QoS Models
QoS models serve as blueprints for implementing QoS. They define how network resources should be allocated, traffic prioritized, and policies enforced, ensuring consistent and efficient QoS implementation across diverse network environments.
Each QoS model offers a different approach to balancing network resources and ensuring appropriate service levels for various types of traffic. The choice depends on network requirements, scalability needs, and the desired level of complexity.
Three commonly used QoS models are:
- Integrated Services (IntServ): IntServ is a fine-grained approach where each network flow is explicitly managed. It uses RSVP (Resource Reservation Protocol) to establish end-to-end communication agreements, ensuring predictable and guaranteed QoS for individual flows. While effective for small-scale networks, it can be complex to implement and scale.
- Differentiated Services (DiffServ): DiffServ simplifies QoS by classifying and marking traffic at the network edge, assigning packets to different classes. Routers then use these markings to prioritize and forward traffic accordingly. DiffServ is more scalable and widely adopted in large networks, making it suitable for the internet's core.
- Best Effort: Best Effort, in contrast to the other two models, provides no QoS guarantees. It treats all traffic equally and aims to deliver packets as quickly as possible without prioritization or resource reservation. This model is used for applications that tolerate variable delays and losses, such as web browsing and email.