private void keepAlive(InstancePingPkg request) {
        final long timeBucket = TimeBucket.getTimeBucket(System.currentTimeMillis(), DownSampling.Minute);
        final String serviceName = namingLengthControl.formatServiceName(request.getService());
        final String instanceName = namingLengthControl.formatInstanceName(request.getServiceInstance());

        if (log.isDebugEnabled()) {
            log.debug("A ping of Service[{}] instance[{}].", serviceName, instanceName);
        }

        ServiceInstanceUpdate serviceInstanceUpdate = new ServiceInstanceUpdate();
        serviceInstanceUpdate.setServiceId(IDManager.ServiceID.buildId(serviceName, true));
        serviceInstanceUpdate.setName(instanceName);
        serviceInstanceUpdate.setTimeBucket(timeBucket);
        sourceReceiver.receive(serviceInstanceUpdate);

        ServiceMeta serviceMeta = new ServiceMeta();
        serviceMeta.setName(serviceName);
        serviceMeta.setTimeBucket(timeBucket);
        serviceMeta.setLayer(Layer.GENERAL);
        sourceReceiver.receive(serviceMeta);
    }
A handler deserializes the message of Service Management and pushes it to downstream.
oap-server/server-fetcher-plugin/kafka-fetcher-plugin/src/main/java/org/apache/skywalking/oap/server/analyzer/agent/kafka/provider/handler/ServiceManagementHandler.java