Achmad Husni Thamrin

Collaborating Remote Computer Laboratory and Distance Learning Approach for Hands-on IT Education

This paper studies the innovative methodology for developing IT education from the traditional face-to-face model to full capability of distance learning by combining a remote computer laboratory and a distance e-learning environment. There are three approaches presented with different implementations of laboratory technologies and learning models. The design challenge is to address the limitations of resources at region-wide learning sites, cost-effectiveness and scalability. Computer virtualization and StarBED computing testbed can achieve a larger scale of laboratory size with less cost of equipment and administration workload. The live learning environment ensures quality of realtime communications during lecture and lab sessions by employing IPv6 Multicast on a satellite UDLR network. The self-paced learning environment is proposed to enable a flexible schedule, resource reusability, and scalability. The lab supervision system is the key component to enhance teaching effectiveness in the self-paced hands-on practice by systematically automating the lab supervision skills of lecturers. These approaches have been evaluated as feasible, cost-effective and scalable by the real implementations of similar Asia-wide workshops. Trade-off overheads and analysis on technology and pedagogy perspectives are made to compare their characteristics.

A temporal view of the topology of dynamic Bittorrent swarms

This paper describes an experimental study of the overlay topologies of real-world Bittorrent networks, focusing on the activity of the nodes of its P2P topology and especially their dynamic relationships. Peer Exchange Protocol (PEX) messages are analyzed to infer topologies and their properties, capturing the variations of their behavior. Our measurements, verified using the Kolmogorov-Smirnov goodness of fit test and the likelihood ratio test and confirmed via simulation, show that a power-law with exponential cutoff is a more plausible model than a pure power-law distribution. We also found that the average clustering coefficient is very low, supporting this observation. Bittorrent swarms are far more dynamic than has been recognized previously, potentially impacting attempts to optimize the performance of the system as well as the accuracy of simulations and analyses.

Internet Technologies and Infrastructure for Asia-Wide Distance Education

SOI Asia project aims at Asia-wide distance education development with its design emphasizing on new model of network technologies that provides wide-coverage high-quality network to support high-quality distance education instead of relying on the available Internet connectivity with inadequate quality. A 13-Mbps unidirectional broadcast satellite covers Asia region enabling lecture sharing among student sites. IPv6 multicast overlay network is established by UDLR and IPv6 tunnel technologies to create a virtual network connecting lecturer-site and student-sites on top of network heterogeneity. Bandwidth optimization and scalability are achieved by IPv6 multicast. QoS using policy routing and ALTQ utilizes and manages bandwidth to ensure high quality lectures. Experiment results show that SOI Asia environment delivers better quality streams with stable rate, high correlation, low data loss and jitter compared to the available Internet connectivity. These design aspects, technology model and experimental results can be the considerations of future region-wide distance education development

PIM-SM configuration and scalability on satellite unidirectional links

This paper considers satellite unidirectional links having a large number of nodes and discusses the PIM-SM configuration on these links if there is no separate multicast routing information base. Looking closely at the PIM-SM specification documents, we propose a PIM-SM configuration that enables multicast traffic to flow on unidirectional links. We also discuss the scalability of PIM-SM on satellite unidirectional links. We expect that the join/prune message suppression strategy is an important element for scaling PIM-SM on these links.

A Remote Hands-on Exercise Environment for an Asia-Wide Real-Time Workshop

This paper discusses the problems of conducting a real-time workshop, where the instructors and the participants are located in different places, and the participants should perform hands-on lab exercises using computers that are located in another place. To address this problem, we implemented a remote hands-on exercise environment using virtual machines and a low-bandwidth remote console access. In this environment, the instructors can monitor each participants exercise progress thus they can give specific feedbacks to the participants. We evaluated this environment using a real-time online workshop. We found that it was easy to setup, and participants had a good user-experience using this environment

Scaling multicast communications by tracking feedback senders

This paper looks at the message implosion problem that may happen on large-scale reliable multicast communications. We propose that receivers track the senders of recent feedback messages and store them in a list to determine the back-off interval to send a feedback message. We call our proposal tracked sender list (TSL). The issues regarding this proposal are how many receivers to be stored in a receivers list, back-off timer intervals, p.d.f selection, and how a receiver stores itself in its list. We analyzed and simulated our proposal using various parameters values in both networks with equal delay and with heterogeneous delays to show the message suppression performance. The results demonstrate that TSL gives a low number of messages over a wide range of receivers even with a short back-off interval and it is not susceptible to packet losses. Our results also show that TSL performs better than other p.d.fs that is used in message suppression.

Dynamic bandwidth configuration system for satellite Internet

In this paper we design and implement a dynamic bandwidth assignment and an Earth station control system for Internet-like satellite-based communication, which may require different link speeds at different times. Satellite links have limited bandwidth, and for satellite communications to work we have to assign a certain bandwidth to each Earth station. Currently, satellite links have fixed bandwidth assignments. If satellite links are to be used for communication in a manner similar to the Internet, some channels may experience congestion while others do not. In order to improve the usage of all channels a dynamic bandwidth assignment function based on traffic is needed. Use of the system proposed in this paper can improve the usage of satellite channels and reduce the administration cost of Earth stations.

Feature selection using genetic algorithm to improve classification in network intrusion detection system

In this paper, we present Genetic Algorithm based optimized feature selections for intrusion detection systems. We used one-point crossover for the Genetic Algorithm parameters instead of two-point crossover used by the previous research as it one-point crossover is faster. For evaluations, we used the NSL-KDD Cup 99 data set and we modified the data set by looking into to the recent attacks, hence making the data set more relevant to the current situations. Several classifiers were used on these data sets and we found that Random Forest gave the best results in terms of the classification rate and the training time. The results also showed that our parameters performed better in these two metrics and the classifications using our optimized features on the modified data sets gave mixed results compared to ones with the original features.

ODMT: On-demand Inter-domain Multicast Tunneling

The tussle in IP multicast, where different enablers have interests that are adverse to each other, has led to a halt in inter-provider multicast deployment and created a situation in which enabling inter-domain multicast routing is considered a deterrent for network providers. This paper presents ODMT (On-demand Inter-domain Multicast Tun- neling), an on-demand inter-provider multicast tunneling that is autonomous in operation and manageable through its definable policy control. In the architectural design, we propose a new approach of enabling inter-provider multicast by decoupling the control-plane and forwarding-plane. Focusing on the control-plane without changing the forwarding- plane, our solution changes the traditional open multicast service model into a more manageable service model in inter-domain multicast operation, hence it eases the Internet-wide multicast deployment.

A Scalable Network Architecture for a Large-scale Uni-directional Link

Effective bandwidth utilization and scalability are vital issues for IP networking over a large-scale uni-directional link (UDL), such as a wide-area wireless broadcast over satellite or terrestrial digital broadcasting. On a large-scale UDL, the current network architecture is not scalable to cover an extraordinary number of receivers that communicate using a Link-layer Tunneling Mechanism (LLTM). This paper proposes a network architecture for a large-scale UDL that: (1) decreases the traffic load of LLTM at the upstream network of the UDL, (2) coordinates the data link layer and network layer of receivers without communications via UDL, and (3) enables neighbor discovery for direct communication between receivers via a bi-directional link that is used as a return path for LLTM. Simulation results showed that our approach reduces by more than 90% the control messages to be sent via UDL compared with IPv6 stateless address autoconfiguration on the existing network architecture. Our proposal improves the UDL bandwidth consumption from O(N) to O(1), so that the bulk of the bandwidth can be utilized for delivering services, not for network configuration of receivers.