• Journal of KIISE:Information Networking
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• v.30 no.5
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• pp.656-667
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• 2003

Congestion control is a key task in reliable multicast along with error control. However, existing tree-based congestion control schemes such as MTCP and TRAMCC are designed for one-to-many reliable multicast and have some drawbacks when they are used for many-to-many reliable multicast. We propose an efficient congestion control mechanism, TMRCC, for tree-based many-to-many reliable multicast protocols. The proposed scheme is based on the congestion windowing mechanism and a rate controller is used in addition. The feedback for error recovery is exploited for congestion control as well to minimize the overhead at the receivers. The ACK timer and the NACK timers are set dynamically reflecting the network condition changes. The rate regulation algorithm in the proposed scheme is designed to help the flows sharing the same link to achieve the fair share quickly The performance of the proposed scheme is evaluated using ns-2. The simulation results show that the proposed scheme outperforms TRAMCC in terms of intra- session fairness and shows good level of responsiveness, TCP-friendliness, and scalability. In addition, we implemented the proposed scheme by integrating with GAM that is one of many-to-many reliable multicast protocols and evaluated the performance in a laboratory-wide testbed.

• ETRI Journal
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• v.29 no.6
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• pp.745-754
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• 2007

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.

• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.165-168
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• 2000

Since the IP multicast was proposed, there have been many research works on reliable multicast protocols［1］. In multicast communication, many reliable multicast schemes were studied in order to overcome packet losses in the network. However the fact that packets are lost in the underlying networks but the solutions are sought in the end hosts makes the search for solutions difficult. If routers can identify packets before dropped from congestion, the routers can initiate recovery process. recovery scheme by routers is proposed. This scheme is much faster than by sender-initiated or receiver-initiated recovery and latency is smaller.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.578-585
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• 2001

IP Multicast that provides best-efforts service does not guarantee reliable delivery of multicast packets. In recent years, there are many approaches to support reliable multicast, but those are insufficient for implementing scalable and reliable multicast over Internet. We propose a Reliable Multicast Architecture(RMA) for scalable and reliable multicast. The RMA model guarantees reliability using a receiver initiated retransmission mechanism, and scalability using a feedback suppression mechanism by Multicast Router(MR). Furthermore, it utilizes underlying multicast routing information to minimize the cost of protocol modification and overheads. Our performance analyses show that RMA is much superior to previous works in the point of scalability and compatibility.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.916-919
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• 2003

Reliable multicast data transmission in a 1:N environment needs more sophisticated error control mechanism than that of in 1:1 environment due to ACK implosion and duplicated retransmission. Although there have been many related research on error control in reliable multicast, real implemented protocols are rare. As one of the reliable multicast transport protocols, ECTP is selected as an international standard reliable multicast protocol by ITU-T and ISO and implemented on RedHat 7.2 machine by us. In this paper, we evaluate the performance of the error control mechanism in the respect of throughput and generated control packet numbers with a real implementation code. From the results, it is concluded that the suitable values of error control parameters can be obtained from the local group size and network environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.605-609
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• 2002

Reliable multicast data transmission in a 1:N environment needs more sophisticated error control mechanism than that of in 1:1 environment due to ACK implosion and duplicated retransmission. Although there have been many related research on error control in reliable multicast, real implemented protocols are rare. As one of the reliable multicast transport protocols, ECTP is selected as an international standard reliable multicast protocol by ITU-T and ISO and implemented on RedHat 7.2 machine by us. In this paper, we evaluate the performance of the error control mechanism in the respect of throughput and generated control packet numbers with a real implementation code. From the results, it is concluded that the suitable values of error control parameters can be obtained from the local group size and network environments.

• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.513-519
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• 2003

In order to deliver multicast traffic efficiently, multicast routing and reliable transmission mechanisms are required. The reliable delivery implies that lost packets must be retransmitted, which in turn requires that transmitted packets be stored in a retransmission buffer. Therefore how to manage a retransmission buffer is important and, in this paper, we try to solve the problem of how many packets should be maintained in the buffer. Our proposed scheme, the timer-based buffer management (TBM), maintains only necessary amount of buffer based on the timer value calculated from the NAKs between the replier and receivers on a multicast tree and can adjust to the dynamic network conditions. By performing simulations, we show that TBM manages the buffer efficiently regardless of the error situation, network size, and so on.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1525-1535
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• 2000

Multicast is the multiparty communication that allows one-to-many communications. There are some multicast applications which are the ways of multiparty communications such as video conference system and white board. This paper proposes a dynamic allocation mechanism of designated receiver by using designated receiver list and a retransmission mechanism with designated receiver for the effective multicasting dta transmission. We designed voice conference system with multicast based on RTP/RTCP. This voice conference system increases the effect of standardization work and enables to exchange reliable standard dta with real time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.1-6
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• 2019

Multicast is an efficient method for real-time transmission in many multimedia applications. It is important to recover lost packets and to manage multicast groups according to the network status in order to improve the reliability of multicast transmissions. In this paper, we propose a method that can efficiently recover lost packets in a large multicast group. In the proposed method, we create a recovery cluster (RC) using a multicast domain (MD) for recovery of lost packets. In the conventional methods, clusters send a request message for lost packets to the senders in order to recover the packets lost from many multicast applications. This increases packet delay time and overhead because of the feedback messages and retransmitted packets. In the proposed method, we improve these problems using the RC, which consists of many MDs (which have overlay multicast senders), and many cluster heads (CHs). We divide the message into blocks, and divide each block into many segments for packet recovery using the CHs. When packet loss occurs, all CHs share the segment information and recover the lost segments at the same time. Simulation results show that the proposed method could improve the packet recovery ratio by about 50% compared to the conventional methods.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.235-246
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• 2002

While the Internet is suffering from the massive data such as video stream, IP multicast can ease the load of the Internet by enabling one copy of digital information to be received by multiple computers simultaneously. But If multicast is based on UDP, packets are delivered using a best-effort Policy without any reliability, congestion control or flow control. Multicast group members can join or leave a multicast group at will, and multicast uses broadcast mechanism, it's very hard to keep security from unauthorized members. In this paper, we introduce a new reliable multicast protocol TRDMF proper for one-to-many multicast model with reliability, flow control, congestion control and key management.