Shie-Yuan Wang

HAWAII: a domain-based approach for supporting mobility in wide-area wireless networks

Mobile IP is the current standard for supporting macromobility of mobile hosts. However, in the case of micromobility support, there are several competing proposals. In this paper, we present the design, implementation, and performance evaluation of HAWAII, a domain-based approach for supporting mobility. HAWAII uses specialized path setup schemes which install host-based forwarding entries in specific routers to support intra-domain micromobility. These path setup schemes deliver excellent performance by reducing mobility related disruption to user applications. Also, mobile hosts retain their network address while moving within the domain, simplifying quality-of-service (QoS) support. Furthermore, reliability is achieved through maintaining soft-state forwarding entries for the mobile hosts and leveraging fault detection mechanisms built in existing intra-domain routing protocols. HAWAII defaults to using Mobile IP for macromobility, thus providing a comprehensive solution for mobility support in wide-area wireless networks.

The design and implementation of the NCTUns 1.0 network simulator

This paper presents the design and implementation of the NCTUns 1.0 network simulator, which is a high-fidelity and extensible network simulator capable of simulating both wired and wireless IP networks. By using an enhanced simulation methodology, a new simulation engine architecture, and a distributed and open-system architecture, the NCTUns 1.0 network simulator is much more powerful than its predecessor--the Harvard network simulator, which was released to the public in 1999. The NCTUns 1.0 network simulator consists of many components. In this paper, we will present the design and implementation of these components and their interactions in detail.

NCTUns tool for wireless vehicular communication network researches

Several goals such as improving road safety and increasing transport efficiency are being pursued in intelligent transportation systems (ITS). Wireless vehicular communication is one technology to achieve these goals. Conducting vehicular experiments on the roads is an approach to studying the effectiveness of wireless vehicular communication. However, such an approach is costly, hard-to-control (repeat), dangerous, and infeasible when many vehicles and people are involved in the field trial. In contrast, the simulation approach does not have these problems. It is a very useful approach and complements the field trial approach. This paper presents NCTUns, an open source integrated simulation platform, for wireless vehicular communication network researches. This tool tightly integrates network and traffic simulations and provides a fast feedback loop between them. Therefore, a simulated vehicle can quickly change its driving behavior such as moving speed and direction when it receives a message from the wireless vehicular communication network. This capability is required by several novel ITS applications such as active collision avoidance systems. In this paper, we present the design, implementation, validation, and performance of this tool.

NCTUns 5.0: A Network Simulator for IEEE 802.11(p) and 1609 Wireless Vehicular Network Researches

NCTUns is a novel network simulator and emulator that has many unique features over traditional network simulators and emulators. It is an open-source software running on Linux and is being used by many researchers in the world. According to the NCTUns official Web site (http://NSL.csie.nctu.edu.tw/nctuns.html), as of June 1, 2008, more than 11,546 people from 124 countries have registered and downloaded this software and these numbers are still fast increasing. In its 5.0 release, NCTUns provides a complete implementation of the IEEE 802.11(p)/1609 standards defined for wireless vehicular networks. In this paper, we present the capabilities of NCTUns 5.0 focusing on its uses for IEEE 802.11(p)/1609 wireless vehicular network researches.

EstiNet openflow network simulator and emulator

In this article, we introduce the EstiNet OpenFlow network simulator and emulator, and present its support for testing the functions and evaluating the performances of software-defined networks¿ OpenFlow controller¿s application programs. EstiNet uses an unique kernel reentering simulation methodology to enable unmodified real applications to run on nodes in its simulated network. As a result, without any modification, real NOX/POX or Floodlight OpenFlow controllers can readily run on a host in an EstiNet simulated network to control thousands of simulated OpenFlow switches. EstiNet has the characteristics of a simulator and an emulator at the same time. It combines the advantages of the simulation and emulation approaches without their respective shortcomings. EstiNet uses real OpenFlow controller programs, real network application programs, and the real TCP/IP protocol stack in the Linux kernel to generate correct, accurate, and repeatable SDN application performance results. In this article, we compare EstiNet with ns-3 and Mininet regarding their capabilities, performance, and scalability.

NCTUns 4.0: An Integrated Simulation Platform for Vehicular Traffic, Communication, and Network Researches

In this paper, we present an integrated simulation platform, called NCTUns, for vehicular traffic, communication, and network researches. This platform combines the capabilities supported by a network simulator and those supported by a traffic simulator. With these simulation capabilities, NCTUns can be used to design protocols for intelligent transportation systems (ITS) communication networks such as a wireless vehicular communication network. Besides, the novel architecture of the platform enables the real-world Linux protocol stack and any real-world application to be used in simulations of such networks. In this paper, we present the design of NCTUns for supporting ITS researches and show its scalability.

A Practical Routing Protocol for Vehicle-formed Mobile Ad Hoc Networks on the Roads

An IVC (Inter-vehicle communication) network is a type of mobile ad hoc networks (MANET) in which high-speed vehicles send, receive, and forward packets via other vehicles on the roads. An IVC network can provide useful applications in future Intelligent Transportation Systems. However, due to frequent network topology changes, a routing path in an IVC network breaks easily. As such, a routing protocol proposed for general MANET (e.g., AODV) performs poorly in IVC networks. To address this problem, we designed and implemented an intelligent flooding-based routing protocol and conducted several field trials to evaluate its performance on the roads. Results obtained from field trials show that (1) our protocol outperforms AODV significantly on IVC networks, and (2) our protocol can make many useful services such as email, ftp, web, video conferencing, and video broadcasting applicable on IVC networks for vehicle users.

Using TCP congestion control to improve the performances of optical burst switched networks

We propose using a modified TCP decoupling approach as a congestion control mechanism for optical burst switched networks. The TCP decoupling approach is a novel way that is applicable to TCP congestion control of any traffic flow (which can be an aggregate) in a network. Since this approach is generic, it has found applications in several areas. In the optical burst switching (OBS) area, because the basic mechanism of the TCP decoupling approach matches the mechanism of the OBS very well, use of a modified TCP decoupling approach to control the traffic load handled by an OBS switch and to regulate the timing in sending bursts is proposed. Our simulation results show that this approach enables an OBS switch to achieve high link utilization while maintaining very low packet (burst) drop rate.

TCP trunking: design, implementation and performance

A TCP trunk is an aggregate traffic stream whose data packets are transported at a rate dynamically determined by the TCPs congestion control. Typically such a trunk is implemented on top of a layer-2 virtual circuit or an MPLS label switched path. A management TCP connection is used to regulate the rate at which the trunk transmits its data packets. Setting up a TCP trunk over a circuit or a path is easy, involving only the two end nodes of a trunk to implement the management TCP connection. A TCP trunk can guarantee minimum bandwidth while being able to grab additional bandwidth when it is available. When carried by a TCP trunk, UDP flows will be constrained in their bandwidth usage, although they themselves do not perform congestion control. Experiments on testbed networks have validated these properties. TCP trunking can be an effective tool for network operators in managing bandwidth sharing between aggregates.

The design and implementation of the NCTUns network simulation engine

Abstract NCTUns is a network simulator running on Linux. It has several unique advantages over traditional network simulators. This paper presents the novel design and implementation of its simulation engine. This paper focuses on how to combine the kernel re-entering and discrete-event simulation methodologies to execute simulations quickly. The performance and scalability of NCTUns are also presented and discussed.