SATNAC 2008 Conference Papers
Network Management & OSS
Title: Implementing a
Trusted Service-Oriented Network Environment
Authors: Emmanuel
Adigun (
Abstract: Trust has become an important feature of security. Originally having its roots in the social sciences, it has fast moved into the field of computer science and more recently into the domain of network security. It is becoming important for scientists to model human trust, especially in a network environment where a lack of trust between network devices, such as routers, can result in poor quality of service and an increase in security compromises. In a network environment there is no “behaviour” indicator for routing devices about other devices on their forwarding path. So, relying on another routing device might be difficult if a secure and reliable service is not available. In this paper we present our ongoing implementation of trust in service-oriented network environments and explain how trust is implemented between network devices.
Title: Economic Mechanisms
for Protecting VoIP Services within the IMS
Authors: Gabriel
Andrews (
Abstract: The IP Multimedia Subsystem (IMS) is the proposed NGN architecture that will be used to provide revolutionary services based on an IP backbone. For successful IMS deployment service providers need to ensure that the services offered to customers are protected. This will ensure that customer satisfaction is upheld and that customers are retained within the network. Customer retention is an essential part of ensuring the needed investment into IMS technologies. This paper analyses a VoIP service offered over an IMS network as a revenue maximization problem. Using this technique we show that it is possible to prevent unsolicited sessions and to maintain customer satisfaction. We will provide guidelines that can be used to ensure that customers are protected from abuse which will result in an economically beneficial situation for all parties.
Title: Energy-Efficient
Distributed Topology Control for Heterogeneous Wireless Mesh Networks
Authors: Felix Aron (
Abstract: The
topology control problem is a well researched topic for energy saving in
wireless ad hoc networks. However, little attention has been given to similar
problems in the case of wireless mesh networks (WMNs) even though WMNs have very
unique characteristics that are different from other wireless multihop networks
e.g., MANETs. This is because many WMNs surveys make the impractical assumption
that since mesh routers are static, energy is not a problem. Consequently, with
specific interests to WMNs applications in rural areas, where power sources are
limited, this work addresses the topology control problem for energy efficiency
in a hybrid WMN of heterogeneous wireless devices with varying transmission
ranges. A localized distributed algorithm is presented which computes an
optimal per-node transmission power such that: (1) a node’s average out
degree is reduced considerably to cover only the nearest neighbours, (2)
network connectivity is maintained and (3) the network lifetime is extended. The performance of the algorithm is
evaluated via several mathematical analyses. Additionally, simulations are done
in the NS-2 simulation environment to show correctness and effectives of the
algorithm.
Title: Gaining Insight into
Customer Churn Prediction using Generalized Additive Neural Networks
Authors: André
de Waal (
Abstract: As the
South African telecommunications industry is opened up, competition for
customers are increasing. Retaining customers is therefore of critical
importance to services providers. Some of the techniques that have been
successfully applied to churn prediction include logistic regression, decision
trees and neural networks. Support vector machines are a recent addition to the
modeler’s arsenal of techniques and seem to be the technique of choice in
many applications as it promises increased accuracy. However, although improved
accuracy in predicting churn is important, gaining insight into reasons for
churn might be the ultimate aim, as this allows the service provider to
introduce interventions that could increase customer retention and therefore
profitability. In this article, a recent development of generalized additive
models, namely Generalized Additive Neural Networks is proposed as a technique
for modeling churn. It not only promises great accuracy, but also ease of
interpretability. Previously, neural networks have been known to offer accurate
predictions, but the black box nature of the model offered little insight or
explanation as to why a customer was about to churn. This shortcoming of neural
networks is overcome by restricting the neural network architecture to a
simplified architecture implementing a generalized additive model and the use
of partial residual plots that provide a graphical view of the relationships
(which could be nonlinear) between the input variables and the target (and
therefore also reasons for churn).
Authors: Olabisi
Falowo (
Abstract: Next generation wireless networks
(NGWN) will be heterogeneous and it is envisioned that joint call admission
control (JCAC) algorithms for NGWN will be user-centric. User centricity
implies that users’ preferences are considered in making radio access
technology (RAT) selection decisions. However, user-centric JCAC algorithms
often lead to highly unbalanced network load, which in turn causes high call
blocking probability and poor radio resource utilization. To address this
problem, we propose dynamic pricing for balancing traffic load among available
RATs in heterogeneous wireless networks utilizing a user-centric JCAC
algorithm. By dynamically adjusting the service price in each of the available
RATs, the proposed user-centric JCAC scheme evens out, as mush as possible, the
unbalanced traffic load caused by independent users’ preferences. The
JCAC scheme uses fuzzy multiple-attribute decision-making technique to select
the most appropriate RAT for each incoming call. We develop a Markov model to
evaluate the overall call blocking/dropping probability, and percentage load in
each RAT in heterogeneous wireless networks. Performance of the proposed JCAC
scheme is compared with the performance
of a scheme that does not incorporate dynamic pricing. Numerical results
are given to show the effectiveness of the proposed JCAC scheme.
Title: Optimized handover
delay in Proxy Mobile IPv6 using IEEE802.21 MIH Services
Authors: Linoh
Magagula (
Abstract: Recent
trends are showing fast convergence of mobile and wireless communication
networks with internet services to provide ubiquitous access to network users.
It is envisioned that these next generation wireless networks will be supported
by an all-IP based infrastructure with the support of heterogeneous wireless
access technologies such as UMTS, WLAN, WiMax, etc. These heterogeneous access
networks differ in many properties and characteristics such as data rates, coverage, capacity, etc.,
as well as mobility, QoS and security requirements. These networks are
complementary to each other, hence their integration will empower mobile users
to be connected to the all-IP based infrastructure using the best available
access network during roaming. However, mobility management across these
heterogeneous wireless networks poses a great challenge, particularly, in
issues of handover including reducing handover delay. The different
characteristics of these networks demand for superior mobility management
schemes for providing seamless handover with minimal handover delay. Hence, the
widely proposed host-based mobility management protocols where the mobile node
is involved in mobility-related signaling may not be ideal for the future
wireless networks. This paper, therefore, proposes a network-based mobility
management framework, based on Proxy Mobile IPv6, to reduce handover delay by
optimizing the authentication delay. The framework incorporates IEEE802.21 to
facilitate the handover across the networks. We show through analysis of the signaling
procedure that the proposed mechanism performs better than the basic Proxy
Mobile IPv6 and host-based mobility management schemes such as HMIPv6.
Authors: Paul Tarwireyi (University of
Abstract: Rural Internet connectivity projects aimed at bridging the digital divide have mushroomed across many developing countries. Most of these projects are deployed as community centered projects. Usually, the initial deployment of the projects is funded by governments, multilateral institutions and non-governmental organizations. After the initial deployment, financial sustainability remains one of the greatest challenges facing these projects. In the light of this, externally funded ICT4D interventions should just be used for “bootstrapping” purposes. The communities should be “groomed” to take care of and sustain these projects, eliminating as soon as possible a dependency on external funding. This paper presents the design and the implementation of a generic architecture for the management of the costs associated with running a computer network connected to the Internet. The proposed system, called the Network Revenue Management System, enables a network to generate revenue, by charging users for the utilization of network resources. The system provides a flexible architecture which allows the exploration of both conventional and non-conventional billing options.