This paper proposes an Intrusion Detection System (IDS) that utilizes Deep Reinforcement Learning (DRL) in a fine-grained manner to enhance the performance of binary and multiclass intrusion classification tasks. The proposed system, named Micro Reinforcement Learning Classifier (MRLC), is evaluated using three standard datasets. MRLC architecture utilizes a fine-grained learning approach to enhance IDS accuracy. Simulation studies demonstrate that MRLC has a high efficiency in discriminating different intrusion classes, outperforming state-of-the-art RL-based methods. The average accuracy of MRLC is 99.56%, 99.99%, 99.01% for NSL-KDD, CIC-IDS2018, and UNSW-NB15 datasets respectively. The implementation codes are available at https://github.com/boshradarabi/MICRO-RL-IDS.
