Light-Weight Multicast Services (LMS): A Router-Assisted Scheme for Reliable Multicast

Abstract

--Building on the success of unicast IP, IP IntroductionAt the core of the Internet architecture lies the simplicity and elegance of IP and its design principles [11]. Internet architects realized early on that by foregoing the wire-like robustness of traditional communications networks (such as the telephone network) and pushing the intelligence to the edges, a network can be built on a much simpler, cheaper and highly scalable infrastructure.The resulting best-effort service model has proven highly flexible. However, the interaction of store-and-forward packet forwarding, finite buffers and bursty sources occasionally leads to congestion and loss. Applications requiring better than best-effort reliability must counteract loss with error control, the component of a communication protocol responsible for reliability [1], [2].IP Multicast [5] debuted in the late 1980s and was hailed as a natural extension of the unicast model. Multicast is a powerful service because it allows a single source to reach a virtually unlimited number of receivers in a very efficient and scalable manner. Multicast is well-suited for applications such as streaming media, distance learning, Internet radio and television, distributed interactive simulation, file transfer, software updates and much more. Continuing the architectural tradition of unicast, IP Multicast adopted a simple, best-effort, anonymous, broadcast-like service, often compared to a radio dial-tone: anyone may tune in and anyone may transmit. Thus, similar to unicast, IP Multicast provides a general service on top of which richer services can be built.Despite the vigorous promotion of multicast by both the research and industry communities, the Internet Service Providers (ISPs) and the users have not yet embraced the service. Many reasons have been cited [38], [39], which include difficulties with inter-domain routing, peering relationships, address allocation, limited address space, security, billing, and the lack of a general scalable and reliable transport service analogous to TCP. This paper addresses the last issue. We present Lightweight Multicast Services (LMS), an extension to IP Multicast, on top of which a general and scalable reliable multicast transport service can be constructed. LMS extends IP Multicast with a set of simple and lightweight services that enhance router forwarding to enable highly scalable, network assisted solutions to reliable multicast. LMS cleanly separates the transport and forwarding components of error control, keeps the former at the endpoints thus avoiding layer violations, and pushes the latter to the routers where it can be implemented most efficiently.Unicast error control mechanisms are not suitable for large-scale multicast due to the many-to-many nature of IP Multicast. Losses in multicast typically affect part of the multicast tree and attempting to recover localized loss leads to the following problems:• Implosion: occurs when the loss of a packet triggers redundant messages (requests and/or retransmissions). In lar...

Calibrating embedded protocols on asynchronous systems

“…[21,31,36] study reliable broadcast or multicast. Reliable communication over unreliable channels is tackled by [7,8,22,28] for classical networks, for interconnection networks by [17,18,29,38], and for mobile and wireless networks by [9,26,27]. More recently, Dolev and Tzachar [12,13] propose a hierarchical structure of network communication that is the key for self-organizing algorithms.…”

TCP-friendly layered video for Internet multicast

“…Due to receiver's heterogeneity, the sender usually adjusts its rate in accordance with the receiver with the worst performance, which results in severe performance degradation for many members. Furthermore, it is a well known problem to design an additional mechanism to avoid feedback implosion, which is critical for sender's performance [9,15,16,19]. On the other hand, layered video can be transmitted via multi-session multicast in the receiver-driven approach [12,13,20,21].…”

Topology discovery service for router-assisted multicast transport

“…Other network-supported reliable multicast schemes have been proposed [8,13,11,15,7]. Space does not permit us to review them all here.…”

“…In the earliest proposals, the augmented router functionality was targeted at facilitating reliable multicast [6,8,13,11,15,7], a problem that has resisted a scalable solution using purely endto-end techniques. Other work [17] promotes active filtering services to improve the performance of specific applications.…”