Reliable Multicast Transport Protocol Research Articles

A Model-based Scalable Reliable Multicast Transport Protocol for Satellite Networks

In this paper, we design a new scalable reliable multicast transport protocol for satellite networks (RMT). This paper is the extensions of paper in [18]. The proposed protocoldoes not require inspection and/or interception of packets at intermediate nodes. The protocol would not require anymodification of satellites, which could be bent-pipe satellites or onboard processing satellites. The proposed protocol is divided in 2 parts: error control part and congestion control part. In error control part, we intend to solve feedback implosion and improve scalability by using a new hybrid of ARQ (Auto Repeat Request) and adaptive forward error correction (AFEC). The AFEC algorithm adapts proactive redundancy levels following the number of receivers and average packet loss rate. This leads to a number of transmissions and the number of feedback signals are virtually independent of the number of receivers. Therefore, wireless link utilization used by the proposed protocol is virtually independent of the number of multicast receivers. In congestion control part, the proposed protocol employs a new window-based congestion control scheme, which is optimized for satellite networks. To be fair to the other traffics, the congestion control mimics congestion control in the wellknown Transmission Control Protocol (TCP) which relies on “packet conservation” principle. To reduce feedback implosion, only a few receivers, ACKers, are selected to report the receiving status. In addition, in order to avoid “drop-to-zero” problem, we use a new simple wireless loss filter algorithm. This loss filter algorithm significantly reduces the probability of the congestion window size to be unnecessarily reduced because of common wireless losses. Furthermore, to improve achievable throughput, we employ slow start threshold adaptation based on estimated bandwidth. The congestion control also deals with variations in network conditions by dynamically electing ACKers.

A reliable multicast transport protocol for information-centric networks

In the past few years, many researchers have argued that the Internet should transit from its traditional endpoint-centric architecture to an information-centric paradigm. One of the advantages of the information-centric model is that the network can easily aggregate requests for the same content and serve them via multicast. Indeed, most information-centric architectures proposed to date offer native support for multicast, promising a vast improvement in the efficiency of content distribution. However, designing efficient reliable transport protocols for multicast is a largely open issue, due to the problem of feedback implosion towards the sender as group size grows. In this paper we propose RMTPSI, a retransmission-based reliable error control protocol for multicast communication designed specifically for information-centric networks. We compare RMTPSI with existing approaches proposed for IP multicast and evaluate its performance via simulation, showing that our approach leads to more efficient content distribution and error recovery than previous solutions.

NEMO 환경에서 RMTP를 지원하기 위한 개선된 경로 최적화 알고리즘

All IP 기반의 네트워크를 위해 이동 단말의 이동성을 지원하는 프로토콜이 현재까지 진행 중이다. 특히 NEMO(NEtwork MObility)는 이동 단말 각각의 이동성을 지원하는 방법이 아닌 이동 단말 그룹, 즉 이동 네트워크의 이동성을 제공하는 것을 목적으로 연구되고 있다. 또한 이러한 환경에서 유선 기반의 기존 프로토콜을 통해 무선이라는 제약을 극복하고 마치 유선 통신처럼 성능을 유지하려는 연구가 진행 중이다. 특히 NEMO 환경에서 기존의 멀티캐스트 방식을 적용하려는 연구가 진행 중이지만, 신뢰성을 가진 멀티캐스트 연구는 전무하다. 따라서 본 논문에서는 NEMO 환경에서 기존 멀티캐스트에 보다 높은 신뢰성을 기반으로 제안된 RMTP(Reliable Multicast Transport Protocol)를 적용하는 방법을 고려하여, 기존 NEMO 환경에 RMTP를 적용하였을 때 발생하는 문제점을 해결하는 효율적인 알고리즘을 제안한다. 또한 본 논문에서 기존의 NEMO 환경에서 RMTP를 그대로 적용했을 때와 제안된 알고리즘을 Delay 측면에서 AR(Access Router)과 TLMR(Top-Level Mobile Router)간의 전송 성공확률과 NEMO 레벨에 따른 성능 비교를 통해 제안된 알고리즘의 우수함을 증명한다. There are lots of researches for mobility of MS(mobile station) in All IP based network. Specially, NEMO(NEwork MObility) is not supporting mobility of each MS but supporting mobility of network that include group of MS. Some research try to overcome limitation of wireless with the protocol in wired state and it maintains the performance such as wire environment. There are no researches about multicast with reliability in NEMO. Therefore, this paper suggests efficient algorithm to solve problems when RMTP(Reliable Multicast Transport Protocol) apply to NEMO environment to support high reliability with multicast. And this paper shows the better performance of proposed algorithm for delay and transmission rate between AR and TLMR comparing with RMTP in NEMO.

Reliable Multicast Transport Protocol: RMTP

This paper presents the design, implementation, and performance of a reliable multicast transport protocol (RMTP). RMTP is based on a hierarchical structure in which receivers are grouped into local regions or domains and in each domain there is a special receiver called a designated receiver (DR) which is responsible for sending acknowledgments periodically to the sender, for processing acknowledgment from receivers in its domain, and for retransmitting lost packets to the corresponding receivers. Since lost packets are recovered by local retransmissions as opposed to retransmissions from the original sender, end-to-end latency is significantly reduced, and the overall throughput is improved as well. Also, since only the DR’s send their acknowledgments to the sender, instead of all receivers sending their acknowledgments to the sender, a single acknowledgment is generated per local region, and this prevents acknowledgment implosion. Receivers in RMTP send their acknowledgments to the DR’s periodically, thereby simplifying error recovery. In addition, lost packets are recovered by selective repeat retransmissions, leading to improved throughput at the cost of minimal additional buffering at the receivers. This paper also describes the implementation of RMTP and its performance on the Internet.

Realization of a Scalable and Reliable Multicast Transport Protocol for Many-to-Many Sessions

In this paper, we present the Enhanced Communication Transport Protocol–Part 5 (ECTP-5), which provides scalable and reliable multicast communication service for many-to-many applications by constructing high quality recovery trees from two-layer logical trees and repairing the losses via unicast automatic repeat request–based error control. In order to realize the protocol, we developed feasible protocol architectures and building blocks including additional functions which deal with engineering details, such as membership dynamics and sender coordination. Experimental results show that ECTP-5 scales well with various session sizes and packet loss rates in terms of control overhead and recovery latency.

An efficient hybrid multicast transport protocol for collaborative virtual environment with networked haptic

In recent years, we have witnessed a growing interest in the synchronous collaboration based class of applications. Several techniques for collaborative virtual environments (CVE), haptic, audio and visual environments (C-HAVE) have been designed. However, several challenging issues remain to be resolved before CVE and C-HAVE become a common place. In this paper, we focus on applications that are based on closely coupled and highly synchronized haptic tasks that require a high-level of coordination among the participants. Four main protocols have been designed to resolve the synchronization issues in such environments: the synchronous collaboration transport protocol, the selective reliable transmission protocol, the reliable multicast transport protocol and the scalable reliable multicast. While these four protocols have shown good performance for CVE and C-HAVE class of applications, none of these protocols has been able to meet all of the basic CVE requirements, i.e., scalability, reliability, synchronization, and minimum delay. In this paper, we present a hybrid protocol that is able to satisfy all of the CVE and C-HAVE requirements and discuss its implementation and results in two tele-surgery applications.

A combined group/tree approach for scalable many-to-many reliable multicast

In this paper, we present the design, implementation, and performance analysis of Group-Aided Multicast (GAM), a scalable many-to-many reliable multicast transport protocol. It achieves high quality ACK trees while keeping the tree maintenance overhead reasonably low in the presence of dynamic group membership and route change. The proposed scheme is supported by a group configuration mechanism that organizes the members in a multicast session into multiple small groups and a tree configuration mechanism that maintains the logical trees according to the underlying multicast routing trees. With the two mechanisms, it builds a two-layer hierarchy of multi-level logical trees from which high-quality per-source ACK trees are generated. Simulation results show that the proposed protocol is more scalable than an existing protocol in terms of processing time for request/repair messages and recovery latency.

Performance Analysis of Reliable Multicast Protocols Using Transparent Proxy Servers on Wired and Wireless Networks

This paper considers the reliable multicast transport protocols used in hybrid networks that include wired and wireless networks and transparent proxy servers. We present four analytic performance models of two extreme reliable multicast transport protocols, sender-initiated and receiver-initiated, and supported and unsupported by transparent proxy servers are considered in each reliable multicast protocol. We analyze the throughputs of these four different models mathematically. Numerical results show that transparent proxy servers give good effects to overall performance. Furthermore, the receiver-initiated reliable multicast supported by transparent proxy servers gives better performances of total throughput than sender-initiated reliable multicast supported by transparent proxy servers. We provide efficiency criterion of the optimal number of transparent proxy servers for each protocol under varying wireless loss probabilities. Numerical results are verified by simulations.

A Model-Based Scalable Reliable Multicast Transport Protocol for Wireless/Mobile Networks

In this paper, we propose the design of a scalable reliable mobile multicast scheme-SRMoM. SRMoM uses well-known Scalable Reliable Multicast (SRM) in the wired networks and a NAK-based ARQ with adaptive Forward Error Correction (AFEC) in the wireless networks. In AFEC, the probability of needing retransmission of original multicast packets after FEC recovery is selectable. This selective property enables the control of channel utilization in the wireless segment for different numbers of Mobile Hosts (MHs). Using this property, the channel utilization of SRMoM is made to be virtually independent of the number of MHs, thus making it extremely scalable. The performance of SRMoM is analyzed with three adaptive FEC algorithms based on three wireless loss models, namely a Gilbert-Elliott channel, a simplified Cilbert-Elliott channel, and a binary symmetric channel, analytically as well as through simulation. Furthermore, the performance of SRMoM is compared with SRM and MRMoM (NAK-based protocol without FEC) through simulation. Using the average number of transmissions per original multicast packet, and wireless link utilization as metrics, we demonstrate that the performance of SRMoM is indeed virtually independent of the number of MHs, and that it results in the lowest number of packet transmissions and lowest channel utilization of reliable mobile multicast protocols thai have been proposed to date.

Tracetree: A Scalable Mechanism to Discover Multicast Tree Topologies in the Internet

The successful deployment of multicast in the Internet requires the availability of good network management solutions. Discovering multicast tree topologies is an important component of this task. Network managers can use topology information to monitor and debug potential multicast forwarding problems. In addition, the collected topology has several other uses, for example, in reliable multicast transport protocols, in multicast congestion control protocols, and in discovering network characteristics. We present a mechanism for discovering multicast tree topologies using the forwarding state in the network. We call our approach tracetree. First, we present the basic operation of tracetree. Then, we explore various issues related to its functionality (e.g., scalability, security, etc.). Next, we provide a detailed evaluation by comparing it to the currently available alternatives. Finally, we discuss a number of deployment issues. We believe that tracetree provides an efficient and scalable mechanism for discovering multicast tree topologies and therefore fills an important void in the area of multicast network management.

TCP-Peachtree: A Multicast Transport Protocol for Satellite IP Networks

In this paper, a reliable multicast transport protocol TCP-Peachtree is proposed for satellite Internet protocol (IP) networks. In addition to the acknowledgment implosion and scalability problems in terrestrial wirelined networks, satellite multicasting has additional problems, i.e., different multicast topology, different type of congestion control problems, and low bandwidth feedback link. In TCP-Peachtree, the modified B+ tree logical hierarchical structure is used to form dynamic multicast groups. Local error recovery and acknowledgment (ACK) aggregations are performed within each subgroup and also via logical subgroups. In order to avoid the overall performance degradation caused by some worst receivers, a local relay scheme is designed. Two new algorithms, jump start and quick recovery, which are based on the usage of a type of low-priority segments called NIL segments, are proposed for congestion control. NIL segments are used to probe the availability of network resources and also for error recovery. The delayed selective acknowledgment (SACK) scheme is adopted to address the bandwidth asymmetry problems and a hold state is developed to address persistent fades. The simulation results show that the congestion control algorithms of TCP-Peachtree outperform the TCP-NewReno when combined with our hierarchical groups and improve the throughput performance during rain fades. It is also shown that TCP-Peachtree achieves fairness and is very highly scalability.

The PGM reliable multicast protocol

Pragmatic general multicast (PGM) is a reliable multicast transport protocol that runs over a best effort datagram service, such as IP multicast. PGM obtains scalability via hierarchy, forward error correction, NAK elimination, and NAK suppression. It employs a novel polling scheme for NAK delay tuning to facilitate scaling up and down. This article describes the architecture of PGM, and discusses performance and security issues. We show that PGM supports asymmetric networks, achieves high network utilization, and is capable of high-speed (> 100 Mb/s) operation. PGM is currently an IETF experimental RFC that has been implemented in both commercial and academic settings.

Bandwidth Analysis and Simulation of Reliable Multicast Transport Protocols

In this paper, an analytical bandwidth evaluation of generic reliable multicast protocols is presented. Our analysis is based on a realistic system model, including data packet and control packet loss, asynchronous local clocks and imperfect scope-limited local groups. Of particular importance are two new classes with aggregated acknowledgments. In contrast to other approaches, these classes provide reliability not only in case of message loss but also in case of node failures. Finally, we have analyzed the influence of the branching factor, i.e. the size of local groups in tree-based approaches, on a protocol's performance, which is an important parameter to improve performance. Our results prove that hierarchical approaches are superior. They provide higher throughput as well as lower bandwidth consumption. However, their performance is influenced by the optimal branching factor setting. The optimal branching factor depends mainly on the probability for receiving messages from other local groups. If this probability is zero, a small branching factor leads to the best results. On the other hand, if this probability is nonzero, which is likely if TTL scoping is used, larger local groups provide better performance. Finally, we have confirmed our analysis with simulation studies of XTP, SRM, RMTP and TMTP.

LE-SBCC: Loss-Event Oriented Source-Based Multicast Congestion Control

Congestion control is an important building block of a Quality of Service (QoS) system for multicast-based multimedia services and applications on the World Wide Web. We propose an end-to-end single-rate source-based multicast congestion control scheme (LE-SBCC) for reliable or unreliable multicast transport protocols. It addresses all the pieces of the single-rate multicast congestion control problem including drop-to-zero issues, TCP friendliness and RTT estimation. The scheme design consists of a cascaded set of filters and a rate-based additive-increase multiplicative-decrease (AIMD) module. These filters together transform the multicast tree to appear like a unicast path for the purposes of congestion control. Unlike TCP, the scheme is not self-clocked but acts upon a stream of loss indications (LIs) from receivers. These LIs are filtered to get a stream of loss events (LEs) (S. Floyd et al., in SIGCOMM 2000, Aug. 2000) (at most one per RTT per receiver). This LE stream is further filtered to extract the maximum LEs from any one receiver. Then the scheme effects at most one rate-reduction per round trip time (RTT). A range of results (simulation and experimental) is presented and compared against the mathematical model of the scheme components. Furthermore, we have successfully adapted TFRC (Op. cit) to our scheme, which is important to multimedia services desiring relatively stable rates over short time scales.

GSC: a generic source-based congestion control algorithm for reliable multicast

This paper presents a simple, generic source-based end-to-end multicast congestion control (GSC) algorithm for reliable multicast transport (RMT) protocols. The algorithm is completely implemented at the source and leverages the reverse control information flow in RMT protocols like PGM or RMTP. Specifically, it does not introduce any new control traffic or new fields in RMT protocol headers. It partially addresses the drop-to-zero problem by introducing a robust, adaptive time-filter based upon RTT (round trip time) estimates collected by observing NAK traffic. This solution allows it to scale for large multicast groups while being adaptive to congestion situation changes in any part of the tree. The algorithm is friendly to TCP in terms of competition for bandwidth shares. The scheme has minimal control traffic requirements and weak RTT estimation requirements.

An application developer's perspective on reliable multicast for distributed interactive media

In this paper we investigate which characteristics reliable multicast services should have in order to be appropriate for use by distributed interactive media applications such as shared whiteboards, networked computer games, or distributed virtual environments. We take a close look at the communication requirements of these applications and at existing approaches to realize reliable multicast. Based on this information we deduce which reliable multicast transport protocols are appropriate for the different aspects of distributed interactive media. Furthermore we discuss how the application program interface of a reliable multicast service should be designed in order to support the development of applications for distributed interactive media.

The breadcrumb forwarding service

If ubiquitously deployed, IP Multicast promises to provide an efficient datagram service for an arbitrary sending host to reach an arbitrary and dynamic set of destination hosts anywhere in the Internet. Unfortunately, two very difficult problems ---interdomain multicast routing and viable end-to-end multicast transport--- have yet to be solved and deployed satisfactorily.This paper proposes that two existing but independent network mechanisms--- the EXPRESS service model and the network component of the Pragmatic Multicast protocol (PGM)--- be synthesized in a scheme we call the Breadcrumb Forwarding Service (BCFS) to simultaneously tackle the problems of interdomain multicast routing and end-to-end reliable multicast. Like EXPRESS, BCFS utilizes explicit-source group join and like PGM, enhances the network forwarding architecture with finer-grained group control. In this paper, we detail BCFS service model and router mechanisms to support the service. To demonstrate the flexibility and efficiency of BCFS, we describe the application examples built on this service model, which can accommodate not only PGM and also a novel reliable multicast transport protocol.

Scalable fair reliable multicast using active services

Scalability is of paramount importance in the design of reliable multicast transport protocols, and requires careful consideration of a number of problems such as feedback implosion, retransmission scoping, distributed loss recovery, and congestion control. In this article, we present a reliable multicast architecture that invokes active services at strategic locations inside the network to comprehensively address these challenges. Active services provide the ability to quickly and efficiently recover from loss at the point of loss. They also exploit the physical hierarchy for feedback aggregation and effective retransmission scoping with minimal router support. We present two protocols, one for packet loss recovery and another for congestion control, and describe an experimental testbed where these have been implemented. Analytical and experimental results are used to demonstrate that the active services architecture improves resource usage, reduces latency for loss recovery, and provides TCP-friendly congestion control.

An overview of reliable multicast transport protocol II

This document provides an overview of the reliable multicast transport protocol II, RMTP-II. RMTP-II is a reliable multicast protocol, designed to reliably and efficiently send data from a few senders to large groups of simultaneous recipients. It works over both symmetric networks and asymmetrical network topologies such as those provided by satellite, cable modem, or ADSL carriers. Before sending, each sender must connect with a trusted top node to receive permission and control parameters for its data stream. The top node provides network managers with a single point of control for the senders, allowing them to monitor and control the traffic being sent. RMTP-II builds on a rich field of existing work, and adds to it the following novel contributions. It differentiates the roles of the nodes in the protocol, provides algorithms for smoothing and control of the return (TRACK) traffic, and provides explicit support for highly asymmetrical networks. It provides explicit network management controls through a centralized point of control, a fully distributed membership protocol that enables positive confirmation of data delivery, and fault recovery algorithms which are integrated to the reliability semantics of the protocol. It includes a novel reliability level called time bounded reliability, and offers a unique combination of TRACKs, NACKs, and FEC for increased scalability and real-time performance. Finally, it integrates distributed algorithms for RTT calculation to each receiver, and provides automatic configuration of receiver nodes.

A comparison of reliable multicast protocols

We analyze the maximum throughput that known classes of reliable multicast transport protocols can attain. A new taxonomy of reliable multicast transport protocols is introduced based on the premise that the mechanisms used to release data at the source after correct delivery should be decoupled from the mechanisms used to pace the transmission of data and to effect error recovery. Receiver-initiated protocols, which are based entirely on negative acknowledgments (NAKS) sent from the receivers to the sender, have been proposed to avoid the implosion of acknowledgements (ACKS) to the source. However, these protocols are shown to require infinite buffers in order to prevent deadlocks. Two other solutions to the ACK-implosion problem are tree-based protocols and ring-based protocols. The first organize the receivers in a tree and send ACKS along the tree; the latter send ACKS to the sender along a ring of receivers. These two classes of protocols are shown to operate correctly with finite buffers. It is shown that tree-based protocols constitute the most scalable class of all reliable multicast protocols proposed to date.