def _get_binding_keys(self, port, host):
        """Get binding keys from the port binding"""
        binding_keys = list()
        switch_binding = port[portbindings.PROFILE].get(
            'local_link_information', None)
        if switch_binding:
            for binding in switch_binding:
                switch_id = binding.get('switch_id')
                port_id = binding.get('port_id')
                binding_keys.append((port['id'], (switch_id, port_id)))
        else:
            binding_keys.append((port['id'], host))
        return binding_keys