A high-throughput secure reliable multicast protocol

Multicast in wireless sensor networks (WSNs) is an efficient way to spread the same data to multiple sensor nodes. It becomes more effective due to the broadcast nature of wireless link, where a message transmitted from one source is inherently received by all one-hop receivers, and therefore, there is no need to transmit the message one by one. Reliable multicast in WSNs is desirable for critical tasks like code updation and query based data collection. The erroneous nature of wireless medium coupled with limited resource of sensor nodes, makes the design of reliable multicast protocol a challenging task. In this work, we propose a time division multiple access (TDMA) based energy aware media access and control (TEA-MAC) protocol for reliable multicast in WSNs. The TDMA eliminates collisions, overhearing and idle listening, which are the main sources of reliability degradation and energy consumption. Furthermore, the proposed protocol is parametric in the sense that it can be used to trade-off reliability with energy and delay as per the requirement of the underlying applications. The performance of TEA-MAC has been evaluated by simulating it using Castalia network simulator. Simulation results show that TEA-MAC is able to considerably improve the performance of multicast communication in WSNs.

To reduce or eliminate the implosion of acknowledgments at the source of a very large multicast group, current reliable multicast protocols either organize the receivers of a group into a tree or ring, or implement negative acknowledgment (NAK) avoidance algorithms based on random timers. All of these approaches have their limitations and advantages. We present a ring-based reliable multicast protocol, called the evenly-loaded ring protocol (ELRP) which removes processing bursts from nodes in the ring. ELRP achieves throughputs as good as those obtained with tree-based protocols and better than those of receiver-initiated protocols with NAK avoidance. We propose a deterministic NAK avoidance (DNKA) algorithm based on ELRP that performs better than the random NAK avoidance scheme (RNKA). Because tree structures are better suited than rings for wide areas involving paths with long delays, we propose the hybrid reliable multicast protocol (HRMP) which organizes receivers into a backbone acknowledgement tree that connects local areas. Any tree-based protocol with positive acknowledgement can be run in the backbone acknowledgement tree, and ELRP is run in the local areas. The maximum achievable throughput in HRMP is analyzed, which shows that it is completely scalable. The delay of DNKA and RNKA schemes are also analyzed which shows that compared with RNKA, DNKA reduces the retransmission delay significantly.

In this paper we examine the impact of widely spread multicast groups on the performance of reliable multicast protocols. In a brief analysis we show that transmission cost for reliable multicast increases rapidly with the distance between retransmitting and receiving hosts. Since this distance is not considered by existing protocols, which are based on retransmissions originated at the sender or receiver, the performance often is rather poor and a new error recovery concept has to be developed. Our approach. the Scalable and Reliable Multicast Transport protocol (SRMT), allows retransmissions by extended multicast routers to limit the path length for error recovery. Moreover, the retransmission load can be further reduced by an XOR combination of packets. SRMT is defined as an overlay network model and therefore can be applied to any existing multicast protocol.

Multicasting plays an important role in internet networks. Supporting wavelength division multiplexed (WDM) multicasting in an IP over WDM network poses interesting problems because some WDM switches may be incapable of switching an incoming signal to more than one output interface. Although some multicast applications, such as audio/video conferencing can tolerate packet error or loss, other applications such as one-to-many file transfer and military applications do not. Hence, an inevitable need for reliable multicasting arises. The reliable multicast protocol ensures the eventual delivery of multicast data to all multicast group members. The reliable multicast is receiver initiated NACK-based and it makes use of feedback suppression in order to avoid NACK and retransmission implosion. The loss recovery burden is distributed over the multicast group members in order to reduce recovery latency and end-to-end delay. The proposed protocol is evaluated in terms of performance metrics for an IP/WDM optical network which will be the candidate for the next generation internet networks.

This paper introduces a reliable multicast transport protocol RCCMP (reliable congestion controlled multicast protocol) that has been designed to be simple, scalable, reliable and TCP-friendly. The congestion control is a central part of the protocol, where the feedback of the worst receiver is used to control a transmission window in a TCP-like fashion. The scalability issue is addressed with an exponential timers scheme, that is also used to estimate the number of receivers involved in the communication. The protocol neither needs support from network elements nor maintains state information dependent of the number of receivers. The paper presents a number of simulation results on its performance. Besides, some design choices are evaluated.

Multicast communication protocols are not immune from failures as a result of packets being dropped due to a broken link or time out processes. Therefore, it is essential to understand how these failures can affect the overall performance of multicast protocols over the Internet. This paper compares the fault-tolerance effect of two reliable multicast protocols: pragmatic general multicast (PGM) and elastic reliable multicast (ERM) in a situation where a multicast-aware node fails and the sub-nodes will have to request a repaired packet. A simulation model is developed in such a way that faults are randomly created on nodes and link for a specified period of time and the fault-tolerance effect on the two multicast protocols is analyzed. The model developed for this paper repeats the simulation for different network size, the results obtained show that the ERM protocol is better than the PGM as the size of the network increases. This finding is key while considering the improvement (or upgrade) of existing multicast protocols. The result is also significant at the early stage of designing new multicast protocols as it provides useful information in allocating scarce resource that can be appropriated to improve other infrastructure in the network.

A Cooperative Reliable Multicast Protocol (CRMP) has been developed to improve real-time data transmission onthe Internet Multicast Backbone (MBone) by adding a retransmit server and some repair servers to the multicastsession in order to recover lost packets. This paper describes a design and implementation of CRMP with Localrecovery (L-CRMP), an extension to the original CRMP. In L-CRMP, each repair server can work as a local serverthat retransmits packets to other repair servers that do not receive them from the source. Our goal in L-CRMP is toreduce the network overhead caused by retransmission packets while keeping the effective loss rate at the receiversapproximately the same.Keywords: MBone, Reliable Multicast, Local recovery 1. INTRODUCTION Real-time multicast applications are transmitted over the Internet through MBone (Multicast Backbone), a logicalnetwork running on top of the IP layer.1'2 Many of them, such as vat (Visual Audio Tool) or nv (Network Video),are based on RTP (Real-time Protocol) that does not support reliability. These applications may often experiencepoor quality due to large packet loss.3'4 A protocol, Cooperative Reliable Multicast Protocol (CRMP), is proposedin reference5 to alleviate the problem. A unique feature of CRMP is that it can be used with the current MBoneapplications without changing the operation of the source or receivers. Receivers that participate in CRMP coexistwith those that do not, but enjoys a better quality.Most reliable multicast protocols are designed for data transmission which requires perfect reliability but isresilient to delay, e.g.,6'7 and references therein. CRMP is however designed for real-time applications and exploitsthe fact that they do not require perfect reliability and, due to their stream nature, do not need acknowledgementfor every packet. In a large heterogeneous network, the delay between the retransmit server and some of the repairservers may be excessive. This motivates our extension of the original CRMP to include local recovery. It exploitsthe fact that loss at different repair servers is not synchronized, and therefore, a retransmission request of a repairserver may be fulfilled by a nearby repair server that has received the packet. In this paper we present a designand implementation of CRMP with local recovery (L—CRMP), and evaluate its performance. In addition to local

Forward error correction (FEC) has been proposed as a technique for implementing efficient reliable multicast (RM). However, FEC incurs costs in encode/decode delay and implementation complexity. How much benefit is provided relative to these costs and how dependent is the benefit on the specific RM protocol? In this paper, we evaluate the benefits of FEC for RM, considering both proactive and reactive use with three RM recovery techniques: duplicate avoidance, limited scope multicast and subcast. Our simulation-based results indicate that FEC provides little benefit for an efficient RM protocol like OTERS and introduces extra delay for multi-point streaming data applications.

Reliable multicast is a technology used in a number of applications such as multi-receiver file transfer, streaming media, multimedia conferencing, collaborative processing etc. Pragmatic general multicast (PGM) is a reliable multicast transport protocol that runs over a best effort datagram service. Through this paper we propose an efficient loss recovery scheme for PGM. In our proposal a PGM router that receives a negative acknowledgement tries for local recovery prior to global recovery. The scheme works well when the sender/DLR is located further away from the PGM router than its receivers and the probability that a local receiver caches the packet is high. If there is a hit, the router retrieves the packet from its neighborhood, this results in a decrease in recovery latency, increase in throughput, reduction in power consumption also it alleviates the load at the sender/DLR.

In current IEEE 802.11 WLAN, the unicast provides a reliable way of communication thanks to the use of acknowledgement feedbacks. As to the multicast, it suffers from unreliability and inefficiency. Recently many protocols have been designed for 802.11 such as Leader Based Protocol (LBP), to provide a reliable multicast transport. Yet no optimal solution has been proposed. In this paper we present Reliable PLCP-based Multicast Protocol (RPMP), a new reliable multicast protocol as an extension to the 802.11g and 802.11a. RPMP achieves reliability through the use of Negative Acknowledgements (NAK). We reduce the transmission overhead of our protocol, compared to other NAK-based proposals, by adding one additional OFDM symbol in the Physical Layer Convergence Procedure (PLCP) header of the multicast frame instead of using additional control frames. Further we show, based on our simulation results that the delivery ratio of RPMP remains at 100% in a lossy channel when it falls down to 50% with the standard. We also show that the efficiency of RPMP is much more enhanced than that of LBP.

The fundamental basis of reliable multicast protocols is loss recovery. Traditionally there are two different ways of recovering missing packets: 1. Forward error correction (FEC) and 2. Automatic repeat request (ARQ) or retransmissions

This document describes the messages and procedures of the Negative- acknowledgment (NACK) Oriented Reliable Multicast (NORM) protocol. This protocol is designed to provide end-to-end reliable transport of bulk data objects or streams over generic IP multicast routing and forwarding services. NORM uses selective, negative acknowledgment mechanism for transport reliability and offers additional protocol mechanisms to allow for operation with minimal a priori coordination among senders and receivers. A congestion control scheme is specified to allow the NORM protocol to fairly share available network bandwidth with other transport protocols such as Transmission Control Protocol (TCP). It is capable of operating with both reciprocal multicast routing among senders and receivers and with asymmetric connectivity (possibly unicast return path) between the senders and receivers. The protocol offers number of features to allow different types of applications or possibly other higher level transport protocols to utilize its service in different ways. The protocol leverages the use of FEC-based repair and other IETF reliable multicast transport (RMT) building blocks in its design. This memo defines an Experimental Protocol for the Internet community.

Cored-Based Tree with Forwarding Regions (CBT-FR); A Protocol for Reliable Multicasting in Mobile Ad Hoc Networks

Tree-based reliable multicast protocols are well-known for being scalable for one-to-many sessions, but their behaviour in terms of throughput and bandwidth requirements has not been identifed for many-to-many sessions. In this paper, existing tree-based reliable multicast protocols are categorised into four classes according to their feedback/retransmission mechanisms. Analysing and comparing them using a new spatial multicast loss model that considers the correlation of packet loss events can yield realistic analysis results. The analysis reveals that for many-to-many sessions, tree-based protocols with unicast NACK, unicast retransmission, and periodic polling are most scalable with respect to throughput and network bandwidth for practical session sizes. The result is contrary to the one-to-many case and it is shown that the reason is that reducing the sender's processing time is a key factor for scaling one-to-many reliable multicast, whereas reducing the receiver's processing time is far more important factor for scalability of many-to-many reliable multicasts.

Two reliable multicast protocols for wireless local area networks (LANs) are proposed: a leader-based protocol with a sliding window, LBPW; a leader-based protocol with a sliding window and n-fold acknowledgement reduction, LBPR(n). They are based on a previously proposed leader-based protocol (LBP). Firstly, a pipelining technique is added into the LBP to form the LBPW so as to make frame transmission efficient. Then, an acknowledgement reduction scheme is incorporated into LBPW to form LBPR(n) to alleviate the ACK/NAK implosion problem. Through numerical examples done by a simulation approach, we demonstrate that these two reliable multicast protocols outperform LBP.