| dc.description.abstract | 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. | en |
