As the type of transmitted data over communication networks started to shift from the human-generated to massive Machine-Type Communications (mMTCs), entirely new applications within the Internet of Things (IoT) market emerged. Recently introduced Cellular IoT (CIoT) communication technologies operating in the licensed frequency spectrum (i.e., Narrowband IoT (NB-IoT) and LTE-M) complemented the already implemented and field-tested technologies (e.g., LoRa(WAN) and Sigfox) transmitting data in license-exempt frequency bands. Owing to the licensed spectrum as well as to the standardization efforts put by the Third Generation Partnership Project (3GPP) and International Telecommunication Union (ITU), the CIoT technologies are supposed to handle the massive number of data transmissions by introducing new categories of communication devices. In this regard, this paper elaborates on the critical parameters of the LTE Cat-M introduced by 3GPP. Along with the highlights of the technology in question, the implementation of LTE Cat-M1 in Network Simulator 3 (NS-3) is presented. Out of the obtained simulation data, the focus is primarily given to the network capacity for mMTC scenarios while utilizing the LTE Cat-M technology. What is even more, the side-by-side evaluation with legacy LTE/LTE-A systems is provided.