Low weight congestion control for multi sender applications

This paper presents a prototype for single-rate reliable multicast congestion control, which has been built into an existing commercial whiteboard. The prototype was developed using a novel scheme that was engineered around conflicting industry provided requirements for collaborative workspaces. This required the scheme to be both low-weight when used with many senders and compatible with NAT, firewalls and reflectors. The key to overcome this conflict was to combine congestion control and recovery feedback. This differs from many current solutions in that they are often designed for use with a wide variety of protocols and thus operate independent of the recovery mechanism. This paper does not go into the detail required to specify a protocol but instead discusses a few important design requirements for multi-sender applications, which are generally not considered by current research, and describes an approach towards meeting these requirements. Document type: Part of book or chapter of boo

Technology for supporting informal communication in multimedia conferencing systems

This dissertation presents work on designing multimedia conferencing systems that better support informal communication among groups. In this case the term “informal” refers to the ability of the system to support unplanned communication and side conversations between members of the group. This contrasts from the classical goal of video-conferencing systems, which was to support room-to-roommeetings between participants at scheduled intervals. The work in the dissertation includes problems related to computer communication and human computer interaction in order to achieve this goal. More specifically, work in the field of computer communication is presented on how to design multimedia systems that use available network resources more efficiently so that a larger number of end users can be supported. This problem of scalability is important when trying to support informal communication because the room-to-room model of deployment is viewed as the primary reason why classical conferencing systems could not support side conversations between participants. Thus, while it may be an option to pack a large number of participants into a few conferencing rooms for a formal meeting, informal communication is better achieved when each participant can join from their own conferencing client. Other work in the field of human computer interaction deals with various usability issues related to improving the flow of unplanned communication. This includes work on the visualization of file systems in order to make it easier for users to locate shared files when coordination and planning on the structure of the file system has not taken place. It also includes user studies that focus on identifying new requirements and new design goals for supporting spontaneous communication. In addition, some interdisciplinary work is also included that seeks to make it easier to unify research in computer communication and human computer interaction so that network resources may be allocated to the various functions in these applications while giving the user the most benefit. A variety of methods are used to investigate the problems including the design and testing of prototypes and algorithms and studies of users in laboratory and naturalistic settings.Godkänd; 2005; 20060916 (ysko)</p

Low-Weight Congestion Control for Multi-sender

This paper presents a prototype for single-rate reliable multicast congestion control, which has been built into an existing commercial whiteboard. The prototype was developed using a novel scheme that was engineered around conflicting industry provided requirements for collaborative workspaces. This required the scheme to be both low-weight when used with many senders and compatible with NAT, firewalls and reflectors. The key to overcome this conflict was to combine congestion control and recovery feedback. This differs from many current solutions in that they are often designed for use with a wide variety of protocols and thus operate independent of the recovery mechanism. This paper does not go into the detail required to specify a protocol but instead discusses a few important design requirements for multi-sender applications, which are generally not considered by current research, and describes an approach towards meeting these requirements

Efficient Workspaces through Semantic Reliability

Transport level protocols typically provide &quot;best-effort&quot; data delivery where no attempts are made to recover lost packets, or &quot;reliable&quot; data delivery where techniques are used to ensure that all data sent out eventually reaches the receiver(s). However, it has been suggested that some applications will perform better when using dynamically configurable reliability based on application level semantics. A general framework has been created with the intent of delivering this type of semantic reliability to a wide variety of applications, but to date little research has been done to demonstrate how any applications can benefit from the use of such a framework. This paper addresses this problem in that it discusses semantic reliability in the context of collaborative workspaces

Low-Weight Congestion Control for Multi-sender Applications

This paper presents a prototype for single-rate reliable multicast congestion control, which has been built into an existing commercial whiteboard. The prototype was developed using a novel scheme that was engineered around conflicting industry provided requirements for collaborative workspaces. This required the scheme to be both low-weight when used with many senders and compatible with NAT, firewalls and reflectors. The key to overcome this conflict was to combine congestion control and recovery feedback. This differs from many current solutions in that they are often designed for use with a wide variety of protocols and thus operate independent of the recovery mechanism. This paper does not go into the detail required to specify a protocol but instead discusses a few important design requirements for multi-sender applications, which are generally not considered by current research, and describes an approach towards meeting these requirements

Low-weight congestion control for multi-sender applications

This paper presents a prototype for single-rate reliable multicast congestion control, which has been built into an existing commercial whiteboard. The prototype was developed using a novel scheme that was engineered around conflicting industry provided requirements for collaborative workspaces. This required the scheme to be both low-weight when used with many senders and compatible with NAT, firewalls and reflectors. The key to overcome this conflict was to combine congestion control and recovery feedback. This differs from many current solutions in that they are often designed for use with a wide variety of protocols and thus operate independent of the recovery mechanism. This paper does not go into the detail required to specify a protocol but instead discusses a few important design requirements for multi-sender applications, which are generally not considered by current research, and describes an approach towards meeting these requirements.Validerad; 2002; 20060918 (ysko

Applying User-behavior to Bandwidth Adaptations in Collaborative Workspace Applications and Video Conferencing

A bandwidth-sharing scheme for group video conferencing is presented in this paper. The key features of the scheme are the monitoring of user behavior and message passing, which are used by each client in order to identify and report their interest in other group members. Each video sender operates on the information about other users&apos; interest in order to adjust the sender&apos;s own frame rate, resolution, and ultimately bandwidth consumption in an attempt to satisfy the current interests of the receivers as well as the overall bandwidth constraints of the session. A general framework, an initial prototype, and a bandwidth allocation algorithm are presented together with experimental results. The experiences from the prototype have prompted refinements to the bandwidth-allocation algorithm that will be important for future implementations. We also conclude that the necessary messaging will not add a significant amount of bandwidth

User-interest Driven Video Adaptation for Collaborative Workspace Applications

This paper presents a bandwidth sharing scheme for group video conferencing