@Override
        public void entity2Storage(final ServiceHierarchyRelationTraffic storageData, final Convert2Storage converter) {
            converter.accept(SERVICE_ID, storageData.getServiceId());
            converter.accept(RELATED_SERVICE_ID, storageData.getRelatedServiceId());
            converter.accept(SERVICE_LAYER, storageData.getServiceLayer().value());
            converter.accept(RELATED_SERVICE_LAYER, storageData.getRelatedServiceLayer().value());
            converter.accept(TIME_BUCKET, storageData.getTimeBucket());
        }
The service layer of the lower service.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/hierarchy/service/ServiceHierarchyRelationTraffic.java