Data handler being configured to handle monitoring data among network entities, wherein the data handler is configured to: obtain a first data request from a first network entity, the first data request comprising a first data identifier, the first data identifier relating to monitoring data; obtain one or more second data identifier from one or more other network entities, wherein the one or more second data identifier is related to the monitoring data to be collected from the one or more other network entities; generate association information based on the first data identifier and the one or more second data identifier; determine, based on the association information, whether the monitoring data to be collected is already available at the data handler , or determine whether the monitoring data to be collected should be collected from the one or more other network entities by the data handler ; and wherein, - if the monitoring data to be collected is not available, upon the basis of a subscription, then the data handler is configured to retrieve the monitoring data to be collected from the one or more other network entities upon the basis of at least one further data request, and wherein the data handler is configured to send and/or forward the retrieved monitoring data to be collected to the first network entity upon receiving the retrieved monitoring data; or wherein - if the monitoring data is available at the data handler, then the data handler is configured to send and/or forward the available monitoring data to the first network entity. obtain a first data request from a first network entity, the first data request comprising a first data identifier, the first data identifier relating to monitoring data; obtain one or more second data identifier from one or more other network entities, wherein the one or more second data identifier is related to the monitoring data to be collected from the one or more other network entities; generate association information based on the first data identifier and the one or more second data identifier; determine, based on the association information, whether the monitoring data to be collected is already available at the data handler , or determine whether the monitoring data to be collected should be collected from the one or more other network entities by the data handler ; and wherein, - if the monitoring data to be collected is not available, upon the basis of a subscription, then the data handler is configured to retrieve the monitoring data to be collected from the one or more other network entities upon the basis of at least one further data request, and wherein the data handler is configured to send and/or forward the retrieved monitoring data to be collected to the first network entity upon receiving the retrieved monitoring data; or wherein - if the monitoring data is available at the data handler, then the data handler is configured to send and/or forward the available monitoring data to the first network entity. - if the monitoring data to be collected is not available, upon the basis of a subscription, then the data handler is configured to retrieve the monitoring data to be collected from the one or more other network entities upon the basis of at least one further data request, and wherein the data handler is configured to send and/or forward the retrieved monitoring data to be collected to the first network entity upon receiving the retrieved monitoring data; or wherein - if the monitoring data is available at the data handler, then the data handler is configured to send and/or forward the available monitoring data to the first network entity. <EOS>