This paper presents the architecture and implementation of a secure wide-area Service Discovery Service (SDS). Service providers use the SDS to advertise descriptions of available or already running services, while clients use the SDS to compose complex queries for locating these services. Service descriptions and queries use the eXtensible Markup Language (XML) to encode such factors as cost, performance, location, and device- or service-specific capabilities. The SDS provides a fault-tolerant, incrementally scalable service for locating services in the wide-area. Security is a core component of the SDS: communications are both encrypted and authenticated where necessary, and the system uses a hybrid access control list and capability system to control access to service information. Wide-area query routing is also a core component of the SDS: all information in the system is potentially reachable by all clients

Most conferencing systems are focused on facilitating one of two types of meetings: those in a single room, consisting entirely of colocated participants, or those with isolated individuals at different physical locations. Our experiences are of a third style: hybrid meetings consisting of both colocated groups and isolated participants. We illustrate the limitations of using an existing desktop-based tools in the shared meeting room portion of this hybrid meeting style, and propose adding a software control substrate matched to the specifics of the application to address the inadequacies. We derive requirements for the in-room applications, and, as a concrete example from the domain, describe the design and implementation of an application for manipulation of in-room shared video display. Our design employs a user interface split across multiple physical devices paired with a control protocol managing communication between them. The client portion runs on wirelessly-connected portable...

We would like to acknowledge and thank several individuals who have helped develop the CHOICE network. In particular, Anand Balachandran, and Srinivasan Venkatachary are two of the original designers and implementers of PANS. Stephen Dahl helped us deploy the network at the Crossroads Mall; Pierre De Vries handled the legal formalities and helped us with usability issues while being our liaison with the product groups Paul Hoeffer designed our web interaction. We also thank Prof. Dave Johnson of Rice University, and Prof. Mary Baker of Stanford University for the well appreciated constructive discussions.

This paper presents a unified set of abstractions and operations for hardware devices, software processes, and media data in a distributed audio and video environment. These abstractions, which are provided through a middleware layer called Indiva, use a file system metaphor to access resources and high-level commands to simplify the development of Internet webcast and distributed collaboration control applications. The design and implementation of Indiva are described and examples are presented to illustrate the usefulness of the abstractions.

Future multimedia services are expected to be available anytime, anywhere, and by using any computing device. However, clients of a multimedia service may vary significantly in their processing capability and network connectivity. In addition, even between the same multimedia service provider and client, there may be dynamic variation in end-to-end resource availability. In such a dynamic and heterogeneous environment, the challenge in multimedia service is to provide each client with satisfactory Quality of Service (QoS), under the constraint of current end-to-end resource availability. Many existing QoS adaptation techniques are very service-specific, and targets only specific types of critical resources. In this paper, we present ServiPoly , an enabling framework for multimedia service provision in dynamic and heterogeneous environments. Instead of providing a specific technique, ServiPoly provides uniform programming interface, architecture, and runtime support that integrate and ...

Abstract: Internet services can now be used from mobile terminals. The main standard supporting this technology, WAP, will enable new services since it is compatible with network technologies like IP and UMTS. In parallel, powerful methods must be proposed to validate the underlying protocols in order to guaratee reliability and interoperability of new products. Our work, based on formal methods, contributes to WAP testing efforts by proposing an approach to the development of interoperability tests. We illustrate this approach with the design of tests suites for the WSP-protocol operating over a WAP transaction service.

This document is devoted to organization of different levels of Service Discovery Protocol at Bluetooth, and as to relationship of devices at usage of it. Keywords Service Discovery Protocol, SDP, Bluetooth, Service Class, Service Attribute, SDP Client, SDP Server 1. INTRODUCTION Service Discovery Protocol (SDP) enables network devices, applications, and services to seek out and find other complementary network devices, applications, and services needed to properly complete specified tasks. The network computing industry has eagerly embraced technologies in this field, welcoming an ever-increasing variety of new service discovery protocols. In this paper will described Bluetooth SDP [1] offer their own unique service discovery methods as part of their protocol stack. Sun has enriched Java with its introduction of Jini. Microsoft promotes Universal Plug and Play (UPnP). The IETF has adopted the service location protocol (SLP). Salutation, an independent consortium of leading techn...

This paper motivates and describes a document-centric framework for component-based distributed systems. In the framework, XML documents are associated with programs that provide either static, immutable interface descriptions as advertisements of functionality at the server-side, or specification of manipulations of these server descriptions to express their usage at clients. We illustrate how the framework allows for 1) remapping of a portion of an existing user interface to a new room control (for example, due to movement of the terminal) 2) viewing of arbitrary subsets andcombinations of the functionality available, and 3) mixing dynamically-generated user interfaces with existing user interfaces. Theuse of a document-centric framework in addition to a conventional object-oriented programming language provides a number of key features. One of the most useful is that it exposes program/UI to referent objects mappings, thereby providing a standard location for manipulation of this in...

In the near future people will be able to move freely and still have seamless network and Internet connectivity. One implication of this new style of interaction is an increased diversity in the types of devices which will be used to maintain connectivity. While many of the Internet protocols have proven successful and long-lived in traditional networks, we believe they will be inappropriate for use in communicating among limited-capability devices. In this paper, we introduce a new network layer protocol for intra-network communication in clouds containing devices with varying processing and communication capabilities. Our proposed protocol, called Pseudo-IP, is designed to operate among devices in the farthest branches/leaves of an intranet while providing inter-network connectivity with other clouds and with the existing IP-based Internet infrastructure. PseudoIP will accommodate a wide range of devices with varying power, processing, and communication capabilities, while supporting...

In the near future users will be able to move freely and still have seamless network and Internet connectivity. We envision that the Internet of the future will interconnect mobile or stationary clouds into the existing IP infrastructure. While many of the Internet protocols are immensely successful in traditional networks, we believe they will be inappropriate for communication among limited-capability devices in amorphous clouds. The question we are trying to address is whether the network layer services provided by IPv4 and IPv6 [1] are necessary and sufficient for supporting heterogeneous devices in these highly dynamic, arbitrarily dense environments. The problem with an IP infrastructure is that, for certain applications, it adds unnecessary complexity. The proposed research is based on the specification of a new network layer protocol for intra-network communication in clouds containing devices with limited processing and communication capabilities. Our Pseudo-IP protocol is des...