diff --git a/accton/accton_util.py b/accton/accton_util.py
new file mode 100644
index 0000000..0bc0f55
--- /dev/null
+++ b/accton/accton_util.py
@@ -0,0 +1,157 @@
+import logging
+
+from oftest import config
+import oftest.base_tests as base_tests
+import ofp
+import time
+from oftest.testutils import *
+
+OFDPA_GROUP_TYPE_SHIFT=28
+OFDPA_VLAN_ID_SHIFT   =16
+OFDPA_TUNNEL_ID_SHIFT =16
+
+#VLAN_TABLE_FLAGS
+VLAN_TABLE_FLAG_ONLY_UNTAG=1
+VLAN_TABLE_FLAG_ONLY_TAG  =2
+VLAN_TABLE_FLAG_ONLY_BOTH =3
+
+def encode_l2_interface_group_id(vlan, id):
+    return id + (vlan << OFDPA_VLAN_ID_SHIFT)
+
+def encode_l2_rewrite_group_id(id):
+    return id + (1 << OFDPA_GROUP_TYPE_SHIFT)
+
+def encode_l3_unicast_group_id(id):
+    return id + (2 << OFDPA_GROUP_TYPE_SHIFT)
+
+def encode_l2_mcast_group_id(vlan, id):
+    return id + (vlan << OFDPA_VLAN_ID_SHIFT) + (3 << OFDPA_GROUP_TYPE_SHIFT)
+
+def encode_l2_flood_group_id(vlan, id):
+    return id + (vlan << OFDPA_VLAN_ID_SHIFT) + (4 << OFDPA_GROUP_TYPE_SHIFT)
+    
+def encode_l3_interface_group_id(id):
+    return id + (5 << OFDPA_GROUP_TYPE_SHIFT)
+
+def encode_l3_mcast_group_id(vlan, id):
+    return id + (vlan << OFDPA_VLAN_ID_SHIFT)+(6 << OFDPA_GROUP_TYPE_SHIFT)
+
+def encode_l3_ecmp_group_id(id):
+    return id + (7 << OFDPA_GROUP_TYPE_SHIFT)
+
+def encode_l2_overlay_flood_group_id(tunnel_id, index):
+    return id + (tunnel_id << OFDPA_TUNNEL_ID_SHIFT)+(8 << OFDPA_GROUP_TYPE_SHIFT)
+
+def encode_l2_overlay_mcast_group_id(tunnel_id, index):
+    return id + (tunnel_id << OFDPA_TUNNEL_ID_SHIFT)+(9 << OFDPA_GROUP_TYPE_SHIFT)
+
+    
+def add_l2_interface_grouop(ctrl, ports, vlan_id=1, is_tagged=False, send_barrier=False):
+    # group table
+    # set up untag groups for each port
+    for of_port in ports:
+        # do stuff
+        group_id = encode_l2_interface_group_id(vlan_id, of_port)
+        if is_tagged:
+            actions = [
+                ofp.action.output(of_port),
+            ]        
+        else:
+            actions = [
+                ofp.action.pop_vlan(),
+                ofp.action.output(of_port),
+            ]
+
+        buckets = [
+            ofp.bucket(actions=actions),
+        ]
+
+        request = ofp.message.group_add(group_type=ofp.OFPGT_INDIRECT,
+                                        group_id=group_id,
+                                        buckets=buckets
+                                       )
+        ctrl.message_send(request)
+
+        if send_barrier:
+            do_barrier(ctrl)
+
+
+def add_l2_mcast_group(ctrl, ports, vlanid, mcast_grp_index):
+    buckets=[]
+    for of_port in ports:
+        group_id = encode_l2_interface_group_id(vlanid, of_port)
+        action=[ofp.action.group(group_id)]
+        buckets.append(ofp.bucket(actions=action))
+
+    group_id =encode_l2_mcast_group_id(vlanid, mcast_grp_index)
+    request = ofp.message.group_add(group_type=ofp.OFPGT_ALL,
+                                    group_id=group_id,
+                                    buckets=buckets
+                                   )
+    ctrl.message_send(request)
+
+
+def add_vlan_table_flow(ctrl, ports, vlan_id=1, flag=VLAN_TABLE_FLAG_ONLY_BOTH, send_barrier=False):
+    # table 10: vlan
+    # goto to table 20
+    for of_port in ports:
+        if (flag == VLAN_TABLE_FLAG_ONLY_TAG) or (flag == VLAN_TABLE_FLAG_ONLY_BOTH):
+            match = ofp.match()
+            match.oxm_list.append(ofp.oxm.in_port(of_port))
+            match.oxm_list.append(ofp.oxm.vlan_vid(0x1000+vlan_id))
+            request = ofp.message.flow_add(
+                table_id=10,
+                cookie=42,
+                match=match,
+                instructions=[
+                  ofp.instruction.goto_table(20)
+                ],
+                priority=0)
+            logging.info("Add vlan %d tagged packets on port %d and go to table 20" %( vlan_id, of_port))
+            ctrl.message_send(request)
+            
+        if (flag == VLAN_TABLE_FLAG_ONLY_UNTAG) or (flag == VLAN_TABLE_FLAG_ONLY_BOTH):
+            match = ofp.match()
+            match.oxm_list.append(ofp.oxm.in_port(of_port))
+            match.oxm_list.append(ofp.oxm.vlan_vid(0))
+            request = ofp.message.flow_add(
+                table_id=10,
+                cookie=42,
+                match=match,
+                instructions=[
+                  ofp.instruction.apply_actions(
+                    actions=[
+                      ofp.action.set_field(ofp.oxm.vlan_vid(0x1000+vlan_id))
+                    ]
+                  ),
+                  ofp.instruction.goto_table(20)
+                ],
+                priority=0)
+            logging.info("Add vlan %d untagged packets on port %d and go to table 20" % (vlan_id, of_port))
+            ctrl.message_send(request)
+
+    if send_barrier:
+        do_barrier(ctrl)
+
+def add_bridge_flow(ctrl, dst_mac, vlanid, group_id, send_barrier=False):
+    match = ofp.match()
+    match.oxm_list.append(ofp.oxm.eth_dst(dst_mac))
+    match.oxm_list.append(ofp.oxm.vlan_vid(0x1000+vlanid))
+    request = ofp.message.flow_add(
+            table_id=50,
+            cookie=42,
+            match=match,
+            instructions=[
+                ofp.instruction.write_actions(
+                    actions=[
+                        ofp.action.group(group_id)]),
+                    ofp.instruction.goto_table(60)
+                ],
+            buffer_id=ofp.OFP_NO_BUFFER,
+            priority=1000) 
+
+    logging.info("Inserting Brdige flow vlan %d, mac %s", vlanid, dst_mac)
+    ctrl.message_send(request)
+
+    if send_barrier:
+        do_barrier(ctrl)            
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