Explain the concept of Quality of Service (QoS) in networking. Describe two common QoS mechanisms and their applications

Quality of Service (QoS) in networking refers to the performance level of a service or a network. QoS involves prioritizing different applications, users, or data flows, or guaranteeing a certain level of performance to a data flow. It is particularly important for the transport of traffic with special requirements. In particular, much of the data traffic in networks is sensitive to delay or jitter, such as real-time audio or video streaming.

Two common QoS mechanisms are:

1. Differentiated Services (DiffServ): This is a computer networking architecture protocol that specifies a simple, scalable and coarse-grained mechanism for classifying and managing network traffic and providing quality of service (QoS) on modern IP networks. DiffServ can, for example, be used to provide low-latency to critical network traffic such as voice or streaming media while providing simple best-effort service to non-critical services such as web traffic or file transfers.

2. Integrated Services (IntServ): This is a model for streaming multimedia applications in Internet Protocol (IP) networks. It reserves network resources to provide QoS on the network. IntServ can guarantee bandwidth, delay, jitter, and packet loss in a network. This is particularly useful for real-time applications such as VoIP, online games, and IPTV, which require a certain level of service to function optimally.

In summary, QoS is a critical aspect of modern networking that ensures that different types of data traffic get the level of service they need. Different QoS mechanisms like DiffServ and IntServ provide different ways to manage and prioritize network traffic.