Extending the UMIOP Specification for Reliable Multicast in CORBA

RelM: reliable multicast for mobile networks

The practical use of IP multicast is starting on the Internet with the development of many reliable multicasts in recent years, and it is supposed that IP multicast will spread rapidly in the near future. At that time, congestion of multiple multicast traffics will occur in a certain network. But the service quality in such a case has not been made clear. Then, we evaluated the reliability of multicast traffic under the congestion of multiple multicast traffics including reliable multicast traffic using an experimental network. In this paper, we present the evaluation results of the experiment, and propose a reliability control scheme applied with QoS technique for improving reliability.

Building on the success of unicast IP, IP Multicast adopted a simple, open, best-effort delivery model with many-to-many semantics. Despite several years of effort, a general, scalable and reliable end-to-end transport protocol analogous to TCP has proven elusive. Proposed solutions are either inflexible, or incur high control overhead. We present Lightweight Multicast Services (LMS), which enhance the IP Multicast model with simple forwarding services to facilitate scalable and efficient (compared to pure end-to-end) solutions to problems such as reliable multicast. In LMS, routers tag and steer control packets to preselected endpoints and perform fine-grain multicast to guide responses to a subset of the group without transport-level processing. LMS divides error control into transport and forwarding components, which allows the former to remain at the end-points while the latter is pushed to the routers, where it can be implemented very efficiently. The division is clean, resulting in significant gains in performance and scalability, while reducing application complexity. LMS reaches beyond reliable multicast to applications such as scalable collect, any-cast, and in general, any application that can benefit from a hierarchy congruent with the underlying topology.

IP multicast plays a very important role in group communication. At the network level IP multicast provides an efficient one-to-many IP packets delivery but without providing any reliability guarantees. Desirable features of reliable multicast include low end-to-end delay, high throughput and scalability. Active networks open a new perspective in providing more efficient solutions to the problems of reliability. However, the existing active reliable multicast protocols are based on receiver-initiated approach for loss recovery. In this paper we propose a new active reliable multicast protocol by combining sender- initiated and receiver-initiated approaches for loss recovery. This approach helps to solve the scalability problems like acknowledgement implosion, recovery load balancing etc.

This document generally describes how to use Forward Error Correction (FEC) codes to efficiently provide and/or augment reliability for data transport. primary focus of this document is the application of FEC codes to one-to-many reliable data transport using IP multicast. This document describes what information is needed to identify a specific FEC code, what information needs to be communicated out-of-band to use the FEC code, and what information is needed in data packets to identify the encoding symbols they carry. procedures for specifying FEC codes and registering them with the Internet Assigned Numbers Authority (IANA) are also described. This document should be read in conjunction with and uses the terminology of the companion document titled, The Use of Forward Error Correction (FEC) in Reliable Multicast.

The so-called media convergence to the Internet is foreseen. As a consequence of this convergence, MANs will face new demands not only in terms of bandwidth, but also in terms of services. To meet these new demands, new MAN architectures are required. WDM-based MAN architectures that tackle the first problem are available not only in the literature, but also on the market. In this paper we deal with the second problem. Specifically, we describe a novel WDM-based MAN architecture that supports group communication, a service that is expected to increase considerably as new applications converge to the Internet. Based on packet switching, the architecture supports both point-to-point and point-to-multipoint communication in the optical domain.

AS businesses become more dependent on IP networks, lots of real-time services are adopted and high availability in networks has become increasingly critical. With the development of carrier grade ethernet, the requirements of high speed metro ethernet device are more urgently. In order to reach the capacity of hundreds of Gbps or Tbps, most of core ethernet switches almost adopted distributed control architecture and large capacity forwarding fabric. When distributed switch works, they always have one CE and many FE. There for, it shows the feature of multicast with one sender and many receivers. It is deserved research for us how to apply reliable multicast to distributed switch inner communication system. In this paper, we present the general architecture of a distributed ethernet switch, focusing on analysis the model of internal communication subsystem. According to its character, a novel reliable multicast communication mechanism based on FEC recovery algorithm has been applied and evaluated in experiment.

Disruption Tolerant Networks (DTNs) are characterized by frequent network partitioning. This causes network connectivity to be opportunistic. In recent years, many collaborative applications have been envisioned for DTNs. These applications rely on the availability of reliable group communication protocols. To address this challenge in DTNs, we propose a scalable multicasting scheme that deterministically guarantees message delivery to all receivers in the group. Also, our scheme makes controlled use of non-multicast nodes to reduce latency of message delivery. Our work introduces a new measure called termination delay, which is the delay incurred in assuring that the receivers have obtained a copy of the message. Simulation results show that the proposed scheme has much smaller delivery latency and termination delay than other schemes in literature.

SummaryOpportunistic network applications are usually assumed to work only with unordered immutable messages, like photos, videos, or music files, while applications that depend on ordered or mutable messages, like chat or shared contents editing applications, are ignored. In this paper, we examine how total ordering can be achieved in an opportunistic network. By leveraging on existing dissemination and causal order algorithms, we propose a commutative replicated data type algorithm on the basis of Logoot for achieving total order without using tombstones in opportunistic networks where message delivery is not guaranteed by the routing layer. Our algorithm is designed to use the nature of the opportunistic network to reduce the metadata size compared to the original Logoot, and even to achieve in some cases higher hit rates compared to the dissemination algorithms when no order is enforced. Finally, we present the results of the experiments for the new algorithm by using an opportunistic network emulator, mobility traces, and Wikipedia pages.

Many applications of wireless sensor networks require collaboration among sensor nodes to achieve a common task. Moreover, this is often dynamic in nature. For instance, in multi-object tracking, sensor nodes that are tracking various moving objects must share information in order to improve the tracking quality. Thus, it is important to have a protocol that maintains group connectivity in such a setting. In this paper, we study the problem of maintaining communication paths among a group of moving agents that have interacted with one another. As its solution, we propose a data structure called the distributed collaboration graph (DCG), which is a communication graph obtained from the agent trajectories. The DCG can be constructed in a purely distributed fashion with very little cost and can be used for group discovery and for multicasting/broadcasting among agents. We also propose a distributed protocol which maintains a communication tree among the agents within the DCG while the agents are moving. This allows us to maintain group connectivity and provides the infrastructure for routing among the moving agents.

This paper focuses on two communication modes, namely Logically Instantaneity (li) and Causal Order (co). These communica- tion modes address two different levels of quality of service in message delivery. li means that it is possible to timestamp communication events with integers in such a way that (1) timestamps increase within each process and (2) the sending and the delivery events associated with each message have the same timestamp. So, there is a logical time frame in which for each message, the send event and the corresponding delivery events occur simultaneously. co means that when a process delivers a message m, its delivery occurs in a context where the receiving process knows all the causal past of m. Actually, Li is a property strictly stronger than co.The paper explores these noteworthy communication modes. Their main interest lies in the fact that they deeply simplify the design of message- passing programs that are intended to run on distributed memory parallel machines or cluster of workstations.KeywordsCausal OrderCluster of WorkstationsCommunication ProtocolDistributed MemoryDistributed SystemsLogical TimeLogical InstantaneityRendezvous

This community service activity is motivated by the local potential of Darungan Hamlet in utilizing herbal plants as health drinks, but is still limited in the aspects of processing, packaging, and marketing. This condition results in low product added value and limited economic opportunities for the community, especially members of the Catleya 3 Dasawisma Group. Motivating the mothers of the Catleya 3 Dasawisma members to become productive individuals will be an opportunity to improve and enhance the quality of family life economically. One effort that can be done is by providing scientific provisions that they can apply by creating something that has economic value. One of these is by making a health drink by utilizing natural resources that can grow well and are abundantly available in Jember. The goal of this activity is to increase the knowledge, skills, and economic independence of the community through innovative herbal dip products and the use of digital technology in marketing. The methods used include socialization, pre-tests and post-tests, training in making herbal dip with three flavors, application of production and packaging technology, and training in creating e-commerce-based marketing accounts. The target of the activity was members of the Catleya 3 Dasawisma Group located in the RT 04/RW 08 area of ​​Darungan Hamlet with a total of 20 participants. The increase in participants' understanding of the use of herbal medicines increased as seen from the average post-test score (80.53±15.80) which was higher than the pre-test score (59.47±13.93). Participants were able to produce herbal dip hygienically and of good quality, package products with attractive labels, and have knowledge related to product marketing through Shopee and Tokopedia. In addition, participants demonstrated independence in managing small businesses based on local potential with the support of production facilities and group communication. This activity succeeded in increasing community knowledge regarding the benefits of traditional medicinal ingredients and how to utilize them, entrepreneurial skills, and expanding participants' knowledge to create e-commerce accounts. Thus, the purpose of community service was achieved, namely the realization of increasing community skills in producing herbal dip sustainably.

Although IP multicast has been rapidly evolving in the last few years, the current Internet is not fully multicast-enabled because of the lack of robust inter-domain routing and controlling protocols. In this paper, we present an alternative architecture for data distribution on Internet called PSRM that realizes semantic reliable, loose synchronized, multicast data delivery. PSRM is not based on global IP multicast, instead it uses a hybrid way to combine unicast delivery with multicast delivery. In PSRM, IP multicast is used only in local area, or multicast domain, to enhance the performance, and these multicast domains are organized into a spanning tree by TCP connections. As PSRM is based upon ALF protocol architecture, we use application-defined semantics to adapt content in a heterogeneous environment. PSRM have been implemented and demonstrated by a prototype distance learning application.

Current group communication services have mostly been implemented on a homogeneous, distributed computing environment. This limits their applicability because most modern distributed computing environment are heterogeneous in nature. This paper describes the design, implementation, and performance evaluation of a CORBA group communication service. Using CORBA to implement a group communication service enables that group communication service to operate in a heterogeneous, distributed computing environment. To evaluate the effect of CORBA on the performance of a group communication service, this paper provides a detailed comparison of the performance measured from three implementations of an atomic broadcast protocol and a group membership protocol. Two of these implementations use CORBA, while the third uses UDP sockets for interprocess communication. The main conclusion is that heterogeneity can be achieved in group communication services by implementing them using CORBA, but there is a substantial performance cost. This performance cost can be reduced to a certain extent by carefully choosing a design and tuning various protocol parameters such as buffer sizes and timer values.

Multicast communication is a topic of intense study by the network research community. The IP Multicast service of the network layer doesn't provide the desired reliability to some multicast applications, and the interest towards approaches to reliable multicast communication has increased. In this work, we focus on the Server Replication method, wherein the data are replicated over a subset of the multicast-capable relaying hosts and retransmission requests from receivers are handled by the nearest Replicated Server. The problem of selecting the best subset of the multicast-capable relaying hosts to replicate the data is NP-Hard. We propose a hybrid metaheuristic to find near optimal solutions for this problem. This proposal is based on a hybrid version of the GRASP metaheuristic that incorporates data mining techniques. Experimental results show that our technique outperforms existing approaches.