diff --git a/src/class/ompi_list.c b/src/class/ompi_list.c
index fd54b40680..6ff760a7a5 100644
--- a/src/class/ompi_list.c
+++ b/src/class/ompi_list.c
@@ -38,7 +38,6 @@ OBJ_CLASS_INSTANCE(
 static void ompi_list_item_construct(ompi_list_item_t *item)
 {
     item->ompi_list_next = item->ompi_list_prev = NULL;
-    item->ompi_list_type = 0;
 }
 
 static void ompi_list_item_destruct(ompi_list_item_t *item)
@@ -58,7 +57,6 @@ static void ompi_list_construct(ompi_list_t *list)
     list->ompi_list_head.ompi_list_next = &list->ompi_list_tail;
     list->ompi_list_tail.ompi_list_prev = &list->ompi_list_head;
     list->ompi_list_tail.ompi_list_next = NULL;
-    list->ompi_list_type = 0;
     list->ompi_list_length = 0;
 }
 
diff --git a/src/class/ompi_list.h b/src/class/ompi_list.h
index 0fc11d3a2d..0d0a4e6914 100644
--- a/src/class/ompi_list.h
+++ b/src/class/ompi_list.h
@@ -16,7 +16,6 @@
 
 extern ompi_class_t   ompi_list_item_t_class;
 extern ompi_class_t   ompi_list_t_class;
-typedef int               ompi_list_type_t;
 
 
 /*
@@ -28,7 +27,6 @@ typedef int               ompi_list_type_t;
 typedef struct ompi_list_item
 {
     ompi_object_t            super;
-    ompi_list_type_t         ompi_list_type;
     volatile struct ompi_list_item   *ompi_list_next;
     volatile struct ompi_list_item   *ompi_list_prev;
 } ompi_list_item_t;
@@ -48,10 +46,9 @@ typedef struct ompi_list_item
  
 typedef struct ompi_list
 {
-    ompi_object_t        super;
-    ompi_list_item_t     ompi_list_head;
-    ompi_list_item_t     ompi_list_tail;
-    ompi_list_type_t     ompi_list_type;
+    ompi_object_t       super;
+    ompi_list_item_t    ompi_list_head;
+    ompi_list_item_t    ompi_list_tail;
     volatile size_t     ompi_list_length;
 } ompi_list_t;
 
@@ -60,16 +57,6 @@ typedef struct ompi_list
  * Inlined accessor functions
  */
 
-static inline ompi_list_type_t ompi_list_get_type(ompi_list_t* list)
-{
-    return list->ompi_list_type;
-}
-
-static inline void ompi_list_set_type(ompi_list_t* list, ompi_list_type_t type)
-{
-    list->ompi_list_type = type;
-}
-
 static inline size_t ompi_list_get_size(ompi_list_t* list)
 {
     return list->ompi_list_length;
diff --git a/src/mca/pml/base/pml_base_request.h b/src/mca/pml/base/pml_base_request.h
index 4cf22072da..0f3943614d 100644
--- a/src/mca/pml/base/pml_base_request.h
+++ b/src/mca/pml/base/pml_base_request.h
@@ -21,7 +21,9 @@ extern ompi_class_t mca_pml_base_request_t_class;
 typedef enum {
     MCA_PML_REQUEST_NULL,
     MCA_PML_REQUEST_SEND,
-    MCA_PML_REQUEST_RECV
+    MCA_PML_REQUEST_RECV,
+    MCA_PML_REQUEST_IPROBE,
+    MCA_PML_REQUEST_PROBE
 } mca_pml_base_request_type_t;
 
 
diff --git a/src/mca/pml/pml.h b/src/mca/pml/pml.h
index c049bdd74c..424ed2f28f 100644
--- a/src/mca/pml/pml.h
+++ b/src/mca/pml/pml.h
@@ -434,6 +434,66 @@ typedef int (*mca_pml_base_wait_all_fn_t)(
 );
 
 
+/**
+ * Probe to poll for pending recv.
+ *
+ * @param src (IN)        Source rank w/in communicator.
+ * @param tag (IN)        User defined tag.
+ * @param comm (IN)       Communicator.
+ * @param matched (OUT)   Flag indicating if matching recv exists.
+ * @param status (OUT)    Completion statuses.
+ * @return                OMPI_SUCCESS or failure status.
+ *
+ */
+typedef int (*mca_pml_base_iprobe_fn_t)(
+    int src,
+    int tag,
+    ompi_communicator_t* comm,
+    int *matched,
+    ompi_status_public_t *status
+);
+
+/**
+ * Blocking probe to wait for pending recv.
+ *
+ * @param src (IN)        Source rank w/in communicator.
+ * @param tag (IN)        User defined tag.
+ * @param comm (IN)       Communicator.
+ * @param status (OUT)    Completion statuses.
+ * @return                OMPI_SUCCESS or failure status.
+ *
+ */
+typedef int (*mca_pml_base_probe_fn_t)(
+    int src,
+    int tag,
+    ompi_communicator_t* comm,
+    ompi_status_public_t *status
+);
+
+/**
+ * Cancel pending operation.
+ * 
+ * @param request (IN)    Request
+ * @return                OMPI_SUCCESS or failure status.
+ *
+ */
+typedef int (*mca_pml_base_cancel_fn_t)(
+    ompi_request_t* request
+);
+
+
+/**
+ * Has a request been cancelled?
+ * 
+ * @param request (IN)    Request
+ * @return                OMPI_SUCCESS or failure status.
+ *
+ */
+typedef int (*mca_pml_base_cancelled_fn_t)(
+    ompi_request_t* request,
+    int *flag
+);
+
 /**
  * Release resources held by a persistent mode request.
  *
@@ -485,6 +545,10 @@ struct mca_pml_1_0_0_t {
     mca_pml_base_test_all_fn_t     pml_test_all;
     mca_pml_base_wait_fn_t         pml_wait;
     mca_pml_base_wait_all_fn_t     pml_wait_all;
+    mca_pml_base_iprobe_fn_t       pml_iprobe;
+    mca_pml_base_probe_fn_t        pml_probe;
+    mca_pml_base_cancel_fn_t       pml_cancel;
+    mca_pml_base_cancelled_fn_t    pml_cancelled;
     mca_pml_base_free_fn_t         pml_free;
     mca_pml_base_null_fn_t         pml_null;
 };
diff --git a/src/mca/pml/teg/src/Makefile.am b/src/mca/pml/teg/src/Makefile.am
index c757edd30b..3702aa0883 100644
--- a/src/mca/pml/teg/src/Makefile.am
+++ b/src/mca/pml/teg/src/Makefile.am
@@ -14,7 +14,9 @@ noinst_LTLIBRARIES = libmca_pml_teg.la
 libmca_pml_teg_la_SOURCES = \
 	pml_teg.c \
 	pml_teg.h \
+	pml_teg_cancel.c \
 	pml_teg_free.c \
+	pml_teg_iprobe.c \
 	pml_teg_irecv.c \
 	pml_teg_isend.c \
 	pml_teg_module.c \
diff --git a/src/mca/pml/teg/src/pml_teg.c b/src/mca/pml/teg/src/pml_teg.c
index c34dffe8e2..7620772feb 100644
--- a/src/mca/pml/teg/src/pml_teg.c
+++ b/src/mca/pml/teg/src/pml_teg.c
@@ -37,6 +37,10 @@ mca_pml_teg_t mca_pml_teg = {
     mca_pml_teg_test_all,
     mca_pml_teg_wait,
     mca_pml_teg_wait_all,
+    mca_pml_teg_iprobe,
+    mca_pml_teg_probe,
+    mca_pml_teg_cancel,
+    mca_pml_teg_cancelled,
     mca_pml_teg_free,
     mca_pml_teg_null
     }
diff --git a/src/mca/pml/teg/src/pml_teg.h b/src/mca/pml/teg/src/pml_teg.h
index b7ae721c2d..10eb1193fc 100644
--- a/src/mca/pml/teg/src/pml_teg.h
+++ b/src/mca/pml/teg/src/pml_teg.h
@@ -119,6 +119,31 @@ extern int mca_pml_teg_control(
 
 extern int mca_pml_teg_progress(void);
 
+extern int mca_pml_teg_iprobe(
+    int dst,
+    int tag,
+    struct ompi_communicator_t* comm,
+    int *matched,
+    ompi_status_public_t* status
+);
+
+extern int mca_pml_teg_probe(
+    int dst,
+    int tag,
+    struct ompi_communicator_t* comm,
+    ompi_status_public_t* status
+);
+
+extern int mca_pml_teg_cancel(
+    ompi_request_t* request
+);
+
+extern int mca_pml_teg_cancelled(
+    ompi_request_t* request,
+    int *flag
+);
+
+
 extern int mca_pml_teg_isend_init(
     void *buf,
     size_t count,
diff --git a/src/mca/pml/teg/src/pml_teg_cancel.c b/src/mca/pml/teg/src/pml_teg_cancel.c
new file mode 100644
index 0000000000..55b0f32a35
--- /dev/null
+++ b/src/mca/pml/teg/src/pml_teg_cancel.c
@@ -0,0 +1,15 @@
+#include "pml_teg.h"
+
+
+int mca_pml_teg_cancel(ompi_request_t* request)
+{
+    return OMPI_SUCCESS;
+}
+
+int mca_pml_teg_cancelled(ompi_request_t* request, int* flag)
+{
+    if(NULL != flag)
+        *flag = 0;
+    return OMPI_SUCCESS;
+}
+
diff --git a/src/mca/pml/teg/src/pml_teg_iprobe.c b/src/mca/pml/teg/src/pml_teg_iprobe.c
new file mode 100644
index 0000000000..28e770c30c
--- /dev/null
+++ b/src/mca/pml/teg/src/pml_teg_iprobe.c
@@ -0,0 +1,87 @@
+#include "pml_teg_recvreq.h"
+
+
+int mca_pml_teg_iprobe(
+    int src,
+    int tag,
+    struct ompi_communicator_t* comm,
+    int* matched,
+    ompi_status_public_t* status)
+{
+    int rc;
+
+    mca_ptl_base_recv_request_t recvreq;
+    OBJ_CONSTRUCT(&recvreq, mca_ptl_base_recv_request_t);
+    recvreq.super.req_type = MCA_PML_REQUEST_IPROBE;
+    MCA_PTL_BASE_RECV_REQUEST_INIT(
+        &recvreq,
+        NULL,
+        0,
+        NULL,
+        src,
+        tag,
+        comm,
+        true);
+
+    if((rc = mca_pml_teg_recv_request_start(&recvreq)) != OMPI_SUCCESS) {
+        OBJ_DESTRUCT(&recvreq);
+        return rc;
+    }
+    if((*matched = recvreq.super.req_mpi_done) == true && (NULL != status)) {
+        *status = recvreq.super.req_status;
+    }
+
+    OBJ_DESTRUCT(&recvreq);
+    return OMPI_SUCCESS;
+}
+
+
+int mca_pml_teg_probe(
+    int src,
+    int tag,
+    struct ompi_communicator_t* comm,
+    ompi_status_public_t* status)
+{
+    int rc;
+    mca_ptl_base_recv_request_t recvreq;
+    OBJ_CONSTRUCT(&recvreq, mca_ptl_base_recv_request_t);
+    recvreq.super.req_type = MCA_PML_REQUEST_PROBE;
+    MCA_PTL_BASE_RECV_REQUEST_INIT(
+        &recvreq,
+        NULL,
+        0,
+        NULL,
+        src,
+        tag,
+        comm,
+        true);
+
+    if((rc = mca_pml_teg_recv_request_start(&recvreq)) != OMPI_SUCCESS) {
+        OBJ_DESTRUCT(&recvreq);
+        return rc;
+    }
+
+    if(recvreq.super.req_mpi_done == false) {
+        /* give up and sleep until completion */
+        if(ompi_using_threads()) {
+            ompi_mutex_lock(&mca_pml_teg.teg_request_lock);
+            mca_pml_teg.teg_request_waiting++;
+            while(recvreq.super.req_mpi_done == false)
+                ompi_condition_wait(&mca_pml_teg.teg_request_cond, &mca_pml_teg.teg_request_lock);
+            mca_pml_teg.teg_request_waiting--;
+            ompi_mutex_unlock(&mca_pml_teg.teg_request_lock);
+        } else {
+            mca_pml_teg.teg_request_waiting++;
+            while(recvreq.super.req_mpi_done == false)
+                ompi_condition_wait(&mca_pml_teg.teg_request_cond, &mca_pml_teg.teg_request_lock);
+            mca_pml_teg.teg_request_waiting--;
+        }
+    }
+
+    if(NULL != status) {
+        *status = recvreq.super.req_status;
+    }
+    OBJ_DESTRUCT(&recvreq);
+    return OMPI_SUCCESS;
+}
+
diff --git a/src/mca/pml/teg/src/pml_teg_sendreq.c b/src/mca/pml/teg/src/pml_teg_sendreq.c
index 92045a9ea0..7a86d818c8 100644
--- a/src/mca/pml/teg/src/pml_teg_sendreq.c
+++ b/src/mca/pml/teg/src/pml_teg_sendreq.c
@@ -48,11 +48,12 @@ void mca_pml_teg_send_request_schedule(mca_ptl_base_send_request_t* req)
          */
         else {
             bytes_to_frag = (ptl_proc->ptl_weight * bytes_remaining) / 100;
+            if(ptl->ptl_max_frag_size != 0 && bytes_to_frag > ptl->ptl_max_frag_size)
+                bytes_to_frag = ptl->ptl_max_frag_size;
         }
 
-        rc = ptl->ptl_put(ptl, ptl_proc->ptl_peer, req, req->req_offset, &bytes_to_frag, 0);
+        rc = ptl->ptl_put(ptl, ptl_proc->ptl_peer, req, req->req_offset, bytes_to_frag, 0);
         if(rc == OMPI_SUCCESS) {
-            req->req_offset += bytes_to_frag;
             bytes_remaining = req->req_bytes_packed - req->req_offset;
         }
     }
diff --git a/src/mca/pml/teg/src/pml_teg_sendreq.h b/src/mca/pml/teg/src/pml_teg_sendreq.h
index fcf5988dd4..0b8af8753e 100644
--- a/src/mca/pml/teg/src/pml_teg_sendreq.h
+++ b/src/mca/pml/teg/src/pml_teg_sendreq.h
@@ -46,7 +46,7 @@ static inline int mca_pml_teg_send_request_start(
     int flags, rc;
 
     /* start the first fragment */
-    if(first_fragment_size <= 0 || req->req_bytes_packed <= first_fragment_size) {
+    if(first_fragment_size == 0 || req->req_bytes_packed <= first_fragment_size) {
         first_fragment_size = req->req_bytes_packed;
         flags = (req->req_send_mode == MCA_PML_BASE_SEND_SYNCHRONOUS) ? 
             MCA_PTL_FLAGS_ACK_MATCHED : 0;
diff --git a/src/mca/ptl/base/ptl_base_recvfrag.h b/src/mca/ptl/base/ptl_base_recvfrag.h
index 4e81434a9f..f551b179e2 100644
--- a/src/mca/ptl/base/ptl_base_recvfrag.h
+++ b/src/mca/ptl/base/ptl_base_recvfrag.h
@@ -54,11 +54,22 @@ static inline bool mca_ptl_base_recv_frag_match(
         request->super.req_peer = header->hdr_src;
         request->super.req_tag = header->hdr_tag;
 
-        /* notify ptl of match */
-        ptl->ptl_matched(ptl, frag);
+        /*
+         * If probe - signal request is complete - but don't notify PTL
+         */
+        if(request->super.req_type == MCA_PML_REQUEST_PROBE) {
 
-        /* process any additional fragments that arrived out of order */
-        frag = (mca_ptl_base_recv_frag_t*)ompi_list_remove_first(&matched_frags);
+             ptl->ptl_recv_progress(request, frag);
+             matched = mca_ptl_base_recv_frag_match(frag, header);
+
+        } else {
+
+            /* notify ptl of match */
+            ptl->ptl_matched(ptl, frag);
+
+            /* process any additional fragments that arrived out of order */
+            frag = (mca_ptl_base_recv_frag_t*)ompi_list_remove_first(&matched_frags);
+        };
     };
     return matched;
 }
diff --git a/src/mca/ptl/base/ptl_base_recvreq.c b/src/mca/ptl/base/ptl_base_recvreq.c
index fe8b6b56e1..c9051afd04 100644
--- a/src/mca/ptl/base/ptl_base_recvreq.c
+++ b/src/mca/ptl/base/ptl_base_recvreq.c
@@ -63,7 +63,8 @@ void mca_ptl_base_recv_request_match_specific(mca_ptl_base_recv_request_t* reque
     /* We didn't find any matches.  Record this irecv so we can match 
      * it when the message comes in.
     */
-    ompi_list_append(pml_comm->c_specific_receives+req_peer, (ompi_list_item_t*)request);
+    if(request->super.req_type != MCA_PML_REQUEST_IPROBE)
+        ompi_list_append(pml_comm->c_specific_receives+req_peer, (ompi_list_item_t*)request);
     THREAD_UNLOCK(&pml_comm->c_matching_lock);
 }
 
@@ -111,7 +112,8 @@ void mca_ptl_base_recv_request_match_wild(mca_ptl_base_recv_request_t* request)
      * it when the message comes in.
     */
  
-    ompi_list_append(&pml_comm->c_wild_receives, (ompi_list_item_t*)request);
+    if(request->super.req_type != MCA_PML_REQUEST_IPROBE)
+        ompi_list_append(&pml_comm->c_wild_receives, (ompi_list_item_t*)request);
     THREAD_UNLOCK(&pml_comm->c_matching_lock);
 }
 
diff --git a/src/mca/ptl/base/ptl_base_recvreq.h b/src/mca/ptl/base/ptl_base_recvreq.h
index cacb163c18..7b4af4237f 100644
--- a/src/mca/ptl/base/ptl_base_recvreq.h
+++ b/src/mca/ptl/base/ptl_base_recvreq.h
@@ -47,21 +47,21 @@ typedef struct mca_ptl_base_recv_request_t mca_ptl_base_recv_request_t;
     comm, \
     persistent) \
 { \
-    request->req_bytes_packed = 0; \
-    request->req_bytes_received = 0; \
-    request->req_bytes_delivered = 0; \
-    request->super.req_sequence = 0; \
-    request->super.req_addr = addr; \
-    request->super.req_count = count; \
-    request->super.req_datatype = datatype; \
-    request->super.req_peer = src; \
-    request->super.req_tag = tag; \
-    request->super.req_comm = comm; \
-    request->super.req_proc = NULL; \
-    request->super.req_persistent = persistent; \
-    request->super.req_mpi_done = false; \
-    request->super.req_pml_done = false; \
-    request->super.req_free_called = false; \
+    (request)->req_bytes_packed = 0; \
+    (request)->req_bytes_received = 0; \
+    (request)->req_bytes_delivered = 0; \
+    (request)->super.req_sequence = 0; \
+    (request)->super.req_addr = addr; \
+    (request)->super.req_count = count; \
+    (request)->super.req_datatype = datatype; \
+    (request)->super.req_peer = src; \
+    (request)->super.req_tag = tag; \
+    (request)->super.req_comm = comm; \
+    (request)->super.req_proc = NULL; \
+    (request)->super.req_persistent = persistent; \
+    (request)->super.req_mpi_done = false; \
+    (request)->super.req_pml_done = false; \
+    (request)->super.req_free_called = false; \
 }
 
 /**
diff --git a/src/mpi/c/cancel.c b/src/mpi/c/cancel.c
index 6632b77b49..281a0732bc 100644
--- a/src/mpi/c/cancel.c
+++ b/src/mpi/c/cancel.c
@@ -5,8 +5,10 @@
 #include <stdio.h>
 
 #include "mpi.h"
+#include "runtime/runtime.h"
 #include "mpi/c/bindings.h"
-
+#include "mca/pml/pml.h"
+                                                                                                                               
 #if OMPI_HAVE_WEAK_SYMBOLS && OMPI_PROFILING_DEFINES
 #pragma weak MPI_Cancel = PMPI_Cancel
 #endif
@@ -15,6 +17,23 @@
 #include "mpi/c/profile/defines.h"
 #endif
 
-int MPI_Cancel(MPI_Request *request) {
-    return MPI_SUCCESS;
+int MPI_Cancel(MPI_Request *request) 
+{
+    int rc;
+    if ( MPI_PARAM_CHECK ) {
+        rc = MPI_SUCCESS;
+        if ( OMPI_MPI_INVALID_STATE ) {
+            rc = MPI_ERR_INTERN;
+        } else if (request == NULL) {
+            rc = MPI_ERR_REQUEST;
+        }
+        OMPI_ERRHANDLER_CHECK(rc, (ompi_communicator_t*)NULL, rc, "MPI_Cancel");
+    }
+                                                                                                                             
+    if (NULL == *request) {
+        return MPI_SUCCESS;
+    }
+    rc = mca_pml.pml_cancel(*request);
+    OMPI_ERRHANDLER_RETURN(rc, (ompi_communicator_t*)NULL, rc, "MPI_Cancel");
 }
+
diff --git a/src/mpi/c/iprobe.c b/src/mpi/c/iprobe.c
index da45739d5e..e24858223a 100644
--- a/src/mpi/c/iprobe.c
+++ b/src/mpi/c/iprobe.c
@@ -5,7 +5,10 @@
 #include "ompi_config.h"
 
 #include "mpi.h"
+#include "runtime/runtime.h"
 #include "mpi/c/bindings.h"
+#include "mca/pml/pml.h"
+
 
 #if OMPI_HAVE_WEAK_SYMBOLS && OMPI_PROFILING_DEFINES
 #pragma weak MPI_Iprobe = PMPI_Iprobe
@@ -15,7 +18,34 @@
 #include "mpi/c/profile/defines.h"
 #endif
 
-int MPI_Iprobe(int source, int tag, MPI_Comm comm, int *flag,
-               MPI_Status *status) {
-    return MPI_SUCCESS;
+int MPI_Iprobe(int source, int tag, MPI_Comm comm, int *flag, MPI_Status *status) 
+{
+    int rc;
+    if (source == MPI_PROC_NULL) {
+        if (status) {
+            status->MPI_SOURCE = MPI_PROC_NULL;
+            status->MPI_TAG = MPI_ANY_TAG;
+            status->MPI_ERROR = MPI_SUCCESS;
+            status->_count = 0;
+        }
+        return MPI_SUCCESS;
+    }
+                                                                                                                    
+    if ( MPI_PARAM_CHECK ) {
+        rc = MPI_SUCCESS;
+        if ( OMPI_MPI_INVALID_STATE ) {
+            rc = MPI_ERR_INTERN;
+        } else if (tag < 0 || tag > MPI_TAG_UB_VALUE) {
+            rc = MPI_ERR_TAG;
+        } else if (ompi_comm_invalid(comm)) {
+            rc = MPI_ERR_COMM;
+        } else if (source != MPI_ANY_SOURCE && ompi_comm_peer_invalid(comm, source)) {
+            rc = MPI_ERR_RANK;
+        }
+        OMPI_ERRHANDLER_CHECK(rc, comm, rc, "MPI_Iprobe");
+    }
+                                                                                                                    
+    rc = mca_pml.pml_iprobe(source, tag, comm, flag, status);
+    OMPI_ERRHANDLER_RETURN(rc, comm, rc, "MPI_Iprobe");
 }
+
diff --git a/src/mpi/c/probe.c b/src/mpi/c/probe.c
index 5aae8e7552..7847ae9c0c 100644
--- a/src/mpi/c/probe.c
+++ b/src/mpi/c/probe.c
@@ -5,7 +5,9 @@
 #include <stdio.h>
 
 #include "mpi.h"
+#include "runtime/runtime.h"
 #include "mpi/c/bindings.h"
+#include "mca/pml/pml.h"
 
 #if OMPI_HAVE_WEAK_SYMBOLS && OMPI_PROFILING_DEFINES
 #pragma weak MPI_Probe = PMPI_Probe
@@ -15,6 +17,34 @@
 #include "mpi/c/profile/defines.h"
 #endif
 
-int MPI_Probe(int source, int tag, MPI_Comm comm, MPI_Status *status) {
-    return MPI_SUCCESS;
+int MPI_Probe(int source, int tag, MPI_Comm comm, MPI_Status *status) 
+{
+    int rc;
+    if (source == MPI_PROC_NULL) {
+        if (status) {
+            status->MPI_SOURCE = MPI_PROC_NULL;
+            status->MPI_TAG = MPI_ANY_TAG;
+            status->MPI_ERROR = MPI_SUCCESS;
+            status->_count = 0;
+        }
+        return MPI_SUCCESS;
+    }
+                                                                                                                  
+    if ( MPI_PARAM_CHECK ) {
+        rc = MPI_SUCCESS;
+        if ( OMPI_MPI_INVALID_STATE ) {
+            rc = MPI_ERR_INTERN;
+        } else if (tag < 0 || tag > MPI_TAG_UB_VALUE) {
+            rc = MPI_ERR_TAG;
+        } else if (ompi_comm_invalid(comm)) {
+            rc = MPI_ERR_COMM;
+        } else if (source != MPI_ANY_SOURCE && ompi_comm_peer_invalid(comm, source)) {
+            rc = MPI_ERR_RANK;
+        }
+        OMPI_ERRHANDLER_CHECK(rc, comm, rc, "MPI_Probe");
+    }
+                                                                                                                  
+    rc = mca_pml.pml_probe(source, tag, comm, status);
+    OMPI_ERRHANDLER_RETURN(rc, comm, rc, "MPI_Probe");
 }
+
diff --git a/src/request/request.c b/src/request/request.c
index f8d759b316..cc8698e990 100644
--- a/src/request/request.c
+++ b/src/request/request.c
@@ -12,12 +12,13 @@ ompi_class_t ompi_request_t_class = {
 };
 
 
-void ompi_request_construct(ompi_request_t* rq)
-{
-}
-
-
-void ompi_request_destruct(ompi_request_t* rq)
+void ompi_request_construct(ompi_request_t* req)
+{
+    req->req_mode = OMPI_REQUEST_INVALID;
+}
+
+
+void ompi_request_destruct(ompi_request_t* req)
 {
 }
 
diff --git a/src/request/request.h b/src/request/request.h
index a58da42479..84974cf165 100644
--- a/src/request/request.h
+++ b/src/request/request.h
@@ -18,9 +18,17 @@ typedef enum {
     OMPI_REQUEST_MAX
 } ompi_request_type_t;
 
+typedef enum {
+    OMPI_REQUEST_INVALID,
+    OMPI_REQUEST_INACTIVE,
+    OMPI_REQUEST_ACTIVE,
+    OMPI_REQUEST_CANCELLED
+} ompi_request_mode_t;
+
 struct ompi_request_t {
     ompi_list_item_t super;
     ompi_request_type_t req_type;
+    ompi_request_mode_t req_mode;
 };
 typedef struct ompi_request_t ompi_request_t;