A framework for implementing Internet Quality of Service in Kenya
The Internet is built on the datagram model, where each individual packet is forwarded independently to its destination. This model has the strength of simplicity and the ability to adapt automatically to changes in network topology. In this model, all packets are given the same forwarding treatment, and no service differentiation is provided. The growth of the Internet has brought with it several new applications which require some level of resource assurance to operate. These resource assurances cannot be addresses in the traditional datagram model, which has limited resource management capabilities inside the network and therefore cannot provide any resource guarantees to users. The concept of Quality of Service (QoS) was thus introduced in order to provide service differentiation and assurance for these services. According to ITU, Internet quality of service is the collective effect of service performance which determines the degree of satisfaction on the part of the user of the service [ITU-T, E.800]. It represents those quantitative and qualitative characteristics of a network system that are necessary to achieve the required functionality of an application [Vogel et al, 1995]. These characteristics are specified though service parameters such as bandwidth, jitter, packet loss, and delay. To support the implementation of QoS capabilities on the Internet, the Internet Community developed two key service models, the differentiated services (Diffserv) and the integrated services (Intserv) models. Diffserv provides QoS capabilities by classifying packets, using the differentiated services code point (DSCP), while Intserv uses RSVP to reserve resources across the network path. In addition, the Intserv over Diffserv was later proposed to provide the benefits of both Diffserv and Intserv end-to-end QoS capabilities. In Kenya, the Internet was introduced in 1992 [Mweu, 2000], and has seen a tremendous growth, especially in the last ten years. This has seen the introduction of many applications, some of which require resource assurances and service differentiation. However, Internet services in Kenya are still based on the best effort service, to a large extent, with very minimal QoS support provided. This report presents an overview of the Internet services in Kenya, and proposes a framework which can be used to specify and implement QoS capabilities for Internet Services in Kenya. The framework proposed herein is based on the Intserv over Diffserv service model, as defined by the Internet Engineering Task Force (IETF). The framework focuses on three service components; infrastructure, user environment and application type. It makes proposals on the mmimum infrastructure requirements, as well as the parameter settings that would be suitable in implementing QoS for these types of services. Three service classes are defined with six associated service types. Each of these service types is targeted towards a specific category of applications, as well as infrastructure capacity. The framework provides a means by which Internet QoS can be provided, and evaluated.