Haptic Virtual Environment Performance Over IP Networks: A case study Rima Tfaily Souayed, Dominique Gaiti Guy Pujolle Université de Technologies de Troyes Université Pierre et Marie Curie 12 Rue Marie Curie, BP 2060 8 Rue du Capitaine Scott 10010 Troyes Cedex, France 75015 Paris, France {Rima.Tfaily, Dominique.Gaiti}@utt.fr Guy.pujolle @lip6.fr Wai Yu,Qiang Gu,Alan Marshall Queen’s University of Belfast School of Electric. & Electro. Eng. Stranmillis Road BT9 5AH- Belfast, UK W.Yu@qub.ac.uk , {Qiang.Gu, Alan.Marshall}@ee.qub.ac.uk Abstract This paper reports on the quality of service (QoS) requirements and the performance of Virtual Environment (VE) Applications deployed in IP networks. We are interested specifically in systems that support communication with end-user through force feedback devices known as haptic interfaces. Little is known about networked haptic interfaces in VE. Our goal is to understand such application QoS requirements as well as the effect of other traffic when they co-exist in the same network. In this paper, we compare the peer-to-peer model with the client-server model. Our motivation is to deploy Distributed Haptic VE applications (DHVE) over a network connecting two departments of Queen’s university of Belfast. This deployment will be used for educational purposes and for implementing further research in this area, and will be evaluated by end-users; hence, the essential realisation of network-based DHVE under realistic network conditions. A set of experiments was conducted to achieve this aim and their results are presented in this paper. Keywords Haptic Virtual Environment, PHANToM, Force Feedback, QoS, IP Networks. I. Introduction Virtual environments (VE) are usually referred to computer-generated-3D worlds where users reside and interact with each other through various computer human interfaces [5]. Haptic Virtual Environments (HVE) is a subset of VE, where, in addition, to visual feedback, force or touch feedback is also provided to the user through a haptic device. HVEs may be categorised based on the location of the haptic device and the haptic simulation. In standalone HVE, for example, training simulation or virtual prototyping, both the haptic virtual environment and the haptic device are on the same machine [5]. In distributed HVEs (DHVE) or otherwise known as tele-haptic applications, the haptic device is separate from the environment and remotely affects and manipulates it. Tele-surgery and tele-operation are two examples of DHVEs. A special case of DHVEs is a collaborative HVE where multiple users, each with his/her own haptic device collaboratively manipulate objects in a shared virtual environment. DHVE applications and services are increasing and cover many fields including: health, tele-learning, industrial training, chemistry, etc; hence, it is important to determine their requirements in term of network resources as well as to measure their affect by other traffic when they co-exist in the same network. DHVEs are shared simulated worlds, which normally run on several network-connected PCs. Each runs a compatible DVE application [2]. DVE applications allow users to interact and collaborate in real time, sharing the same virtual world. Each DVE application, participating in the simulation, has a number of objects or entities. The changing states of entities are communicated over the network by sending “update messages”. DHVEs have their own criteria that are influenced by network parameters and application parameters [20]. These criteria are the following: Proceedings of the Seventh IEEE International Symposium on Distributed Simulation and Real-Time Applications (DS-RT’03) 1530-1990/03 $17.00 © 2003 IEEE