diff --git a/src/core/ddsc/CMakeLists.txt b/src/core/ddsc/CMakeLists.txt
index b29de10..571e2fb 100644
--- a/src/core/ddsc/CMakeLists.txt
+++ b/src/core/ddsc/CMakeLists.txt
@@ -13,7 +13,6 @@ PREPEND(srcs_ddsc "${CMAKE_CURRENT_LIST_DIR}/src"
     dds_alloc.c
     dds_builtin.c
     dds_coherent.c
-    dds_iid.c
     dds_participant.c
     dds_reader.c
     dds_writer.c
@@ -24,7 +23,6 @@ PREPEND(srcs_ddsc "${CMAKE_CURRENT_LIST_DIR}/src"
     dds_domain.c
     dds_instance.c
     dds_qos.c
-    dds_tkmap.c
     dds_entity.c
     dds_key.c
     dds_querycond.c
@@ -57,7 +55,6 @@ PREPEND(hdrs_private_ddsc "${CMAKE_CURRENT_LIST_DIR}/src"
     dds__builtin.h
     dds__domain.h
     dds__entity.h
-    dds__iid.h
     dds__init.h
     dds__key.h
     dds__listener.h
@@ -71,7 +68,6 @@ PREPEND(hdrs_private_ddsc "${CMAKE_CURRENT_LIST_DIR}/src"
     dds__rhc.h
     dds__stream.h
     dds__subscriber.h
-    dds__tkmap.h
     dds__topic.h
     dds__types.h
     dds__write.h
diff --git a/src/core/ddsc/src/dds__rhc.h b/src/core/ddsc/src/dds__rhc.h
index 13ff911..3007692 100644
--- a/src/core/ddsc/src/dds__rhc.h
+++ b/src/core/ddsc/src/dds__rhc.h
@@ -24,7 +24,7 @@ extern "C" {
 struct rhc;
 struct nn_xqos;
 struct ddsi_serdata;
-struct tkmap_instance;
+struct ddsi_tkmap_instance;
 struct proxy_writer_info;
 
 struct rhc * dds_rhc_new (dds_reader * reader, const struct ddsi_sertopic * topic);
@@ -36,7 +36,7 @@ uint32_t dds_rhc_lock_samples (struct rhc * rhc);
 DDS_EXPORT bool dds_rhc_store
 (
   struct rhc * __restrict rhc, const struct proxy_writer_info * __restrict pwr_info,
-  struct ddsi_serdata * __restrict sample, struct tkmap_instance * __restrict tk
+  struct ddsi_serdata * __restrict sample, struct ddsi_tkmap_instance * __restrict tk
 );
 void dds_rhc_unregister_wr (struct rhc * __restrict rhc, const struct proxy_writer_info * __restrict pwr_info);
 void dds_rhc_relinquish_ownership (struct rhc * __restrict rhc, const uint64_t wr_iid);
diff --git a/src/core/ddsc/src/dds__tkmap.h b/src/core/ddsc/src/dds__tkmap.h
deleted file mode 100644
index c25be3e..0000000
--- a/src/core/ddsc/src/dds__tkmap.h
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0 which is available at
- * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
- * v. 1.0 which is available at
- * http://www.eclipse.org/org/documents/edl-v10.php.
- *
- * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
- */
-#ifndef _DDS_TKMAP_H_
-#define _DDS_TKMAP_H_
-
-#include "dds__types.h"
-#include "os/os_atomics.h"
-
-#if defined (__cplusplus)
-extern "C" {
-#endif
-
-struct tkmap;
-struct ddsi_serdata;
-struct dds_topic;
-
-struct tkmap_instance
-{
-  struct ddsi_serdata * m_sample;
-  struct tkmap * m_map;
-  uint64_t m_iid;
-  os_atomic_uint32_t m_refc;
-};
-
-
-struct tkmap * dds_tkmap_new (void);
-void dds_tkmap_free (_Inout_ _Post_invalid_ struct tkmap *tkmap);
-void dds_tkmap_instance_ref (_In_ struct tkmap_instance *tk);
-uint64_t dds_tkmap_lookup (_In_ struct tkmap *tkmap, _In_ const struct ddsi_serdata *serdata);
-_Check_return_ bool dds_tkmap_get_key (_In_ struct tkmap * map, const struct ddsi_sertopic *topic, _In_ uint64_t iid, _Out_ void * sample);
-_Check_return_ struct tkmap_instance * dds_tkmap_find(
-        _In_ struct ddsi_serdata * sd,
-        _In_ const bool rd,
-        _In_ const bool create);
-_Check_return_ struct tkmap_instance * dds_tkmap_find_by_id (_In_ struct tkmap * map, _In_ uint64_t iid);
-
-DDS_EXPORT _Check_return_ struct tkmap_instance * dds_tkmap_lookup_instance_ref (_In_ struct ddsi_serdata * sd);
-DDS_EXPORT void dds_tkmap_instance_unref (_In_ struct tkmap_instance * tk);
-
-#if defined (__cplusplus)
-}
-#endif
-#endif
diff --git a/src/core/ddsc/src/dds__types.h b/src/core/ddsc/src/dds__types.h
index 4821c76..158d14e 100644
--- a/src/core/ddsc/src/dds__types.h
+++ b/src/core/ddsc/src/dds__types.h
@@ -259,13 +259,6 @@ typedef struct dds_waitset
 }
 dds_waitset;
 
-typedef struct dds_iid
-{
-  uint64_t counter;
-  uint32_t key[4];
-}
-dds_iid;
-
 /* Globals */
 
 typedef struct dds_globals
diff --git a/src/core/ddsc/src/dds_domain.c b/src/core/ddsc/src/dds_domain.c
index 4b3e23e..4c10db5 100644
--- a/src/core/ddsc/src/dds_domain.c
+++ b/src/core/ddsc/src/dds_domain.c
@@ -10,7 +10,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include "dds__domain.h"
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 
 static int dds_domain_compare (const int32_t * a, const int32_t * b)
 {
diff --git a/src/core/ddsc/src/dds_init.c b/src/core/ddsc/src/dds_init.c
index 5759f75..19d11fc 100644
--- a/src/core/ddsc/src/dds_init.c
+++ b/src/core/ddsc/src/dds_init.c
@@ -15,11 +15,11 @@
 #include "os/os.h"
 #include "dds__init.h"
 #include "dds__rhc.h"
-#include "dds__tkmap.h"
-#include "dds__iid.h"
 #include "dds__domain.h"
 #include "dds__err.h"
 #include "dds__builtin.h"
+#include "ddsi/ddsi_iid.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "ddsi/ddsi_serdata.h"
 #include "ddsi/q_servicelease.h"
 #include "ddsi/q_entity.h"
@@ -239,7 +239,6 @@ extern void dds_fini (void)
 
 static int dds__init_plugin (void)
 {
-  dds_iid_init ();
   if (dds_global.m_dur_init) (dds_global.m_dur_init) ();
   return 0;
 }
@@ -247,7 +246,6 @@ static int dds__init_plugin (void)
 static void dds__fini_plugin (void)
 {
   if (dds_global.m_dur_fini) (dds_global.m_dur_fini) ();
-  dds_iid_fini ();
 }
 
 void ddsi_plugin_init (void)
@@ -265,12 +263,6 @@ void ddsi_plugin_init (void)
   ddsi_plugin.rhc_plugin.rhc_unregister_wr_fn = dds_rhc_unregister_wr;
   ddsi_plugin.rhc_plugin.rhc_relinquish_ownership_fn = dds_rhc_relinquish_ownership;
   ddsi_plugin.rhc_plugin.rhc_set_qos_fn = dds_rhc_set_qos;
-  ddsi_plugin.rhc_plugin.rhc_lookup_fn = dds_tkmap_lookup_instance_ref;
-  ddsi_plugin.rhc_plugin.rhc_unref_fn = dds_tkmap_instance_unref;
-
-  /* Register iid generator */
-
-  ddsi_plugin.iidgen_fn = dds_iid_gen;
 }
 
 
diff --git a/src/core/ddsc/src/dds_instance.c b/src/core/ddsc/src/dds_instance.c
index f1f6ec4..bfb3252 100644
--- a/src/core/ddsc/src/dds_instance.c
+++ b/src/core/ddsc/src/dds_instance.c
@@ -16,8 +16,8 @@
 #include "dds__write.h"
 #include "dds__writer.h"
 #include "dds__rhc.h"
-#include "dds__tkmap.h"
 #include "dds__err.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "ddsi/ddsi_serdata.h"
 #include "ddsi/q_entity.h"
 #include "ddsi/q_thread.h"
@@ -50,14 +50,14 @@ dds_dispose_ih(
     return dds_dispose_ih_ts(writer, handle, dds_time());
 }
 
-static struct tkmap_instance*
+static struct ddsi_tkmap_instance*
 dds_instance_find(
         _In_ const dds_topic *topic,
         _In_ const void *data,
         _In_ const bool create)
 {
     struct ddsi_serdata *sd = ddsi_serdata_from_sample (topic->m_stopic, SDK_KEY, data);
-    struct tkmap_instance * inst = dds_tkmap_find (sd, false, create);
+    struct ddsi_tkmap_instance * inst = ddsi_tkmap_find (sd, false, create);
     ddsi_serdata_unref (sd);
     return inst;
 }
@@ -68,10 +68,10 @@ dds_instance_remove(
         _In_opt_ const void *data,
         _In_     dds_instance_handle_t handle)
 {
-    struct tkmap_instance * inst;
+    struct ddsi_tkmap_instance * inst;
 
     if (handle != DDS_HANDLE_NIL) {
-        inst = dds_tkmap_find_by_id (gv.m_tkmap, handle);
+        inst = ddsi_tkmap_find_by_id (gv.m_tkmap, handle);
     } else {
         assert (data);
         inst = dds_instance_find (topic, data, false);
@@ -83,7 +83,7 @@ dds_instance_remove(
         if (asleep) {
             thread_state_awake(thr);
         }
-        dds_tkmap_instance_unref (inst);
+        ddsi_tkmap_instance_unref (inst);
         if (asleep) {
             thread_state_asleep(thr);
         }
@@ -133,7 +133,7 @@ dds_register_instance(
         _Out_ dds_instance_handle_t *handle,
         _In_ const void *data)
 {
-    struct tkmap_instance * inst;
+    struct ddsi_tkmap_instance * inst;
     dds_entity *wr;
     dds_return_t ret;
     dds__retcode_t rc;
@@ -241,7 +241,7 @@ dds_unregister_instance_ih_ts(
     bool autodispose = true;
     dds_write_action action = DDS_WR_ACTION_UNREGISTER;
     dds_entity *wr;
-    struct tkmap *map;
+    struct ddsi_tkmap *map;
     const dds_topic *topic;
     void *sample;
 
@@ -263,7 +263,7 @@ dds_unregister_instance_ih_ts(
     map = gv.m_tkmap;
     topic = dds_instance_info((dds_entity*)wr);
     sample = dds_alloc (topic->m_descriptor->m_size);
-    if (dds_tkmap_get_key (map, topic->m_stopic, handle, sample)) {
+    if (ddsi_tkmap_get_key (map, topic->m_stopic, handle, sample)) {
         ret = dds_write_impl ((dds_writer*)wr, sample, timestamp, action);
     } else{
         DDS_ERROR("No instance related with the provided handle is found\n");
@@ -354,10 +354,10 @@ dds_dispose_ih_ts(
 
     rc = dds_writer_lock(writer, &wr);
     if (rc == DDS_RETCODE_OK) {
-        struct tkmap *map = gv.m_tkmap;
+        struct ddsi_tkmap *map = gv.m_tkmap;
         const dds_topic *topic = dds_instance_info((dds_entity*)wr);
         void *sample = dds_alloc (topic->m_descriptor->m_size);
-        if (dds_tkmap_get_key (map, topic->m_stopic, handle, sample)) {
+        if (ddsi_tkmap_get_key (map, topic->m_stopic, handle, sample)) {
             ret = dds_dispose_impl(wr, sample, handle, timestamp);
         } else {
             DDS_ERROR("No instance related with the provided handle is found\n");
@@ -381,7 +381,7 @@ dds_instance_lookup(
 {
     dds_instance_handle_t ih = DDS_HANDLE_NIL;
     const dds_topic * topic;
-    struct tkmap * map = gv.m_tkmap;
+    struct ddsi_tkmap * map = gv.m_tkmap;
     struct ddsi_serdata *sd;
 
     if(data == NULL){
@@ -392,7 +392,7 @@ dds_instance_lookup(
     topic = dds_instance_info_by_hdl (entity);
     if (topic) {
         sd = ddsi_serdata_from_sample (topic->m_stopic, SDK_KEY, data);
-        ih = dds_tkmap_lookup (map, sd);
+        ih = ddsi_tkmap_lookup (map, sd);
         ddsi_serdata_unref (sd);
     } else {
         DDS_ERROR("Acquired topic is NULL\n");
@@ -410,7 +410,7 @@ dds_instance_get_key(
 {
     dds_return_t ret;
     const dds_topic * topic;
-    struct tkmap * map = gv.m_tkmap;
+    struct ddsi_tkmap * map = gv.m_tkmap;
 
     if(data == NULL){
         DDS_ERROR("Argument data is NULL\n");
@@ -426,7 +426,7 @@ dds_instance_get_key(
     }
     memset (data, 0, topic->m_descriptor->m_size);
 
-    if (dds_tkmap_get_key (map, topic->m_stopic, inst, data)) {
+    if (ddsi_tkmap_get_key (map, topic->m_stopic, inst, data)) {
         ret = DDS_RETCODE_OK;
     } else{
         DDS_ERROR("No instance related with the provided entity is found\n");
diff --git a/src/core/ddsc/src/dds_read.c b/src/core/ddsc/src/dds_read.c
index 6133dd7..3e459e1 100644
--- a/src/core/ddsc/src/dds_read.c
+++ b/src/core/ddsc/src/dds_read.c
@@ -13,7 +13,7 @@
 #include <string.h>
 #include "dds__entity.h"
 #include "dds__reader.h"
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "dds__rhc.h"
 #include "dds__err.h"
 #include "ddsi/q_thread.h"
@@ -137,7 +137,7 @@ dds_read_impl(
         goto fail;
     }
     if (hand != DDS_HANDLE_NIL) {
-        if (dds_tkmap_find_by_id(gv.m_tkmap, hand) == NULL) {
+        if (ddsi_tkmap_find_by_id(gv.m_tkmap, hand) == NULL) {
             DDS_ERROR("Could not find instance\n");
             ret = DDS_ERRNO(DDS_RETCODE_PRECONDITION_NOT_MET);
             dds_read_unlock(rd, cond);
diff --git a/src/core/ddsc/src/dds_rhc.c b/src/core/ddsc/src/dds_rhc.c
index 72e4260..e54a7b2 100644
--- a/src/core/ddsc/src/dds_rhc.c
+++ b/src/core/ddsc/src/dds_rhc.c
@@ -24,7 +24,7 @@
 #include "dds__entity.h"
 #include "dds__reader.h"
 #include "dds__rhc.h"
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "util/ut_hopscotch.h"
 
 #include "util/ut_avl.h"
@@ -253,7 +253,7 @@ struct rhc_instance
   nn_wctime_t tstamp;          /* source time stamp of last update */
   struct rhc_instance *next;   /* next non-empty instance in arbitrary ordering */
   struct rhc_instance *prev;
-  struct tkmap_instance *tk;   /* backref into TK for unref'ing */
+  struct ddsi_tkmap_instance *tk;   /* backref into TK for unref'ing */
   struct rhc_sample a_sample;  /* pre-allocated storage for 1 sample */
 };
 
@@ -504,7 +504,7 @@ static void free_instance (void *vnode, void *varg)
   {
     remove_inst_from_nonempty_list (rhc, inst);
   }
-  dds_tkmap_instance_unref (inst->tk);
+  ddsi_tkmap_instance_unref (inst->tk);
   dds_free (inst);
 }
 
@@ -1023,12 +1023,12 @@ static struct rhc_instance * alloc_new_instance
 (
   const struct proxy_writer_info *pwr_info,
   struct ddsi_serdata *serdata,
-  struct tkmap_instance *tk
+  struct ddsi_tkmap_instance *tk
 )
 {
   struct rhc_instance *inst;
 
-  dds_tkmap_instance_ref (tk);
+  ddsi_tkmap_instance_ref (tk);
   inst = dds_alloc (sizeof (*inst));
   inst->iid = tk->m_iid;
   inst->tk = tk;
@@ -1052,7 +1052,7 @@ static rhc_store_result_t rhc_store_new_instance
   struct rhc *rhc,
   const struct proxy_writer_info *pwr_info,
   struct ddsi_serdata *sample,
-  struct tkmap_instance *tk,
+  struct ddsi_tkmap_instance *tk,
   const bool has_data,
   status_cb_data_t * cb_data
 )
@@ -1124,7 +1124,7 @@ static rhc_store_result_t rhc_store_new_instance
 bool dds_rhc_store
 (
   struct rhc * __restrict rhc, const struct proxy_writer_info * __restrict pwr_info,
-  struct ddsi_serdata * __restrict sample, struct tkmap_instance * __restrict tk
+  struct ddsi_serdata * __restrict sample, struct ddsi_tkmap_instance * __restrict tk
 )
 {
   const uint64_t wr_iid = pwr_info->iid;
diff --git a/src/core/ddsc/src/dds_topic.c b/src/core/ddsc/src/dds_topic.c
index 5e88b9d..dc63198 100644
--- a/src/core/ddsc/src/dds_topic.c
+++ b/src/core/ddsc/src/dds_topic.c
@@ -24,7 +24,7 @@
 #include "ddsi/ddsi_sertopic.h"
 #include "ddsi/q_ddsi_discovery.h"
 #include "os/os_atomics.h"
-#include "dds__iid.h"
+#include "ddsi/ddsi_iid.h"
 
 #define DDS_TOPIC_STATUS_MASK                                    \
                         DDS_INCONSISTENT_TOPIC_STATUS
@@ -423,7 +423,7 @@ dds_create_topic(
         st = dds_alloc (sizeof (*st));
 
         os_atomic_st32 (&st->c.refc, 1);
-        st->c.iid = dds_iid_gen ();
+        st->c.iid = ddsi_iid_gen ();
         st->c.status_cb = dds_topic_status_cb;
         st->c.status_cb_entity = top;
         st->c.name_typename = key;
diff --git a/src/core/ddsc/src/dds_whc.c b/src/core/ddsc/src/dds_whc.c
index c1dca65..1f02d62 100644
--- a/src/core/ddsc/src/dds_whc.c
+++ b/src/core/ddsc/src/dds_whc.c
@@ -18,7 +18,7 @@
 #include "ddsi/q_unused.h"
 #include "ddsi/q_config.h"
 #include "dds__whc.h"
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 
 #include "util/ut_avl.h"
 #include "util/ut_hopscotch.h"
@@ -55,7 +55,7 @@ struct whc_intvnode {
 struct whc_idxnode {
   uint64_t iid;
   seqno_t prune_seq;
-  struct tkmap_instance *tk;
+  struct ddsi_tkmap_instance *tk;
   unsigned headidx;
 #if __STDC_VERSION__ >= 199901L
   struct whc_node *hist[];
@@ -128,7 +128,7 @@ static unsigned whc_default_remove_acked_messages_full (struct whc_impl *whc, se
 static unsigned whc_default_remove_acked_messages (struct whc *whc, seqno_t max_drop_seq, struct whc_state *whcst, struct whc_node **deferred_free_list);
 static void whc_default_free_deferred_free_list (struct whc *whc, struct whc_node *deferred_free_list);
 static void whc_default_get_state(const struct whc *whc, struct whc_state *st);
-static int whc_default_insert (struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct tkmap_instance *tk);
+static int whc_default_insert (struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk);
 static seqno_t whc_default_next_seq (const struct whc *whc, seqno_t seq);
 static bool whc_default_borrow_sample (const struct whc *whc, seqno_t seq, struct whc_borrowed_sample *sample);
 static bool whc_default_borrow_sample_key (const struct whc *whc, const struct ddsi_serdata *serdata_key, struct whc_borrowed_sample *sample);
@@ -324,7 +324,7 @@ static struct whc_node *whc_findkey (const struct whc_impl *whc, const struct dd
   } template;
   struct whc_idxnode *n;
   check_whc (whc);
-  template.idxn.iid = dds_tkmap_lookup(gv.m_tkmap, serdata_key);
+  template.idxn.iid = ddsi_tkmap_lookup(gv.m_tkmap, serdata_key);
   n = ut_hhLookup (whc->idx_hash, &template.idxn);
   if (n == NULL)
     return NULL;
@@ -537,7 +537,7 @@ static void delete_one_sample_from_idx (struct whc_impl *whc, struct whc_node *w
 #endif
     if (!ut_hhRemove (whc->idx_hash, idxn))
       assert (0);
-    dds_tkmap_instance_unref(idxn->tk);
+    ddsi_tkmap_instance_unref(idxn->tk);
     os_free (idxn);
   }
   whcn->idxnode = NULL;
@@ -1081,7 +1081,7 @@ static struct whc_node *whc_default_insert_seq (struct whc_impl *whc, seqno_t ma
   return newn;
 }
 
-static int whc_default_insert (struct whc *whc_generic, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct tkmap_instance *tk)
+static int whc_default_insert (struct whc *whc_generic, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk)
 {
   struct whc_impl * const whc = (struct whc_impl *)whc_generic;
   struct whc_node *newn = NULL;
@@ -1190,7 +1190,7 @@ static int whc_default_insert (struct whc *whc_generic, seqno_t max_drop_seq, se
       unsigned i;
       idxn = os_malloc (sizeof (*idxn) + whc->idxdepth * sizeof (idxn->hist[0]));
       DDS_LOG(DDS_LC_WHC, " idxn %p", (void *)idxn);
-      dds_tkmap_instance_ref(tk);
+      ddsi_tkmap_instance_ref(tk);
       idxn->iid = tk->m_iid;
       idxn->tk = tk;
       idxn->prune_seq = 0;
diff --git a/src/core/ddsc/src/dds_write.c b/src/core/ddsc/src/dds_write.c
index f0fe316..73e5f4d 100644
--- a/src/core/ddsc/src/dds_write.c
+++ b/src/core/ddsc/src/dds_write.c
@@ -13,7 +13,7 @@
 #include <string.h>
 #include "dds__writer.h"
 #include "dds__write.h"
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "ddsi/q_error.h"
 #include "ddsi/q_thread.h"
 #include "ddsi/q_xmsg.h"
@@ -115,7 +115,7 @@ static int
 deliver_locally(
         _In_ struct writer *wr,
         _In_ struct ddsi_serdata *payload,
-        _In_ struct tkmap_instance *tk)
+        _In_ struct ddsi_tkmap_instance *tk)
 {
     dds_return_t ret = DDS_RETCODE_OK;
     os_mutexLock (&wr->rdary.rdary_lock);
@@ -193,7 +193,7 @@ dds_write_impl(
     const bool writekey = action & DDS_WR_KEY_BIT;
     dds_writer * writer = (dds_writer*) wr;
     struct writer * ddsi_wr = writer->m_wr;
-    struct tkmap_instance * tk;
+    struct ddsi_tkmap_instance * tk;
     struct ddsi_serdata *d;
 
     if (data == NULL) {
@@ -220,7 +220,7 @@ dds_write_impl(
                     ((action & DDS_WR_UNREGISTER_BIT) ? NN_STATUSINFO_UNREGISTER : 0) ;
     d->timestamp.v = tstamp;
     ddsi_serdata_ref(d);
-    tk = (ddsi_plugin.rhc_plugin.rhc_lookup_fn) (d);
+    tk = ddsi_tkmap_lookup_instance_ref(d);
     w_rc = write_sample_gc (writer->m_xp, ddsi_wr, d, tk);
 
     if (w_rc >= 0) {
@@ -243,7 +243,7 @@ dds_write_impl(
         ret = deliver_locally (ddsi_wr, d, tk);
     }
     ddsi_serdata_unref(d);
-    (ddsi_plugin.rhc_plugin.rhc_unref_fn) (tk);
+    ddsi_tkmap_instance_unref(tk);
 
     if (asleep) {
         thread_state_asleep (thr);
@@ -267,7 +267,7 @@ dds_writecdr_impl(
     struct thread_state1 * const thr = lookup_thread_state ();
     const bool asleep = !vtime_awake_p (thr->vtime);
     struct writer * ddsi_wr = wr->m_wr;
-    struct tkmap_instance * tk;
+    struct ddsi_tkmap_instance * tk;
 
     if (wr->m_topic->filter_fn) {
         abort();
@@ -283,7 +283,7 @@ dds_writecdr_impl(
         ((action & DDS_WR_UNREGISTER_BIT) ? NN_STATUSINFO_UNREGISTER : 0) ;
     d->timestamp.v = tstamp;
     ddsi_serdata_ref(d);
-    tk = (ddsi_plugin.rhc_plugin.rhc_lookup_fn) (d);
+    tk = ddsi_tkmap_lookup_instance_ref(d);
     w_rc = write_sample_gc (wr->m_xp, ddsi_wr, d, tk);
     if (w_rc >= 0) {
         /* Flush out write unless configured to batch */
@@ -306,7 +306,7 @@ dds_writecdr_impl(
         ret = deliver_locally (ddsi_wr, d, tk);
     }
     ddsi_serdata_unref(d);
-    (ddsi_plugin.rhc_plugin.rhc_unref_fn) (tk);
+    ddsi_tkmap_instance_unref(tk);
 
     if (asleep) {
         thread_state_asleep (thr);
diff --git a/src/core/ddsc/src/dds_writer.c b/src/core/ddsc/src/dds_writer.c
index 3e9f1fe..4a958e6 100644
--- a/src/core/ddsc/src/dds_writer.c
+++ b/src/core/ddsc/src/dds_writer.c
@@ -20,7 +20,7 @@
 #include "dds__qos.h"
 #include "dds__err.h"
 #include "dds__init.h"
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "dds__whc.h"
 #include "ddsc/ddsc_project.h"
 
diff --git a/src/core/ddsi/CMakeLists.txt b/src/core/ddsi/CMakeLists.txt
index 039c4a6..f88393b 100644
--- a/src/core/ddsi/CMakeLists.txt
+++ b/src/core/ddsi/CMakeLists.txt
@@ -23,6 +23,8 @@ PREPEND(srcs_ddsi "${CMAKE_CURRENT_LIST_DIR}/src"
     ddsi_sertopic.c
     ddsi_sertopic_default.c
     ddsi_rhc_plugin.c
+    ddsi_iid.c
+    ddsi_tkmap.c
     q_addrset.c
     q_bitset_inlines.c
     q_bswap.c
@@ -74,6 +76,8 @@ PREPEND(hdrs_private_ddsi "${CMAKE_CURRENT_LIST_DIR}/include/ddsi"
     ddsi_sertopic.h
     ddsi_serdata_default.h
     ddsi_rhc_plugin.h
+    ddsi_iid.h
+    ddsi_tkmap.h
     probes-constants.h
     q_addrset.h
     q_align.h
diff --git a/src/core/ddsc/src/dds__iid.h b/src/core/ddsi/include/ddsi/ddsi_iid.h
similarity index 69%
rename from src/core/ddsc/src/dds__iid.h
rename to src/core/ddsi/include/ddsi/ddsi_iid.h
index b7134d4..a5b9528 100644
--- a/src/core/ddsc/src/dds__iid.h
+++ b/src/core/ddsi/include/ddsi/ddsi_iid.h
@@ -12,15 +12,25 @@
 #ifndef _DDS_IID_H_
 #define _DDS_IID_H_
 
-#include "dds__types.h"
+#include "os/os.h"
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
-void dds_iid_init (void);
-void dds_iid_fini (void);
-uint64_t dds_iid_gen (void);
+struct ddsi_iid {
+#if OS_ATOMIC64_SUPPORT
+  os_atomic_uint64_t counter;
+#else
+  os_mutex lock;
+  uint64_t counter;
+#endif
+  uint32_t key[4];
+};
+
+void ddsi_iid_init (void);
+void ddsi_iid_fini (void);
+uint64_t ddsi_iid_gen (void);
 
 #if defined (__cplusplus)
 }
diff --git a/src/core/ddsi/include/ddsi/ddsi_rhc_plugin.h b/src/core/ddsi/include/ddsi/ddsi_rhc_plugin.h
index ba378a3..0516e89 100644
--- a/src/core/ddsi/include/ddsi/ddsi_rhc_plugin.h
+++ b/src/core/ddsi/include/ddsi/ddsi_rhc_plugin.h
@@ -14,7 +14,7 @@
 
 struct rhc;
 struct nn_xqos;
-struct tkmap_instance;
+struct ddsi_tkmap_instance;
 struct ddsi_serdata;
 struct ddsi_sertopic;
 struct entity_common;
@@ -33,14 +33,12 @@ struct ddsi_rhc_plugin
   void (*rhc_fini_fn) (struct rhc *rhc);
   bool (*rhc_store_fn)
   (struct rhc * __restrict rhc, const struct proxy_writer_info * __restrict pwr_info,
-   struct ddsi_serdata * __restrict sample, struct tkmap_instance * __restrict tk);
+   struct ddsi_serdata * __restrict sample, struct ddsi_tkmap_instance * __restrict tk);
   void (*rhc_unregister_wr_fn)
   (struct rhc * __restrict rhc, const struct proxy_writer_info * __restrict pwr_info);
   void (*rhc_relinquish_ownership_fn)
   (struct rhc * __restrict rhc, const uint64_t wr_iid);
   void (*rhc_set_qos_fn) (struct rhc * rhc, const struct nn_xqos * qos);
-  struct tkmap_instance * (*rhc_lookup_fn) (struct ddsi_serdata *serdata);
-  void (*rhc_unref_fn) (struct tkmap_instance *tk);
 };
 
 void make_proxy_writer_info(struct proxy_writer_info *pwr_info, const struct entity_common *e, const struct nn_xqos *xqos);
diff --git a/src/core/ddsi/include/ddsi/ddsi_tkmap.h b/src/core/ddsi/include/ddsi/ddsi_tkmap.h
new file mode 100644
index 0000000..82cc825
--- /dev/null
+++ b/src/core/ddsi/include/ddsi/ddsi_tkmap.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+#ifndef _DDS_TKMAP_H_
+#define _DDS_TKMAP_H_
+
+#include "dds__types.h"
+#include "os/os_atomics.h"
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+struct ddsi_tkmap;
+struct ddsi_serdata;
+struct dds_topic;
+
+struct ddsi_tkmap_instance
+{
+  struct ddsi_serdata * m_sample;
+  struct ddsi_tkmap * m_map;
+  uint64_t m_iid;
+  os_atomic_uint32_t m_refc;
+};
+
+
+struct ddsi_tkmap * ddsi_tkmap_new (void);
+void ddsi_tkmap_free (_Inout_ _Post_invalid_ struct ddsi_tkmap *tkmap);
+void ddsi_tkmap_instance_ref (_In_ struct ddsi_tkmap_instance *tk);
+uint64_t ddsi_tkmap_lookup (_In_ struct ddsi_tkmap *tkmap, _In_ const struct ddsi_serdata *serdata);
+_Check_return_ bool ddsi_tkmap_get_key (_In_ struct ddsi_tkmap * map, const struct ddsi_sertopic *topic, _In_ uint64_t iid, _Out_ void * sample);
+_Check_return_ struct ddsi_tkmap_instance * ddsi_tkmap_find(
+        _In_ struct ddsi_serdata * sd,
+        _In_ const bool rd,
+        _In_ const bool create);
+_Check_return_ struct ddsi_tkmap_instance * ddsi_tkmap_find_by_id (_In_ struct ddsi_tkmap * map, _In_ uint64_t iid);
+
+DDS_EXPORT _Check_return_ struct ddsi_tkmap_instance * ddsi_tkmap_lookup_instance_ref (_In_ struct ddsi_serdata * sd);
+DDS_EXPORT void ddsi_tkmap_instance_unref (_In_ struct ddsi_tkmap_instance * tk);
+
+#if defined (__cplusplus)
+}
+#endif
+#endif
diff --git a/src/core/ddsi/include/ddsi/q_config.h b/src/core/ddsi/include/ddsi/q_config.h
index 087b685..30989b1 100644
--- a/src/core/ddsi/include/ddsi/q_config.h
+++ b/src/core/ddsi/include/ddsi/q_config.h
@@ -414,10 +414,6 @@ struct ddsi_plugin
 
   /* Read cache */
   struct ddsi_rhc_plugin rhc_plugin;
-
-  /* IID generator */
-
-  uint64_t (*iidgen_fn) (void);
 };
 
 extern struct config OSAPI_EXPORT config;
diff --git a/src/core/ddsi/include/ddsi/q_globals.h b/src/core/ddsi/include/ddsi/q_globals.h
index 91a2123..7c19652 100644
--- a/src/core/ddsi/include/ddsi/q_globals.h
+++ b/src/core/ddsi/include/ddsi/q_globals.h
@@ -18,11 +18,11 @@
 
 #include "util/ut_fibheap.h"
 
-
 #include "ddsi/q_plist.h"
 #include "ddsi/q_protocol.h"
 #include "ddsi/q_nwif.h"
 #include "ddsi/q_sockwaitset.h"
+#include "ddsi/ddsi_iid.h"
 
 #ifdef DDSI_INCLUDE_ENCRYPTION
 #include "ddsi/q_security.h" /* for q_securityDecoderSet */
@@ -47,7 +47,7 @@ struct ddsi_tran_listener;
 struct ddsi_tran_factory;
 struct ut_thread_pool_s;
 struct debug_monitor;
-struct tkmap;
+struct ddsi_tkmap;
 
 typedef struct ospl_in_addr_node {
    nn_locator_t loc;
@@ -90,7 +90,8 @@ struct q_globals {
   volatile int deaf;
   volatile int mute;
 
-  struct tkmap * m_tkmap;
+  struct ddsi_tkmap * m_tkmap;
+  struct ddsi_iid dds_iid;
 
   /* Hash tables for participants, readers, writers, proxy
      participants, proxy readers and proxy writers by GUID
diff --git a/src/core/ddsi/include/ddsi/q_transmit.h b/src/core/ddsi/include/ddsi/q_transmit.h
index 7573592..1f87abd 100644
--- a/src/core/ddsi/include/ddsi/q_transmit.h
+++ b/src/core/ddsi/include/ddsi/q_transmit.h
@@ -25,7 +25,7 @@ struct writer;
 struct whc_state;
 struct proxy_reader;
 struct ddsi_serdata;
-struct tkmap_instance;
+struct ddsi_tkmap_instance;
 
 /* Writing new data; serdata_twrite (serdata) is assumed to be really
    recentish; serdata is unref'd.  If xp == NULL, data is queued, else
@@ -34,8 +34,8 @@ struct tkmap_instance;
    "nogc": no GC may occur, so it may not block to throttle the writer if the high water mark of the WHC is reached, which implies true KEEP_LAST behaviour.  This is true for all the DDSI built-in writers.
    "gc": GC may occur, which means the writer history and watermarks can be anything.  This must be used for all application data.
  */
-int write_sample_gc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct tkmap_instance *tk);
-int write_sample_nogc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct tkmap_instance *tk);
+int write_sample_gc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk);
+int write_sample_nogc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk);
 int write_sample_gc_notk (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata);
 int write_sample_nogc_notk (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata);
 
diff --git a/src/core/ddsi/include/ddsi/q_whc.h b/src/core/ddsi/include/ddsi/q_whc.h
index 1a99e65..f5bc549 100644
--- a/src/core/ddsi/include/ddsi/q_whc.h
+++ b/src/core/ddsi/include/ddsi/q_whc.h
@@ -18,7 +18,7 @@ extern "C" {
 
 struct ddsi_serdata;
 struct nn_plist;
-struct tkmap_instance;
+struct ddsi_tkmap_instance;
 struct whc_node; /* opaque, but currently used for deferred free lists */
 struct whc;
 
@@ -70,7 +70,7 @@ typedef void (*whc_free_t)(struct whc *whc);
    reliable readers that have not acknowledged all data */
 /* max_drop_seq must go soon, it's way too ugly. */
 /* plist may be NULL or os_malloc'd, WHC takes ownership of plist */
-typedef int (*whc_insert_t)(struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct tkmap_instance *tk);
+typedef int (*whc_insert_t)(struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk);
 typedef unsigned (*whc_downgrade_to_volatile_t)(struct whc *whc, struct whc_state *st);
 typedef unsigned (*whc_remove_acked_messages_t)(struct whc *whc, seqno_t max_drop_seq, struct whc_state *whcst, struct whc_node **deferred_free_list);
 typedef void (*whc_free_deferred_free_list_t)(struct whc *whc, struct whc_node *deferred_free_list);
@@ -118,7 +118,7 @@ inline bool whc_sample_iter_borrow_next (struct whc_sample_iter *it, struct whc_
 inline void whc_free (struct whc *whc) {
   whc->ops->free (whc);
 }
-inline int whc_insert (struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct tkmap_instance *tk) {
+inline int whc_insert (struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk) {
   return whc->ops->insert (whc, max_drop_seq, seq, plist, serdata, tk);
 }
 inline unsigned whc_downgrade_to_volatile (struct whc *whc, struct whc_state *st) {
diff --git a/src/core/ddsc/src/dds_iid.c b/src/core/ddsi/src/ddsi_iid.c
similarity index 69%
rename from src/core/ddsc/src/dds_iid.c
rename to src/core/ddsi/src/ddsi_iid.c
index 1809dd8..d8c092d 100644
--- a/src/core/ddsc/src/dds_iid.c
+++ b/src/core/ddsi/src/ddsi_iid.c
@@ -9,13 +9,10 @@
  *
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
-#include "dds__iid.h"
+#include "ddsi/ddsi_iid.h"
 #include "ddsi/q_time.h"
 #include "ddsi/q_globals.h"
 
-static os_mutex dds_iid_lock_g;
-static dds_iid dds_iid_g;
-
 static void dds_tea_encrypt (uint32_t v[2], const uint32_t k[4])
 {
   /* TEA encryption straight from Wikipedia */
@@ -43,37 +40,50 @@ static void dds_tea_decrypt (uint32_t v[2], const uint32_t k[4])
   v[0]=v0; v[1]=v1;
 }
 
-uint64_t dds_iid_gen (void)
+uint64_t ddsi_iid_gen (void)
 {
   uint64_t iid;
   union { uint64_t u64; uint32_t u32[2]; } tmp;
 
-  os_mutexLock (&dds_iid_lock_g);
-  tmp.u64 = ++dds_iid_g.counter;
-  dds_tea_encrypt (tmp.u32, dds_iid_g.key);
+#if OS_ATOMIC64_SUPPORT
+  tmp.u64 = os_atomic_inc64_nv (&gv.dds_iid.counter);
+#else
+  os_mutexLock (&gv.dds_iid.lock);
+  tmp.u64 = ++gv.dds_iid.counter;
+  os_mutexUnlock (&gv.dds_iid.lock);
+#endif
+
+  dds_tea_encrypt (tmp.u32, gv.dds_iid.key);
   iid = tmp.u64;
-  os_mutexUnlock (&dds_iid_lock_g);
   return iid;
 }
 
-void dds_iid_init (void)
+void ddsi_iid_init (void)
 {
   union { uint64_t u64; uint32_t u32[2]; } tmp;
   nn_wctime_t tnow = now ();
 
-  os_mutexInit (&dds_iid_lock_g);
+#if ! OS_ATOMIC64_SUPPORT
+  os_mutexInit (&gv.dds_iid.lock);
+#endif
 
-  dds_iid_g.key[0] = (uint32_t) ((uintptr_t) &dds_iid_g);
-  dds_iid_g.key[1] = (uint32_t) tnow.v;
-  dds_iid_g.key[2] = (uint32_t) (tnow.v >> 32);
-  dds_iid_g.key[3] = 0xdeadbeef;
+  gv.dds_iid.key[0] = (uint32_t) os_procIdSelf();
+  gv.dds_iid.key[1] = (uint32_t) tnow.v;
+  gv.dds_iid.key[2] = (uint32_t) (tnow.v >> 32);
+  gv.dds_iid.key[3] = 0xdeadbeef;
 
   tmp.u64 = 0;
-  dds_tea_decrypt (tmp.u32, dds_iid_g.key);
-  dds_iid_g.counter = tmp.u64;
+  dds_tea_decrypt (tmp.u32, gv.dds_iid.key);
+#if OS_ATOMIC64_SUPPORT
+  os_atomic_st64 (&gv.dds_iid.counter, tmp.u64);
+#else
+  gv.dds_iid.counter = tmp.u64;
+#endif
 }
 
-void dds_iid_fini (void)
+void ddsi_iid_fini (void)
 {
-  os_mutexDestroy (&dds_iid_lock_g);
+#if ! OS_ATOMIC64_SUPPORT
+  os_mutexDestroy (&gv.dds_iid.lock);
+#endif
 }
diff --git a/src/core/ddsi/src/ddsi_serdata_default.c b/src/core/ddsi/src/ddsi_serdata_default.c
index 548a92e..52552e7 100644
--- a/src/core/ddsi/src/ddsi_serdata_default.c
+++ b/src/core/ddsi/src/ddsi_serdata_default.c
@@ -24,7 +24,7 @@
 #include <string.h>
 #include "os/os.h"
 #include "dds__key.h"
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "dds__stream.h"
 #include "ddsi/q_radmin.h"
 #include "ddsi/ddsi_serdata_default.h"
diff --git a/src/core/ddsc/src/dds_tkmap.c b/src/core/ddsi/src/ddsi_tkmap.c
similarity index 78%
rename from src/core/ddsc/src/dds_tkmap.c
rename to src/core/ddsi/src/ddsi_tkmap.c
index 951ede2..089aaf5 100644
--- a/src/core/ddsc/src/dds_tkmap.c
+++ b/src/core/ddsi/src/ddsi_tkmap.c
@@ -17,8 +17,8 @@
 #include "ddsi/q_globals.h"
 #include "ddsi/q_config.h"
 #include "ddsi/sysdeps.h"
-#include "dds__tkmap.h"
-#include "dds__iid.h"
+#include "ddsi/ddsi_iid.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "util/ut_hopscotch.h"
 #include "dds__stream.h"
 #include "os/os.h"
@@ -27,7 +27,7 @@
 #define REFC_DELETE 0x80000000
 #define REFC_MASK   0x0fffffff
 
-struct tkmap
+struct ddsi_tkmap
 {
   struct ut_chh * m_hh;
   os_mutex m_lock;
@@ -49,20 +49,20 @@ static void gc_buckets (void *a)
 
 static void gc_tkmap_instance_impl (struct gcreq *gcreq)
 {
-  struct tkmap_instance *tk = gcreq->arg;
+  struct ddsi_tkmap_instance *tk = gcreq->arg;
   ddsi_serdata_unref (tk->m_sample);
   dds_free (tk);
   gcreq_free (gcreq);
 }
 
-static void gc_tkmap_instance (struct tkmap_instance *tk)
+static void gc_tkmap_instance (struct ddsi_tkmap_instance *tk)
 {
   struct gcreq *gcreq = gcreq_new (gv.gcreq_queue, gc_tkmap_instance_impl);
   gcreq->arg = tk;
   gcreq_enqueue (gcreq);
 }
 
-static uint32_t dds_tk_hash (const struct tkmap_instance * inst)
+static uint32_t dds_tk_hash (const struct ddsi_tkmap_instance * inst)
 {
   return inst->m_sample->hash;
 }
@@ -72,7 +72,7 @@ static uint32_t dds_tk_hash_void (const void * inst)
   return dds_tk_hash (inst);
 }
 
-static int dds_tk_equals (const struct tkmap_instance *a, const struct tkmap_instance *b)
+static int dds_tk_equals (const struct ddsi_tkmap_instance *a, const struct ddsi_tkmap_instance *b)
 {
   return (a->m_sample->ops == b->m_sample->ops) ? ddsi_serdata_eqkey (a->m_sample, b->m_sample) : 0;
 }
@@ -82,9 +82,9 @@ static int dds_tk_equals_void (const void *a, const void *b)
   return dds_tk_equals (a, b);
 }
 
-struct tkmap * dds_tkmap_new (void)
+struct ddsi_tkmap * ddsi_tkmap_new (void)
 {
-  struct tkmap *tkmap = dds_alloc (sizeof (*tkmap));
+  struct ddsi_tkmap *tkmap = dds_alloc (sizeof (*tkmap));
   tkmap->m_hh = ut_chhNew (1, dds_tk_hash_void, dds_tk_equals_void, gc_buckets);
   os_mutexInit (&tkmap->m_lock);
   os_condInit (&tkmap->m_cond, &tkmap->m_lock);
@@ -93,12 +93,12 @@ struct tkmap * dds_tkmap_new (void)
 
 static void free_tkmap_instance (void *vtk, UNUSED_ARG(void *f_arg))
 {
-  struct tkmap_instance *tk = vtk;
+  struct ddsi_tkmap_instance *tk = vtk;
   ddsi_serdata_unref (tk->m_sample);
   os_free (tk);
 }
 
-void dds_tkmap_free (_Inout_ _Post_invalid_ struct tkmap * map)
+void ddsi_tkmap_free (_Inout_ _Post_invalid_ struct ddsi_tkmap * map)
 {
   ut_chhEnumUnsafe (map->m_hh, free_tkmap_instance, NULL);
   ut_chhFree (map->m_hh);
@@ -107,10 +107,10 @@ void dds_tkmap_free (_Inout_ _Post_invalid_ struct tkmap * map)
   dds_free (map);
 }
 
-uint64_t dds_tkmap_lookup (_In_ struct tkmap * map, _In_ const struct ddsi_serdata * sd)
+uint64_t ddsi_tkmap_lookup (_In_ struct ddsi_tkmap * map, _In_ const struct ddsi_serdata * sd)
 {
-  struct tkmap_instance dummy;
-  struct tkmap_instance * tk;
+  struct ddsi_tkmap_instance dummy;
+  struct ddsi_tkmap_instance * tk;
   dummy.m_sample = (struct ddsi_serdata *) sd;
   tk = ut_chhLookup (map->m_hh, &dummy);
   return (tk) ? tk->m_iid : DDS_HANDLE_NIL;
@@ -127,7 +127,7 @@ tkmap_get_key_arg;
 
 static void dds_tkmap_get_key_fn (void * vtk, void * varg)
 {
-  struct tkmap_instance * tk = vtk;
+  struct ddsi_tkmap_instance * tk = vtk;
   tkmap_get_key_arg * arg = (tkmap_get_key_arg*) varg;
   if (tk->m_iid == arg->m_iid)
   {
@@ -137,7 +137,7 @@ static void dds_tkmap_get_key_fn (void * vtk, void * varg)
 }
 
 _Check_return_
-bool dds_tkmap_get_key (_In_ struct tkmap * map, const struct ddsi_sertopic *topic, _In_ uint64_t iid, _Out_ void * sample)
+bool ddsi_tkmap_get_key (_In_ struct ddsi_tkmap * map, const struct ddsi_sertopic *topic, _In_ uint64_t iid, _Out_ void * sample)
 {
   tkmap_get_key_arg arg = { topic, iid, sample, false };
   os_mutexLock (&map->m_lock);
@@ -149,13 +149,13 @@ bool dds_tkmap_get_key (_In_ struct tkmap * map, const struct ddsi_sertopic *top
 typedef struct
 {
   uint64_t m_iid;
-  struct tkmap_instance * m_inst;
+  struct ddsi_tkmap_instance * m_inst;
 }
 tkmap_get_inst_arg;
 
 static void dds_tkmap_get_inst_fn (void * vtk, void * varg)
 {
-  struct tkmap_instance * tk = vtk;
+  struct ddsi_tkmap_instance * tk = vtk;
   tkmap_get_inst_arg * arg = (tkmap_get_inst_arg*) varg;
   if (tk->m_iid == arg->m_iid)
   {
@@ -164,7 +164,7 @@ static void dds_tkmap_get_inst_fn (void * vtk, void * varg)
 }
 
 _Check_return_
-struct tkmap_instance * dds_tkmap_find_by_id (_In_ struct tkmap * map, _In_ uint64_t iid)
+struct ddsi_tkmap_instance * ddsi_tkmap_find_by_id (_In_ struct ddsi_tkmap * map, _In_ uint64_t iid)
 {
   tkmap_get_inst_arg arg = { iid, NULL };
   ut_chhEnumUnsafe (map->m_hh, dds_tkmap_get_inst_fn, &arg);
@@ -184,14 +184,14 @@ struct tkmap_instance * dds_tkmap_find_by_id (_In_ struct tkmap * map, _In_ uint
 #endif
 
 _Check_return_
-struct tkmap_instance * dds_tkmap_find(
+struct ddsi_tkmap_instance * ddsi_tkmap_find(
         _In_ struct ddsi_serdata * sd,
         _In_ const bool rd,
         _In_ const bool create)
 {
-  struct tkmap_instance dummy;
-  struct tkmap_instance * tk;
-  struct tkmap * map = gv.m_tkmap;
+  struct ddsi_tkmap_instance dummy;
+  struct ddsi_tkmap_instance * tk;
+  struct ddsi_tkmap * map = gv.m_tkmap;
 
   dummy.m_sample = sd;
 retry:
@@ -222,7 +222,7 @@ retry:
     tk->m_sample = ddsi_serdata_to_topicless (sd);
     tk->m_map = map;
     os_atomic_st32 (&tk->m_refc, 1);
-    tk->m_iid = dds_iid_gen ();
+    tk->m_iid = ddsi_iid_gen ();
     if (!ut_chhAdd (map->m_hh, tk))
     {
       /* Lost a race from another thread, retry */
@@ -240,18 +240,18 @@ retry:
 }
 
 _Check_return_
-struct tkmap_instance * dds_tkmap_lookup_instance_ref (_In_ struct ddsi_serdata * sd)
+struct ddsi_tkmap_instance * ddsi_tkmap_lookup_instance_ref (_In_ struct ddsi_serdata * sd)
 {
   assert (vtime_awake_p (lookup_thread_state ()->vtime));
-  return dds_tkmap_find (sd, true, true);
+  return ddsi_tkmap_find (sd, true, true);
 }
 
-void dds_tkmap_instance_ref (_In_ struct tkmap_instance *tk)
+void ddsi_tkmap_instance_ref (_In_ struct ddsi_tkmap_instance *tk)
 {
   os_atomic_inc32 (&tk->m_refc);
 }
 
-void dds_tkmap_instance_unref (_In_ struct tkmap_instance * tk)
+void ddsi_tkmap_instance_unref (_In_ struct ddsi_tkmap_instance * tk)
 {
   uint32_t old, new;
   assert (vtime_awake_p(lookup_thread_state()->vtime));
@@ -267,7 +267,7 @@ void dds_tkmap_instance_unref (_In_ struct tkmap_instance * tk)
   } while (!os_atomic_cas32(&tk->m_refc, old, new));
   if (new == REFC_DELETE)
   {
-    struct tkmap *map = tk->m_map;
+    struct ddsi_tkmap *map = tk->m_map;
 
     /* Remove from hash table */
     int removed = ut_chhRemove(map->m_hh, tk);
diff --git a/src/core/ddsi/src/q_entity.c b/src/core/ddsi/src/q_entity.c
index ae487e1..dfea79d 100644
--- a/src/core/ddsi/src/q_entity.c
+++ b/src/core/ddsi/src/q_entity.c
@@ -42,6 +42,8 @@
 
 #include "ddsi/sysdeps.h"
 #include "dds__whc.h"
+#include "ddsi/ddsi_iid.h"
+#include "ddsi/ddsi_tkmap.h"
 
 struct deleted_participant {
   ut_avlNode_t avlnode;
@@ -158,7 +160,7 @@ static void entity_common_init (struct entity_common *e, const struct nn_guid *g
   e->guid = *guid;
   e->kind = kind;
   e->name = os_strdup (name ? name : "");
-  e->iid = (ddsi_plugin.iidgen_fn) ();
+  e->iid = ddsi_iid_gen ();
   os_mutexInit (&e->lock);
   e->onlylocal = onlylocal;
 }
@@ -1613,7 +1615,7 @@ static void writer_add_local_connection (struct writer *wr, struct reader *rd)
       struct proxy_writer_info pwr_info;
       struct ddsi_serdata *payload = sample.serdata;
       /* FIXME: whc has tk reference in its index nodes, which is what we really should be iterating over anyway, and so we don't really have to look them up anymore */
-      struct tkmap_instance *tk = (ddsi_plugin.rhc_plugin.rhc_lookup_fn) (payload);
+      struct ddsi_tkmap_instance *tk = ddsi_tkmap_lookup_instance_ref(payload);
       make_proxy_writer_info(&pwr_info, &wr->e, wr->xqos);
       (void)(ddsi_plugin.rhc_plugin.rhc_store_fn) (rd->rhc, &pwr_info, payload, tk);
     }
diff --git a/src/core/ddsi/src/q_init.c b/src/core/ddsi/src/q_init.c
index 037d794..58464ef 100644
--- a/src/core/ddsi/src/q_init.c
+++ b/src/core/ddsi/src/q_init.c
@@ -57,8 +57,9 @@
 #include "ddsi/ddsi_mcgroup.h"
 #include "ddsi/ddsi_serdata_default.h"
 
-#include "dds__tkmap.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "dds__whc.h"
+#include "ddsi/ddsi_iid.h"
 
 static void add_peer_addresses (struct addrset *as, const struct config_peer_listelem *list)
 {
@@ -772,7 +773,7 @@ static struct ddsi_sertopic *make_special_topic (uint16_t enc_id, const struct d
   st->c.ops = &ddsi_sertopic_ops_default;
   st->c.serdata_ops = ops;
   st->c.serdata_basehash = ddsi_sertopic_compute_serdata_basehash (st->c.serdata_ops);
-  st->c.iid = ddsi_plugin.iidgen_fn();
+  st->c.iid = ddsi_iid_gen ();
   st->native_encoding_identifier = enc_id;
   st->nkeys = 1;
   return (struct ddsi_sertopic *)st;
@@ -880,6 +881,7 @@ int rtps_init (void)
   /* Initialize implementation (Lite or OSPL) */
 
   ddsi_plugin_init ();
+  ddsi_iid_init ();
 
   gv.tstart = now ();    /* wall clock time, used in logs */
 
@@ -1060,7 +1062,7 @@ int rtps_init (void)
   gv.spdp_defrag = nn_defrag_new (NN_DEFRAG_DROP_OLDEST, config.defrag_unreliable_maxsamples);
   gv.spdp_reorder = nn_reorder_new (NN_REORDER_MODE_ALWAYS_DELIVER, config.primary_reorder_maxsamples);
 
-  gv.m_tkmap = dds_tkmap_new ();
+  gv.m_tkmap = ddsi_tkmap_new ();
 
   if (gv.m_factory->m_connless)
   {
@@ -1339,7 +1341,7 @@ err_mc_conn:
     ddsi_conn_free (gv.data_conn_uc);
   free_group_membership(gv.mship);
 err_unicast_sockets:
-  dds_tkmap_free (gv.m_tkmap);
+  ddsi_tkmap_free (gv.m_tkmap);
   nn_reorder_free (gv.spdp_reorder);
   nn_defrag_free (gv.spdp_defrag);
   os_mutexDestroy (&gv.spdp_lock);
@@ -1368,6 +1370,7 @@ err_unicast_sockets:
   nn_plist_fini (&gv.default_plist_pp);
   ddsi_serdatapool_free (gv.serpool);
   nn_xmsgpool_free (gv.xmsgpool);
+  ddsi_iid_fini ();
   (ddsi_plugin.fini_fn) ();
 #ifdef DDSI_INCLUDE_NETWORK_PARTITIONS
 err_network_partition_addrset:
@@ -1621,7 +1624,7 @@ void rtps_term (void)
     }
   }
 
-  dds_tkmap_free (gv.m_tkmap);
+  ddsi_tkmap_free (gv.m_tkmap);
 
   ephash_free (gv.guid_hash);
   gv.guid_hash = NULL;
@@ -1663,6 +1666,7 @@ OS_WARNING_MSVC_ON(6001);
 
   ddsi_serdatapool_free (gv.serpool);
   nn_xmsgpool_free (gv.xmsgpool);
+  ddsi_iid_fini ();
   (ddsi_plugin.fini_fn) ();
   DDS_LOG(DDS_LC_CONFIG, "Finis.\n");
 }
diff --git a/src/core/ddsi/src/q_receive.c b/src/core/ddsi/src/q_receive.c
index 3a8e0a7..10f8310 100644
--- a/src/core/ddsi/src/q_receive.c
+++ b/src/core/ddsi/src/q_receive.c
@@ -46,6 +46,7 @@
 #include "ddsi/q_globals.h"
 #include "ddsi/q_static_assert.h"
 #include "ddsi/q_init.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "ddsi/ddsi_mcgroup.h"
 #include "ddsi/ddsi_serdata.h"
 #include "ddsi/ddsi_serdata_default.h" /* FIXME: get rid of this */
@@ -1995,8 +1996,8 @@ static int deliver_user_data (const struct nn_rsample_info *sampleinfo, const st
    the PRISMTECH_WRITER_INFO thing is completely meaningless to
    us */
   {
-    struct tkmap_instance * tk;
-    tk = (ddsi_plugin.rhc_plugin.rhc_lookup_fn) (payload);
+    struct ddsi_tkmap_instance * tk;
+    tk = ddsi_tkmap_lookup_instance_ref(payload);
     if (tk)
     {
       struct proxy_writer_info pwr_info;
@@ -2075,7 +2076,7 @@ retry:
           if (pwr_locked) os_mutexLock (&pwr->e.lock);
         }
       }
-      (ddsi_plugin.rhc_plugin.rhc_unref_fn) (tk);
+      ddsi_tkmap_instance_unref (tk);
     }
   }
   ddsi_serdata_unref (payload);
diff --git a/src/core/ddsi/src/q_transmit.c b/src/core/ddsi/src/q_transmit.c
index 4c0a412..6c314da 100644
--- a/src/core/ddsi/src/q_transmit.c
+++ b/src/core/ddsi/src/q_transmit.c
@@ -31,7 +31,7 @@
 #include "ddsi/q_unused.h"
 #include "ddsi/q_hbcontrol.h"
 #include "ddsi/q_static_assert.h"
-
+#include "ddsi/ddsi_tkmap.h"
 #include "ddsi/ddsi_serdata.h"
 #include "ddsi/ddsi_sertopic.h"
 
@@ -851,7 +851,7 @@ int enqueue_sample_wrlock_held (struct writer *wr, seqno_t seq, const struct nn_
   return enqueued ? 0 : -1;
 }
 
-static int insert_sample_in_whc (struct writer *wr, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct tkmap_instance *tk)
+static int insert_sample_in_whc (struct writer *wr, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk)
 {
   /* returns: < 0 on error, 0 if no need to insert in whc, > 0 if inserted */
   int do_insert, insres, res;
@@ -1027,7 +1027,7 @@ static int maybe_grow_whc (struct writer *wr)
   return 0;
 }
 
-static int write_sample_eot (struct nn_xpack *xp, struct writer *wr, struct nn_plist *plist, struct ddsi_serdata *serdata, struct tkmap_instance *tk, int end_of_txn, int gc_allowed)
+static int write_sample_eot (struct nn_xpack *xp, struct writer *wr, struct nn_plist *plist, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk, int end_of_txn, int gc_allowed)
 {
   int r;
   seqno_t seq;
@@ -1163,33 +1163,33 @@ drop:
   return r;
 }
 
-int write_sample_gc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct tkmap_instance *tk)
+int write_sample_gc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk)
 {
   return write_sample_eot (xp, wr, NULL, serdata, tk, 0, 1);
 }
 
-int write_sample_nogc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct tkmap_instance *tk)
+int write_sample_nogc (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk)
 {
   return write_sample_eot (xp, wr, NULL, serdata, tk, 0, 0);
 }
 
 int write_sample_gc_notk (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata)
 {
-  struct tkmap_instance *tk;
+  struct ddsi_tkmap_instance *tk;
   int res;
-  tk = (ddsi_plugin.rhc_plugin.rhc_lookup_fn) (serdata);
+  tk = ddsi_tkmap_lookup_instance_ref (serdata);
   res = write_sample_eot (xp, wr, NULL, serdata, tk, 0, 1);
-  (ddsi_plugin.rhc_plugin.rhc_unref_fn) (tk);
+  ddsi_tkmap_instance_unref (tk);
   return res;
 }
 
 int write_sample_nogc_notk (struct nn_xpack *xp, struct writer *wr, struct ddsi_serdata *serdata)
 {
-  struct tkmap_instance *tk;
+  struct ddsi_tkmap_instance *tk;
   int res;
-  tk = (ddsi_plugin.rhc_plugin.rhc_lookup_fn) (serdata);
+  tk = ddsi_tkmap_lookup_instance_ref (serdata);
   res = write_sample_eot (xp, wr, NULL, serdata, tk, 0, 0);
-  (ddsi_plugin.rhc_plugin.rhc_unref_fn) (tk);
+  ddsi_tkmap_instance_unref (tk);
   return res;
 }
 
diff --git a/src/core/ddsi/src/q_whc.c b/src/core/ddsi/src/q_whc.c
index dd7e95c..3be0df2 100644
--- a/src/core/ddsi/src/q_whc.c
+++ b/src/core/ddsi/src/q_whc.c
@@ -22,7 +22,7 @@ extern inline void whc_return_sample (struct whc *whc, struct whc_borrowed_sampl
 extern inline void whc_sample_iter_init (const struct whc *whc, struct whc_sample_iter *it);
 extern inline bool whc_sample_iter_borrow_next (struct whc_sample_iter *it, struct whc_borrowed_sample *sample);
 extern inline void whc_free (struct whc *whc);
-extern int whc_insert (struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct tkmap_instance *tk);
+extern int whc_insert (struct whc *whc, seqno_t max_drop_seq, seqno_t seq, struct nn_plist *plist, struct ddsi_serdata *serdata, struct ddsi_tkmap_instance *tk);
 extern unsigned whc_downgrade_to_volatile (struct whc *whc, struct whc_state *st);
 extern unsigned whc_remove_acked_messages (struct whc *whc, seqno_t max_drop_seq, struct whc_state *whcst, struct whc_node **deferred_free_list);
 extern void whc_free_deferred_free_list (struct whc *whc, struct whc_node *deferred_free_list);
diff --git a/src/core/ddsi/src/q_xevent.c b/src/core/ddsi/src/q_xevent.c
index fb545ac..7f9ee9a 100644
--- a/src/core/ddsi/src/q_xevent.c
+++ b/src/core/ddsi/src/q_xevent.c
@@ -38,6 +38,7 @@
 #include "ddsi/q_xmsg.h"
 #include "ddsi/ddsi_serdata.h"
 #include "ddsi/ddsi_serdata_default.h"
+#include "ddsi/ddsi_tkmap.h"
 #include "dds__whc.h"
 
 #include "ddsi/sysdeps.h"
@@ -1128,7 +1129,7 @@ static void write_pmd_message (struct nn_xpack *xp, struct participant *pp, unsi
     char pad[offsetof (ParticipantMessageData_t, value) + PMD_DATA_LENGTH];
   } u;
   struct ddsi_serdata *serdata;
-  struct tkmap_instance *tk;
+  struct ddsi_tkmap_instance *tk;
 
   if ((wr = get_builtin_writer (pp, NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_MESSAGE_WRITER)) == NULL)
   {
@@ -1150,9 +1151,9 @@ static void write_pmd_message (struct nn_xpack *xp, struct participant *pp, unsi
   serdata = ddsi_serdata_from_sample (gv.rawcdr_topic, SDK_DATA, &raw);
   serdata->timestamp = now ();
 
-  tk = (ddsi_plugin.rhc_plugin.rhc_lookup_fn) (serdata);
+  tk = ddsi_tkmap_lookup_instance_ref(serdata);
   write_sample_nogc (xp, wr, serdata, tk);
-  (ddsi_plugin.rhc_plugin.rhc_unref_fn) (tk);
+  ddsi_tkmap_instance_unref(tk);
 #undef PMD_DATA_LENGTH
 }