Quality Of Service Enabled Cross-Layer Multicast Framework For Mobile Ad Hoc Networks.

Rangkaian ad hoc bergerak merupakan suatu rangkaian tanpa wayar yang boleh dibentuk secara bebas, dinamik serta disusunatur dan ditadbir dalam bentuk topologi rangkaian sementara dan arbitrari. Mobile ad hoc networks (MANETs) are wireless networks that can freely and dynamically be created, organized and administered into arbitrary and temporary network topologies

Real Time Multiple Codecs Switching Architecture For Video Conferencing.

Trend terkini yang berhubung kait dengan khidmat video internet telah merubah dengan mendadak cara kita berfikir dan berkerja. Perkhidmatan-perkhidmatan ini telah memperluaskan ruang lingkup teknologi serta memberi peluang kepada perkembangan idea-idea penyiaran tanpa sempadan dan memendekkan jarak komunikasi secara geografi melalui telesidang video. Current trends related to internet video services have drastically transformed the way we think and work. These services have expanded the new scope of technology and have given opportunity for broadcasting ideas without any boundaries as well as shortened the vast geographical distances for communications through video conferencing

A layered multicast packet video system

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references.Issued also on microfiche from Lange Micrographics.Software based desktop videoconferencing tools are developed to demonstrate techniques necessary for video delivery in heterogeneous packet networks. Using the current network infrastructure and no network resource reservation, a one-to-many implementation is designed around a two-layer pyramidal video coder. During periods of congestion, the network routers give priority to the base layer, which by itself allows reconstruction of reasonable quality video. Receiver feedback is used to lower the output rate of the encoder's low priority pyramidal layer when all receivers are suffering high packet loss. Each of the two layers is transmitted on a separate multicast channel. Under persistent congestion, an individual receiver will discard the low priority pyramidal layer, which allows the network to prune the multicast tree 'd congestion. A new scheme is examined where if the other receivers back and avoi are agreeable, the source will respond to a receiver pruning its pyramidal layer by lowering its rate and allowing the receiver to quickly rejoin the pyramidal layer at a quality level higher than what the high priority base layer can provide by itself. Another new scheme is described where an agent on the receiver's local router provides spare capacity information to assist the receiver in its decision to rejoin the pyramidal layer

Network convergence and QoS for future multimedia services in the VISION project

The emerging use of real-time 3D-based multimedia applications imposes strict quality of service (QoS) requirements on both access and core networks. These requirements and their impact to provide end-to-end 3D videoconferencing services have been studied within the Spanish-funded VISION project, where different scenarios were implemented showing an agile stereoscopic video call that might be offered to the general public in the near future. In view of the requirements, we designed an integrated access and core converged network architecture which provides the requested QoS to end-to-end IP sessions. Novel functional blocks are proposed to control core optical networks, the functionality of the standard ones is redefined, and the signaling improved to better meet the requirements of future multimedia services. An experimental test-bed to assess the feasibility of the solution was also deployed. In such test-bed, set-up and release of end-to-end sessions meeting specific QoS requirements are shown and the impact of QoS degradation in terms of the user perceived quality degradation is quantified. In addition, scalability results show that the proposed signaling architecture is able to cope with large number of requests introducing almost negligible delay