Page 14 - ITUJournal Future and evolving technologies Volume 2 (2021), Issue 1

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 1

An evaluation of cryptocurrency payment channel networks and their privacy
implications
Pages 35–44
Enes Erdin, Suat Mercan, Kemal Akkaya

Cryptocurrencies redefined how money can be stored and transferred among users. However, public
blockchain-based cryptocurrencies suffer from high transaction waiting times and fees. To address these
challenges, the payment channel network concept is touted as the most viable solution to be used for
micro-payments. The idea is exchanging the ownership of money by keeping the state of the accounts
locally which provides transaction approvals in seconds. Such attention on payment channel networks
has inspired many recent studies that focus on how to design them and allocate channels such that the
transactions will be secure and efficient. However, as payment channel networks are emerging and
reaching a large number of users, privacy issues are becoming more relevant, this raises concerns about
exposing not only individual habits but also businesses' revenues. In this paper, we first propose a
categorization of the existing payment networks formed on top of blockchain-backed cryptocurrencies.
After discussing several emerging attacks on user/business privacy in these payment channel networks,
we qualitatively evaluate them based on a number of privacy metrics that relate to our case. Based on
the discussions on the strengths and weaknesses of the approaches, we offer possible directions for
research for the future of privacy based payment channel networks.
View Article

Controller placement optimization for Software Defined Wide Area Networks
(SDWAN)
Pages 45–66
Lusani Mamushiane, Joyce Mwangama, Albert Lysko
Software Defined Networking (SDN) has emerged as a promising solution to revolutionize network
deployment, operations and economic growth. This paradigm aims to address management and
configuration complexities in legacy networks so as to reduce the total cost associated with deploying
and running telecommunication infrastructures. At the heart of SDN is a controller which oversees
orchestration of resources. An important problem that must be addressed during the initial design of an
SDN-based network deployment is to find the optimal number of controllers and their locations, to
achieve desired operational efficiency. This problem constitutes competing objectives such as latency,
load balancing, and reliability. We apply Silhouette Analysis, Gap Statistics and the Partition Around
Medoids (PAM) algorithms and, unlike previous work, we add a new method for solving the controller
placement problem using an emulation orchestration platform. Our approach aims to optimize
controller-to-node latency, alleviate control-plane signalling overhead and ensure control-plane
resiliency. Our results for South African national research network (SANReN) reveal that deploying
two controllers yields the lowest latency, reduces control-plane signalling overhead and guarantees
control-plane resiliency. Our approach can be used by network operators as a guideline to start
integrating SDN or plan a new SDN deployment, by helping them make quick automatic decisions
regarding optimal controller placement.
View Article

– xii –