diff --git a/orte/mca/db/daemon/db_daemon.c b/orte/mca/db/daemon/db_daemon.c
index 60cc001d91..6d02550677 100644
--- a/orte/mca/db/daemon/db_daemon.c
+++ b/orte/mca/db/daemon/db_daemon.c
@@ -82,18 +82,21 @@ static orte_rmcast_channel_t my_group_channel;
 /* local functions */
 static void callback_fn(int status,
                         orte_rmcast_channel_t channel,
+                        orte_rmcast_seq_t seq_num,
                         orte_rmcast_tag_t tag,
                         orte_process_name_t *sender,
                         opal_buffer_t *buf, void* cbdata);
 
 static void recv_cmd(int status,
                      orte_rmcast_channel_t channel,
+                     orte_rmcast_seq_t seq_num,
                      orte_rmcast_tag_t tag,
                      orte_process_name_t *sender,
                      opal_buffer_t *buf, void* cbdata);
 
 static void recv_ack(int status,
                      orte_rmcast_channel_t channel,
+                     orte_rmcast_seq_t seq_num,
                      orte_rmcast_tag_t tag,
                      orte_process_name_t *sender,
                      opal_buffer_t *buf, void* cbdata);
@@ -322,6 +325,7 @@ static int remove_data(char *key)
 
 static void callback_fn(int status,
                         orte_rmcast_channel_t channel,
+                        orte_rmcast_seq_t seq_num,
                         orte_rmcast_tag_t tag,
                         orte_process_name_t *sender,
                         opal_buffer_t *buf, void* cbdata)
@@ -331,6 +335,7 @@ static void callback_fn(int status,
 
 static void recv_ack(int status,
                      orte_rmcast_channel_t channel,
+                     orte_rmcast_seq_t seq_num,
                      orte_rmcast_tag_t tag,
                      orte_process_name_t *sender,
                      opal_buffer_t *buf, void* cbdata)
@@ -342,6 +347,7 @@ static void recv_ack(int status,
 
 static void recv_cmd(int status,
                      orte_rmcast_channel_t channel,
+                     orte_rmcast_seq_t seq_num,
                      orte_rmcast_tag_t tag,
                      orte_process_name_t *sender,
                      opal_buffer_t *buf, void* cbdata)
diff --git a/orte/mca/grpcomm/mcast/grpcomm_mcast.c b/orte/mca/grpcomm/mcast/grpcomm_mcast.c
index caa50c842f..56d17e88e7 100644
--- a/orte/mca/grpcomm/mcast/grpcomm_mcast.c
+++ b/orte/mca/grpcomm/mcast/grpcomm_mcast.c
@@ -70,6 +70,7 @@ orte_grpcomm_base_module_t orte_grpcomm_mcast_module = {
 /* Local functions */
 static void daemon_recv(int status,
                         orte_rmcast_channel_t channel,
+                        orte_rmcast_seq_t seq_num,
                         orte_rmcast_tag_t tag,
                         orte_process_name_t *sender,
                         opal_buffer_t *buf, void* cbdata);
@@ -459,6 +460,7 @@ static int get_proc_attr(const orte_process_name_t proc,
 
 static void daemon_recv(int status,
                         orte_rmcast_channel_t channel,
+                        orte_rmcast_seq_t seq_num,
                         orte_rmcast_tag_t tag,
                         orte_process_name_t *sender,
                         opal_buffer_t *buf, void* cbdata)
diff --git a/orte/mca/rmcast/base/private.h b/orte/mca/rmcast/base/private.h
index be2cca38e9..24b8120493 100644
--- a/orte/mca/rmcast/base/private.h
+++ b/orte/mca/rmcast/base/private.h
@@ -75,6 +75,7 @@ typedef struct {
     opal_list_item_t item;
     orte_process_name_t name;
     orte_rmcast_channel_t channel;
+    orte_rmcast_seq_t seq_num;
     bool recvd;
     orte_rmcast_tag_t tag;
     orte_rmcast_flag_t flags;
diff --git a/orte/mca/rmcast/base/rmcast_base_fns.c b/orte/mca/rmcast/base/rmcast_base_fns.c
index 847193d5d9..285477ce08 100644
--- a/orte/mca/rmcast/base/rmcast_base_fns.c
+++ b/orte/mca/rmcast/base/rmcast_base_fns.c
@@ -264,7 +264,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
     }
     
     OPAL_OUTPUT_VERBOSE((5, orte_rmcast_base.rmcast_output,
-                         "%s rmcast:base:process_recv sender: %s channel: %d tag: %d %s seq_num: %d",
+                         "%s rmcast:base:process_recv sender: %s channel: %d tag: %d %s seq_num: %lu",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME),
                          ORTE_NAME_PRINT(&name), channel, (int)tag,
                          (0 == flag) ? "iovecs" : "buffer", recvd_seq_num));
@@ -328,7 +328,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
                                      "%s rmcast:base:recv delivering iovecs to channel %d tag %d",
                                      ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), ptr->channel, (int)tag));
                 
-                ptr->cbfunc_iovec(ORTE_SUCCESS, ptr->channel, tag,
+                ptr->cbfunc_iovec(ORTE_SUCCESS, ptr->channel, recvd_seq_num, tag,
                                   &name, iovec_array, iovec_count, ptr->cbdata);
                 /* if it isn't persistent, remove it */
                 if (!(ORTE_RMCAST_PERSISTENT & ptr->flags)) {
@@ -345,6 +345,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
                                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME)));
                     goto cleanup;
                 }
+                ptr->seq_num = recvd_seq_num;
                 /* copy over the iovec array since it will be released by
                  * the blocking recv
                  */
@@ -370,7 +371,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
                                      "%s rmcast:base:recv delivering buffer to channel %d tag %d",
                                      ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), ptr->channel, (int)tag));
                 
-                ptr->cbfunc_buffer(ORTE_SUCCESS, ptr->channel, tag,
+                ptr->cbfunc_buffer(ORTE_SUCCESS, ptr->channel, recvd_seq_num, tag,
                                    &name, recvd_buf, ptr->cbdata);
                 /* if it isn't persistent, remove it */
                 if (!(ORTE_RMCAST_PERSISTENT & ptr->flags)) {
@@ -390,7 +391,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
                 OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
                                      "%s rmcast:base:recv copying buffer for blocking recv",
                                      ORTE_NAME_PRINT(ORTE_PROC_MY_NAME)));
-                
+                ptr->seq_num = recvd_seq_num;
                 /* copy the buffer across since it will be released
                  * by the blocking recv
                  */
diff --git a/orte/mca/rmcast/rmcast.h b/orte/mca/rmcast/rmcast.h
index 91aba3cce3..b8430d0dad 100644
--- a/orte/mca/rmcast/rmcast.h
+++ b/orte/mca/rmcast/rmcast.h
@@ -52,12 +52,14 @@ BEGIN_C_DECLS
  */
 typedef void (*orte_rmcast_callback_buffer_fn_t)(int status,
                                                  orte_rmcast_channel_t channel,
+                                                 orte_rmcast_seq_t seq_num,
                                                  orte_rmcast_tag_t tag,
                                                  orte_process_name_t *sender,
                                                  opal_buffer_t *buf, void* cbdata);
 
 typedef void (*orte_rmcast_callback_fn_t)(int status,
                                           orte_rmcast_channel_t channel,
+                                          orte_rmcast_seq_t seq_num,
                                           orte_rmcast_tag_t tag,
                                           orte_process_name_t *sender,
                                           struct iovec *msg, int count, void* cbdata);
@@ -96,6 +98,7 @@ typedef int (*orte_rmcast_base_module_send_nb_fn_t)(orte_rmcast_channel_t channe
 typedef int (*orte_rmcast_base_module_recv_buffer_fn_t)(orte_process_name_t *sender,
                                                         orte_rmcast_channel_t channel,
                                                         orte_rmcast_tag_t tag,
+                                                        orte_rmcast_seq_t *seq_num,
                                                         opal_buffer_t *buf);
 
 /* non-blocking receive buffer messages from a multicast channel */
@@ -109,6 +112,7 @@ typedef int (*orte_rmcast_base_module_recv_buffer_nb_fn_t)(orte_rmcast_channel_t
 typedef int (*orte_rmcast_base_module_recv_fn_t)(orte_process_name_t *sender,
                                                  orte_rmcast_channel_t channel,
                                                  orte_rmcast_tag_t tag,
+                                                 orte_rmcast_seq_t *seq_num,
                                                  struct iovec **msg, int *count);
 
 /* non-blocking receive iovec messages from a multicast channel */
diff --git a/orte/mca/rmcast/rmcast_types.h b/orte/mca/rmcast/rmcast_types.h
index a1f01642b2..57cdf19006 100644
--- a/orte/mca/rmcast/rmcast_types.h
+++ b/orte/mca/rmcast/rmcast_types.h
@@ -74,10 +74,10 @@ typedef uint8_t orte_rmcast_flag_t;
 #define ORTE_RMCAST_PERSISTENT      0x01
 
 /* message sequence number */
-typedef uint32_t orte_rmcast_seq_t;
-#define ORTE_RMCAST_SEQ_MAX         UINT32_MAX-1
-#define ORTE_RMCAST_SEQ_INVALID     UINT32_MAX
-#define ORTE_RMCAST_SEQ_T   OPAL_UINT32
+typedef size_t orte_rmcast_seq_t;
+#define ORTE_RMCAST_SEQ_MAX         SIZE_MAX-1
+#define ORTE_RMCAST_SEQ_INVALID     SIZE_MAX
+#define ORTE_RMCAST_SEQ_T   OPAL_SIZE
 
 END_C_DECLS
 
diff --git a/orte/mca/rmcast/tcp/rmcast_tcp.c b/orte/mca/rmcast/tcp/rmcast_tcp.c
index b3e1565b53..8908a43c61 100644
--- a/orte/mca/rmcast/tcp/rmcast_tcp.c
+++ b/orte/mca/rmcast/tcp/rmcast_tcp.c
@@ -83,6 +83,7 @@ static int tcp_send_nb(orte_rmcast_channel_t channel,
 static int tcp_recv_buffer(orte_process_name_t *sender,
                            orte_rmcast_channel_t channel,
                            orte_rmcast_tag_t tag,
+                           orte_rmcast_seq_t *seq_num,
                            opal_buffer_t *buf);
 
 static int tcp_recv_buffer_nb(orte_rmcast_channel_t channel,
@@ -94,6 +95,7 @@ static int tcp_recv_buffer_nb(orte_rmcast_channel_t channel,
 static int tcp_recv(orte_process_name_t *sender,
                     orte_rmcast_channel_t channel,
                     orte_rmcast_tag_t tag,
+                    orte_rmcast_seq_t *seq_num,
                     struct iovec **msg, int *count);
 
 static int tcp_recv_nb(orte_rmcast_channel_t channel,
@@ -278,6 +280,7 @@ static bool send_complete, send_buf_complete;
 
 static void internal_snd_cb(int status,
                             orte_rmcast_channel_t channel,
+                            orte_rmcast_seq_t seq_num,
                             orte_rmcast_tag_t tag,
                             orte_process_name_t *sender,
                             struct iovec *msg, int count, void *cbdata)
@@ -287,6 +290,7 @@ static void internal_snd_cb(int status,
 
 static void internal_snd_buf_cb(int status,
                                 orte_rmcast_channel_t channel,
+                                orte_rmcast_seq_t seq_num,
                                 orte_rmcast_tag_t tag,
                                 orte_process_name_t *sender,
                                 opal_buffer_t *buf, void *cbdata)
@@ -444,14 +448,14 @@ static int queue_xmit(rmcast_base_send_t *snd,
     if (NULL != snd->buf) {
         /* call the cbfunc if required */
         if (NULL != snd->cbfunc_buffer) {
-            snd->cbfunc_buffer(rc, channel, snd->tag,
+            snd->cbfunc_buffer(rc, channel, ch->seq_num, snd->tag,
                                ORTE_PROC_MY_NAME,
                                snd->buf, snd->cbdata);
         }
     } else {
         /* call the cbfunc if required */
         if (NULL != snd->cbfunc_iovec) {
-            snd->cbfunc_iovec(rc, channel, snd->tag,
+            snd->cbfunc_iovec(rc, channel, ch->seq_num, snd->tag,
                               ORTE_PROC_MY_NAME,
                               snd->iovec_array, snd->iovec_count, snd->cbdata);
         }
@@ -577,9 +581,10 @@ static int tcp_send_buffer_nb(orte_rmcast_channel_t channel,
 }
 
 static int tcp_recv(orte_process_name_t *name,
-                      orte_rmcast_channel_t channel,
-                      orte_rmcast_tag_t tag,
-                      struct iovec **msg, int *count)
+                    orte_rmcast_channel_t channel,
+                    orte_rmcast_tag_t tag,
+                    orte_rmcast_seq_t *seq_num,
+                    struct iovec **msg, int *count)
 {
     rmcast_base_recv_t *recvptr;
     int ret;
@@ -608,6 +613,7 @@ static int tcp_recv(orte_process_name_t *name,
         name->jobid = recvptr->name.jobid;
         name->vpid = recvptr->name.vpid;
     }
+    *seq_num = recvptr->seq_num;
     *msg = recvptr->iovec_array;
     *count = recvptr->iovec_count;
     
@@ -655,6 +661,7 @@ static int tcp_recv_nb(orte_rmcast_channel_t channel,
 static int tcp_recv_buffer(orte_process_name_t *name,
                            orte_rmcast_channel_t channel,
                            orte_rmcast_tag_t tag,
+                           orte_rmcast_seq_t *seq_num,
                            opal_buffer_t *buf)
 {
     rmcast_base_recv_t *recvptr;
@@ -688,6 +695,7 @@ static int tcp_recv_buffer(orte_process_name_t *name,
         name->jobid = recvptr->name.jobid;
         name->vpid = recvptr->name.vpid;
     }
+    *seq_num = recvptr->seq_num;
     if (ORTE_SUCCESS != (ret = opal_dss.copy_payload(buf, recvptr->buf))) {
         ORTE_ERROR_LOG(ret);
     }
diff --git a/orte/mca/rmcast/udp/rmcast_udp.c b/orte/mca/rmcast/udp/rmcast_udp.c
index 8079a1d9ab..9bc09ccf8e 100644
--- a/orte/mca/rmcast/udp/rmcast_udp.c
+++ b/orte/mca/rmcast/udp/rmcast_udp.c
@@ -78,6 +78,7 @@ static int udp_send_nb(orte_rmcast_channel_t channel,
 static int udp_recv_buffer(orte_process_name_t *sender,
                              orte_rmcast_channel_t channel,
                              orte_rmcast_tag_t tag,
+                           orte_rmcast_seq_t *seq_num,
                              opal_buffer_t *buf);
 
 static int udp_recv_buffer_nb(orte_rmcast_channel_t channel,
@@ -89,6 +90,7 @@ static int udp_recv_buffer_nb(orte_rmcast_channel_t channel,
 static int udp_recv(orte_process_name_t *sender,
                       orte_rmcast_channel_t channel,
                       orte_rmcast_tag_t tag,
+                    orte_rmcast_seq_t *seq_num,
                       struct iovec **msg, int *count);
 
 static int udp_recv_nb(orte_rmcast_channel_t channel,
@@ -249,6 +251,7 @@ static void finalize(void)
 /* internal blocking send support */
 static void internal_snd_cb(int status,
                             orte_rmcast_channel_t channel,
+                            orte_rmcast_seq_t seq_num,
                             orte_rmcast_tag_t tag,
                             orte_process_name_t *sender,
                             struct iovec *msg, int count, void *cbdata)
@@ -258,6 +261,7 @@ static void internal_snd_cb(int status,
 
 static void internal_snd_buf_cb(int status,
                                 orte_rmcast_channel_t channel,
+                                orte_rmcast_seq_t seq_num,
                                 orte_rmcast_tag_t tag,
                                 orte_process_name_t *sender,
                                 opal_buffer_t *buf, void *cbdata)
@@ -432,6 +436,7 @@ static int udp_send_buffer_nb(orte_rmcast_channel_t channel,
 static int udp_recv(orte_process_name_t *name,
                     orte_rmcast_channel_t channel,
                     orte_rmcast_tag_t tag,
+                    orte_rmcast_seq_t *seq_num,
                     struct iovec **msg, int *count)
 {
     rmcast_base_recv_t *recvptr;
@@ -461,6 +466,7 @@ static int udp_recv(orte_process_name_t *name,
         name->jobid = recvptr->name.jobid;
         name->vpid = recvptr->name.vpid;
     }
+    *seq_num = recvptr->seq_num;
     *msg = recvptr->iovec_array;
     *count = recvptr->iovec_count;
     
@@ -507,6 +513,7 @@ static int udp_recv_nb(orte_rmcast_channel_t channel,
 static int udp_recv_buffer(orte_process_name_t *name,
                              orte_rmcast_channel_t channel,
                              orte_rmcast_tag_t tag,
+                           orte_rmcast_seq_t *seq_num,
                              opal_buffer_t *buf)
 {
     rmcast_base_recv_t *recvptr;
@@ -540,6 +547,7 @@ static int udp_recv_buffer(orte_process_name_t *name,
         name->jobid = recvptr->name.jobid;
         name->vpid = recvptr->name.vpid;
     }
+    *seq_num = recvptr->seq_num;
     if (ORTE_SUCCESS != (ret = opal_dss.copy_payload(buf, recvptr->buf))) {
         ORTE_ERROR_LOG(ret);
     }
@@ -1005,13 +1013,13 @@ static int xmit_data(rmcast_base_channel_t *chan, rmcast_base_send_t *snd)
         if (NULL != snd->buf) {
             /* call the cbfunc if required */
             if (NULL != snd->cbfunc_buffer) {
-                snd->cbfunc_buffer(rc, chan->channel, snd->tag,
+                snd->cbfunc_buffer(rc, chan->channel, chan->seq_num, snd->tag,
                                    ORTE_PROC_MY_NAME, snd->buf, snd->cbdata);
             }
         } else {
             /* call the cbfunc if required */
             if (NULL != snd->cbfunc_iovec) {
-                snd->cbfunc_iovec(rc, chan->channel, snd->tag, ORTE_PROC_MY_NAME,
+                snd->cbfunc_iovec(rc, chan->channel, chan->seq_num, snd->tag, ORTE_PROC_MY_NAME,
                                   snd->iovec_array, snd->iovec_count, snd->cbdata);
             }
         }
diff --git a/orte/mca/sensor/heartbeat/sensor_heartbeat.c b/orte/mca/sensor/heartbeat/sensor_heartbeat.c
index 7a4da0916a..ab8c39f86b 100644
--- a/orte/mca/sensor/heartbeat/sensor_heartbeat.c
+++ b/orte/mca/sensor/heartbeat/sensor_heartbeat.c
@@ -62,11 +62,13 @@ static void send_heartbeat(int fd, short event, void *arg);
 #if ORTE_ENABLE_MULTICAST
 static void recv_rmcast_beats(int status,
                               orte_rmcast_channel_t channel,
+                              orte_rmcast_seq_t seq_num,
                               orte_rmcast_tag_t tag,
                               orte_process_name_t *sender,
                               opal_buffer_t *buf, void* cbdata);
 static void rmcast_callback_fn(int status,
                                orte_rmcast_channel_t channel,
+                               orte_rmcast_seq_t seq_num,
                                orte_rmcast_tag_t tag,
                                orte_process_name_t *sender,
                                opal_buffer_t *buf, void* cbdata);
@@ -305,6 +307,7 @@ static void check_heartbeat(int fd, short dummy, void *arg)
 #if ORTE_ENABLE_MULTICAST
 static void recv_rmcast_beats(int status,
                               orte_rmcast_channel_t channel,
+                              orte_rmcast_seq_t seq_num,
                               orte_rmcast_tag_t tag,
                               orte_process_name_t *sender,
                               opal_buffer_t *buf, void* cbdata)
@@ -335,6 +338,7 @@ static void recv_rmcast_beats(int status,
 
 static void rmcast_callback_fn(int status,
                                orte_rmcast_channel_t channel,
+                               orte_rmcast_seq_t seq_num,
                                orte_rmcast_tag_t tag,
                                orte_process_name_t *sender,
                                opal_buffer_t *buf, void* cbdata)
diff --git a/orte/test/system/orte_mcast.c b/orte/test/system/orte_mcast.c
index 2448b66b26..17f82d38dd 100644
--- a/orte/test/system/orte_mcast.c
+++ b/orte/test/system/orte_mcast.c
@@ -21,22 +21,27 @@
 
 static void cbfunc(int status,
                    orte_rmcast_channel_t channel,
+                   orte_rmcast_seq_t seq_num,
                    orte_rmcast_tag_t tag,
                    orte_process_name_t *sender,
                    opal_buffer_t *buf, void *cbdata);
 static void cbfunc_buf_snt(int status,
                            orte_rmcast_channel_t channel,
+                           orte_rmcast_seq_t seq_num,
                            orte_rmcast_tag_t tag,
                            orte_process_name_t *sender,
                            opal_buffer_t *buf, void *cbdata);
 
 static void cbfunc_iovec(int status,
                          orte_rmcast_channel_t channel,
+                         orte_rmcast_seq_t seq_num,
                          orte_rmcast_tag_t tag,
                          orte_process_name_t *sender,
                          struct iovec *msg, int count, void* cbdata);
 
 static int datasize=1024;
+static orte_rmcast_seq_t recvd_seq_num=0;
+static orte_rmcast_seq_t sent_seq_num=0;
 
 static void send_data(int fd, short flags, void *arg)
 {
@@ -58,7 +63,8 @@ static void send_data(int fd, short flags, void *arg)
                                                          cbfunc_buf_snt, NULL))) {
         ORTE_ERROR_LOG(rc);
         return;
-    }        
+    }
+    sent_seq_num++;
     /* create an iovec array */
     for (i=0; i < 3; i++) {
         iovec_array[i].iov_base = (uint8_t*)malloc(datasize);
@@ -71,10 +77,16 @@ static void send_data(int fd, short flags, void *arg)
         ORTE_ERROR_LOG(rc);
         return;
     }
+    sent_seq_num++;
+
+    if (0 == (sent_seq_num % 100)) {
+        opal_output(0, "SENT SEQ_NUM %lu", sent_seq_num);
+    }
+
     /* reset the timer */
-    now.tv_sec = 5;
-    now.tv_usec = 0;
-    opal_evtimer_add(tmp, &now);
+    now.tv_sec = 0;
+    now.tv_usec = 1000;
+    opal_event_evtimer_add(tmp, &now);
 }
 
 int main(int argc, char* argv[])
@@ -107,7 +119,7 @@ int main(int argc, char* argv[])
         orte_grpcomm.barrier();
 
         /* wake up every 5 seconds and send something */
-        ORTE_TIMER_EVENT(5, 0, send_data);
+        ORTE_TIMER_EVENT(0, 1000, send_data);
     } else {
         /* setup to recv data on our channel */
         if (ORTE_SUCCESS != (rc = orte_rmcast.recv_buffer_nb(ORTE_RMCAST_GROUP_OUTPUT_CHANNEL,
@@ -133,6 +145,7 @@ blast:
 
 static void cbfunc(int status,
                    orte_rmcast_channel_t channel,
+                   orte_rmcast_seq_t seq_num,
                    orte_rmcast_tag_t tag,
                    orte_process_name_t *sender,
                    opal_buffer_t *buffer, void *cbdata)
@@ -143,32 +156,46 @@ static void cbfunc(int status,
     rc = 1;
     opal_dss.unpack(buffer, &i32, &rc, OPAL_INT32);
 
-    opal_output(0, "%s GOT BUFFER MESSAGE from %s on channel %d tag %d with value %d\n",
-            ORTE_NAME_PRINT(ORTE_PROC_MY_NAME),
-            ORTE_NAME_PRINT(sender), channel, tag, i32);
+    if (0 < recvd_seq_num) {
+        if ((seq_num - recvd_seq_num) != 1) {
+            opal_output(0, "%s MESSAGE LOST seq %lu recvd_seq %lu",
+                        ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), seq_num, recvd_seq_num);
+        }
+    }
+    recvd_seq_num = seq_num;
+
+    if (0 == (recvd_seq_num % 100)) {
+        opal_output(0, "RECVD SEQ_NUM %lu", recvd_seq_num);
+    }
 
 }
 
 static void cbfunc_iovec(int status,
                          orte_rmcast_channel_t channel,
+                         orte_rmcast_seq_t seq_num,
                          orte_rmcast_tag_t tag,
                          orte_process_name_t *sender,
                          struct iovec *msg, int count, void* cbdata)
 {
-    int rc;
-    
-    opal_output(0, "%s GOT IOVEC MESSAGE from %s of %d elements on tag %d\n",
-            ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), ORTE_NAME_PRINT(sender), count, tag);
+    if (0 < recvd_seq_num) {
+        if ((seq_num - recvd_seq_num) != 1) {
+            opal_output(0, "%s MESSAGE LOST seq %lu recvd_seq %lu",
+                        ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), seq_num, recvd_seq_num);
+        }
+    }
+    recvd_seq_num = seq_num;
 
+    if (0 == (recvd_seq_num % 100)) {
+        opal_output(0, "RECVD SEQ_NUM %lu", recvd_seq_num);
+    }
 }
 
 static void cbfunc_buf_snt(int status,
                            orte_rmcast_channel_t channel,
+                           orte_rmcast_seq_t seq_num,
                            orte_rmcast_tag_t tag,
                            orte_process_name_t *sender,
                            opal_buffer_t *buf, void *cbdata)
-{
-    opal_output(0, "%s BUFFERED_NB SEND COMPLETE\n", ORTE_NAME_PRINT(ORTE_PROC_MY_NAME));
-    
+{    
     OBJ_RELEASE(buf);
 }