code: def _update_redundancy_router_interfaces(self, context, router,
                                               port, modified_port_data,
                                               redundancy_router_ids=None,
                                               ha_settings_db=None):
          
          router_id = router['id']
          if ha_settings_db is None:
              ha_settings_db = self._get_ha_settings_by_router_id(context,
                                                                  router_id)
          if ha_settings_db is None:
              return
          e_context = context.elevated()
  
          rr_ids = self._get_redundancy_router_ids(e_context, router_id)
          port_info_list = self._core_plugin.get_ports(
              e_context, filters={'device_id': rr_ids,
                                  'network_id': [port['network_id']]},
              fields=['device_id', 'id'])
          for port_info in port_info_list:
              self._core_plugin.update_port(e_context, port_info['id'],
                                            modified_port_data)
          self._update_hidden_port(e_context, port['id'], modified_port_data)
docs: To be called when the router interfaces are updated,
          like in the case of change in port admin_state_up status