The main objective to use wireless sensor network (WSN) is to collect data from various nodes and send this data to sink for processing. This is typically the scenario in any real time application of WSN. The proposed paper discusses the issues in routing for data aggregation with respect to QOS metrics. The paper presents literary on various existing solutions for these issues highlighting the key features, pros and cons, compares the results and performance of protocols with respect to QoS metrics and pitches the research challenges to be solved. © Research India Publications.