diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index a24d54f4..f7ced8f1 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -332,6 +332,10 @@ static int session_new(nghttp2_session **session_ptr,
   if(rv != 0) {
     goto fail_ob_ss_pq;
   }
+  rv = nghttp2_pq_init(&(*session_ptr)->ob_da_pq, outbound_item_compar);
+  if(rv != 0) {
+    goto fail_ob_da_pq;
+  }
 
   rv = nghttp2_hd_deflate_init(&(*session_ptr)->hd_deflater);
   if(rv != 0) {
@@ -429,6 +433,8 @@ static int session_new(nghttp2_session **session_ptr,
  fail_hd_inflater:
   nghttp2_hd_deflate_free(&(*session_ptr)->hd_deflater);
  fail_hd_deflater:
+  nghttp2_pq_free(&(*session_ptr)->ob_da_pq);
+ fail_ob_da_pq:
   nghttp2_pq_free(&(*session_ptr)->ob_ss_pq);
  fail_ob_ss_pq:
   nghttp2_pq_free(&(*session_ptr)->ob_pq);
@@ -542,6 +548,7 @@ void nghttp2_session_del(nghttp2_session *session)
 
   ob_pq_free(&session->ob_pq);
   ob_pq_free(&session->ob_ss_pq);
+  ob_pq_free(&session->ob_da_pq);
   active_outbound_item_reset(&session->aob);
   session_inbound_frame_reset(session);
   nghttp2_hd_deflate_free(&session->hd_deflater);
@@ -573,9 +580,9 @@ int nghttp2_session_reprioritize_stream
        session->roots.num_streams <= NGHTTP2_MAX_DEP_TREE_LENGTH) {
 
       rv = nghttp2_stream_dep_all_your_stream_are_belong_to_us
-        (stream, &session->ob_pq, session->last_cycle);
+        (stream, &session->ob_da_pq, session->last_cycle);
     } else {
-      rv = nghttp2_stream_dep_make_root(stream, &session->ob_pq,
+      rv = nghttp2_stream_dep_make_root(stream, &session->ob_da_pq,
                                         session->last_cycle);
     }
 
@@ -596,7 +603,7 @@ int nghttp2_session_reprioritize_stream
                    stream, stream->stream_id));
 
     nghttp2_stream_dep_remove_subtree(dep_stream);
-    nghttp2_stream_dep_make_root(dep_stream, &session->ob_pq,
+    nghttp2_stream_dep_make_root(dep_stream, &session->ob_da_pq,
                                  session->last_cycle);
   }
 
@@ -609,16 +616,16 @@ int nghttp2_session_reprioritize_stream
 
   if(root_stream->num_substreams + stream->num_substreams >
      NGHTTP2_MAX_DEP_TREE_LENGTH) {
-    rv = nghttp2_stream_dep_make_root(stream, &session->ob_pq,
+    rv = nghttp2_stream_dep_make_root(stream, &session->ob_da_pq,
                                       session->last_cycle);
   } else {
     if(pri_spec->exclusive) {
       rv = nghttp2_stream_dep_insert_subtree(dep_stream, stream,
-                                             &session->ob_pq,
+                                             &session->ob_da_pq,
                                              session->last_cycle);
     } else {
       rv = nghttp2_stream_dep_add_subtree(dep_stream, stream,
-                                          &session->ob_pq,
+                                          &session->ob_da_pq,
                                           session->last_cycle);
     }
   }
@@ -715,7 +722,7 @@ int nghttp2_session_add_frame(nghttp2_session *session,
         item->weight = stream->effective_weight;
         item->cycle = session->last_cycle;
 
-        rv = nghttp2_stream_attach_data(stream, item, &session->ob_pq,
+        rv = nghttp2_stream_attach_data(stream, item, &session->ob_da_pq,
                                         session->last_cycle);
       }
     }
@@ -823,7 +830,7 @@ nghttp2_stream* nghttp2_session_open_stream(nghttp2_session *session,
     if(pri_spec->exclusive &&
        session->roots.num_streams <= NGHTTP2_MAX_DEP_TREE_LENGTH) {
       rv = nghttp2_stream_dep_all_your_stream_are_belong_to_us
-        (stream, &session->ob_pq, session->last_cycle);
+        (stream, &session->ob_da_pq, session->last_cycle);
 
       /* Since no dpri is changed in dependency tree, the above
          function call never fail. */
@@ -879,7 +886,7 @@ int nghttp2_session_close_stream(nghttp2_session *session, int32_t stream_id,
 
     item = stream->data_item;
 
-    rv = nghttp2_stream_detach_data(stream, &session->ob_pq,
+    rv = nghttp2_stream_detach_data(stream, &session->ob_da_pq,
                                     session->last_cycle);
 
     if(rv != 0) {
@@ -1775,7 +1782,7 @@ static int session_prep_frame(nghttp2_session *session,
       int rv2;
 
       if(stream) {
-        rv2 = nghttp2_stream_detach_data(stream, &session->ob_pq,
+        rv2 = nghttp2_stream_detach_data(stream, &session->ob_da_pq,
                                          session->last_cycle);
 
         if(nghttp2_is_fatal(rv2)) {
@@ -1790,9 +1797,14 @@ static int session_prep_frame(nghttp2_session *session,
     next_readmax = nghttp2_session_next_data_read(session, stream);
 
     if(next_readmax == 0) {
-      rv = nghttp2_stream_defer_data(stream,
-                                     NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL,
-                                     &session->ob_pq, session->last_cycle);
+
+      /* This must be true since we only pop DATA frame item from
+         queue when session->remote_window_size > 0 */
+      assert(session->remote_window_size > 0);
+
+      rv = nghttp2_stream_defer_data
+        (stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL,
+         &session->ob_da_pq, session->last_cycle);
 
       if(nghttp2_is_fatal(rv)) {
         return rv;
@@ -1808,7 +1820,7 @@ static int session_prep_frame(nghttp2_session *session,
                                         data_frame);
     if(framerv == NGHTTP2_ERR_DEFERRED) {
       rv = nghttp2_stream_defer_data(stream, NGHTTP2_STREAM_FLAG_DEFERRED_USER,
-                                     &session->ob_pq, session->last_cycle);
+                                     &session->ob_da_pq, session->last_cycle);
 
       if(nghttp2_is_fatal(rv)) {
         return rv;
@@ -1819,7 +1831,7 @@ static int session_prep_frame(nghttp2_session *session,
       return NGHTTP2_ERR_DEFERRED;
     }
     if(framerv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
-      rv = nghttp2_stream_detach_data(stream, &session->ob_pq,
+      rv = nghttp2_stream_detach_data(stream, &session->ob_da_pq,
                                       session->last_cycle);
 
       if(nghttp2_is_fatal(rv)) {
@@ -1834,7 +1846,7 @@ static int session_prep_frame(nghttp2_session *session,
       return framerv;
     }
     if(framerv < 0) {
-      rv = nghttp2_stream_detach_data(stream, &session->ob_pq,
+      rv = nghttp2_stream_detach_data(stream, &session->ob_da_pq,
                                       session->last_cycle);
 
       if(nghttp2_is_fatal(rv)) {
@@ -1851,6 +1863,7 @@ static int session_prep_frame(nghttp2_session *session,
   }
 }
 
+/* Used only for tests */
 nghttp2_outbound_item* nghttp2_session_get_ob_pq_top
 (nghttp2_session *session)
 {
@@ -1860,89 +1873,121 @@ nghttp2_outbound_item* nghttp2_session_get_ob_pq_top
 nghttp2_outbound_item* nghttp2_session_get_next_ob_item
 (nghttp2_session *session)
 {
+  nghttp2_outbound_item *item, *headers_item;
+
   if(nghttp2_pq_empty(&session->ob_pq)) {
     if(nghttp2_pq_empty(&session->ob_ss_pq)) {
-      return NULL;
-    } else {
-      /* Return item only when concurrent connection limit is not
-         reached */
-      if(session_is_outgoing_concurrent_streams_max(session)) {
+      if(session->remote_window_size == 0 ||
+         nghttp2_pq_empty(&session->ob_da_pq)) {
         return NULL;
-      } else {
-        return nghttp2_pq_top(&session->ob_ss_pq);
       }
+
+      return nghttp2_pq_top(&session->ob_da_pq);
     }
-  } else {
-    if(nghttp2_pq_empty(&session->ob_ss_pq)) {
-      return nghttp2_pq_top(&session->ob_pq);
-    } else {
-      nghttp2_outbound_item *item, *headers_item;
-      item = nghttp2_pq_top(&session->ob_pq);
-      headers_item = nghttp2_pq_top(&session->ob_ss_pq);
-      if(session_is_outgoing_concurrent_streams_max(session) ||
-         item->weight > headers_item->weight ||
-         (item->weight == headers_item->weight &&
-          item->seq < headers_item->seq)) {
-        return item;
-      } else {
-        return headers_item;
+
+    /* Return item only when concurrent connection limit is not
+       reached */
+    if(session_is_outgoing_concurrent_streams_max(session)) {
+      if(session->remote_window_size == 0 ||
+         nghttp2_pq_empty(&session->ob_da_pq)) {
+        return NULL;
       }
+
+      return nghttp2_pq_top(&session->ob_da_pq);
     }
+
+    return nghttp2_pq_top(&session->ob_ss_pq);
   }
+
+  if(nghttp2_pq_empty(&session->ob_ss_pq)) {
+    return nghttp2_pq_top(&session->ob_pq);
+  }
+
+  item = nghttp2_pq_top(&session->ob_pq);
+  headers_item = nghttp2_pq_top(&session->ob_ss_pq);
+
+  if(session_is_outgoing_concurrent_streams_max(session) ||
+     item->weight > headers_item->weight ||
+     (item->weight == headers_item->weight &&
+      item->seq < headers_item->seq)) {
+    return item;
+  }
+
+  return headers_item;
 }
 
 nghttp2_outbound_item* nghttp2_session_pop_next_ob_item
 (nghttp2_session *session)
 {
+  nghttp2_outbound_item *item, *headers_item;
+
   if(nghttp2_pq_empty(&session->ob_pq)) {
     if(nghttp2_pq_empty(&session->ob_ss_pq)) {
-      return NULL;
-    } else {
-      /* Pop item only when concurrent connection limit is not
-         reached */
-      if(session_is_outgoing_concurrent_streams_max(session)) {
+      if(session->remote_window_size == 0 ||
+         nghttp2_pq_empty(&session->ob_da_pq)) {
         return NULL;
-      } else {
-        nghttp2_outbound_item *item;
-        item = nghttp2_pq_top(&session->ob_ss_pq);
-        nghttp2_pq_pop(&session->ob_ss_pq);
-
-        item->queued = 0;
-
-        return item;
       }
-    }
-  } else {
-    if(nghttp2_pq_empty(&session->ob_ss_pq)) {
-      nghttp2_outbound_item *item;
-      item = nghttp2_pq_top(&session->ob_pq);
-      nghttp2_pq_pop(&session->ob_pq);
+
+      item = nghttp2_pq_top(&session->ob_da_pq);
+      nghttp2_pq_pop(&session->ob_da_pq);
 
       item->queued = 0;
 
       return item;
-    } else {
-      nghttp2_outbound_item *item, *headers_item;
-      item = nghttp2_pq_top(&session->ob_pq);
-      headers_item = nghttp2_pq_top(&session->ob_ss_pq);
-      if(session_is_outgoing_concurrent_streams_max(session) ||
-         item->weight > headers_item->weight ||
-         (item->weight == headers_item->weight &&
-          item->seq < headers_item->seq)) {
-        nghttp2_pq_pop(&session->ob_pq);
-
-        item->queued = 0;
-
-        return item;
-      } else {
-        nghttp2_pq_pop(&session->ob_ss_pq);
-
-        headers_item->queued = 0;
-
-        return headers_item;
-      }
     }
+
+    /* Pop item only when concurrent connection limit is not
+       reached */
+    if(session_is_outgoing_concurrent_streams_max(session)) {
+      if(session->remote_window_size == 0 ||
+         nghttp2_pq_empty(&session->ob_da_pq)) {
+        return NULL;
+      }
+
+      item = nghttp2_pq_top(&session->ob_da_pq);
+      nghttp2_pq_pop(&session->ob_da_pq);
+
+      item->queued = 0;
+
+      return item;
+    }
+
+    item = nghttp2_pq_top(&session->ob_ss_pq);
+    nghttp2_pq_pop(&session->ob_ss_pq);
+
+    item->queued = 0;
+
+    return item;
   }
+
+  if(nghttp2_pq_empty(&session->ob_ss_pq)) {
+    item = nghttp2_pq_top(&session->ob_pq);
+    nghttp2_pq_pop(&session->ob_pq);
+
+    item->queued = 0;
+
+    return item;
+  }
+
+  item = nghttp2_pq_top(&session->ob_pq);
+  headers_item = nghttp2_pq_top(&session->ob_ss_pq);
+
+  if(session_is_outgoing_concurrent_streams_max(session) ||
+     item->weight > headers_item->weight ||
+     (item->weight == headers_item->weight &&
+      item->seq < headers_item->seq)) {
+    nghttp2_pq_pop(&session->ob_pq);
+
+    item->queued = 0;
+
+    return item;
+  }
+
+  nghttp2_pq_pop(&session->ob_ss_pq);
+
+  headers_item->queued = 0;
+
+  return headers_item;
 }
 
 static int session_call_before_frame_send(nghttp2_session *session,
@@ -2144,7 +2189,7 @@ static int session_after_frame_sent(nghttp2_session *session)
     }
 
     if(stream && data_frame->eof) {
-      rv = nghttp2_stream_detach_data(stream, &session->ob_pq,
+      rv = nghttp2_stream_detach_data(stream, &session->ob_da_pq,
                                       session->last_cycle);
 
       if(nghttp2_is_fatal(rv)) {
@@ -2205,7 +2250,7 @@ static int session_after_frame_sent(nghttp2_session *session)
     if(nghttp2_session_predicate_data_send(session,
                                            data_frame->hd.stream_id) != 0) {
       if(stream) {
-        rv = nghttp2_stream_detach_data(stream, &session->ob_pq,
+        rv = nghttp2_stream_detach_data(stream, &session->ob_da_pq,
                                         session->last_cycle);
 
         if(nghttp2_is_fatal(rv)) {
@@ -2235,12 +2280,28 @@ static int session_after_frame_sent(nghttp2_session *session)
       next_readmax = nghttp2_session_next_data_read(session, stream);
 
       if(next_readmax == 0) {
-        rv = nghttp2_stream_defer_data
-          (stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL, &session->ob_pq,
-           session->last_cycle);
 
-        if(nghttp2_is_fatal(rv)) {
-          return rv;
+        if(session->remote_window_size == 0 &&
+           stream->remote_window_size > 0) {
+
+          /* If DATA cannot be sent solely due to connection level
+             window size, just push item to queue again.  We never pop
+             DATA item while connection level window size is 0. */
+          rv = nghttp2_pq_push(&session->ob_da_pq, aob->item);
+
+          if(nghttp2_is_fatal(rv)) {
+            return rv;
+          }
+
+          aob->item->queued = 1;
+        } else {
+          rv = nghttp2_stream_defer_data
+            (stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL,
+             &session->ob_da_pq, session->last_cycle);
+
+          if(nghttp2_is_fatal(rv)) {
+            return rv;
+          }
         }
 
         aob->item = NULL;
@@ -2257,9 +2318,9 @@ static int session_after_frame_sent(nghttp2_session *session)
         return rv;
       }
       if(rv == NGHTTP2_ERR_DEFERRED) {
-        rv = nghttp2_stream_defer_data(stream,
-                                       NGHTTP2_STREAM_FLAG_DEFERRED_USER,
-                                       &session->ob_pq, session->last_cycle);
+        rv = nghttp2_stream_defer_data
+          (stream, NGHTTP2_STREAM_FLAG_DEFERRED_USER,
+           &session->ob_da_pq, session->last_cycle);
 
         if(nghttp2_is_fatal(rv)) {
           return rv;
@@ -2282,7 +2343,7 @@ static int session_after_frame_sent(nghttp2_session *session)
           return rv;
         }
 
-        rv = nghttp2_stream_detach_data(stream, &session->ob_pq,
+        rv = nghttp2_stream_detach_data(stream, &session->ob_da_pq,
                                         session->last_cycle);
 
         if(nghttp2_is_fatal(rv)) {
@@ -2299,7 +2360,7 @@ static int session_after_frame_sent(nghttp2_session *session)
     }
 
     if(stream->dpri == NGHTTP2_STREAM_DPRI_TOP) {
-      rv = nghttp2_pq_push(&session->ob_pq, aob->item);
+      rv = nghttp2_pq_push(&session->ob_da_pq, aob->item);
 
       if(nghttp2_is_fatal(rv)) {
         return rv;
@@ -3218,7 +3279,7 @@ static int update_remote_initial_window_size_func
      stream->remote_window_size > 0 &&
      arg->session->remote_window_size > 0) {
 
-    rv = nghttp2_stream_resume_deferred_data(stream, &arg->session->ob_pq,
+    rv = nghttp2_stream_resume_deferred_data(stream, &arg->session->ob_da_pq,
                                              arg->session->last_cycle);
 
     if(nghttp2_is_fatal(rv)) {
@@ -3793,44 +3854,9 @@ static int session_process_altsvc_frame(nghttp2_session *session)
   return nghttp2_session_on_altsvc_received(session, frame);
 }
 
-static int push_back_deferred_data_func(nghttp2_map_entry *entry, void *ptr)
-{
-  int rv;
-  nghttp2_session *session;
-  nghttp2_stream *stream;
-
-  session = (nghttp2_session*)ptr;
-  stream = (nghttp2_stream*)entry;
-
-  /* If DATA frame is deferred due to flow control, push it back to
-     outbound queue. */
-  if(nghttp2_stream_check_deferred_by_flow_control(stream) &&
-     stream->remote_window_size > 0) {
-
-    rv = nghttp2_stream_resume_deferred_data(stream, &session->ob_pq,
-                                             session->last_cycle);
-
-    if(nghttp2_is_fatal(rv)) {
-      return rv;
-    }
-  }
-  return 0;
-}
-
-/*
- * Push back deferred DATA frames to queue if they are deferred due to
- * connection-level flow control.
- */
-static int session_push_back_deferred_data(nghttp2_session *session)
-{
-  return nghttp2_map_each(&session->streams,
-                          push_back_deferred_data_func, session);
-}
-
 static int session_on_connection_window_update_received
 (nghttp2_session *session, nghttp2_frame *frame)
 {
-  int rv;
   /* Handle connection-level flow control */
   if(frame->window_update.window_size_increment == 0 ||
      NGHTTP2_MAX_WINDOW_SIZE - frame->window_update.window_size_increment <
@@ -3839,17 +3865,7 @@ static int session_on_connection_window_update_received
       (session, frame, NGHTTP2_FLOW_CONTROL_ERROR, NULL);
   }
   session->remote_window_size += frame->window_update.window_size_increment;
-  /* To queue the DATA deferred by connection-level flow-control, we
-     have to check all streams. Bad. */
-  if(session->remote_window_size > 0) {
 
-    rv = session_push_back_deferred_data(session);
-    if(rv != 0) {
-      /* FATAL */
-      assert(rv < NGHTTP2_ERR_FATAL);
-      return rv;
-    }
-  }
   return session_call_on_frame_received(session, frame);
 }
 
@@ -3881,10 +3897,9 @@ static int session_on_stream_window_update_received
   stream->remote_window_size += frame->window_update.window_size_increment;
 
   if(stream->remote_window_size > 0 &&
-     session->remote_window_size > 0 &&
      nghttp2_stream_check_deferred_by_flow_control(stream)) {
 
-    rv = nghttp2_stream_resume_deferred_data(stream, &session->ob_pq,
+    rv = nghttp2_stream_resume_deferred_data(stream, &session->ob_da_pq,
                                              session->last_cycle);
 
     if(nghttp2_is_fatal(rv)) {
@@ -5505,6 +5520,8 @@ int nghttp2_session_want_write(nghttp2_session *session)
 
   if(session->aob.item == NULL &&
      nghttp2_pq_empty(&session->ob_pq) &&
+     (nghttp2_pq_empty(&session->ob_da_pq) ||
+      session->remote_window_size == 0) &&
      (nghttp2_pq_empty(&session->ob_ss_pq) ||
       session_is_outgoing_concurrent_streams_max(session))) {
     return 0;
@@ -5852,7 +5869,7 @@ int nghttp2_session_resume_data(nghttp2_session *session, int32_t stream_id)
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
 
-  rv = nghttp2_stream_resume_deferred_data(stream, &session->ob_pq,
+  rv = nghttp2_stream_resume_deferred_data(stream, &session->ob_da_pq,
                                            session->last_cycle);
 
   if(nghttp2_is_fatal(rv)) {
@@ -5864,7 +5881,8 @@ int nghttp2_session_resume_data(nghttp2_session *session, int32_t stream_id)
 
 size_t nghttp2_session_get_outbound_queue_size(nghttp2_session *session)
 {
-  return nghttp2_pq_size(&session->ob_pq)+nghttp2_pq_size(&session->ob_ss_pq);
+  return nghttp2_pq_size(&session->ob_pq) +
+    nghttp2_pq_size(&session->ob_ss_pq) + nghttp2_pq_size(&session->ob_da_pq);
 }
 
 int32_t nghttp2_session_get_stream_effective_recv_data_length
diff --git a/lib/nghttp2_session.h b/lib/nghttp2_session.h
index 4c6943ee..45323090 100644
--- a/lib/nghttp2_session.h
+++ b/lib/nghttp2_session.h
@@ -136,10 +136,13 @@ typedef enum {
 struct nghttp2_session {
   nghttp2_map /* <nghttp2_stream*> */ streams;
   nghttp2_stream_roots roots;
-  /* Queue for outbound frames other than stream-creating HEADERS */
+  /* Queue for outbound frames other than stream-creating HEADERS and
+     DATA */
   nghttp2_pq /* <nghttp2_outbound_item*> */ ob_pq;
   /* Queue for outbound stream-creating HEADERS frame */
   nghttp2_pq /* <nghttp2_outbound_item*> */ ob_ss_pq;
+  /* QUeue for DATA frame */
+  nghttp2_pq /* <nghttp2_outbound_item*> */ ob_da_pq;
   nghttp2_active_outbound_item aob;
   nghttp2_inbound_frame iframe;
   nghttp2_hd_deflater hd_deflater;
diff --git a/tests/nghttp2_session_test.c b/tests/nghttp2_session_test.c
index 02e327a1..83ffd9c2 100644
--- a/tests/nghttp2_session_test.c
+++ b/tests/nghttp2_session_test.c
@@ -2563,7 +2563,7 @@ void test_nghttp2_session_on_window_update_received(void)
   data_item->frame_cat = NGHTTP2_CAT_DATA;
 
   CU_ASSERT(0 == nghttp2_stream_attach_data(stream, data_item,
-                                            &session->ob_pq,
+                                            &session->ob_da_pq,
                                             session->last_cycle));
 
   nghttp2_frame_window_update_init(&frame.window_update, NGHTTP2_FLAG_NONE,
@@ -2575,7 +2575,7 @@ void test_nghttp2_session_on_window_update_received(void)
 
   CU_ASSERT(0 == nghttp2_stream_defer_data
             (stream, NGHTTP2_STREAM_FLAG_DEFERRED_FLOW_CONTROL,
-             &session->ob_pq, session->last_cycle));
+             &session->ob_da_pq, session->last_cycle));
 
   CU_ASSERT(0 == nghttp2_session_on_window_update_received(session, &frame));
   CU_ASSERT(2 == user_data.frame_recv_cb_called);
@@ -4538,7 +4538,7 @@ void test_nghttp2_session_defer_data(void)
 
   /* Resume deferred DATA */
   CU_ASSERT(0 == nghttp2_session_resume_data(session, 1));
-  item = nghttp2_session_get_ob_pq_top(session);
+  item = (nghttp2_outbound_item*)nghttp2_pq_top(&session->ob_da_pq);
   OB_DATA(item)->data_prd.read_callback =
     fixed_length_data_source_read_callback;
   ud.block_count = 1;
@@ -4556,7 +4556,7 @@ void test_nghttp2_session_defer_data(void)
 
   /* Resume deferred DATA */
   CU_ASSERT(0 == nghttp2_session_resume_data(session, 1));
-  item = nghttp2_session_get_ob_pq_top(session);
+  item = (nghttp2_outbound_item*)nghttp2_pq_top(&session->ob_da_pq);
   OB_DATA(item)->data_prd.read_callback =
     fixed_length_data_source_read_callback;
   ud.block_count = 1;
@@ -5579,7 +5579,8 @@ void test_nghttp2_session_stream_dep_add_subtree(void)
    *    d
    */
 
-  nghttp2_stream_dep_add_subtree(a, e, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_add_subtree(a, e, &session->ob_da_pq,
+                                 session->last_cycle);
 
   /* becomes
    * a
@@ -5630,7 +5631,8 @@ void test_nghttp2_session_stream_dep_add_subtree(void)
    *    d
    */
 
-  nghttp2_stream_dep_insert_subtree(a, e, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_insert_subtree(a, e, &session->ob_da_pq,
+                                    session->last_cycle);
 
   /* becomes
    * a
@@ -5823,7 +5825,7 @@ void test_nghttp2_session_stream_dep_all_your_stream_are_belong_to_us(void)
 
   nghttp2_stream_dep_remove_subtree(c);
   CU_ASSERT(0 == nghttp2_stream_dep_all_your_stream_are_belong_to_us
-            (c, &session->ob_pq, session->last_cycle));
+            (c, &session->ob_da_pq, session->last_cycle));
 
   /*
    * c
@@ -5861,7 +5863,7 @@ void test_nghttp2_session_stream_dep_all_your_stream_are_belong_to_us(void)
 
   nghttp2_stream_dep_remove_subtree(c);
   CU_ASSERT(0 == nghttp2_stream_dep_all_your_stream_are_belong_to_us
-            (c, &session->ob_pq, session->last_cycle));
+            (c, &session->ob_da_pq, session->last_cycle));
 
   /*
    * c
@@ -5898,7 +5900,7 @@ void test_nghttp2_session_stream_dep_all_your_stream_are_belong_to_us(void)
 
   nghttp2_stream_dep_remove_subtree(c);
   CU_ASSERT(0 == nghttp2_stream_dep_all_your_stream_are_belong_to_us
-            (c, &session->ob_pq, session->last_cycle));
+            (c, &session->ob_da_pq, session->last_cycle));
 
   /*
    * c
@@ -5951,7 +5953,7 @@ void test_nghttp2_session_stream_attach_data(void)
 
   db = create_data_ob_item();
 
-  nghttp2_stream_attach_data(b, db, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_attach_data(b, db, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
@@ -5966,7 +5968,7 @@ void test_nghttp2_session_stream_attach_data(void)
 
   dc = create_data_ob_item();
 
-  nghttp2_stream_attach_data(c, dc, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_attach_data(c, dc, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
@@ -5982,7 +5984,7 @@ void test_nghttp2_session_stream_attach_data(void)
 
   da = create_data_ob_item();
 
-  nghttp2_stream_attach_data(a, da, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_attach_data(a, da, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_REST == b->dpri);
@@ -5993,7 +5995,7 @@ void test_nghttp2_session_stream_attach_data(void)
 
   CU_ASSERT(1 == da->queued);
 
-  nghttp2_stream_detach_data(a, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_detach_data(a, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
@@ -6005,7 +6007,7 @@ void test_nghttp2_session_stream_attach_data(void)
 
   dd = create_data_ob_item();
 
-  nghttp2_stream_attach_data(d, dd, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_attach_data(d, dd, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
@@ -6017,7 +6019,7 @@ void test_nghttp2_session_stream_attach_data(void)
 
   CU_ASSERT(0 == dd->queued);
 
-  nghttp2_stream_detach_data(c, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_detach_data(c, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
@@ -6060,11 +6062,11 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   de = create_data_ob_item();
 
-  nghttp2_stream_attach_data(e, de, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_attach_data(e, de, &session->ob_da_pq, session->last_cycle);
 
   db = create_data_ob_item();
 
-  nghttp2_stream_attach_data(b, db, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_attach_data(b, db, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
@@ -6079,7 +6081,8 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
   /* Insert subtree e under a */
 
   nghttp2_stream_dep_remove_subtree(e);
-  nghttp2_stream_dep_insert_subtree(a, e, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_insert_subtree(a, e, &session->ob_da_pq,
+                                    session->last_cycle);
 
   /*
    * a
@@ -6104,7 +6107,7 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   nghttp2_stream_dep_remove_subtree(b);
 
-  nghttp2_stream_dep_make_root(b, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_make_root(b, &session->ob_da_pq, session->last_cycle);
 
   /*
    * a       b
@@ -6130,7 +6133,7 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   nghttp2_stream_dep_remove_subtree(a);
 
-  nghttp2_stream_dep_make_root(a, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_make_root(a, &session->ob_da_pq, session->last_cycle);
 
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
@@ -6143,7 +6146,7 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   nghttp2_stream_dep_remove_subtree(c);
 
-  nghttp2_stream_dep_make_root(c, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_make_root(c, &session->ob_da_pq, session->last_cycle);
 
   /*
    * a       b     c
@@ -6162,12 +6165,13 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   dd = create_data_ob_item();
 
-  nghttp2_stream_attach_data(d, dd, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_attach_data(d, dd, &session->ob_da_pq, session->last_cycle);
 
   /* Add subtree c to a */
 
   nghttp2_stream_dep_remove_subtree(c);
-  nghttp2_stream_dep_add_subtree(a, c, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_add_subtree(a, c, &session->ob_da_pq,
+                                 session->last_cycle);
 
   /*
    * a       b
@@ -6194,7 +6198,8 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
   /* Insert b under a */
 
   nghttp2_stream_dep_remove_subtree(b);
-  nghttp2_stream_dep_insert_subtree(a, b, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_insert_subtree(a, b, &session->ob_da_pq,
+                                    session->last_cycle);
 
   /*
    * a
@@ -6221,7 +6226,7 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
   /* Remove subtree b */
 
   nghttp2_stream_dep_remove_subtree(b);
-  nghttp2_stream_dep_make_root(b, &session->ob_pq, session->last_cycle);
+  nghttp2_stream_dep_make_root(b, &session->ob_da_pq, session->last_cycle);
 
   /*
    * b       a