Downstream DHCP trap flow (at NNI) not programmed

The openolt_flow_mgr attempts to create tcont/gemport for the dhcp trap flow.

def divide_and_add_flow(self, intf_id, onu_id, uni_id, port_no, classifier,
┆ ┆ ┆ ┆ ┆ ┆ action, flow):

┆ self.log.debug('sorting flow', intf_id=intf_id, onu_id=onu_id,
┆ ┆ ┆ ┆ ┆ uni_id=uni_id, port_no=port_no, classifier=classifier,
┆ ┆ ┆ ┆ ┆ action=action)

┆ alloc_id, gem_ports = self.create_tcont_gemport(intf_id, onu_id,
┆ ┆ ┆ ┆ ┆ ┆ ┆ ┆ ┆ ┆ ┆ ┆ ┆ uni_id, flow.table_id)

20190320T225742.538 ERROR MainThread openolt_flow_mgr.create_tcont_gemport

{'instance_id': 'vcore-0_1553122552', 'ip': '10.90.0.122:9191', 'exception': 'Traceback (most recent call last):\n File "/voltha/voltha/adapters/openolt/openolt_flow_mgr.py", line 414, in create_tcont_gemport\n ofp_port_name = self.data_model.serial_number(intf_id, onu_id)\n File "/voltha/voltha/adapters/openolt/openolt_data_model.py", line 389, in serial_number\n % (intf_id, onu_id))\nValueError: serial_number not found, intf_id=0, onu_id=0', 'vcore_id': '0001'}