diff --git a/src/communicator/comm_cid.c b/src/communicator/comm_cid.c
index 8cd722ee7d..376eeb1454 100644
--- a/src/communicator/comm_cid.c
+++ b/src/communicator/comm_cid.c
@@ -68,6 +68,131 @@ static int ompi_comm_allreduce_intra_oob (int *inbuf, int* outbuf,
                                           int send_first );
 
 
+#ifdef MULTI_THREADS
+static ompi_mutex_t ompi_cid_lock;
+static volatile ompi_list_t registered_threads;
+static volatile int running_cid=-1;
+
+
+int ompi_comm_nextcid ( ompi_communicator_t* newcomm, 
+                        ompi_communicator_t* comm, 
+                        ompi_communicator_t* bridgecomm, 
+                        void* local_leader,
+                        void* remote_leader,
+                        int mode, int send_first )
+{
+
+    int nextlocal_cid;
+    int nextcid;
+    int done=0;
+    int response=0, glresponse=0;
+    int flag;
+    int start=ompi_mpi_communicators.lowest_free;
+    int i;
+    
+    ompi_comm_cid_allredfct* allredfnct;
+
+    /** 
+     * Determine which implementation of allreduce we have to use
+     * for the current scenario 
+     */
+    switch (mode) 
+        {
+        case OMPI_COMM_CID_INTRA: 
+            allredfnct=(ompi_comm_cid_allredfct*)ompi_comm_allreduce_intra;
+            break;
+        case OMPI_COMM_CID_INTER:
+            allredfnct=(ompi_comm_cid_allredfct*)ompi_comm_allreduce_inter;
+            break;
+        case OMPI_COMM_CID_INTRA_BRIDGE: 
+            allredfnct=(ompi_comm_cid_allredfct*)ompi_comm_allreduce_intra_bridge;
+            break;
+        case OMPI_COMM_CID_INTRA_OOB: 
+            allredfnct=(ompi_comm_cid_allredfct*)ompi_comm_allreduce_intra_oob;
+            break;
+        default: 
+            return MPI_UNDEFINED;
+            break;
+        }
+
+
+    /* Lock the list
+       register threads in registered_threads 
+       unlock
+    */
+
+    while (!done) {
+	/* lock 
+	   if (!lowest_cid ) {
+	     unlock;
+	     continue;
+           }
+
+           unlock;      
+	*/
+	   
+	/**
+	 * This is the real algorithm described in the doc 
+	 */
+
+	for (i=start; i<OMPI_MAX_COMM ;i++) {
+            flag=ompi_pointer_array_test_and_set_item(&ompi_mpi_communicators, i, comm);
+            if (true == flag) {
+                nextlocal_cid = i;
+                break;
+            }
+        }
+
+        (allredfnct)(&nextlocal_cid, &nextcid, 1, MPI_MAX, comm, bridgecomm,
+                     local_leader, remote_leader, send_first );
+        if (nextcid == nextlocal_cid) {
+            response = 1; /* fine with me */
+        }
+        else {
+            ompi_pointer_array_set_item(&ompi_mpi_communicators, 
+                                        nextlocal_cid, NULL);
+
+            flag = ompi_pointer_array_test_and_set_item(&ompi_mpi_communicators, 
+                                                         nextcid, comm );
+            if (true == flag) {
+                response = 1; /* works as well */
+            }
+            else {
+                response = 0; /* nope, not acceptable */
+            }
+        }
+        
+        (allredfnct)(&response, &glresponse, 1, MPI_MIN, comm, bridgecomm,
+                         local_leader, remote_leader, send_first );
+        if (1 == glresponse) {
+            done = 1;             /* we are done */
+            break;
+        }
+	else if ( 0 == glresponse ) {
+	    if ( 1 == response ) {
+		/* we could use that, but other don't agree */
+		ompi_pointer_array_set_item(&ompi_mpi_communicators, 
+					    nextcid, NULL);
+	    }
+	    start = nextcid+1; /* that's where we can start the next round */
+	}
+    }
+    
+    /* set the according values to the newcomm */
+    newcomm->c_contextid = nextcid;
+    newcomm->c_f_to_c_index = newcomm->c_contextid;
+    ompi_pointer_array_set_item (&ompi_mpi_communicators, nextcid, newcomm);
+
+    /* 
+       lock
+       unregister 
+       unlock
+    */
+    
+    return (MPI_SUCCESS);
+}
+#endif
+
 int ompi_comm_nextcid ( ompi_communicator_t* newcomm, 
                         ompi_communicator_t* comm, 
                         ompi_communicator_t* bridgecomm, 
diff --git a/src/communicator/comm_dyn.c b/src/communicator/comm_dyn.c
index 18c6ea63c6..d95b194431 100644
--- a/src/communicator/comm_dyn.c
+++ b/src/communicator/comm_dyn.c
@@ -46,7 +46,14 @@ int ompi_comm_connect_accept ( ompi_communicator_t *comm, int root,
            information of the remote process. Therefore, we have to
            exchange that.
         */
-        rport = ompi_comm_get_rport (port,send_first,group->grp_proc_pointers[rank], tag);
+	if ( OMPI_COMM_JOIN_TAG != tag ) {
+	    rport = ompi_comm_get_rport (port,send_first,
+					 group->grp_proc_pointers[rank], tag);
+	}
+	else {
+	    rport = port;
+	}
+	    
 
         /* Exchange number of processes and msg length on both sides */
 	ompi_buffer_init (&nbuf, size*sizeof(ompi_process_name_t));
diff --git a/src/communicator/communicator.h b/src/communicator/communicator.h
index f3d7eb5fa7..69dff1aa8a 100644
--- a/src/communicator/communicator.h
+++ b/src/communicator/communicator.h
@@ -39,6 +39,10 @@ extern ompi_class_t ompi_communicator_t_class;
 
 #define OMPI_COMM_SET_HIDDEN(comm) ((comm)->c_flags |= OMPI_COMM_HIDDEN)
 
+/* a special tag to recognize an MPI_Comm_join in the comm_connect_accept
+   routine. */
+#define OMPI_COMM_JOIN_TAG  32000
+
 /** 
  * Modes reqquired for accquiring the new comm-id.
  * The first (INTER/INTRA) indicates whether the