Jean-François Huard

The IEEE P1520 standards initiative for programmable network interfaces

This article discusses the need for standard software interfaces for programming of networks, specifically for service and signaling control, through programming interfaces. The objective is to enable the development of open signaling, control, and management applications as well as higher-level multimedia services on networks. The scope of this effort includes ATM switches, circuit switches, IP routers, and hybrid switches such as those that provide for fast switching of IP packets over an ATM backbone. The basic ideas represented herein are in the process of development as a standard for application programming interfaces for networks under IEEE Standards Project IEEE P1520.

On QOS mapping in multimedia networks

A framework for studying ATM network QOS mapping between various levels in the information transport protocol stack and a platform for evaluating the mapping rules by performing concurrent network and application level measurements of QOS are presented. An empirical loss mapping rule between the application (frame) level and network (cell) level is given. The rule was tested using two 10 minute motion JPEG video clips and a 30 minute MPEG-2 VBR video clip under 55 different network load conditions and gives results within a 3% error margin.

A programmable transport architecture with QoS guarantees

The emergence of distributed multimedia applications exhibiting significantly more stringent quality of service requirements than conventional data-oriented applications calls for new transport protocols with different characteristics to coexist and be integrated within single applications. The different delivery requirements posed by these diverse multimedia applications often imply the need for highly customized protocol implementations. Hence, application developers are faced with the threat of code obsolescence caused by the development of even newer delivery techniques. We present an object-oriented transport architecture that allows for dynamically binding a variety of protocol stacks on a per-call basis. By binding protocol stacks together, the special needs of the application can be met without the need to rewrite the code. This differs significantly from the traditional transport architecture which assumes preinstalled transport protocol stacks that cannot be customized. To illustrate some of the advantages provided by the architecture, we describe the transport component of the first reference implementation of the 150 MPEG-4 Delivery Multimedia Integration Framework and demonstrate how quickly it was implemented in our framework.

Meeting QOS guarantees by end-to-end QOS monitoring and adaptation

The design and implementation of the transport layer of a native ATM (asynchronous tranfer mode) protocol stack and its embedding into an overall architecture that provides end-to-end quality of service (QOS) is presented. Within this architecture, the typical transport functionalities are enlarged with QOS monitoring and adaptation mechanisms. A QOS-based API (application programming interface) is proposed that shields application programmers from the complexity of QOS management and control. Both unicast and multicast connections supporting interactive multimedia applications are considered.

On Realizing a Broadband Kernel for Multimedia Networks

We describe a prototype implementation of a broadband kernel, an open programming environment that facilitates the easy creation of network services and provides mechanisms for efficient resource allocation. We present a service creation methodology and show how scalable multimedia network services can be constructed from a set of broadband kernel services. As a proof of concept, we built a multi-party teleconferencing service upon the broadband kernel. The service creation framework has the following characteristics: binding of different classes of transport protocols to the application, dynamic renegotiation of application QOS using the signalling network and, support for multiple resource reservation algorithms.

On End-to-End QOS Mapping

A framework for studying the end-to-end QOS mapping between the various levels of the transport protocol stack is presented. A platform for evaluating end-to-end QOS that supports concurrent network, transport and application level measurements is described. QOS measurements for various video clips indicate that the loss bound obtained under the assumption of uniformly distributed cell losses within a video frame is too conservative.

Realizing the MPEG-4 multimedia delivery framework

MPEG-4 is an emerging international standard based on the encoding of audiovisual data using object description techniques. This novel approach to encoding allows MPEG-4-based multimedia applications to dynamically compose complex scenes from one or more elementary stream objects. These stream objects are carried within potentially hundreds of channels. As a result, the underlying transport system must support the rapid creation and release of such channels with QoS guarantees. In addition to defining the format, structure and rules of composition of these objects, MPEG-4 also specifies a general application and transport delivery framework called the delivery multimedia integration framework (DMIF). DMIFs main purpose is to hide the details of the transport network from the user, as well as to ensure signaling and transport interoperability between end-systems. We describe the first reference implementation of the MPEG-4 DMIF standard for the ISO, including a full specification of the DMIF application interface. The DAI offers the required functionality for realizing multimedia applications without any concerns regarding the selected communication protocol. The realization of DMIF is greatly facilitated by xbind, a broadband kernel that provides connection management, routing, QoS mapping, and intelligent selection of suitable transport protocol stacks. The resulting system, called XDMIF, supports different QoS requirements, and the rapid creation and release of numerous transport channels, along with efficient management of network resources.