The effect of physical and link layers on IP QoS

In the traditional Internet Engineering Task Force (IETF) network model, Internet protocol (IP) provided only an unreliable, best-effort delivery service. As a result, the effects of the physical and data-link layers on IP performance were ignored. In the current Internet service provider (ISP) environment, service-level agreements (SLA) require that IP-based services provide quality of service (QoS) guarantees. These guarantees (e.g., asynchronous transfer mode [ATM], connection admission control, and frame relay [FR] traffic policing) are often based on or enforced through physical and link-layer provisioning parameters. In this paper, we examine the effects of the ATM and FR physical and data-link layers and their inter-working on IP performance. Specifically, we characterize the impact of ATM and FR impairments, traffic policing, and inter-working on IP traffic