Читать книгу Service Level Management in Emerging Environments - Nader Mbarek - Страница 39

The IoT is a combination of different technologies and heterogeneous networks providing various types of services. Consequently, several types of data and flows with different or even contradictory constraints can coexist in the same IoT environment. From this observation follows the need for integrating QoS to satisfy the needs of each data type (Gubbi 2013). QoS is a critical element in the IoT, given that the large number of connected objects leads to a considerable increase in the volume of data in this type of environment. This increase may create congestion that affects the performance of the IoT system. In this context, QoS mechanisms optimize performance by identifying different traffic and applying the differentiated treatment. Performance management also helps reduce costs and improve scalability in the IoT environment (Bhaddurgatte and Kumar 2015).

QoS models used in traditional computer networks such as IntServ (Braden et al., 1994) and DiffServ (Babiarz et al., 2006) are difficult to implement in the IoT. This difficulty arises due to the constraints in terms of memory and computation capacities that IoT objects have as well as the wide scope of IoT and the random deployment of these objects. Thus, new and adapted QoS models must be offered to provide IoT services with a guarantee of connectivity, performance and, generally, of QoS (Premila et al. 2015).

Various international organizations have emphasized the importance of guaranteeing QoS in the IoT. ITU-T studied the importance of integrating QoS in the IoT environment in Y.2066 (ITU-T 2014), stating that prioritizing IoT services is an essential requirement. In addition, Y.2066 indicates that the prioritization feature makes it possible to satisfy the different service requirements for various IoT user groups. In other words, differentiated services should be supported, so that the IoT can provide different Service Level Agreements (SLAs). On the other hand, LinkLabs, an American company developing technologies for computer networks, indicates that the integration of QoS into IoT allows better management of the capabilities and resources in this type of environment to provide reliable and optimized infrastructure for connectivity of IoT objects. According to LinkLabs, in order to offer secure and predictable IoT services, QoS mechanisms will help manage delays, jitter, bandwidth and packet loss by categorizing traffic and recording the limits of communication channels (Ray 2016). The following section examines the requirements in terms of guaranteeing QoS as well as the responses provided within the different layers of the IoT architecture.