Comparison of tree-based reliable multicast protocols for many-to-many sessions

Even though tree-based reliable multicast protocols are known to be most scalable for one-to-many sessions, there is still an open question whether these protocols are also scalable for many-to-many sessions. In this paper, we analyze and compare two promising multicast protocols - the receiver-initiated protocol with NACK suppression and the tree-based protocol - using a new spatial loss model. The proposed model considers the correlation of packet loss events for more realistic analysis unlike the previous work. The analysis results show that the tree-based protocol achieves much higher throughput than the receiver-initiated protocol for a many-to-many session as the number of participants in the session becomes larger.

This paper contains a detailed description of the congestion control algorithm of TRAM, a tree-based reliable multicast protocol. This algorithm takes advantage of regular acknowledgements from the receivers that propagate back to the sender via the repair tree. This scalable feedback mechanism is used to collect receiver credits. Complementing the windowing mechanism, packet transmission is smoothed by using a data rate commensurate with the window size. Additional details, such as how to prune slow receivers, and how to implement the rate scheduler on non-real-time systems are also discussed. The performance of the congestion control algorithm is then evaluated in extended LANs, and wide area networks. The fairness of bandwidth-sharing with other (TCP) traffic is also evaluated.

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.

\n Tree-based reliable multicast protocols are known to provide better\n scalability than the protocols based on pure sender- and\n receiver-initiated schemes. However, previous analytical work that\n has provided these results is based on a system model which assumes\n reliable control message delivery and synchronized local clocks.\n These assumptions are questionable simplifications, since they favor\n protocols using multicasted negative acknowledgments with NAK\n avoidance scheme. In this paper, we extend previous analysis by\n taking into account control data loss and asynchronous local clocks.\n\n We further analyze a new protocol class with particular importance,\n the tree-based approach with aggregated acknowledgments. In contrast\n to other approaches, this class provides reliability not only in\n case of message loss but also in case of node failures. Our results\n show that the additional overhead to cope with node failures is very\n low and therefore acceptable for reliable multicast implementations.\n

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.

A reliable multicast protocol enables a process to multicast a message to a group of processes in a way that ensures that all honest destination-group members receive the same message, even if some group members and the multicast initiator are maliciously faulty. Reliable multicast has been shown to be useful for building multiparty cryptographic protocols and secure distributed services. We present a high-throughput reliable multicast protocol that tolerates the malicious behavior of up to fewer than one-third of the group members. Our protocol achieves high-throughput using a novel technique for chaining multicasts, whereby the cost of ensuring agreement on each multicast message is amortized over many multicasts. This is coupled with a novel flow-control mechanism that yields low multicast latency.

Reliable multicast in wireless ad hoc networks is important for the applications such as distributed computing, chat, and whiteboard. Due to the wireless channel characteristics, obtaining the reliability in multicast packet transmission is a difficult and challenging task. Even though IEEE 802.11 is widely adopted medium access control (MAC) protocol in wireless ad hoc networks, it does not support reliable multicast. Thus, several MAC layer protocols have been proposed that can provide reliable multicast. In this paper, we propose the reliable multicast MAC protocol which is based on the orthogonal frequency division multiple access (OFDMA) systems. The proposed method reduces the overhead required for control packets. Analysis results validate the reliability and efficiency of our multicast MAC protocol.KeywordsMedium Access ControlMedium Access Control ProtocolPacket DelayControl PacketOrthogonal Frequency Division Multiple AccessThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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.

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.

Tree-based reliable multicast protocols provide scalability by distributing error-recovery tasks among several repair nodes. These repair nodes integrate the status information of several receiver nodes and perform local error recovery for these nodes using the data stored in their buffers. We propose a buffer management scheme that uses both positive and negative acknowledgments to manage these buffers in an efficient manner. Under our scheme, receiver nodes send negative acknowledgments to repair nodes to request packet retransmissions. At infrequent intervals, they also send positive acknowledgements to indicate which packets can be safely discarded from the buffer of their repair node. Our scheme reduces delay in error recovery, because the packets requested from the repair nodes are always available in their buffers. It achieves this goal without increasing the server workload because (a) each receiver node only sends infrequent positive acknowledgments and (b) their sending times are randomized among all the receiver nodes. We also show how our scheme can be extended to provide full flow control and eliminate buffer overflows.

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.

In wireless sensor networks (WSN), flooding increases the reliability in terms of successful transmission of a packet with higher overhead. The flooding consumes the resources of the network quickly, especially in sensor networks, mobile ad-hoc networks, and vehicular ad-hoc networks in terms of the lifetime of the node, lifetime of the network, and battery lifetime, etc. This paper aims to develop an efficient and reliable protocol by using multicasting and unicasting to overcome the issue of higher overhead due to flooding. Unicasting is used when the desired destination is at a minimum distance to avoid an extra overhead and increases the efficiency of the network in terms of overhead and energy because unicasting is favorable where the distance is minimum. Similarly, multicasting is used when the desired destination is at maximum distance and increases the network’s reliability in terms of throughput. The results are implemented in the Department of Computer Science, Bacha Khan University Charsadda (BKUC), Pakistan, as well as in the Network Simulator-2 (NS-2). The results are compared with benchmark schemes such as PUMA and ERASCA, and based on the results, the performance of the proposed approach is improved in terms of overhead, throughput, and packet delivery fraction by avoiding flooding.

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.

We present the router-assisted error control model (RRMEC), which takes advantage of the location and knowledge of the topology of routers to build a logical tree, and uses the repair host associated with the routers to buffer the data packet and perform retransmission recovery tasks. This model can establish a hierarchy being congruent with the multicast distribution tree and solve the major problem on reliable multicast efficiently. This paper gives the implementation of a prototype in active network, i.e., ANRM. The ANRM can provide an efficient method for rapid update and deployment of reliable multicast protocol.