Satoshi Itaya

A high-performance multimedia streaming model on multi-source streaming approach in peer-to-peer networks

A peer-to-peer (P2P) network is composed of large number of peer computers which are cooperating by exchanging messages in networks. In multimedia streaming applications, multimedia data is required to be efficiently and reliably delivered to processes in a real-time manner. In order to support scalable and reliable multimedia streaming service, we newly discuss a multi-source streaming way where multiple source peers transmit packets of multimedia content to each peer. Each of the source peers transmits different packets with some redundancy to the peer in order to be tolerant of some number of faulty peers and packets lost.

A fault-tolerant model for wireless sensor-actor system

In a wireless sensor and actor network (WSAN), a group of sensors and actors are geographically distributed and linked by wireless networks. Sensors gather information sensed for an event in the physical world and send them to actors. Actors perform appropriate actions on actuation devices by making a decision on receipt of sensed information from sensors. Sensors are low cost, low powered devices with limited energy, computation, and wireless communication capabilities. Sensors may not only stop by fault but also suffer from arbitrary faults. Furthermore, wireless communication is less reliable due to noise and shortage of power of sensors. Reliable real time communication among sensors, actors, and actuation devices, is required in WSAN applications. We newly propose a multi-actor/multi-sensor (MAMS) model. In addition, multiple actors may perform actions on receipt of sensed information. Multiple redundant execution of an action on each device has to be prevented and conflicting actions on each device from multiple actors have to be serialized. In this paper, we discuss how to make WSAN reliable and available and how to reliably and non-redundantly perform actions with realtime constraints.

Scalable peer-to-peer multimedia streaming model in heterogeneous networks

In a peer-to-peer (P2P) overlay network, a large number and various types of peer processes are cooperating by using multimedia contents like movies. Multimedia streaming is a key technology to realize multimedia applications. Here, multimedia contents are required to be reliable and continuously delivered to processes in a realtime manner. In this paper, we newly discuss a heterogeneous asynchronous multi-source streaming (HAMS) model where multiple contents peers transmit packets of a multimedia content to a requesting leaf peer to increase the throughput, reliability, and scalability in P2P overlay networks.

HAMS: scalable peer-to-peer multimedia streaming model in heterogeneous networks

In a peer-to-peer (P2P) overlay network, a large number and various types of peer processes are interconnected in networks and are cooperating by using multimedia contents like movies and music. Here, multimedia contents are in nature distributed to peers in various ways like downloading and caching to the peers. Multimedia streaming is a key technology to realize multimedia applications in networks. In multimedia streaming applications, multimedia contents are required to be reliable and continuously delivered to processes in a real-time manner. Some contents peer may not send packets of a content at a required rate due to limited computation resource and a communication channel may not support enough Quality of Service (QoS) due to congestions and faults. Thus, P2P overlay networks are in nature heterogeneous. In this paper, we newly discuss a heterogeneous asynchronous multisource streaming (HAMS) model where multiple contents peers transmit packets of a multimedia content to a requesting leaf peer to increase the throughput, reliability, and scalability in P2P overlay networks. Here, some pair of channels between contents and leaf peers may support different QoS. Peers may be faulty and some pair of contents peers may have different transmission rates. Finally, we show the HAMS model can support higher throughput and shorter transmission time than the other models in the evaluation.

Distributed Coordination Protocols to Realize Scalable Multimedia Streaming in Peer-to-Peer Overlay Networks

Multimedia contents are distributed to peers in various ways in peer-to-peer (P2P) overlay networks. A peer which holds a content, even a part of a content can provide other peers with the content. Multimedia streaming is more significant in multimedia applications than downloading ways in Internet applications. We discuss how to support peers with multimedia streaming service by using multiple contents peers. In our distributed multi-source streaming model, a collection of multiple contents peers in parallel transmit packets of a multimedia content to a requesting leaf peer to realize the reliability and scalability without any centralized controller. Even if some peer stops by fault and is degraded in performance and packets are lost and delayed in networks, a requesting leaf peer receives every data of a content at the required rate. We discuss a pair of flooding-based protocols, distributed and tree-based coordination protocols DCoP and TCoP, to synchronize multiple contents peers to reliably and efficiently deliver packets to a requesting peer. A peer can be redundantly selected by multiple peers in DCoP but it taken by at most one peer in TCoP. We evaluate the protocols in terms of how long it takes and how many messages are transmitted to synchronize multiple contents peers

QoS-based synchronous/asynchronous data transmission model in group communication

A large-scale network like the Internet is composed of various types of communication channels. Here, each communication channel supports quality of service (QoS) which may be different from others. In group communication, each process sends a message to multiple processes while receiving messages from multiple processes. In addition, messages are required to be causally delivered. In order to realize the atomic and ordered delivery of messages, even if a process with enough QoS channel receives messages, the process has to wait to deliver the messages until another process with lower QoS channel receives the messages. Thus, multimedia data cannot be delivered to processes so as to satisfy the real-time constraint if a slower process is included in a group. In this paper, we discuss group communication protocols by which multimedia messages can be delivered to a process with same time constraint properties which satisfy QoS requirements of multimedia messages.

Distributed Coordination for Scalable Multimedia Streaming Model

We discuss how to realize the multimedia streaming service by using multiple peers in a peer-to-peer (P2P) overlay network. Here, multimedia contents are required to be reliably delivered to processes in a real-time manner. Multimedia contents are distributed to peers in various ways like downloading. A peer which holds a content can provide other peers with the content. In our distributed multi-source streaming model, a collection of peers in parallel and redundantly transmit packets of a multimedia content to a requesting peer to realize the reliability and scalability without centralized controller. Even if some peer is faulty and packets are lost and delayed, a requesting peer receives every data of a content at the required rate. Furthermore, multiple peers start transmitting packets to a leaf peer and change packets to be transmitted and transmission rate without centralized controller to support shorter response time.

Scalable multimedia streaming model in heterogeneous networks

In a Peer-to-Peer (P2P) overlay network, a large number and various types of peers are cooperating by exchanging multimedia contents. Here, multimedia streaming is a key technology to realise multimedia applications. In multimedia streaming applications, multimedia contents are required to be efficiently delivered to processes in a real-time manner. Some contents peer may not send packets at a required rate and a communication channel may not support enough Quality of Service (QoS). In this paper, we newly discuss a Heterogeneous Asynchronous Multi-Source Streaming (HAMS) model where multiple contents peers transmit packets of a multimedia content to a requesting leaf peer to realise high reliability and scalability.

Distributed coordination for scalable multi-source multimedia streaming model

Multimedia contents are distributed to peers in various ways like downloading in peer-to-peer (P2P) overlay networks. A peer which holds a content, even a part of a content can provide other peers with the content. Multimedia streaming is more significant in multimedia applications than downloading way. We discuss how to support the multimedia streaming service by using multiple contents peers. In our distributed multi-source streaming (MSS) model, a collection of peers in parallel transmit packets of a multimedia content to a requesting peer to realize the reliability and scalability without centralized controllers. Even if some peer stops by fault and is degraded in performance and packets are lost and delayed in networks, a requesting peer receives every data of a content at the required rate. We discuss how to synchronize multiple contents peers to reliably and efficiently deliver packets to a requesting peer

Asynchronous Multi-source Streaming Protocol to Realize High-Performance Multimedia Communication

In multimedia streaming applications on P2P overlay networks, multimedia data in contents peers has to be efficiently and reliably delivered to large number of leaf peers in a real-time manner. In this paper, we propose an asynchronous multi-source streaming (AMSS) model where multiple contents peers transmit packets of multimedia contents to each requesting leaf peer. Here, each of the contents peers transmits different packets with some redundancy to the leaf peer. Even if some contents peers are faulty or packets are lost, each leaf peer can receive all the packets in a real-time manner. In addition, multiple contents peers transmit in parallel packets to leaf peers