6. Conclusion Multimedia Client File Servers Multimedia Transport System Negotiation at the Client Side

eter value higher (or lower depending on the QoS parameter, e.g. higher for delay and lower for jitter) than the one corresponding to a proposal we increase the mark of this proposal by one. Hence the best solution gets the minimum mark. If the mark of the best solution is zero, the negotiation succeeds. Otherwise the user must give some new values. If the best mark is got by several proposals, then they have to be compared. The best one is the cheapest one, for instance. But it may also be the one which requires the minimum delay. Acknowledgement: We would like to thank all who have contributed to this article, in particular our investigators in the CITR project. evaluate the time required to access the document, the delay of conversion (e.g. from MPEG to MJPEG, from colour to black&white), etc. Evaluation of the mark during the static negotiation For each monomedia, the server provides a set of tuples which correspond to the formats which can be supplied. In order to compute a mark to find out the best proposal regarding the user wishes, the server offers are compared with the user request. Each time the user asks for a param-First monomedia associate profile set profile_flag = profile set negotiation_flag = not_negotiated Remove the format not supported by the OS Last monomedia? Get a non negotiated monomedia Calculate the cost of the multimedia document an other monomedia to be negotiated? Calculate the mark of the best offer mark = 0? set negotiation_flag = negotiated the client accepts the cost? next monomedia Change the user wishes Change the user wishes Get a non negotiated monomedia yes yes yes yes no no no no Initiation static negotiation Thus, for each monomedia, we create a cell as shown below: Three steps have been identified while performing the local QoS negotiation: (1) initialization, (2) static negotiation, and (3) dynamic negotiation (1) Initialization: During the initialization, the monomedia are linked to a default profile of their media type. This profile is the default QoS parameters values. The flags are set (profile_flag=true, negotiation_flag=NotNegotiated). The server offers with a format that is not supported by the local end-system are removed. (2) Static negotiation: We consider all the monomedia that have the negotiation flag set to NotNe-gotiated. Then, the server offers are compared with the user wishes and the best proposal is determined. The best proposal is the …