'Unplug patch ports between trunk bridge and given bridge.
The method unplugs one patch port on the given bridge side using
port MAC and ID as external IDs.  The other endpoint of patch port is
attached to the trunk bridge.  Then it sets vlan tag represented by
segmentation_id.  Everything is done in a single OVSDB transaction so
either all operations succeed or fail.
:param br_int: an integration bridge where peer endpoint of patch port
will be created.'

def plug(self, br_int):

    ovsdb = self.bridge.ovsdb
    with ovsdb.transaction() as txn:
        super(SubPort, self).plug(br_int)
        txn.add(ovsdb.db_set('Port', self.patch_port_trunk_name, ('tag', self.segmentation_id)))
