Label switching technology is a flexible and high performance method for forwarding layer three packets that are mapped to layer two flows. Each label switch router, LSR, needs a specific label for every flow, where the number of labels depends on the mapping and granularity of flows. Data and control driven methods are the most significant and popular methods in label mapping policy. The above mentioned methods have been investigated. The possible pitfalls of each method are identified for an optimal operation and performance. One of the most significant difficulties is the rate of flows creation and deletion. This issue is vital in both scalability and implementation of networks and is more significant in data driven methods. In this paper, a new flow-Subnet Flow-has been proposed which increases the performance in data driven methods. The simulation results show fair improvement in performance and validity of the Subnet Flow.