At what OSI model layer does DiffServ operate?

DiffServ, or Differentiated Services, operates at Layer 3 of the OSI model, which is the Network Layer. This layer is responsible for routing packets across different networks and managing data traffic. DiffServ provides a scalable and flexible method for classifying and managing network traffic by assigning different levels of service to various types of data flows. This capability allows for improved performance and quality of service (QoS) for applications requiring specific bandwidth and latency characteristics.

In practice, DiffServ achieves this through the use of per-hop behaviors (PHBs), which dictate how packets should be handled by each router along the path based on their assigned class. This classification occurs at the Network Layer, where the actual routing and forwarding of packets take place, making it vital for managing the network's overall performance effectively. The differentiation of service levels allows network operators to ensure that critical applications receive the necessary resources while less critical traffic is managed proportionately.