Papers by Francisco Garcia
The integration of distributed multimedia systems around the unifying theme of quality of service... more The integration of distributed multimedia systems around the unifying theme of quality of service (QOS) is addressed. A set of key QOS requirements is presented and mapped onto a provisional QOS architecture (QOS-A) that has emerged from a experimental system designed and implemented at Lancaster. The scope of the discussion is limited to aspects of a QOS-A for the support of continuous media communications. Also, the focus is on asynchronous transfer mode (ATM) at the network layer rather than the full range of multiservice networks. Functions and mechanisms for QOS support are examined and placed within the evolving QOS-A
In this paper we describe ongoing work in protocol support for distributed multimedia application... more In this paper we describe ongoing work in protocol support for distributed multimedia applications. This work concerns the provision of suitable transport mechanisms to convey multimedia information (text, and digital voice and video) between multimedia workstations in a distributed system. There are two parts to the Lancaster multimedia work. First, we have developed an abstract model for multimedia communications that is based on the use of streams; and second, we have built an experimental system on which to test the implementation of protocols based on this model. This paper reports on both aspects of the Lancaster work, describing the results so far and identifying areas to be investigated further.
IEEE Journal on Selected Areas in Communications, 1996
The nature of distributed multimedia applications is such that they require multipeer communicati... more The nature of distributed multimedia applications is such that they require multipeer communication support mechanisms. The multimedia traffic needs to be delivered to end-systems, networks and end-users in a form that they can handle while satisfying the constraints imposed by the multimedia application. Quality of Service (QoS) mechanisms that can ensure full quality media playout at high-performance workstations, while at the same time providing appropriately filtered lower quality media for playout at other end-systems, are required. Existing multicast support mechanisms are deficient for this purpose, in a heterogeneous environment, because they work on a common denominator premise where the quality delivered depends on the least capable link or node involved in the multicast session. This paper proposes and analyses the use of filtering mechanisms as a means of supporting disparate receiver capabilities and QoS requirements. The paper describes the implementation of a number of filtering mechanisms and highlights the communications architecture within which these mechanisms are built. This architecture constitutes a specific network topology and a new protocol family developed within a UNIX-like operating system.
Computer Communication Review, 1992
The desire lo transfer continuous media such a.r digital audio and video across packet switched n... more The desire lo transfer continuous media such a.r digital audio and video across packet switched networks imposes a number of new requirements on transport level communication services. This paper identifies a number of these requirements in the context of an experimental distributed multimedia
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Papers by Francisco Garcia