Shinsuke Miwa

Performance evaluation of DTN implementations on a large-scale network emulation testbed

In this paper we present a series of experiments that evaluate the performance of two DTN implementations, DTN2 and IBR-DTN, in urban mobility scenarios. The experiments were carried out on the wireless network emulation testbed named QOMB, which was extended to support such DTN evaluations. Our quantitative assessment verified the basic behavior of the DTN implementations, but also identified scalability issues for DTN2 in scenarios with as few as 26 nodes. These results emphasize the need for more extensive large-scale experiments with DTN applications and protocols for comprehensive evaluations in view of functionality validation and performance optimization. This can be readily achieved through the use of emulation testbeds such as the one that we have developed.

Experiences in emulating 10K AS topology with massive VM multiplexing

New technologies that will be introduced to the Internet should be practically tested for effectiveness and for side effects. A realistic environment that simulates the Internet is needed to experimentally test such technologies, which will be widely deployed on the Internet. To support experimentation in a realistic, Internet-like environment, we are now trying to construct an Internet on a testbed. We describe our method of constructing an Internet-like environment on the testbed using a virtualization technology and estimation of the inter-AS network on StarBED with Xen and our prototype system. We stably constructed a 10,000-AS network using 150 testbed nodes and estimated its performance and feasibility.

Design issues of an isolated sandbox used to analyze malwares

Recent viruses, worms, and bots, called malwares, often have anti-analysis functions such as mechanisms that confirm connectivity to certain Internet hosts and detect virtualized environments. We discuss how malwares can be kept alive in an analyzing environment by disabling their anti-analyzing mechanisms. To avoid any impacts to/from the Internet, we conclude that analyzing environments should be disconnected from the Internet but must be able to make malwares believe that they are connected to the real Internet. We also conclude that, for executing environments to analyze anti-virtualization malwares, they should not be virtualized but must be as easily reconstructable as a virtualized environment. To reconcile these cross-purposes, we propose an approach that consists of a mimetic Internet and a malware incubator with swappable actual nodes. We implemented a prototype system and conducted an experiment to test the adequacy of our approach.

Network emulation testbed for DTN applications and protocols

Wireless devices are widely used today to access the Internet, despite the intermittent network connectivity they often provide, especially in mobile circumstances. The paradigm of Delay/Disruption Tolerant Networks (DTN) can be applied in such cases to improve the user experience. In this paper we present a network testbed for DTN applications and protocols that we developed based on the generic-purpose wireless network emulation testbed named QOMB. Our testbed is intended for quantitative performance assessments of DTN application and protocol implementations in realistic scenarios. We illustrate the practicality of our emulation testbed through a series of experiments with the DTN2 and IBR-DTN implementations, focusing on mobility in urban environments. The scalability issues that we have identified for DTN2 emphasize the need to perform large-scale repeatable evaluations of DTN applications and protocols for functionality validation and performance optimization.

Educational environment on StarBED: case study of SOI Asia 2008 Spring Global E-Workshop

Hands-on experiences are indispensable to train IT operators. However, it is often difficult to conduct hands-on practices in many locations due to lack of resources such as PCs and network equipments. The cost of gathering lecturers and participants at one hands-on site is another possible problem in this situation. Utilization of remotely located hands-on environment is one of the solution to solve these problems. StarBED is a testbed facility for conducting network experiments. Installation of any OSes, adjusting the network topologies according to the requirements can be easily realized utilizing StarBED and SpringOS. A software suite, SpringOS, was developed exclusively for automating the experiment setups in StarBED. This facility could be used to address the problems of lack of resources and high cost for traveling. This research conducted a region-wide remote hands-on workshop utilizing the StarBED inviting 42 participants from 10 Asian countries. The workshop was designed so that the remote participants do not have to travel to single place, and prepare same specification PCs at each site. Through the collected data and feedback, the proposed workshop model was proved to be feasible and effective. This paper describes the requirements and approaches for region-wide remote hands-on workshop utilizing StarBED for building target hands-on environment. As the contents of the conducted workshop could be applied to the general IT human resource development programs, this paper could be useful for the future remote hands-on programs to train IT operators.

Behavioral Mobility Model with Geographic Constraints

Wireless networks offer the opportunity for the users to move as they use the network in scenarios such as voice and video communication, search-and-rescue operations, etc. User mobility typically takes place in inhabited areas, hence it is subject to constraints regarding the road and building infrastructure in those areas. In this paper we propose a mobility model that takes into account such realistic topographical data. The model is driven by rules that replicate the behavior of mobile users as they proceed towards a destination. We implemented this mobility model in the QOMET wireless network emulation set of tools, and we evaluated it from several perspectives, including through a 50-node OLSR case study in an urban environment. The results demonstrate the advantages of our mobility model in terms of realism and practical applicability.

XBurner: A XENebula-Based Native Traffic-Generation Platform

There are two types of network traffic in experimental environments. One is traffic which is derived from target elements and the other one is background traffic which is derived from surrounding elements. There is very little knowledge on the relationships between new elements and existing elements; therefore, surrounding elements that seem to have no apparent relationship with the target elements should also introduced into the environmental environments. Therefore emulating background traffic is important to take realistic experimental results.

GINTATE: Scalable and Extensible Deep Packet Inspection System for Encrypted Network Traffic: Session Resumption in Transport Layer Security Communication Considered Harmful to DPI

Deep packet inspection (DPI) is a basic monitoring technology, which realizes network traffic control based on application payload. The technology is used to prevent threats (e.g., intrusion detection systems, firewalls) and extract information (e.g., content filtering systems). Moreover, transport layer security (TLS) monitoring is required because of the increasing use of the TLS protocol, particularly by hypertext transfer protocol secure (HTTPS). TLS monitoring is different from TCP monitoring in two aspects. First, monitoring systems cannot inspect the content in TLS communication, which is encrypted. Second, TLS communication is a session unit composed of one or more TCP connections. In enterprise networks, dedicated TLS proxies are deployed to perform TLS monitoring. However, the proxies cannot be used when monitored devices are unable to use a custom certificate. Additionally, these networks contain problems of scale and complexity that affect the monitoring. Therefore, the DPI processing using another method requires high-speed processing and various protocol analyses across TCP connections in TLS monitoring. However, it is difficult to realize both simultaneously. We propose GINTATE, which decrypts TLS communication using shared keys and monitors the results. GINTATE is a scalable architecture that uses distributed computing and considers relational sessions across multiple TCP connections in TLS communication. Additionally, GINTATE achieves DPI processing by adding an extensible analysis module. By comparing GINTATE against other systems, we show that it can perform DPI processing by managing relational sessions via distributed computing and that it is scalable.

Emulation-Based ICT System Resiliency Verification for Disaster Situations

Disaster situations require resilient ICT systems in order to provide as good as possible communication conditions in such catastrophic circumstances. The resiliency verification of ICT systems is however difficult, because reproducing large-scale disaster conditions in production networks is impossible without affecting their users. In this paper we present an emulation-based approach for evaluating the resiliency of ICT systems in disaster situations. This is achieved by reproducing disaster-like conditions in a emulated environment running on a large-scale test bed on which actual network protocols and applications are executed in real time. The experimental results presented in the paper demonstrate how the effects of both the emulated disasters and those of the recovery technologies we subsequently deploy can be quantified objectively. This methodology can be used to improve the resilience of the systems under test.

Wireless network performance evaluation through emulation: WiMAX case study

In this paper we present a framework for evaluating wireless network performance through emulation. The framework uses a hybrid design in which the PHY layer is represented by a probabilistic model, whereas the MAC layer is executed as a functional module. Actual network applications and protocols are employed in order to create realistic test conditions. We use WiMAX as a case study to show the feasibility of our emulation approach. A standard-based model for the WiMAX PHY was developed, and it was integrated with theWiMAX MAC implementation in ns-3 to make WiMAX performance evaluation through emulation possible. Several experimental results, both in static and mobile scenarios, demonstrate the validity of the framework and indicate some of its potential uses.