diff --git a/include/Makefile.am b/include/Makefile.am
index 456b8ef..7af7e01 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -95,6 +95,7 @@
                        osmocom/gsm/gsm29205.h \
                        osmocom/gsm/gsm0808_utils.h \
                        osmocom/gsm/gsm23003.h \
+                       osmocom/gsm/gsm23236.h \
                        osmocom/gsm/gsm29118.h \
                        osmocom/gsm/gsm48.h \
                        osmocom/gsm/gsm48_arfcn_range_encode.h \
diff --git a/include/osmocom/gsm/gsm23236.h b/include/osmocom/gsm/gsm23236.h
new file mode 100644
index 0000000..23b003a
--- /dev/null
+++ b/include/osmocom/gsm/gsm23236.h
@@ -0,0 +1,60 @@
+/*! \file gsm23236.h
+ * API to handle Network Resource Indicator (NRI) values and ranges for MSC pooling, as in 3GPP TS 23.236.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <osmocom/core/linuxlist.h>
+
+#define OSMO_NRI_BITLEN_MIN 1
+#define OSMO_NRI_BITLEN_MAX 15
+#define OSMO_NRI_BITLEN_DEFAULT 10
+
+/*! One range of NRI values. An NRI is a Network Resource Indicator, a number of a configured bit length (typically 10
+ * bit). In an MSC pool for load balancing, it is used to indicate which MSC has issued a TMSI: the NRI is located with
+ * its most significant bit located on the TMSI's second octet's most significant bit. See 3GPP TS 23.236. */
+struct osmo_nri_range {
+	struct llist_head entry;
+
+	/*! First value of the NRI range, i.e. inclusive. */
+	int16_t first;
+	/*! Last value of the NRI range, i.e. inclusive. */
+	int16_t last;
+};
+
+/*! A list of struct osmo_nri_range. Use osmo_nri_ranges_alloc() to create, and osmo_nri_ranges_free() (or talloc_free()
+ * on the parent context) to destroy. Always use osmo_nri_ranges_add() to insert entries, to ensure that the list
+ * remains sorted by 'first' values, which some of the osmo_nri_ranges API assumes to always be true.
+ *
+ * This struct serves as talloc context for the osmo_nri_range entries in the list, simplifying function signatures. It
+ * also makes the API future proof, to easily accomodate possible future additions.
+ */
+struct osmo_nri_ranges {
+	/* List of struct osmo_nri_range entries, talloc allocated from the parent struct osmo_nri_ranges. */
+	struct llist_head entries;
+};
+
+int osmo_nri_v_validate(int16_t nri_v, uint8_t nri_bitlen);
+bool osmo_nri_v_matches_ranges(int16_t nri_v, const struct osmo_nri_ranges *nri_ranges);
+int osmo_nri_v_limit_by_ranges(int16_t *nri_v, const struct osmo_nri_ranges *nri_ranges, uint32_t nri_bitlen);
+
+int osmo_tmsi_nri_v_get(int16_t *nri_v, uint32_t tmsi, uint8_t nri_bitlen);
+int osmo_tmsi_nri_v_set(uint32_t *tmsi, int16_t nri_v, uint8_t nri_bitlen);
+int osmo_tmsi_nri_v_limit_by_ranges(uint32_t *tmsi, const struct osmo_nri_ranges *nri_ranges, uint8_t nri_bitlen);
+
+int osmo_nri_range_validate(const struct osmo_nri_range *range, uint8_t nri_bitlen);
+bool osmo_nri_range_overlaps_ranges(const struct osmo_nri_range *range, const struct osmo_nri_ranges *nri_ranges);
+
+struct osmo_nri_ranges *osmo_nri_ranges_alloc(void *ctx);
+void osmo_nri_ranges_free(struct osmo_nri_ranges *nri_ranges);
+int osmo_nri_ranges_add(struct osmo_nri_ranges *nri_ranges, const struct osmo_nri_range *add);
+int osmo_nri_ranges_del(struct osmo_nri_ranges *nri_ranges, const struct osmo_nri_range *del);
+int osmo_nri_ranges_vty_add(const char **message, struct osmo_nri_range *added_range,
+			    struct osmo_nri_ranges *nri_ranges, int argc, const char **argv, uint8_t nri_bitlen);
+int osmo_nri_ranges_vty_del(const char **message, struct osmo_nri_range *removed_range,
+			    struct osmo_nri_ranges *nri_ranges, int argc, const char **argv);
+int osmo_nri_ranges_to_str_buf(char *buf, size_t buflen, const struct osmo_nri_ranges *nri_ranges);
+char *osmo_nri_ranges_to_str_c(void *ctx, const struct osmo_nri_ranges *nri_ranges);
diff --git a/src/gsm/Makefile.am b/src/gsm/Makefile.am
index eeb1164..0e879e9 100644
--- a/src/gsm/Makefile.am
+++ b/src/gsm/Makefile.am
@@ -31,7 +31,7 @@
 			milenage/aes-internal.c milenage/aes-internal-enc.c \
 			milenage/milenage.c gan.c ipa.c gsm0341.c apn.c \
 			gsup.c gsup_sms.c gprs_gea.c gsm0503_conv.c oap.c gsm0808_utils.c \
-			gsm23003.c mncc.c bts_features.c oap_client.c \
+			gsm23003.c gsm23236.c mncc.c bts_features.c oap_client.c \
 			gsm29118.c gsm48_rest_octets.c cbsp.c gsm48049.c i460_mux.c
 libgsmint_la_LDFLAGS = -no-undefined
 libgsmint_la_LIBADD = $(top_builddir)/src/libosmocore.la
diff --git a/src/gsm/gsm23236.c b/src/gsm/gsm23236.c
new file mode 100644
index 0000000..01d0eb3
--- /dev/null
+++ b/src/gsm/gsm23236.c
@@ -0,0 +1,560 @@
+/*! \file gsm23236.c
+ * Utility function implementations related to 3GPP TS 23.236 */
+/*
+ * (C) 2020 sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Neels Hofmeyr <nhofmeyr@sysmocom.de>
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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 <errno.h>
+#include <stdlib.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/gsm/gsm23236.h>
+
+/*! Validate that the given NRI is valid for a given nri_bitlen range.
+ * \param[in] nri_v  NRI value to validate.
+ * \param[in] nri_bitlen  Valid NRI range in nr of bits used; if nri_bitlen > OSMO_NRI_BITLEN_MAX, nri_v is only
+ *                        checked to not be marked invalid.
+ * \returns 0 if valid, <0 if the NRI is <0, >0 if the NRI surpasses the range.
+ */
+int osmo_nri_v_validate(int16_t nri_v, uint8_t nri_bitlen)
+{
+	if (nri_v < 0)
+		return -1;
+	if (nri_bitlen < OSMO_NRI_BITLEN_MIN)
+		return 1;
+	if (nri_bitlen < OSMO_NRI_BITLEN_MAX && (nri_v >> nri_bitlen))
+		return 1;
+	return 0;
+}
+
+/*! Match NRI value against a list NRI ranges. */
+static bool nri_v_matches_range(const struct osmo_nri_range *range, int16_t nri_v)
+{
+	return range && nri_v >= range->first && nri_v <= range->last;
+}
+
+/*! Return true if the ranges overlap, i.e. one or more NRI values appear in both ranges. */
+static bool nri_range_overlaps_range(const struct osmo_nri_range *a, const struct osmo_nri_range *b)
+{
+	return nri_v_matches_range(b, a->first) || nri_v_matches_range(b, a->last)
+		|| nri_v_matches_range(a, b->first) || nri_v_matches_range(a, b->last);
+}
+
+/*! Return true if the ranges overlap or are directly adjacent to each other. */
+static bool nri_range_touches(const struct osmo_nri_range *a, const struct osmo_nri_range *b)
+{
+	/* The first > last check may seem redundant, but ensures integer overflow safety. */
+	return nri_range_overlaps_range(a, b)
+		|| (a->first > b->last && a->first == b->last + 1)
+		|| (b->first > a->last && b->first == a->last + 1);
+}
+
+/*! Grow target range to also span range 'add'. Only useful for touching ranges, since all values between the two ranges
+ * are also included. */
+static void nri_range_extend(struct osmo_nri_range *target, const struct osmo_nri_range *add)
+{
+	target->first = OSMO_MIN(target->first, add->first);
+	target->last = OSMO_MAX(target->last, add->last);
+}
+
+/*! Return true when the given NRI value appears in the list of NRI ranges.
+ * \param[in] nri_v  NRI value to look for.
+ * \param[in] nri_ranges  List NRI ranges.
+ * \returns true iff nri_v appears anywhere in nri_ranges.
+ */
+bool osmo_nri_v_matches_ranges(int16_t nri_v, const struct osmo_nri_ranges *nri_ranges)
+{
+	struct osmo_nri_range *range;
+	if (!nri_ranges)
+		return false;
+	llist_for_each_entry(range, &nri_ranges->entries, entry) {
+		if (nri_v_matches_range(range, nri_v))
+			return true;
+	}
+	return false;
+}
+
+/*! Modulo and shift the given NRI value so that it becomes a value present in a list of NRI ranges.
+ * Only range values within nri_bitlen are used.
+ * \param[inout] nri_v  The NRI value to limit, e.g. random bits or an increment counter value.
+ * \param[in] nri_ranges  List of NRI ranges indicating valid NRI values, where no entries may overlap in range values,
+ *                        and all entries must be valid (first <= last).
+ * \returns 0 on success, negative on error.
+ */
+int osmo_nri_v_limit_by_ranges(int16_t *nri_v, const struct osmo_nri_ranges *nri_ranges, uint32_t nri_bitlen)
+{
+	struct osmo_nri_range *range;
+	uint32_t total_values = 0;
+	int16_t v = *nri_v;
+	int16_t range_max = (((int16_t)1) << nri_bitlen) - 1;
+
+	if (v < 0 || !nri_ranges)
+		return -1;
+
+	/* Sum up total amount of range values */
+	llist_for_each_entry(range, &nri_ranges->entries, entry) {
+		if (osmo_nri_range_validate(range, 255))
+			return -1;
+		if (range->first > range_max)
+			continue;
+		total_values += OSMO_MIN(range_max, range->last) - range->first + 1;
+	}
+
+	/* Modulo the given NRI value by that, and pick that nth value from the given ranges.
+	 * (nri_ranges is pretty much guaranteed to be sorted and range_max checks thus would no longer be needed, but
+	 * just check them anyway.) */
+	v %= total_values;
+	llist_for_each_entry(range, &nri_ranges->entries, entry) {
+		uint32_t len;
+		if (range->first > range_max)
+			continue;
+		len = OSMO_MIN(range_max, range->last) - range->first + 1;
+		if (v < len) {
+			*nri_v = range->first + v;
+			return 0;
+		}
+		v -= len;
+	}
+
+	/* Nothing found -- there are no entires or my math is off. */
+	return -1;
+}
+
+/*! Retrieve the Network Resource Indicator bits from a TMSI or p-TMSI.
+ * Useful for MSC pooling as described by 3GPP TS 23.236.
+ * \param[out] nri_v  Write the extracted NRI value to this location (if non-NULL). If 0 is returned, it is guaranteed
+ *                    that nri_v >= 0. On non-zero return code, nri_v == -1.
+ * \param[in] tmsi  TMSI value containing NRI bits.
+ * \param[in] nri_bitlen  Length of the NRI value in number of bits,
+ *                        OSMO_NRI_BITLEN_MIN <= nri_bitlen <= * OSMO_NRI_BITLEN_MAX.
+ * \return 0 on success, negative on error (i.e. if nri_bitlen is not in the valid range).
+ */
+int osmo_tmsi_nri_v_get(int16_t *nri_v, uint32_t tmsi, uint8_t nri_bitlen)
+{
+	uint8_t lowest_bit;
+	if (nri_v)
+		*nri_v = -1;
+	if (nri_bitlen < OSMO_NRI_BITLEN_MIN || nri_bitlen > OSMO_NRI_BITLEN_MAX)
+		return -1;
+	/* If not interested in the NRI value, exit here. */
+	if (!nri_v)
+		return 0;
+	/* According to 3GPP TS 23.236, the most significant bit of the NRI is always bit 23.
+	 * (So this is not a temporary placeholder 23 we sometimes like to use, it is an actually specified 23!) */
+	lowest_bit = 23 - (nri_bitlen - 1);
+	/* ????xxxxxx??????? -> 0000000????xxxxxx  tmsi >> lowest_bit
+	 *                   ->            xxxxxx  & (bitmask that is nri_bitlen bits wide)
+	 */
+	*nri_v = (tmsi >> lowest_bit) & ((((uint32_t)1) << nri_bitlen) - 1);
+	return 0;
+}
+
+/*! Write Network Resource Indicator bits into a TMSI or p-TMSI.
+ * Overwrite the NRI bits with a given NRI value in a TMSI or p-TMSI.
+ * Useful for MSC pooling as described by 3GPP TS 23.236.
+ * \param[inout] tmsi  A base TMSI or p-TMSI to replace the NRI value in, result is written back to this location.
+ * \param[in] nri_v  The NRI value to place in the tmsi.
+ * \param[in] nri_bitlen  Length of the NRI value in number of bits,
+ *                        OSMO_NRI_BITLEN_MIN <= nri_bitlen <= * OSMO_NRI_BITLEN_MAX.
+ * \return 0 on success, negative on error (i.e. if nri_bitlen is not in the valid range or if tmsi is NULL).
+ */
+int osmo_tmsi_nri_v_set(uint32_t *tmsi, int16_t nri_v, uint8_t nri_bitlen)
+{
+	uint8_t lowest_bit;
+	uint32_t v_mask;
+	if (nri_bitlen < OSMO_NRI_BITLEN_MIN || nri_bitlen > OSMO_NRI_BITLEN_MAX)
+		return -1;
+	if (nri_v < 0)
+		return -1;
+	if (!tmsi)
+		return -1;
+	lowest_bit = 23 - (nri_bitlen - 1);
+	v_mask = ((((uint32_t)1) << nri_bitlen) - 1) << lowest_bit;
+	*tmsi = ((*tmsi) & ~v_mask) | ((((uint32_t)nri_v) << lowest_bit) & v_mask);
+	return 0;
+}
+
+/*! Apply osmo_nri_v_limit_by_ranges() in-place on the NRI value included in a TMSI.
+ * Extract the NRI value from the TMSI, limit that to be part of the ranges given in 'nri_ranges', and place the
+ * resulting NRI value back in the TMSI.
+ * \param[inout] tmsi  TMSI value of which to modify the NRI bits, e.g. fresh randomized bits.
+ * \param[in] nri_ranges  List of NRI ranges indicating valid NRI values, where no entries may overlap in range values,
+ *                        and all entries must be valid (first <= last).
+ * \param[in] nri_bitlen  Valid NRI range in nr of bits used.
+ * \returns 0 on success, negative on error.
+ */
+int osmo_tmsi_nri_v_limit_by_ranges(uint32_t *tmsi, const struct osmo_nri_ranges *nri_ranges, uint8_t nri_bitlen)
+{
+	int rc;
+	int16_t nri_v;
+	rc = osmo_tmsi_nri_v_get(&nri_v, *tmsi, nri_bitlen);
+	if (rc)
+		return rc;
+	rc = osmo_nri_v_limit_by_ranges(&nri_v, nri_ranges, nri_bitlen);
+	if (rc)
+		return rc;
+	return osmo_tmsi_nri_v_set(tmsi, nri_v, nri_bitlen);
+}
+
+/*! Validate that the given NRI range is valid for a given nri_bitlen range.
+ * \param[in] nri_range  NRI value range to validate.
+ * \param[in] nri_bitlen  Valid NRI range in nr of bits used. If nri_bitlen > OSMO_NRI_BITLEN_MAX, the NRI range is only
+ *                        validated to be first <= last and non-negative, not checked to fit a bit length range,
+ * \returns 0 if valid, -1 or 1 if range->first is invalid, -2 or 2 if range->last is invalid, -3 if first > last.
+ */
+int osmo_nri_range_validate(const struct osmo_nri_range *range, uint8_t nri_bitlen)
+{
+	int rc;
+	rc = osmo_nri_v_validate(range->first, nri_bitlen);
+	if (rc)
+		return rc;
+	rc = osmo_nri_v_validate(range->last, nri_bitlen);
+	if (rc)
+		return 2 * rc;
+	if (range->first > range->last)
+		return -3;
+	return 0;
+}
+
+/*! Return true when the given NRI range has at least one NRI value that appears in a list of other NRI ranges.
+ * \param[in] range  NRI range to look for.
+ * \param[in] nri_ranges  List NRI ranges.
+ * \returns true iff any NRI value from 'range' appears anywhere in nri_ranges.
+ */
+bool osmo_nri_range_overlaps_ranges(const struct osmo_nri_range *range, const struct osmo_nri_ranges *nri_ranges)
+{
+	struct osmo_nri_range *i;
+	if (!nri_ranges)
+		return false;
+	llist_for_each_entry(i, &nri_ranges->entries, entry) {
+		if (nri_range_overlaps_range(i, range))
+			return true;
+	}
+	return false;
+}
+
+/*! Allocate an empty struct osmo_nri_ranges (list of struct osmo_nri_range).
+ * \param ctx  Talloc context to allocate from.
+ * \return allocated empty list.
+ */
+struct osmo_nri_ranges *osmo_nri_ranges_alloc(void *ctx)
+{
+	struct osmo_nri_ranges *nri_ranges;
+	nri_ranges = talloc_zero(ctx, struct osmo_nri_ranges);
+	OSMO_ASSERT(nri_ranges);
+	INIT_LLIST_HEAD(&nri_ranges->entries);
+	return nri_ranges;
+}
+
+/*! Free a struct osmo_nri_ranges.
+ * \param nri_ranges The list to discard.
+ */
+void osmo_nri_ranges_free(struct osmo_nri_ranges *nri_ranges)
+{
+	if (nri_ranges)
+		talloc_free(nri_ranges);
+}
+
+/*! Insert a new struct osmo_nri_range in an osmo_nri_ranges list, so that it remains sorted by 'first' values. */
+static void nri_ranges_add_entry_sorted(struct osmo_nri_ranges *nri_ranges, struct osmo_nri_range *add)
+{
+	struct osmo_nri_range *r;
+	struct llist_head *at_pos;
+	OSMO_ASSERT(nri_ranges);
+	at_pos = nri_ranges->entries.prev;
+	llist_for_each_entry(r, &nri_ranges->entries, entry) {
+		if (r->first <= add->first)
+			continue;
+		at_pos = r->entry.prev;
+		break;
+	}
+	llist_add(&add->entry, at_pos);
+}
+
+/*! Add a range of NRI values to a list of nri_range structs.
+ * Intelligently add and/or combine the entries in a list of NRI ranges to also include the NRI range given in 'add'.
+ * The list remains sorted by 'first' values.
+ * \param[inout] nri_ranges  List of talloc allocated struct osmo_nri_range entries to add the new range to.
+ * \param[in] add  NRI range to add to 'nri_ranges'.
+ * \returns 0 on success, negative on error (if the range in 'add' is invalid).
+ */
+int osmo_nri_ranges_add(struct osmo_nri_ranges *nri_ranges, const struct osmo_nri_range *add)
+{
+	struct osmo_nri_range *range;
+	struct osmo_nri_range *range_next;
+	struct osmo_nri_range *target = NULL;
+
+	if (osmo_nri_range_validate(add, 255))
+		return -1;
+	if (!nri_ranges)
+		return -1;
+
+	/* Is there an entry overlapping this range? */
+	llist_for_each_entry(range, &nri_ranges->entries, entry) {
+		if (!nri_range_touches(range, add))
+			continue;
+		target = range;
+	}
+
+	if (!target) {
+		/* No overlaps with existing ranges, create a new one. */
+		target = talloc_zero(nri_ranges, struct osmo_nri_range);
+		OSMO_ASSERT(target);
+		*target = *add;
+		nri_ranges_add_entry_sorted(nri_ranges, target);
+		return 0;
+	}
+
+	/* Overlap found, join into existing entry */
+	nri_range_extend(target, add);
+
+	/* Remove redundant entries */
+	llist_for_each_entry_safe(range, range_next, &nri_ranges->entries, entry) {
+		if (range == target)
+			continue;
+		if (!nri_range_touches(target, range))
+			continue;
+		nri_range_extend(target, range);
+		llist_del(&range->entry);
+		talloc_free(range);
+	}
+	return 0;
+}
+
+/*! Remove a range of NRI values from a list of nri_range structs.
+ * Intelligently drop and/or cut or split the entries in a list of NRI ranges to no longer include the NRI range given
+ * in 'del'. Note that after this, the list may have more entries than before, if a range was split into two smaller
+ * ranges.
+ * \param[inout] nri_ranges  List of talloc allocated struct osmo_nri_range entries to remove values from.
+ * \param[in] del  NRI range to remove from 'nri_ranges'.
+ * \returns 0 on success, negative on error (if the range in 'del' is invalid).
+ */
+int osmo_nri_ranges_del(struct osmo_nri_ranges *nri_ranges, const struct osmo_nri_range *del)
+{
+	struct osmo_nri_range *range;
+	struct osmo_nri_range *range_next;
+
+	if (osmo_nri_range_validate(del, 255))
+		return -1;
+	if (!nri_ranges)
+		return -1;
+
+	llist_for_each_entry_safe(range, range_next, &nri_ranges->entries, entry) {
+		bool head;
+		bool tail;
+		if (!nri_range_overlaps_range(range, del))
+			continue;
+
+		head = nri_v_matches_range(range, del->first) && (del->first > range->first);
+		tail = nri_v_matches_range(range, del->last) && (del->last < range->last);
+
+		if (head && tail) {
+			/* Range cut in two */
+			struct osmo_nri_range *new_tail;
+
+			/* Add a new entry for the tail section */
+			new_tail = talloc_zero(nri_ranges, struct osmo_nri_range);
+			OSMO_ASSERT(new_tail);
+			*new_tail = (struct osmo_nri_range){
+				.first = del->last + 1,
+				.last = range->last,
+			};
+			llist_add(&new_tail->entry, &range->entry);
+
+			/* Existing entry becomes the head section */
+			range->last = del->first - 1;
+		} else if (head) {
+			/* Range reduced, a head remains */
+			range->last = del->first - 1;
+		} else if (tail) {
+			/* Range reduced, a tail remains */
+			range->first = del->last + 1;
+		} else {
+			/* nothing remains */
+			llist_del(&range->entry);
+			talloc_free(range);
+		}
+	}
+	return 0;
+}
+
+/*! Compose a human readable representation of a list of NRI ranges in a buffer, like "23..42,123..142".
+ * \param[out] buf  Target buffer.
+ * \param[in] buflen  sizeof(buf).
+ * \param[in] nri_ranges  List NRI ranges.
+ * \returns strlen() of string that would be written if the buffer is large enough, like snprintf().
+ */
+int osmo_nri_ranges_to_str_buf(char *buf, size_t buflen, const struct osmo_nri_ranges *nri_ranges)
+{
+	struct osmo_nri_range *range;
+	struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+	bool first = true;
+	if (!nri_ranges || llist_empty(&nri_ranges->entries)) {
+		OSMO_STRBUF_PRINTF(sb, "empty");
+		return sb.chars_needed;
+	}
+	llist_for_each_entry(range, &nri_ranges->entries, entry) {
+		OSMO_STRBUF_PRINTF(sb, "%s%d..%d", first ? "" : ",", range->first, range->last);
+	}
+	return sb.chars_needed;
+}
+
+/*! Compose a human readable representation of a list of NRI ranges in a talloc buffer, like "23..42,123..142".
+ * \param[in] ctx  Talloc context.
+ * \param[in] nri_ranges  List of NRI ranges.
+ * \returns a talloc allocated string.
+ */
+char *osmo_nri_ranges_to_str_c(void *ctx, const struct osmo_nri_ranges *nri_ranges)
+{
+	OSMO_NAME_C_IMPL(ctx, 16, "ERROR", osmo_nri_ranges_to_str_buf, nri_ranges);
+}
+
+/*! Parse a string to an NRI value, allowing both decimal and hexadecimal formats; useful for VTY config
+ * implementations.
+ * \param[out] dst  Write the resulting NRI value to this location.
+ * \param[in] str  Decimal "511" or hex "0x1ff" string to parse.
+ * \returns 0 on success, negative on error.
+ */
+static int osmo_nri_parse(int16_t *dst, const char *str)
+{
+	char *endp;
+	int64_t val;
+	int base = 10;
+
+	if (osmo_str_startswith(str, "0x")) {
+		str += 2;
+		base = 16;
+	}
+
+	if (!str || !str[0])
+		return -1;
+
+	errno = 0;
+	val = strtoull(str, &endp, base);
+	if (errno || *endp != '\0')
+		return -1;
+
+	if (val < 0 || val > INT16_MAX)
+		return -1;
+
+	*dst = val;
+	return 0;
+}
+
+/*! Parse string arguments to a struct osmo_nri_range; useful for VTY config implementations.
+ * Validate and parse 'first' and optional 'last' string arguments into struct osmo_nri_range values.
+ * The strings may be in decimal format ("511") or hexadecimal with leading "0x" ("0x1ff").
+ * If only one of 'first'/'last' is provided, the resulting range will have only that value (first == last).
+ * \param[out] nri_range  Target for parsed values.
+ * \param[in] first_str  Decimal or hex string, representing the first value in the range, or NULL if omitted.
+ * \param[in] last_str  Decimal or hex string, representing the last value in the range, or NULL if omitted.
+ * \returns 0 on success, negative on error.
+ */
+static int osmo_nri_parse_range(struct osmo_nri_range *nri_range, const char *first_str, const char *last_str)
+{
+	if (!nri_range)
+		return -1;
+	if (!first_str) {
+		first_str = last_str;
+		last_str = NULL;
+		if (!first_str)
+			return -1;
+	}
+	if (osmo_nri_parse(&nri_range->first, first_str))
+		return -1;
+	nri_range->last = nri_range->first;
+	if (last_str) {
+		if (osmo_nri_parse(&nri_range->last, last_str))
+			return -1;
+	}
+	return 0;
+}
+
+/*! VTY implementation for adding an NRI range to a list of ranges.
+ * Parse one or, if present, two argv arguments, which must be numbers representing the first and last value to add to
+ * the list of NRI ranges, in decimal format ("511") or hexadecimal with leading "0x" ("0x1ff"). If the range values
+ * surpass the nri_bitlen, return a warning in 'message', but still add the values to the list.
+ * \param[out] message  Returned string constant to alert the user with, or NULL if all is well.
+ * \param[out] added_range  If not NULL, write the range parsing result to this location.
+ * \param[in] nri_ranges  List NRI ranges to add to.
+ * \param[in] argc  Argument count.
+ * \param[in] argv  Argument list.
+ * \param[in] nri_bitlen  Valid NRI range in nr of bits used.
+ * \returns 0 on success, -1 on error, 1 for a warning (if adding was successful but the added range surpasses
+ *          nri_bitlen).
+ */
+int osmo_nri_ranges_vty_add(const char **message, struct osmo_nri_range *added_range,
+			    struct osmo_nri_ranges *nri_ranges, int argc, const char **argv, uint8_t nri_bitlen)
+{
+	struct osmo_nri_range add_range;
+	if (osmo_nri_parse_range(&add_range, argv[0], argc > 1 ? argv[1] : NULL)) {
+		*message = "Error: cannot parse NRI range";
+		return -1;
+	}
+
+	if (added_range)
+		*added_range = add_range;
+
+	if (osmo_nri_ranges_add(nri_ranges, &add_range)) {
+		*message = "Error: failed to add NRI range";
+		return -1;
+	}
+
+	if (nri_bitlen <= OSMO_NRI_BITLEN_MAX && osmo_nri_range_validate(&add_range, nri_bitlen)) {
+		*message = "Warning: NRI range surpasses current NRI bitlen";
+		return 1;
+	}
+
+	*message = NULL;
+	return 0;
+}
+
+/*! VTY implementation for removing an NRI range from a list of ranges.
+ * Parse one or, if present, two argv arguments, which must be numbers representing the first and last value to remove
+ * from the list of NRI ranges, in decimal format ("511") or hexadecimal with leading "0x" ("0x1ff").
+ * \param[out] message  Returned string constant to alert the user with, or NULL if all is well.
+ * \param[out] removed_range  If not NULL, write the range parsing result to this location.
+ * \param[in] nri_ranges  List of NRI ranges to remove from.
+ * \param[in] argc  Argument count.
+ * \param[in] argv  Argument list.
+ * \returns 0 on success, -1 on error, 1 for a warning.
+ */
+int osmo_nri_ranges_vty_del(const char **message, struct osmo_nri_range *removed_range,
+			    struct osmo_nri_ranges *nri_ranges, int argc, const char **argv)
+{
+	struct osmo_nri_range del_range;
+	if (osmo_nri_parse_range(&del_range, argv[0], argc > 1 ? argv[1] : NULL)) {
+		*message = "Error: cannot parse NRI range";
+		return -1;
+	}
+
+	if (removed_range)
+		*removed_range = del_range;
+
+	if (osmo_nri_ranges_del(nri_ranges, &del_range)) {
+		*message = "Error: failed to remove NRI range";
+		return -1;
+	}
+
+	*message = NULL;
+	return 0;
+}
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 2837aa5..ac9aeb2 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -678,5 +678,22 @@
 osmo_i460_subchan_del;
 osmo_i460_ts_init;
 
+osmo_nri_v_validate;
+osmo_nri_v_matches_ranges;
+osmo_nri_v_limit_by_ranges;
+osmo_tmsi_nri_v_get;
+osmo_tmsi_nri_v_set;
+osmo_tmsi_nri_v_limit_by_ranges;
+osmo_nri_range_validate;
+osmo_nri_range_overlaps_ranges;
+osmo_nri_ranges_alloc;
+osmo_nri_ranges_free;
+osmo_nri_ranges_add;
+osmo_nri_ranges_del;
+osmo_nri_ranges_vty_add;
+osmo_nri_ranges_vty_del;
+osmo_nri_ranges_to_str_buf;
+osmo_nri_ranges_to_str_c;
+
 local: *;
 };
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 5e810e6..2a364d5 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -23,6 +23,7 @@
 		 coding/coding_test conv/conv_gsm0503_test		\
 		 abis/abis_test endian/endian_test sercomm/sercomm_test	\
 		 prbs/prbs_test gsm23003/gsm23003_test 			\
+		 gsm23236/gsm23236_test                                 \
 		 codec/codec_ecu_fr_test timer/clk_override_test	\
 		 oap/oap_client_test gsm29205/gsm29205_test		\
 		 logging/logging_vty_test				\
@@ -246,6 +247,9 @@
 gsm23003_gsm23003_test_SOURCES = gsm23003/gsm23003_test.c
 gsm23003_gsm23003_test_LDADD = $(LDADD) $(top_builddir)/src/gsm/libosmogsm.la
 
+gsm23236_gsm23236_test_SOURCES = gsm23236/gsm23236_test.c
+gsm23236_gsm23236_test_LDADD = $(LDADD) $(top_builddir)/src/gsm/libosmogsm.la
+
 tdef_tdef_test_SOURCES = tdef/tdef_test.c
 tdef_tdef_test_LDADD = $(LDADD)
 
@@ -336,6 +340,7 @@
 	     conv/conv_gsm0503_test.ok endian/endian_test.ok 		\
 	     sercomm/sercomm_test.ok prbs/prbs_test.ok			\
 	     gsm29205/gsm29205_test.ok gsm23003/gsm23003_test.ok        \
+	     gsm23236/gsm23236_test.ok                                  \
 	     timer/clk_override_test.ok					\
 	     oap/oap_client_test.ok oap/oap_client_test.err		\
 	     vty/vty_transcript_test.vty				\
diff --git a/tests/gsm23236/gsm23236_test.c b/tests/gsm23236/gsm23236_test.c
new file mode 100644
index 0000000..14c5ce3
--- /dev/null
+++ b/tests/gsm23236/gsm23236_test.c
@@ -0,0 +1,620 @@
+/*
+ * (C) 2020 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Neels Hofmeyr <nhofmeyr@sysmocom.de>
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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 <errno.h>
+#include <strings.h>
+#include <string.h>
+
+#include <osmocom/gsm/gsm23236.h>
+#include <osmocom/core/utils.h>
+
+void *ctx;
+bool ok = true;
+
+void bitdump(uint8_t count, uint32_t val)
+{
+	uint32_t bit;
+	if (count < 1)
+		return;
+	for (bit = ((uint32_t)1) << (count - 1); bit; bit >>= 1)
+		printf("%c", (val & bit)? '1' : '0');
+}
+
+struct nri_v_get_set_test {
+	uint32_t tmsi;
+	uint8_t nri_bitlen;
+	int16_t expect_get_nri;
+	int expect_get_rc;
+	int16_t set_nri_v;
+	uint32_t expect_tmsi;
+	int expect_set_rc;
+};
+
+struct nri_v_get_set_test nri_v_get_set_tests[] = {
+	{
+		.tmsi = 0,
+		.nri_bitlen = 10,
+		.expect_get_nri = 0,
+		.set_nri_v = 0,
+		.expect_tmsi = 0,
+	},
+	{
+		.tmsi = 0,
+		.nri_bitlen = 10,
+		.expect_get_nri = 0,
+		.set_nri_v = 0x7fff,
+		.expect_tmsi = 0x00ffc000
+	},
+	{
+		.tmsi = 0xffffffff,
+		.nri_bitlen = 10,
+		.expect_get_nri = 0x3ff,
+		.set_nri_v = 0,
+		.expect_tmsi = 0xff003fff
+	},
+	{
+		.tmsi = 0xffffffff,
+		.nri_bitlen = 10,
+		.expect_get_nri = 0x3ff,
+		.set_nri_v = 0x7fff,
+		.expect_tmsi = 0xffffffff
+	},
+	{
+		.tmsi = 0,
+		.nri_bitlen = 5,
+		.expect_get_nri = 0,
+		.set_nri_v = 0,
+		.expect_tmsi = 0,
+	},
+	{
+		.tmsi = 0,
+		.nri_bitlen = 5,
+		.expect_get_nri = 0,
+		.set_nri_v = 0x7fff,
+		.expect_tmsi = 0x00f80000
+	},
+	{
+		.tmsi = 0xffffffff,
+		.nri_bitlen = 5,
+		.expect_get_nri = 0x1f,
+		.set_nri_v = 0,
+		.expect_tmsi = 0xff07ffff
+	},
+	{
+		.tmsi = 0xffffffff,
+		.nri_bitlen = 5,
+		.expect_get_nri = 0x1f,
+		.set_nri_v = 0x7fff,
+		.expect_tmsi = 0xffffffff
+	},
+	{
+		.tmsi = 0x01234567,
+		.nri_bitlen = 8,
+		.expect_get_nri = 0x23,
+		.set_nri_v = 0x42,
+		.expect_tmsi = 0x01424567
+	},
+	{
+		.tmsi = 0x01234567,
+		.nri_bitlen = 15,
+		.expect_get_nri = 0x2345 >> 1,
+		.set_nri_v = 0x7fff,
+		.expect_tmsi = 0x01ffff67
+	},
+	{
+		.tmsi = 0x01234567,
+		.nri_bitlen = 16,
+		.expect_get_rc = -1,
+		.expect_get_nri = -1,
+		.set_nri_v = 0x7fff,
+		.expect_set_rc = -1,
+		.expect_tmsi = 0x01234567,
+	},
+	{
+		.tmsi = 0x01234567,
+		.nri_bitlen = 0,
+		.expect_get_rc = -1,
+		.expect_get_nri = -1,
+		.set_nri_v = 0x7fff,
+		.expect_set_rc = -1,
+		.expect_tmsi = 0x01234567,
+	},
+};
+
+void test_nri_v_get_set()
+{
+	struct nri_v_get_set_test *t;
+
+	for (t = nri_v_get_set_tests; t < &nri_v_get_set_tests[ARRAY_SIZE(nri_v_get_set_tests)]; t++) {
+		int16_t nri_v = 0;
+		uint32_t tmsi2;
+		int rc;
+
+		rc = osmo_tmsi_nri_v_get(&nri_v, t->tmsi, t->nri_bitlen);
+		printf("\nosmo_tmsi_nri_v_get(0x%08x, %u) -> nri_v=0x%x rc=%d\n", t->tmsi, t->nri_bitlen, nri_v, rc);
+		if (!rc) {
+			printf("........|NRI->..................\n");
+			bitdump(32, t->tmsi);
+			printf(" tmsi  nri_bitlen=%u\n", t->nri_bitlen);
+			printf("        ");
+			bitdump(t->nri_bitlen, nri_v);
+			printf(" = 0x%x", nri_v);
+		}
+		if (nri_v == t->expect_get_nri && rc == t->expect_get_rc) {
+			printf(" ok\n");
+		} else {
+			printf(" ERROR: expected nri_v=0x%x rc=%d\n", t->expect_get_nri, t->expect_get_rc);
+			ok = false;
+		}
+
+		tmsi2 = t->tmsi;
+		rc = osmo_tmsi_nri_v_set(&tmsi2, t->set_nri_v, t->nri_bitlen);
+		printf("osmo_tmsi_nri_v_set(0x%08x, 0x%x, %u) -> tmsi=0x%08x rc=%d\n", t->tmsi, t->set_nri_v, t->nri_bitlen,
+		       tmsi2, rc);
+		if (!rc) {
+			printf("        ");
+			bitdump(t->nri_bitlen, t->set_nri_v);
+			printf("\n");
+			bitdump(32, tmsi2);
+		}
+		if (tmsi2 == t->expect_tmsi && rc == t->expect_set_rc) {
+			printf(" ok\n");
+		} else {
+			printf(" ERROR: expected tmsi=0x%08x rc=%d\n", t->expect_tmsi, t->expect_set_rc);
+			ok = false;
+		}
+	}
+}
+
+struct nri_validate_tc {
+	int16_t nri;
+	uint8_t nri_bitlen;
+	int expect_rc;
+};
+
+struct nri_validate_tc nri_validate_tests[] = {
+	{ .nri = INT16_MIN, .nri_bitlen = 10, .expect_rc = -1 },
+	{ .nri = -23, .nri_bitlen = 10, .expect_rc = -1 },
+	{ .nri = -1, .nri_bitlen = 10, .expect_rc = -1 },
+	{ .nri = 0, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .nri = (1 << 10) - 1, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .nri = (1 << 10), .nri_bitlen = 10, .expect_rc = 1 },
+	{ .nri = INT16_MAX, .nri_bitlen = 10, .expect_rc = 1 },
+
+	{ .nri = INT16_MIN, .nri_bitlen = 5, .expect_rc = -1 },
+	{ .nri = -23, .nri_bitlen = 5, .expect_rc = -1 },
+	{ .nri = -1, .nri_bitlen = 5, .expect_rc = -1 },
+	{ .nri = 0, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .nri = (1 << 5) - 1, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .nri = (1 << 5), .nri_bitlen = 5, .expect_rc = 1 },
+	{ .nri = INT16_MAX, .nri_bitlen = 5, .expect_rc = 1 },
+
+	{ .nri = INT16_MIN, .nri_bitlen = 1, .expect_rc = -1 },
+	{ .nri = -23, .nri_bitlen = 1, .expect_rc = -1 },
+	{ .nri = -1, .nri_bitlen = 1, .expect_rc = -1 },
+	{ .nri = 0, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .nri = 1, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .nri = 2, .nri_bitlen = 1, .expect_rc = 1 },
+	{ .nri = INT16_MAX, .nri_bitlen = 1, .expect_rc = 1 },
+
+	{ .nri = INT16_MIN, .nri_bitlen = 0, .expect_rc = -1 },
+	{ .nri = -23, .nri_bitlen = 0, .expect_rc = -1 },
+	{ .nri = -1, .nri_bitlen = 0, .expect_rc = -1 },
+	{ .nri = 0, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .nri = 1, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .nri = INT16_MAX, .nri_bitlen = 0, .expect_rc = 1 },
+};
+
+void test_nri_validate()
+{
+	struct nri_validate_tc *t;
+	printf("\n%s()\n", __func__);
+	for (t = nri_validate_tests; (t - nri_validate_tests) < ARRAY_SIZE(nri_validate_tests); t++) {
+		int rc = osmo_nri_v_validate(t->nri, t->nri_bitlen);
+		printf("osmo_nri_v_validate(%d, %u) = %d ", t->nri, t->nri_bitlen, rc);
+		if (rc == t->expect_rc) {
+			printf("ok\n");
+		} else {
+			printf("ERROR, expected rc = %d\n", t->expect_rc);
+			ok = false;
+		}
+	}
+}
+
+struct nri_range_validate_tc {
+	struct osmo_nri_range range;
+	uint8_t nri_bitlen;
+	int expect_rc;
+};
+
+struct nri_range_validate_tc nri_range_validate_tests[] = {
+	{ .range = { .first = INT16_MIN, .last = INT16_MIN }, .nri_bitlen = 10, .expect_rc = -1 },
+	{ .range = { .first = -23, .last = -23 }, .nri_bitlen = 10, .expect_rc = -1 },
+	{ .range = { .first = -1, .last = -1 }, .nri_bitlen = 10, .expect_rc = -1 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .range = { .first = (1 << 10) - 1, .last = (1 << 10) - 1 }, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .range = { .first = (1 << 10), .last = (1 << 10) }, .nri_bitlen = 10, .expect_rc = 1 },
+	{ .range = { .first = INT16_MAX, .last = INT16_MAX }, .nri_bitlen = 10, .expect_rc = 1 },
+
+	{ .range = { .first = INT16_MIN, .last = INT16_MIN }, .nri_bitlen = 5, .expect_rc = -1 },
+	{ .range = { .first = -23, .last = -23 }, .nri_bitlen = 5, .expect_rc = -1 },
+	{ .range = { .first = -1, .last = -1 }, .nri_bitlen = 5, .expect_rc = -1 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .range = { .first = (1 << 5) - 1, .last = (1 << 5) - 1 }, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .range = { .first = (1 << 5), .last = (1 << 5) }, .nri_bitlen = 5, .expect_rc = 1 },
+	{ .range = { .first = INT16_MAX, .last = INT16_MAX }, .nri_bitlen = 5, .expect_rc = 1 },
+
+	{ .range = { .first = INT16_MIN, .last = INT16_MIN }, .nri_bitlen = 1, .expect_rc = -1 },
+	{ .range = { .first = -23, .last = -23 }, .nri_bitlen = 1, .expect_rc = -1 },
+	{ .range = { .first = -1, .last = -1 }, .nri_bitlen = 1, .expect_rc = -1 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .range = { .first = 1, .last = 1 }, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .range = { .first = 2, .last = 2 }, .nri_bitlen = 1, .expect_rc = 1 },
+	{ .range = { .first = INT16_MAX, .last = INT16_MAX }, .nri_bitlen = 1, .expect_rc = 1 },
+
+	{ .range = { .first = INT16_MIN, .last = INT16_MIN }, .nri_bitlen = 0, .expect_rc = -1 },
+	{ .range = { .first = -23, .last = -23 }, .nri_bitlen = 0, .expect_rc = -1 },
+	{ .range = { .first = -1, .last = -1 }, .nri_bitlen = 0, .expect_rc = -1 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .range = { .first = 1, .last = 1 }, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .range = { .first = INT16_MAX, .last = INT16_MAX }, .nri_bitlen = 0, .expect_rc = 1 },
+
+
+	{ .range = { .first = 0, .last = INT16_MIN }, .nri_bitlen = 10, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = -23 }, .nri_bitlen = 10, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = -1 }, .nri_bitlen = 10, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .range = { .first = 0, .last = (1 << 10) - 1 }, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .range = { .first = 0, .last = (1 << 10) }, .nri_bitlen = 10, .expect_rc = 2 },
+	{ .range = { .first = 0, .last = INT16_MAX }, .nri_bitlen = 10, .expect_rc = 2 },
+
+	{ .range = { .first = 0, .last = INT16_MIN }, .nri_bitlen = 5, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = -23 }, .nri_bitlen = 5, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = -1 }, .nri_bitlen = 5, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .range = { .first = 0, .last = (1 << 5) - 1 }, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .range = { .first = 0, .last = (1 << 5) }, .nri_bitlen = 5, .expect_rc = 2 },
+	{ .range = { .first = 0, .last = INT16_MAX }, .nri_bitlen = 5, .expect_rc = 2 },
+
+	{ .range = { .first = 0, .last = INT16_MIN }, .nri_bitlen = 1, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = -23 }, .nri_bitlen = 1, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = -1 }, .nri_bitlen = 1, .expect_rc = -2 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .range = { .first = 0, .last = 1 }, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .range = { .first = 0, .last = 2 }, .nri_bitlen = 1, .expect_rc = 2 },
+	{ .range = { .first = 0, .last = INT16_MAX }, .nri_bitlen = 1, .expect_rc = 2 },
+
+	{ .range = { .first = 0, .last = INT16_MIN }, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .range = { .first = 0, .last = -23 }, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .range = { .first = 0, .last = -1 }, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .range = { .first = 0, .last = 1 }, .nri_bitlen = 0, .expect_rc = 1 },
+	{ .range = { .first = 0, .last = INT16_MAX }, .nri_bitlen = 0, .expect_rc = 1 },
+
+
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .range = { .first = 1, .last = 0 }, .nri_bitlen = 10, .expect_rc = -3 },
+	{ .range = { .first = (1 << 10) - 1, .last = (1 << 10) - 1 }, .nri_bitlen = 10, .expect_rc = 0 },
+	{ .range = { .first = (1 << 10) - 1, .last = (1 << 10) - 2 }, .nri_bitlen = 10, .expect_rc = -3 },
+	{ .range = { .first = (1 << 10) - 1, .last = 0 }, .nri_bitlen = 10, .expect_rc = -3 },
+
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .range = { .first = 1, .last = 0 }, .nri_bitlen = 5, .expect_rc = -3 },
+	{ .range = { .first = (1 << 5) - 1, .last = (1 << 5) - 1 }, .nri_bitlen = 5, .expect_rc = 0 },
+	{ .range = { .first = (1 << 5) - 1, .last = (1 << 5) - 2 }, .nri_bitlen = 5, .expect_rc = -3 },
+	{ .range = { .first = (1 << 5) - 1, .last = 0 }, .nri_bitlen = 5, .expect_rc = -3 },
+
+	{ .range = { .first = 0, .last = 0 }, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .range = { .first = 1, .last = 1 }, .nri_bitlen = 1, .expect_rc = 0 },
+	{ .range = { .first = 1, .last = 0 }, .nri_bitlen = 1, .expect_rc = -3 },
+
+};
+
+void test_nri_range_validate()
+{
+	struct nri_range_validate_tc *t;
+	printf("\n%s()\n", __func__);
+	for (t = nri_range_validate_tests; (t - nri_range_validate_tests) < ARRAY_SIZE(nri_range_validate_tests); t++) {
+		int rc = osmo_nri_range_validate(&t->range, t->nri_bitlen);
+		printf("osmo_nri_range_validate({%d,%d}, %u) = %d ", t->range.first, t->range.last, t->nri_bitlen, rc);
+		if (rc == t->expect_rc) {
+			printf("ok\n");
+		} else {
+			printf("ERROR, expected rc = %d\n", t->expect_rc);
+			ok = false;
+		}
+	}
+}
+
+void dump_list(const struct osmo_nri_ranges *nri_ranges)
+{
+	struct osmo_nri_range *r;
+	printf("nri_ranges = {\n");
+	llist_for_each_entry(r, &nri_ranges->entries, entry) {
+		printf("  { %d, %d },\n", r->first, r->last);
+		if (osmo_nri_range_validate(r, 255)) {
+			ok = false;
+			printf("    ^^^^^ ERROR: invalid range\n");
+		}
+	}
+	printf("};\n");
+}
+
+void test_nri_list()
+{
+	struct osmo_nri_ranges *nri_ranges = osmo_nri_ranges_alloc(ctx);
+	printf("\n%s()\n", __func__);
+
+#define ADD(FIRST, LAST) do { \
+		struct osmo_nri_range r = { .first = FIRST, .last = LAST }; \
+		int rc; \
+		rc = osmo_nri_ranges_add(nri_ranges, &r); \
+		printf("osmo_nri_ranges_add(%d, %d) -> %d\n", r.first, r.last, rc); \
+		dump_list(nri_ranges); \
+	} while(0)
+
+#define DEL(FIRST, LAST) do { \
+		struct osmo_nri_range r = { .first = FIRST, .last = LAST }; \
+		int rc; \
+		rc = osmo_nri_ranges_del(nri_ranges, &r); \
+		printf("osmo_nri_ranges_del(%d, %d) -> %d\n", r.first, r.last, rc); \
+		dump_list(nri_ranges); \
+	} while(0)
+
+#define MATCHES(NRI, EXPECT_MATCH) do { \
+		bool matches = osmo_nri_v_matches_ranges(NRI, nri_ranges); \
+		printf("osmo_nri_v_matches_ranges(%d) -> %s\n", NRI, matches ? "true" : "false"); \
+		if (matches != EXPECT_MATCH) { \
+			ok = false; \
+			printf("  ^ ERROR: expected " #EXPECT_MATCH "\n"); \
+		} \
+	} while(0)
+
+#define OVERLAPS(FIRST, LAST, EXPECT_OVERLAP) do { \
+		struct osmo_nri_range r = { .first = FIRST, .last = LAST }; \
+		bool overlaps = osmo_nri_range_overlaps_ranges(&r, nri_ranges); \
+		printf("osmo_nri_range_overlaps_ranges(%d, %d) -> %s\n", r.first, r.last, overlaps ? "true" : "false"); \
+		if (overlaps != EXPECT_OVERLAP) { \
+			ok = false; \
+			printf("  ^ ERROR: expected " #EXPECT_OVERLAP "\n"); \
+		} \
+	} while(0)
+
+	dump_list(nri_ranges);
+	MATCHES(INT16_MIN, false);
+	MATCHES(-1, false);
+	MATCHES(0, false);
+	MATCHES(INT16_MAX, false);
+	MATCHES(100, false);
+	OVERLAPS(INT16_MIN, -1, false);
+	OVERLAPS(-100, 100, false);
+	OVERLAPS(10, 20, false);
+
+	ADD(100, 200);
+	MATCHES(INT16_MIN, false);
+	MATCHES(-1, false);
+	MATCHES(0, false);
+	MATCHES(INT16_MAX, false);
+	MATCHES(99, false);
+	MATCHES(100, true);
+	MATCHES(101, true);
+	MATCHES(199, true);
+	MATCHES(200, true);
+	MATCHES(201, false);
+	OVERLAPS(INT16_MIN, -1, false);
+	OVERLAPS(-100, 100, true);
+	OVERLAPS(10, 20, false);
+	OVERLAPS(10, 99, false);
+	OVERLAPS(10, 100, true);
+	OVERLAPS(10, 150, true);
+	OVERLAPS(99, 99, false);
+	OVERLAPS(100, 100, true);
+	OVERLAPS(150, 300, true);
+	OVERLAPS(200, 300, true);
+	OVERLAPS(201, 300, false);
+
+	printf("\ndel from start:\n");
+	DEL(0, 110);
+	DEL(111, 111);
+	DEL(112, 199);
+	MATCHES(INT16_MIN, false);
+	MATCHES(-1, false);
+	MATCHES(0, false);
+	MATCHES(INT16_MAX, false);
+	MATCHES(199, false);
+	MATCHES(200, true);
+	MATCHES(201, false);
+	OVERLAPS(INT16_MIN, -1, false);
+	OVERLAPS(-1000, 1000, true);
+	OVERLAPS(0, 199, false);
+	OVERLAPS(0, 200, true);
+	OVERLAPS(0, 201, true);
+	OVERLAPS(0, 1000, true);
+	OVERLAPS(199, 199, false);
+	OVERLAPS(200, 200, true);
+	OVERLAPS(201, 201, false);
+
+	printf("\ndel from end:\n");
+	ADD(100, 200);
+	DEL(190, INT16_MAX);
+	DEL(189, 189);
+	DEL(101, 188);
+	MATCHES(INT16_MIN, false);
+	MATCHES(-1, false);
+	MATCHES(0, false);
+	MATCHES(INT16_MAX, false);
+	MATCHES(99, false);
+	MATCHES(100, true);
+	MATCHES(101, false);
+
+	printf("\ndel from middle:\n");
+	ADD(100, 200);
+	DEL(150, 160);
+	DEL(110, 120);
+	DEL(130, 130);
+	DEL(180, 190);
+	MATCHES(INT16_MIN, false);
+	MATCHES(-1, false);
+	MATCHES(0, false);
+	MATCHES(INT16_MAX, false);
+	MATCHES(99, false);
+	MATCHES(100, true);
+	MATCHES(109, true);
+	MATCHES(110, false);
+	MATCHES(120, false);
+	MATCHES(121, true);
+	MATCHES(129, true);
+	MATCHES(130, false);
+	MATCHES(131, true);
+	MATCHES(148, true);
+	MATCHES(149, true);
+	MATCHES(150, false);
+	MATCHES(160, false);
+	MATCHES(161, true);
+	MATCHES(170, true);
+	MATCHES(179, true);
+	MATCHES(180, false);
+	MATCHES(185, false);
+	MATCHES(190, false);
+	MATCHES(191, true);
+	MATCHES(195, true);
+	MATCHES(200, true);
+	MATCHES(201, false);
+	MATCHES(1000, false);
+	OVERLAPS(110, 120, false);
+	OVERLAPS(110, 130, true);
+	OVERLAPS(100, 200, true);
+
+	printf("\ndel across whole chunks:\n");
+	DEL(115, 185);
+	DEL(105, 195);
+	DEL(0, 1000);
+
+	printf("\nadd to join chunks:\n");
+	ADD(0, 100);
+	DEL(11, 19);
+	DEL(23, 23);
+	DEL(30, 41);
+	ADD(23, 23);
+	ADD(11, 41);
+	MATCHES(0, true);
+	MATCHES(10, true);
+	MATCHES(11, true);
+	MATCHES(24, true);
+	MATCHES(41, true);
+	MATCHES(42, true);
+	MATCHES(100, true);
+	MATCHES(101, false);
+
+	printf("\nborder cases:\n");
+	ADD(0, 0);
+	ADD(INT16_MAX, INT16_MAX);
+	ADD(1, INT16_MAX - 1);
+	MATCHES(INT16_MIN, false);
+	MATCHES(-1, false);
+	MATCHES(0, true);
+	MATCHES(INT16_MAX, true);
+	DEL(0, 0);
+	DEL(INT16_MAX, INT16_MAX);
+	DEL(1, INT16_MAX - 1);
+
+	printf("\nrange errors:\n");
+	ADD(-1, -1);
+	ADD(-20, -10);
+	ADD(100, 1);
+	ADD(0, INT16_MAX);
+	DEL(-1, -1);
+	DEL(-20, -10);
+	DEL(100, 1);
+}
+
+void test_nri_limit_by_ranges()
+{
+	const uint8_t nri_bitlen = 8;
+	const int16_t expect_nri_vals[] = { 10, 20, 21, 30, 31, 32 };
+	int i;
+	struct osmo_nri_ranges *nri_ranges = osmo_nri_ranges_alloc(ctx);
+	printf("\n%s()\n", __func__);
+
+	ADD(10, 10);
+	ADD(20, 21);
+	ADD(30, 32);
+
+	for (i = 0; i < 19; i++) {
+		int rc;
+		int16_t nri_v;
+		int16_t expect_nri_v = expect_nri_vals[i % ARRAY_SIZE(expect_nri_vals)];
+
+		nri_v = i;
+		rc = osmo_nri_v_limit_by_ranges(&nri_v, nri_ranges, nri_bitlen);
+		printf("osmo_nri_v_limit_by_ranges(%d) -> nri_v=%d rc=%d", i, nri_v, rc);
+		if (!rc && nri_v == expect_nri_v) {
+			printf(" ok\n");
+		} else {
+			printf(" ERROR: expected nri_v=%d rc=0\n", expect_nri_v);
+			ok = false;
+		}
+	}
+	for (i = 0; i < 19; i++) {
+		int rc;
+		int16_t nri_v;
+		uint32_t tmsi, tmsi2;
+		int16_t expect_nri_v = expect_nri_vals[i % ARRAY_SIZE(expect_nri_vals)];
+
+		tmsi = 0;
+		osmo_tmsi_nri_v_set(&tmsi, i, nri_bitlen);
+		tmsi2 = tmsi;
+		rc = osmo_tmsi_nri_v_limit_by_ranges(&tmsi2, nri_ranges, nri_bitlen);
+		osmo_tmsi_nri_v_get(&nri_v, tmsi2, nri_bitlen);
+		printf("osmo_tmsi_nri_v_limit_by_ranges(0x%08x, %u) -> tmsi=0x%08x nri_v=%d rc=%d",
+		       tmsi, nri_bitlen, tmsi2, nri_v, rc);
+		if (!rc && nri_v == expect_nri_v) {
+			printf(" ok\n");
+		} else {
+			printf(" ERROR: expected nri_v=%d rc=0\n", expect_nri_v);
+			ok = false;
+		}
+	}
+}
+
+int main()
+{
+	ctx = talloc_named_const(NULL, 0, "nri_test");
+
+	test_nri_v_get_set();
+	test_nri_validate();
+	test_nri_range_validate();
+	test_nri_list();
+	test_nri_limit_by_ranges();
+
+	talloc_free(ctx);
+	if (!ok) {
+		printf("\nFAIL\n");
+		return -1;
+	}
+
+	printf("\npass\n");
+	return 0;
+}
+
diff --git a/tests/gsm23236/gsm23236_test.ok b/tests/gsm23236/gsm23236_test.ok
new file mode 100644
index 0000000..22630bf
--- /dev/null
+++ b/tests/gsm23236/gsm23236_test.ok
@@ -0,0 +1,514 @@
+
+osmo_tmsi_nri_v_get(0x00000000, 10) -> nri_v=0x0 rc=0
+........|NRI->..................
+00000000000000000000000000000000 tmsi  nri_bitlen=10
+        0000000000 = 0x0 ok
+osmo_tmsi_nri_v_set(0x00000000, 0x0, 10) -> tmsi=0x00000000 rc=0
+        0000000000
+00000000000000000000000000000000 ok
+
+osmo_tmsi_nri_v_get(0x00000000, 10) -> nri_v=0x0 rc=0
+........|NRI->..................
+00000000000000000000000000000000 tmsi  nri_bitlen=10
+        0000000000 = 0x0 ok
+osmo_tmsi_nri_v_set(0x00000000, 0x7fff, 10) -> tmsi=0x00ffc000 rc=0
+        1111111111
+00000000111111111100000000000000 ok
+
+osmo_tmsi_nri_v_get(0xffffffff, 10) -> nri_v=0x3ff rc=0
+........|NRI->..................
+11111111111111111111111111111111 tmsi  nri_bitlen=10
+        1111111111 = 0x3ff ok
+osmo_tmsi_nri_v_set(0xffffffff, 0x0, 10) -> tmsi=0xff003fff rc=0
+        0000000000
+11111111000000000011111111111111 ok
+
+osmo_tmsi_nri_v_get(0xffffffff, 10) -> nri_v=0x3ff rc=0
+........|NRI->..................
+11111111111111111111111111111111 tmsi  nri_bitlen=10
+        1111111111 = 0x3ff ok
+osmo_tmsi_nri_v_set(0xffffffff, 0x7fff, 10) -> tmsi=0xffffffff rc=0
+        1111111111
+11111111111111111111111111111111 ok
+
+osmo_tmsi_nri_v_get(0x00000000, 5) -> nri_v=0x0 rc=0
+........|NRI->..................
+00000000000000000000000000000000 tmsi  nri_bitlen=5
+        00000 = 0x0 ok
+osmo_tmsi_nri_v_set(0x00000000, 0x0, 5) -> tmsi=0x00000000 rc=0
+        00000
+00000000000000000000000000000000 ok
+
+osmo_tmsi_nri_v_get(0x00000000, 5) -> nri_v=0x0 rc=0
+........|NRI->..................
+00000000000000000000000000000000 tmsi  nri_bitlen=5
+        00000 = 0x0 ok
+osmo_tmsi_nri_v_set(0x00000000, 0x7fff, 5) -> tmsi=0x00f80000 rc=0
+        11111
+00000000111110000000000000000000 ok
+
+osmo_tmsi_nri_v_get(0xffffffff, 5) -> nri_v=0x1f rc=0
+........|NRI->..................
+11111111111111111111111111111111 tmsi  nri_bitlen=5
+        11111 = 0x1f ok
+osmo_tmsi_nri_v_set(0xffffffff, 0x0, 5) -> tmsi=0xff07ffff rc=0
+        00000
+11111111000001111111111111111111 ok
+
+osmo_tmsi_nri_v_get(0xffffffff, 5) -> nri_v=0x1f rc=0
+........|NRI->..................
+11111111111111111111111111111111 tmsi  nri_bitlen=5
+        11111 = 0x1f ok
+osmo_tmsi_nri_v_set(0xffffffff, 0x7fff, 5) -> tmsi=0xffffffff rc=0
+        11111
+11111111111111111111111111111111 ok
+
+osmo_tmsi_nri_v_get(0x01234567, 8) -> nri_v=0x23 rc=0
+........|NRI->..................
+00000001001000110100010101100111 tmsi  nri_bitlen=8
+        00100011 = 0x23 ok
+osmo_tmsi_nri_v_set(0x01234567, 0x42, 8) -> tmsi=0x01424567 rc=0
+        01000010
+00000001010000100100010101100111 ok
+
+osmo_tmsi_nri_v_get(0x01234567, 15) -> nri_v=0x11a2 rc=0
+........|NRI->..................
+00000001001000110100010101100111 tmsi  nri_bitlen=15
+        001000110100010 = 0x11a2 ok
+osmo_tmsi_nri_v_set(0x01234567, 0x7fff, 15) -> tmsi=0x01ffff67 rc=0
+        111111111111111
+00000001111111111111111101100111 ok
+
+osmo_tmsi_nri_v_get(0x01234567, 16) -> nri_v=0xffffffff rc=-1
+ ok
+osmo_tmsi_nri_v_set(0x01234567, 0x7fff, 16) -> tmsi=0x01234567 rc=-1
+ ok
+
+osmo_tmsi_nri_v_get(0x01234567, 0) -> nri_v=0xffffffff rc=-1
+ ok
+osmo_tmsi_nri_v_set(0x01234567, 0x7fff, 0) -> tmsi=0x01234567 rc=-1
+ ok
+
+test_nri_validate()
+osmo_nri_v_validate(-32768, 10) = -1 ok
+osmo_nri_v_validate(-23, 10) = -1 ok
+osmo_nri_v_validate(-1, 10) = -1 ok
+osmo_nri_v_validate(0, 10) = 0 ok
+osmo_nri_v_validate(1023, 10) = 0 ok
+osmo_nri_v_validate(1024, 10) = 1 ok
+osmo_nri_v_validate(32767, 10) = 1 ok
+osmo_nri_v_validate(-32768, 5) = -1 ok
+osmo_nri_v_validate(-23, 5) = -1 ok
+osmo_nri_v_validate(-1, 5) = -1 ok
+osmo_nri_v_validate(0, 5) = 0 ok
+osmo_nri_v_validate(31, 5) = 0 ok
+osmo_nri_v_validate(32, 5) = 1 ok
+osmo_nri_v_validate(32767, 5) = 1 ok
+osmo_nri_v_validate(-32768, 1) = -1 ok
+osmo_nri_v_validate(-23, 1) = -1 ok
+osmo_nri_v_validate(-1, 1) = -1 ok
+osmo_nri_v_validate(0, 1) = 0 ok
+osmo_nri_v_validate(1, 1) = 0 ok
+osmo_nri_v_validate(2, 1) = 1 ok
+osmo_nri_v_validate(32767, 1) = 1 ok
+osmo_nri_v_validate(-32768, 0) = -1 ok
+osmo_nri_v_validate(-23, 0) = -1 ok
+osmo_nri_v_validate(-1, 0) = -1 ok
+osmo_nri_v_validate(0, 0) = 1 ok
+osmo_nri_v_validate(1, 0) = 1 ok
+osmo_nri_v_validate(32767, 0) = 1 ok
+
+test_nri_range_validate()
+osmo_nri_range_validate({-32768,-32768}, 10) = -1 ok
+osmo_nri_range_validate({-23,-23}, 10) = -1 ok
+osmo_nri_range_validate({-1,-1}, 10) = -1 ok
+osmo_nri_range_validate({0,0}, 10) = 0 ok
+osmo_nri_range_validate({1023,1023}, 10) = 0 ok
+osmo_nri_range_validate({1024,1024}, 10) = 1 ok
+osmo_nri_range_validate({32767,32767}, 10) = 1 ok
+osmo_nri_range_validate({-32768,-32768}, 5) = -1 ok
+osmo_nri_range_validate({-23,-23}, 5) = -1 ok
+osmo_nri_range_validate({-1,-1}, 5) = -1 ok
+osmo_nri_range_validate({0,0}, 5) = 0 ok
+osmo_nri_range_validate({31,31}, 5) = 0 ok
+osmo_nri_range_validate({32,32}, 5) = 1 ok
+osmo_nri_range_validate({32767,32767}, 5) = 1 ok
+osmo_nri_range_validate({-32768,-32768}, 1) = -1 ok
+osmo_nri_range_validate({-23,-23}, 1) = -1 ok
+osmo_nri_range_validate({-1,-1}, 1) = -1 ok
+osmo_nri_range_validate({0,0}, 1) = 0 ok
+osmo_nri_range_validate({1,1}, 1) = 0 ok
+osmo_nri_range_validate({2,2}, 1) = 1 ok
+osmo_nri_range_validate({32767,32767}, 1) = 1 ok
+osmo_nri_range_validate({-32768,-32768}, 0) = -1 ok
+osmo_nri_range_validate({-23,-23}, 0) = -1 ok
+osmo_nri_range_validate({-1,-1}, 0) = -1 ok
+osmo_nri_range_validate({0,0}, 0) = 1 ok
+osmo_nri_range_validate({1,1}, 0) = 1 ok
+osmo_nri_range_validate({32767,32767}, 0) = 1 ok
+osmo_nri_range_validate({0,-32768}, 10) = -2 ok
+osmo_nri_range_validate({0,-23}, 10) = -2 ok
+osmo_nri_range_validate({0,-1}, 10) = -2 ok
+osmo_nri_range_validate({0,0}, 10) = 0 ok
+osmo_nri_range_validate({0,1023}, 10) = 0 ok
+osmo_nri_range_validate({0,1024}, 10) = 2 ok
+osmo_nri_range_validate({0,32767}, 10) = 2 ok
+osmo_nri_range_validate({0,-32768}, 5) = -2 ok
+osmo_nri_range_validate({0,-23}, 5) = -2 ok
+osmo_nri_range_validate({0,-1}, 5) = -2 ok
+osmo_nri_range_validate({0,0}, 5) = 0 ok
+osmo_nri_range_validate({0,31}, 5) = 0 ok
+osmo_nri_range_validate({0,32}, 5) = 2 ok
+osmo_nri_range_validate({0,32767}, 5) = 2 ok
+osmo_nri_range_validate({0,-32768}, 1) = -2 ok
+osmo_nri_range_validate({0,-23}, 1) = -2 ok
+osmo_nri_range_validate({0,-1}, 1) = -2 ok
+osmo_nri_range_validate({0,0}, 1) = 0 ok
+osmo_nri_range_validate({0,1}, 1) = 0 ok
+osmo_nri_range_validate({0,2}, 1) = 2 ok
+osmo_nri_range_validate({0,32767}, 1) = 2 ok
+osmo_nri_range_validate({0,-32768}, 0) = 1 ok
+osmo_nri_range_validate({0,-23}, 0) = 1 ok
+osmo_nri_range_validate({0,-1}, 0) = 1 ok
+osmo_nri_range_validate({0,0}, 0) = 1 ok
+osmo_nri_range_validate({0,1}, 0) = 1 ok
+osmo_nri_range_validate({0,32767}, 0) = 1 ok
+osmo_nri_range_validate({0,0}, 10) = 0 ok
+osmo_nri_range_validate({1,0}, 10) = -3 ok
+osmo_nri_range_validate({1023,1023}, 10) = 0 ok
+osmo_nri_range_validate({1023,1022}, 10) = -3 ok
+osmo_nri_range_validate({1023,0}, 10) = -3 ok
+osmo_nri_range_validate({0,0}, 5) = 0 ok
+osmo_nri_range_validate({1,0}, 5) = -3 ok
+osmo_nri_range_validate({31,31}, 5) = 0 ok
+osmo_nri_range_validate({31,30}, 5) = -3 ok
+osmo_nri_range_validate({31,0}, 5) = -3 ok
+osmo_nri_range_validate({0,0}, 1) = 0 ok
+osmo_nri_range_validate({1,1}, 1) = 0 ok
+osmo_nri_range_validate({1,0}, 1) = -3 ok
+
+test_nri_list()
+nri_ranges = {
+};
+osmo_nri_v_matches_ranges(-32768) -> false
+osmo_nri_v_matches_ranges(-1) -> false
+osmo_nri_v_matches_ranges(0) -> false
+osmo_nri_v_matches_ranges(32767) -> false
+osmo_nri_v_matches_ranges(100) -> false
+osmo_nri_range_overlaps_ranges(-32768, -1) -> false
+osmo_nri_range_overlaps_ranges(-100, 100) -> false
+osmo_nri_range_overlaps_ranges(10, 20) -> false
+osmo_nri_ranges_add(100, 200) -> 0
+nri_ranges = {
+  { 100, 200 },
+};
+osmo_nri_v_matches_ranges(-32768) -> false
+osmo_nri_v_matches_ranges(-1) -> false
+osmo_nri_v_matches_ranges(0) -> false
+osmo_nri_v_matches_ranges(32767) -> false
+osmo_nri_v_matches_ranges(99) -> false
+osmo_nri_v_matches_ranges(100) -> true
+osmo_nri_v_matches_ranges(101) -> true
+osmo_nri_v_matches_ranges(199) -> true
+osmo_nri_v_matches_ranges(200) -> true
+osmo_nri_v_matches_ranges(201) -> false
+osmo_nri_range_overlaps_ranges(-32768, -1) -> false
+osmo_nri_range_overlaps_ranges(-100, 100) -> true
+osmo_nri_range_overlaps_ranges(10, 20) -> false
+osmo_nri_range_overlaps_ranges(10, 99) -> false
+osmo_nri_range_overlaps_ranges(10, 100) -> true
+osmo_nri_range_overlaps_ranges(10, 150) -> true
+osmo_nri_range_overlaps_ranges(99, 99) -> false
+osmo_nri_range_overlaps_ranges(100, 100) -> true
+osmo_nri_range_overlaps_ranges(150, 300) -> true
+osmo_nri_range_overlaps_ranges(200, 300) -> true
+osmo_nri_range_overlaps_ranges(201, 300) -> false
+
+del from start:
+osmo_nri_ranges_del(0, 110) -> 0
+nri_ranges = {
+  { 111, 200 },
+};
+osmo_nri_ranges_del(111, 111) -> 0
+nri_ranges = {
+  { 112, 200 },
+};
+osmo_nri_ranges_del(112, 199) -> 0
+nri_ranges = {
+  { 200, 200 },
+};
+osmo_nri_v_matches_ranges(-32768) -> false
+osmo_nri_v_matches_ranges(-1) -> false
+osmo_nri_v_matches_ranges(0) -> false
+osmo_nri_v_matches_ranges(32767) -> false
+osmo_nri_v_matches_ranges(199) -> false
+osmo_nri_v_matches_ranges(200) -> true
+osmo_nri_v_matches_ranges(201) -> false
+osmo_nri_range_overlaps_ranges(-32768, -1) -> false
+osmo_nri_range_overlaps_ranges(-1000, 1000) -> true
+osmo_nri_range_overlaps_ranges(0, 199) -> false
+osmo_nri_range_overlaps_ranges(0, 200) -> true
+osmo_nri_range_overlaps_ranges(0, 201) -> true
+osmo_nri_range_overlaps_ranges(0, 1000) -> true
+osmo_nri_range_overlaps_ranges(199, 199) -> false
+osmo_nri_range_overlaps_ranges(200, 200) -> true
+osmo_nri_range_overlaps_ranges(201, 201) -> false
+
+del from end:
+osmo_nri_ranges_add(100, 200) -> 0
+nri_ranges = {
+  { 100, 200 },
+};
+osmo_nri_ranges_del(190, 32767) -> 0
+nri_ranges = {
+  { 100, 189 },
+};
+osmo_nri_ranges_del(189, 189) -> 0
+nri_ranges = {
+  { 100, 188 },
+};
+osmo_nri_ranges_del(101, 188) -> 0
+nri_ranges = {
+  { 100, 100 },
+};
+osmo_nri_v_matches_ranges(-32768) -> false
+osmo_nri_v_matches_ranges(-1) -> false
+osmo_nri_v_matches_ranges(0) -> false
+osmo_nri_v_matches_ranges(32767) -> false
+osmo_nri_v_matches_ranges(99) -> false
+osmo_nri_v_matches_ranges(100) -> true
+osmo_nri_v_matches_ranges(101) -> false
+
+del from middle:
+osmo_nri_ranges_add(100, 200) -> 0
+nri_ranges = {
+  { 100, 200 },
+};
+osmo_nri_ranges_del(150, 160) -> 0
+nri_ranges = {
+  { 100, 149 },
+  { 161, 200 },
+};
+osmo_nri_ranges_del(110, 120) -> 0
+nri_ranges = {
+  { 100, 109 },
+  { 121, 149 },
+  { 161, 200 },
+};
+osmo_nri_ranges_del(130, 130) -> 0
+nri_ranges = {
+  { 100, 109 },
+  { 121, 129 },
+  { 131, 149 },
+  { 161, 200 },
+};
+osmo_nri_ranges_del(180, 190) -> 0
+nri_ranges = {
+  { 100, 109 },
+  { 121, 129 },
+  { 131, 149 },
+  { 161, 179 },
+  { 191, 200 },
+};
+osmo_nri_v_matches_ranges(-32768) -> false
+osmo_nri_v_matches_ranges(-1) -> false
+osmo_nri_v_matches_ranges(0) -> false
+osmo_nri_v_matches_ranges(32767) -> false
+osmo_nri_v_matches_ranges(99) -> false
+osmo_nri_v_matches_ranges(100) -> true
+osmo_nri_v_matches_ranges(109) -> true
+osmo_nri_v_matches_ranges(110) -> false
+osmo_nri_v_matches_ranges(120) -> false
+osmo_nri_v_matches_ranges(121) -> true
+osmo_nri_v_matches_ranges(129) -> true
+osmo_nri_v_matches_ranges(130) -> false
+osmo_nri_v_matches_ranges(131) -> true
+osmo_nri_v_matches_ranges(148) -> true
+osmo_nri_v_matches_ranges(149) -> true
+osmo_nri_v_matches_ranges(150) -> false
+osmo_nri_v_matches_ranges(160) -> false
+osmo_nri_v_matches_ranges(161) -> true
+osmo_nri_v_matches_ranges(170) -> true
+osmo_nri_v_matches_ranges(179) -> true
+osmo_nri_v_matches_ranges(180) -> false
+osmo_nri_v_matches_ranges(185) -> false
+osmo_nri_v_matches_ranges(190) -> false
+osmo_nri_v_matches_ranges(191) -> true
+osmo_nri_v_matches_ranges(195) -> true
+osmo_nri_v_matches_ranges(200) -> true
+osmo_nri_v_matches_ranges(201) -> false
+osmo_nri_v_matches_ranges(1000) -> false
+osmo_nri_range_overlaps_ranges(110, 120) -> false
+osmo_nri_range_overlaps_ranges(110, 130) -> true
+osmo_nri_range_overlaps_ranges(100, 200) -> true
+
+del across whole chunks:
+osmo_nri_ranges_del(115, 185) -> 0
+nri_ranges = {
+  { 100, 109 },
+  { 191, 200 },
+};
+osmo_nri_ranges_del(105, 195) -> 0
+nri_ranges = {
+  { 100, 104 },
+  { 196, 200 },
+};
+osmo_nri_ranges_del(0, 1000) -> 0
+nri_ranges = {
+};
+
+add to join chunks:
+osmo_nri_ranges_add(0, 100) -> 0
+nri_ranges = {
+  { 0, 100 },
+};
+osmo_nri_ranges_del(11, 19) -> 0
+nri_ranges = {
+  { 0, 10 },
+  { 20, 100 },
+};
+osmo_nri_ranges_del(23, 23) -> 0
+nri_ranges = {
+  { 0, 10 },
+  { 20, 22 },
+  { 24, 100 },
+};
+osmo_nri_ranges_del(30, 41) -> 0
+nri_ranges = {
+  { 0, 10 },
+  { 20, 22 },
+  { 24, 29 },
+  { 42, 100 },
+};
+osmo_nri_ranges_add(23, 23) -> 0
+nri_ranges = {
+  { 0, 10 },
+  { 20, 29 },
+  { 42, 100 },
+};
+osmo_nri_ranges_add(11, 41) -> 0
+nri_ranges = {
+  { 0, 100 },
+};
+osmo_nri_v_matches_ranges(0) -> true
+osmo_nri_v_matches_ranges(10) -> true
+osmo_nri_v_matches_ranges(11) -> true
+osmo_nri_v_matches_ranges(24) -> true
+osmo_nri_v_matches_ranges(41) -> true
+osmo_nri_v_matches_ranges(42) -> true
+osmo_nri_v_matches_ranges(100) -> true
+osmo_nri_v_matches_ranges(101) -> false
+
+border cases:
+osmo_nri_ranges_add(0, 0) -> 0
+nri_ranges = {
+  { 0, 100 },
+};
+osmo_nri_ranges_add(32767, 32767) -> 0
+nri_ranges = {
+  { 0, 100 },
+  { 32767, 32767 },
+};
+osmo_nri_ranges_add(1, 32766) -> 0
+nri_ranges = {
+  { 0, 32767 },
+};
+osmo_nri_v_matches_ranges(-32768) -> false
+osmo_nri_v_matches_ranges(-1) -> false
+osmo_nri_v_matches_ranges(0) -> true
+osmo_nri_v_matches_ranges(32767) -> true
+osmo_nri_ranges_del(0, 0) -> 0
+nri_ranges = {
+  { 1, 32767 },
+};
+osmo_nri_ranges_del(32767, 32767) -> 0
+nri_ranges = {
+  { 1, 32766 },
+};
+osmo_nri_ranges_del(1, 32766) -> 0
+nri_ranges = {
+};
+
+range errors:
+osmo_nri_ranges_add(-1, -1) -> -1
+nri_ranges = {
+};
+osmo_nri_ranges_add(-20, -10) -> -1
+nri_ranges = {
+};
+osmo_nri_ranges_add(100, 1) -> -1
+nri_ranges = {
+};
+osmo_nri_ranges_add(0, 32767) -> 0
+nri_ranges = {
+  { 0, 32767 },
+};
+osmo_nri_ranges_del(-1, -1) -> -1
+nri_ranges = {
+  { 0, 32767 },
+};
+osmo_nri_ranges_del(-20, -10) -> -1
+nri_ranges = {
+  { 0, 32767 },
+};
+osmo_nri_ranges_del(100, 1) -> -1
+nri_ranges = {
+  { 0, 32767 },
+};
+
+test_nri_limit_by_ranges()
+osmo_nri_ranges_add(10, 10) -> 0
+nri_ranges = {
+  { 10, 10 },
+};
+osmo_nri_ranges_add(20, 21) -> 0
+nri_ranges = {
+  { 10, 10 },
+  { 20, 21 },
+};
+osmo_nri_ranges_add(30, 32) -> 0
+nri_ranges = {
+  { 10, 10 },
+  { 20, 21 },
+  { 30, 32 },
+};
+osmo_nri_v_limit_by_ranges(0) -> nri_v=10 rc=0 ok
+osmo_nri_v_limit_by_ranges(1) -> nri_v=20 rc=0 ok
+osmo_nri_v_limit_by_ranges(2) -> nri_v=21 rc=0 ok
+osmo_nri_v_limit_by_ranges(3) -> nri_v=30 rc=0 ok
+osmo_nri_v_limit_by_ranges(4) -> nri_v=31 rc=0 ok
+osmo_nri_v_limit_by_ranges(5) -> nri_v=32 rc=0 ok
+osmo_nri_v_limit_by_ranges(6) -> nri_v=10 rc=0 ok
+osmo_nri_v_limit_by_ranges(7) -> nri_v=20 rc=0 ok
+osmo_nri_v_limit_by_ranges(8) -> nri_v=21 rc=0 ok
+osmo_nri_v_limit_by_ranges(9) -> nri_v=30 rc=0 ok
+osmo_nri_v_limit_by_ranges(10) -> nri_v=31 rc=0 ok
+osmo_nri_v_limit_by_ranges(11) -> nri_v=32 rc=0 ok
+osmo_nri_v_limit_by_ranges(12) -> nri_v=10 rc=0 ok
+osmo_nri_v_limit_by_ranges(13) -> nri_v=20 rc=0 ok
+osmo_nri_v_limit_by_ranges(14) -> nri_v=21 rc=0 ok
+osmo_nri_v_limit_by_ranges(15) -> nri_v=30 rc=0 ok
+osmo_nri_v_limit_by_ranges(16) -> nri_v=31 rc=0 ok
+osmo_nri_v_limit_by_ranges(17) -> nri_v=32 rc=0 ok
+osmo_nri_v_limit_by_ranges(18) -> nri_v=10 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00000000, 8) -> tmsi=0x000a0000 nri_v=10 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00010000, 8) -> tmsi=0x00140000 nri_v=20 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00020000, 8) -> tmsi=0x00150000 nri_v=21 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00030000, 8) -> tmsi=0x001e0000 nri_v=30 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00040000, 8) -> tmsi=0x001f0000 nri_v=31 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00050000, 8) -> tmsi=0x00200000 nri_v=32 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00060000, 8) -> tmsi=0x000a0000 nri_v=10 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00070000, 8) -> tmsi=0x00140000 nri_v=20 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00080000, 8) -> tmsi=0x00150000 nri_v=21 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00090000, 8) -> tmsi=0x001e0000 nri_v=30 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x000a0000, 8) -> tmsi=0x001f0000 nri_v=31 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x000b0000, 8) -> tmsi=0x00200000 nri_v=32 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x000c0000, 8) -> tmsi=0x000a0000 nri_v=10 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x000d0000, 8) -> tmsi=0x00140000 nri_v=20 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x000e0000, 8) -> tmsi=0x00150000 nri_v=21 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x000f0000, 8) -> tmsi=0x001e0000 nri_v=30 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00100000, 8) -> tmsi=0x001f0000 nri_v=31 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00110000, 8) -> tmsi=0x00200000 nri_v=32 rc=0 ok
+osmo_tmsi_nri_v_limit_by_ranges(0x00120000, 8) -> tmsi=0x000a0000 nri_v=10 rc=0 ok
+
+pass
diff --git a/tests/testsuite.at b/tests/testsuite.at
index 4ff6671..a4c28f9 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -344,6 +344,12 @@
 AT_CHECK([$abs_top_builddir/tests/gsm23003/gsm23003_test], [0], [expout], [ignore])
 AT_CLEANUP
 
+AT_SETUP([gsm23236])
+AT_KEYWORDS([gsm23236])
+cat $abs_srcdir/gsm23236/gsm23236_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/gsm23236/gsm23236_test], [0], [expout], [ignore])
+AT_CLEANUP
+
 AT_SETUP([tdef])
 AT_KEYWORDS([tdef])
 cat $abs_srcdir/tdef/tdef_test.ok > expout