_T_LOCATION_UPD },
+	{ 0x80, 0xe0, CHREQ_T_PAG_R_ANY },
+	{ 0x20, 0xf0, CHREQ_T_PAG_R_TCH_F },
+	{ 0x30, 0xf0, CHREQ_T_PAG_R_TCH_FH },
+};
+
+static const enum gsm_chan_t ctype_by_chreq[] = {
+	[CHREQ_T_EMERG_CALL]		= GSM_LCHAN_TCH_F,
+	[CHREQ_T_CALL_REEST_TCH_F]	= GSM_LCHAN_TCH_F,
+	[CHREQ_T_CALL_REEST_TCH_H]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_CALL_REEST_TCH_H_DBL]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_SDCCH]			= GSM_LCHAN_SDCCH,
+	[CHREQ_T_TCH_F]			= GSM_LCHAN_TCH_F,
+	[CHREQ_T_VOICE_CALL_TCH_H]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_DATA_CALL_TCH_H]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_LOCATION_UPD]		= GSM_LCHAN_SDCCH,
+	[CHREQ_T_PAG_R_ANY]		= GSM_LCHAN_SDCCH,
+	[CHREQ_T_PAG_R_TCH_F]		= GSM_LCHAN_TCH_F,
+	[CHREQ_T_PAG_R_TCH_FH]		= GSM_LCHAN_TCH_F,
+};
+
+enum gsm_chan_t get_ctype_by_chreq(struct gsm_bts *bts, u_int8_t ra)
+{
+	int i;
+	/* FIXME: determine if we set NECI = 0 in the BTS SI4 */
+
+	for (i = 0; i < ARRAY_SIZE(chreq_type_neci0); i++) {
+		const struct chreq *chr = &chreq_type_neci0[i];
+		if ((ra & chr->mask) == chr->val)
+			return ctype_by_chreq[chr->type];
+	}
+	fprintf(stderr, "Unknown CHANNEL REQUEST RQD 0x%02x\n", ra);
+	return GSM_LCHAN_SDCCH;
+}
diff --git a/src/gsm_data.c b/src/gsm_data.c
index a4d0e8b..e5ba906 100644
--- a/src/gsm_data.c
+++ b/src/gsm_data.c
@@ -1,4 +1,5 @@
 /* (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ *
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -21,7 +22,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "gsm_data.h"
+#include <openbsc/gsm_data.h>
 
 struct gsm_network *gsm_network_init(unsigned int num_bts, u_int8_t country_code,
 				     u_int8_t network_code)
@@ -57,12 +58,24 @@
 
 			for (k = 0; k < 8; k++) {
 				struct gsm_bts_trx_ts *ts = &trx->ts[k];
+				int l;
 				
 				ts->trx = trx;
 				ts->nr = k;
+				ts->pchan = GSM_PCHAN_NONE;
+
+				for (l = 0; l < TS_MAX_LCHAN; l++) {
+					struct gsm_lchan *lchan;
+					lchan = &ts->lchan[l];
+
+					lchan->ts = ts;
+					lchan->nr = l;
+					lchan->type = GSM_LCHAN_NONE;
+				}
 			}
 		}
 
 		bts->num_trx = 1;	/* FIXME */
 	}
+	return net;
 }
diff --git a/src/gsm_subscriber.c b/src/gsm_subscriber.c
index 76d2e35..6a67c49 100644
--- a/src/gsm_subscriber.c
+++ b/src/gsm_subscriber.c
@@ -1,6 +1,7 @@
 /* Dummy implementation of a subscriber database, roghly HLR/VLR functionality */
 
 /* (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ *
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -20,7 +21,7 @@
  */
 
 
-#include "gsm_subscriber.h"
+#include <openbsc/gsm_subscriber.h>
 
 static struct gsm_subscriber subscr = {
 	.name = "Test User 1",
diff --git a/src/misdn.c b/src/misdn.c
index 6b23223..49b858f 100644
--- a/src/misdn.c
+++ b/src/misdn.c
@@ -1,6 +1,6 @@
-/* OpenBSC Abis interface to mISDNuser
- *
- * (C) 2008 by Harald Welte <laforge@gnumonks.org>
+/* OpenBSC Abis interface to mISDNuser */
+
+/* (C) 2008 by Harald Welte <laforge@gnumonks.org>
  *
  * All Rights Reserved
  *
@@ -30,27 +30,39 @@
 #include <sys/ioctl.h>
 #include <mISDNif.h>
 
-#define AF_COMPATIBILITY_FUNC
-#include <compat_af_isdn.h>
+//#define AF_COMPATIBILITY_FUNC
+//#include <compat_af_isdn.h>
+#define AF_ISDN 34
+#define PF_ISDN AF_ISDN
+
+#include <openbsc/select.h>
+#include <openbsc/msgb.h>
+#include <openbsc/debug.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/abis_nm.h>
+#include <openbsc/abis_rsl.h>
 
 #define NUM_E1_TS	32
 
 /* data structure for one E1 interface with A-bis */
 struct mi_e1_handle {
 	struct gsm_bts *bts;
-
 	/* The mISDN card number of the card we use */
 	int cardnr;
-
 	/* The RSL adress */
 	struct sockaddr_mISDN l2addr;
-
 	/* The OML adress */
 	struct sockaddr_mISDN omladdr;
+	/* list (queue) of to-be-sent msgb's */
+	struct llist_head rsl_tx_list;
+	struct llist_head oml_tx_list;
 
-	struct gsm_fd fd[NUM_E1_TS];
+	struct bsc_fd fd[NUM_E1_TS];
 };
 
+/* FIXME: this needs to go */
+static struct mi_e1_handle *global_e1h;
+
 #define SAPI_L2ML	0
 #define SAPI_OML	62
 #define SAPI_RSL	63
@@ -74,13 +86,18 @@
 {
 	struct mi_e1_handle *e1h = bfd->data;
 	struct msgb *msg = msgb_alloc(TS1_ALLOC_SIZE);
-	struct sockaddr_mISDN l2dadr;
+	struct sockaddr_mISDN l2addr;
+	struct mISDNhead *hh;
 	socklen_t alen;
+	int ret;
 
 	if (!msg)
 		return -ENOMEM;
 
-	msg->bts = e1h->bts;
+	hh = (struct mISDNhead *) msg->data;
+
+	/* FIXME: Map TEI/SAPI to TRX */
+	msg->trx = e1h->bts->c0;
 
 	alen = sizeof(l2addr);
 	ret = recvfrom(bfd->fd, msg->data, 300, 0,
@@ -104,7 +121,7 @@
 	switch (hh->prim) {
 	case DL_INFORMATION_IND:
 		DEBUGP(DMI, "got DL_INFORMATION_IND\n");
-		struct sockaddr_mISDN *sa;
+		struct sockaddr_mISDN *sa = NULL;
 		char *lstr = "UNKN";
 
 		switch (l2addr.tei) {
@@ -117,11 +134,13 @@
 			lstr = "RSL";
 			break;
 		default:
-			continue;
+			break;
 		}
-		DEBUGP(DMI, "%s use channel(%d) sapi(%d) tei(%d) for now\n",
-			lstr, l2addr.channel, l2addr.sapi, l2addr.tei);
-		memcpy(sa, &l2addr, sizeof(l2addr));
+		if (sa) {
+			DEBUGP(DMI, "%s use channel(%d) sapi(%d) tei(%d) for now\n",
+				lstr, l2addr.channel, l2addr.sapi, l2addr.tei);
+			memcpy(sa, &l2addr, sizeof(l2addr));
+		}
 		break;
 	case DL_ESTABLISH_IND:
 		DEBUGP(DMI, "got DL_ESTABLISH_IND\n");
@@ -164,14 +183,39 @@
 static int handle_ts1_write(struct bsc_fd *bfd)
 {
 	struct mi_e1_handle *e1h = bfd->data;
+	struct msgb *msg;
+	struct mISDNhead *hh;
+	int ret, no_rsl = 0;
 
-	/* FIXME: dequeue a pending msgb for RSL / OML */
-	
-	/* prepend the mISDNhead */
-	hh = (struct mISDNhed *) msg_
-	hh->prim = DL_DATA_REQ;
+	msg = msgb_dequeue(&e1h->rsl_tx_list);
+	if (!msg)
+		no_rsl = 1;
+	else {
+		/* prepend the mISDNhead */
+		hh = (struct mISDNhead *) msgb_push(msg, sizeof(*hh));
+		hh->prim = DL_DATA_REQ;
 
-	/* FIXME: send it off */
+		ret = sendto(bfd->fd, msg->data, msg->len, 0,
+			     (struct sockaddr *)&e1h->l2addr,
+			     sizeof(e1h->l2addr));
+		usleep(100000);
+	}
+	msg = msgb_dequeue(&e1h->rsl_tx_list);
+	if (!msg) {
+		if (no_rsl)
+			bfd->when &= ~BSC_FD_WRITE;
+	} else {
+		/* prepend the mISDNhead */
+		hh = (struct mISDNhead *) msgb_push(msg, sizeof(*hh));
+		hh->prim = DL_DATA_REQ;
+
+		ret = sendto(bfd->fd, msg->data, msg->len, 0,
+			     (struct sockaddr *)&e1h->omladdr,
+			     sizeof(e1h->omladdr));
+		usleep(100000);
+	}
+
+	return ret;
 }
 
 static int handle_tsX_read(struct bsc_fd *bfd)
@@ -179,13 +223,13 @@
 	/* FIXME: read from a B channel TS */
 }
 
-static int handle_TsX_write(struct bsc_fd *bfd)
+static int handle_tsX_write(struct bsc_fd *bfd)
 {
 	/* FIXME: write to a B channel TS */
 }
 
 /* callback from select.c in case one of the fd's can be read/written */
-static int misdn_fd_cb(struct gsm_fd *bfd, unsigned int what)
+static int misdn_fd_cb(struct bsc_fd *bfd, unsigned int what)
 {
 	unsigned int e1_ts = bfd->priv_nr;
 	int rc = 0;
@@ -208,13 +252,33 @@
 	return rc;
 }
 
-static int mi_setup(devinfo_t *di)
+int abis_rsl_sendmsg(struct msgb *msg)
 {
-	int ts, sk, ret;
-	struct mISDN_devinfo	devinfo;
+	struct mi_e1_handle *e1h = global_e1h;
+
+	msgb_enqueue(&e1h->rsl_tx_list, msg);
+	e1h->fd[0].when |= BSC_FD_WRITE;
+
+	return 0;
+}
+
+int abis_nm_sendmsg(struct msgb *msg)
+{
+	struct mi_e1_handle *e1h = global_e1h;
+
+	msgb_enqueue(&e1h->oml_tx_list, msg);
+	e1h->fd[0].when |= BSC_FD_WRITE;
+
+	return 0;
+}
+
+static int mi_e1_setup(struct mi_e1_handle *e1h)
+{
+	int ts, sk, ret, cnt;
+	struct mISDN_devinfo devinfo;
 
 	sk = socket(PF_ISDN, SOCK_RAW, ISDN_P_BASE);
-	if (sk < 0)
+	if (sk < 0) {
 		fprintf(stderr, "could not open socket %s\n", strerror(errno));
 		return sk;
 	}
@@ -245,16 +309,22 @@
 
 	/* TS0 is CRC4, don't need any fd for it */
 	for (ts = 1; ts < NUM_E1_TS; ts++) {
-		unsigned int idx = i-1;
+		unsigned int idx = ts-1;
 		struct bsc_fd *bfd = &e1h->fd[idx];
 		struct sockaddr_mISDN addr;
 
-		if (ts == 1)
+		bfd->data = e1h;
+		bfd->priv_nr = ts;
+		bfd->cb = misdn_fd_cb;
+
+		if (ts == 1) {
 			bfd->fd = socket(PF_ISDN, SOCK_RAW, ISDN_P_LAPD_NT);
-		else
+			bfd->when = BSC_FD_READ;
+		} else
 			bfd->fd = socket(PF_ISDN, SOCK_DGRAM, ISDN_P_B_RAW);
 
-		if (bfd->fd < 0)
+
+		if (bfd->fd < 0) {
 			fprintf(stderr, "could not open socket %s\n",
 				strerror(errno));
 			return bfd->fd;
@@ -272,10 +342,35 @@
 
 		ret = bind(bfd->fd, (struct sockaddr *) &addr, sizeof(addr));
 		if (ret < 0) {
-			fprintf(stdout, "could not bind l2 socket %s\n",
+			fprintf(stderr, "could not bind l2 socket %s\n",
 				strerror(errno));
 			return -EIO;
 		}
+
+		ret = bsc_register_fd(bfd);
+		if (ret < 0) {
+			fprintf(stderr, "could not register FD: %s\n",
+				strerror(ret));
+			return ret;
+		}
 	}
+
+	return 0;
 }
 
+int mi_setup(struct gsm_bts *bts, int cardnr)
+{
+	struct mi_e1_handle *e1h;
+
+	e1h = malloc(sizeof(*e1h));
+	memset(e1h, 0, sizeof(*e1h));
+
+	e1h->cardnr = cardnr;
+	e1h->bts = bts;
+	INIT_LLIST_HEAD(&e1h->oml_tx_list);
+	INIT_LLIST_HEAD(&e1h->rsl_tx_list);
+
+	global_e1h = e1h;
+
+	return mi_e1_setup(e1h);
+}
diff --git a/src/msgb.c b/src/msgb.c
index ab356de..f5330c3 100644
--- a/src/msgb.c
+++ b/src/msgb.c
@@ -22,7 +22,7 @@
 #include <stdlib.h>
 #include <sys/types.h>
 
-#include "msgb.h"
+#include <openbsc/msgb.h>
 
 struct msgb *msgb_alloc(u_int16_t size)
 {
@@ -38,7 +38,7 @@
 	msg->head = msg->data;
 	msg->data = msg->data;
 	/* reset tail pointer */
-	msg->tail = msg->data - msg->head;
+	msg->tail = msg->data;
 	//msg->end = msg->tail + size;
 
 	return msg;
@@ -48,3 +48,20 @@
 {
 	free(m);
 }
+
+void msgb_enqueue(struct llist_head *queue, struct msgb *msg)
+{
+	llist_add_tail(&msg->list, queue);
+}
+
+struct msgb *msgb_dequeue(struct llist_head *queue)
+{
+	struct llist_head *lh;
+
+	if (llist_empty(queue))
+		return NULL;
+
+	lh = queue->next;
+
+	return llist_entry(lh, struct msgb, list);
+}
diff --git a/src/select.c b/src/select.c
index 0d95cfb..4af1670 100644
--- a/src/select.c
+++ b/src/select.c
@@ -32,11 +32,11 @@
 	/* make FD nonblocking */
 	flags = fcntl(fd->fd, F_GETFL);
 	if (flags < 0)
-		return -1;
+		return flags;
 	flags |= O_NONBLOCK;
 	flags = fcntl(fd->fd, F_SETFL, flags);
 	if (flags < 0)
-		return -1;
+		return flags;
 
 	/* Register FD */
 	if (fd->fd > maxfd)