Reed-solomon forward error correction (FEC) schemes, RFC 5510

This document describes a Fully-Specified Forward Error Correction (FEC) Scheme for the Reed-Solomon FEC codes over GF(2^^m), where m is in {2..16}, and its application to the reliable delivery of data objects on the packet erasure channel (i.e., a communication path where packets are either received without any corruption or discarded during transmission). This document also describes a Fully-Specified FEC Scheme for the special case of Reed-Solomon codes over GF(2^^8) when there is no encoding symbol group. Finally, in the context of the Under-Specified Small Block Systematic FEC Scheme (FEC Encoding ID 129), this document assigns an FEC Instance ID to the special case of Reed-Solomon codes over GF(2^^8). Reed-Solomon codes belong to the class of Maximum Distance Separable (MDS) codes, i.e., they enable a receiver to recover the k source symbols from any set of k received symbols. The schemes described here are compatible with the implementation from Luigi Rizzo

RTSP-based Mobile Peer-to-Peer Streaming System

Peer-to-peer is emerging as a potentially disruptive technology for content distribution in the mobile Internet. In addition to the already well-known peer-to-peer file sharing, real-time peer-to-peer streaming is gaining popularity. This paper presents an effective real-time peer-to-peer streaming system for the mobile environment. The basis for the system is a scalable overlay network which groups peer into clusters according to their proximity using RTT values between peers as a criteria for the cluster selection. The actual media delivery in the system is implemented using the partial RTP stream concept: the original RTP sessions related to a media delivery are split into a number of so-called partial streams according to a predefined set of parameters in such a way that it allows low-complexity reassembly of the original media session in real-time at the receiving end. Partial streams also help in utilizing the upload capacity with finer granularity than just per one original stream. This is beneficial in mobile environments where bandwidth can be scarce

Solutions for Large-Scale Content Delivery over the Internet Protocol

The current trend is going more and more towards IP-based delivery for all kind of digital content. At the same time, the increasing quality of the digital media is simultaneously increasing the size of the media, which will also increase the requirements for the capacity in the content delivery path. It is obvious that the traditional content delivery based on the client-server model will easily overload the delivery network and none of the customers will be happy about the quality of the service. Hence, more scalable solutions in the digital content distribution area are needed. In the best-effort service, like in the IP datagram forwarding, the successful delivery of a packet to its receivers is not guaranteed in the network layer. So, in IP-based applications, failures in the content delivery path between the sender and receiver will cause packet losses, which have to be dealt with in the transport or application layers. Another reason for packet losses in a multi-sender P2P environment is a peer churn which will cause the media being sent to a receiver to be temporarily interrupted. This Thesis studies large-scale content delivery over the Internet Protocol, mainly at the scalability and reliability point of view, in two separate research areas: (a) file delivery to large user population, and (b) real-time P2P media streaming in a mobile networking environment. Multicast-based file delivery is one of the most efficient ways to deliver the same content to a large user population, but reliability becomes a concern, because multicast techniques are commonly based on unreliable transport protocols to scale up to large and massive receiver groups. As it is shown in this Thesis, FEC data carousel will be the best way to provide reliability in most cases when the total amount of data which is transmitted in the delivery system is used as a critical factor. In P2P content distribution, overlay network structure and data partitioning are very important issues from the scalability point of view. A random mesh-based overlay architecture provides flexibility for handling peer departures, but good general connectivity between peers is better achieved using for example clustered overlay architecture. In P2P delivery, a downloading client becomes a leecher peer when it has at least one complete block, so with a small enough block size the number of alternative source peers will increase faster. Data partitioning in P2P media streaming applications is even more demanding. Partitioning based on fixed byte ranges, like in P2P file delivery, is not suitable for streaming a continuous media, which is of variable bit rate nature. In contrast to file delivery where one does not care if the data parts arrive in the original order or not, since the viewing experience will be anyhow the same once the file is fully downloaded, P2P media streaming applications require that all data is received relatively close to its playback position. Good user experience is achieved by using client side buffers to eliminate the network induced delay and jitter. With bigger buffer size it is possible to smooth the variation between packet arrival times and have also time for packet loss recovery. On the other hand, the smaller the buffering time is the faster the playback can be started. The real-time P2P media streaming system presented in this Thesis contains several important improvements to enhance the mobile usage, like small ten seconds initial buffering time, ten seconds reception buffer due to the RTP usage, and the partial RTP stream concept, which allow a single media stream to be effectively received simultaneously from multiple senders

Solutions for Large-Scale Content Delivery over the Internet Protocol

The current trend is going more and more towards IP-based delivery for all kind of digital content. At the same time, the increasing quality of the digital media is simultaneously increasing the size of the media, which will also increase the requirements for the capacity in the content delivery path. It is obvious that the traditional content delivery based on the client-server model will easily overload the delivery network and none of the customers will be happy about the quality of the service. Hence, more scalable solutions in the digital content distribution area are needed. In the best-effort service, like in the IP datagram forwarding, the successful delivery of a packet to its receivers is not guaranteed in the network layer. So, in IP-based applications, failures in the content delivery path between the sender and receiver will cause packet losses, which have to be dealt with in the transport or application layers. Another reason for packet losses in a multi-sender P2P environment is a peer churn which will cause the media being sent to a receiver to be temporarily interrupted. This Thesis studies large-scale content delivery over the Internet Protocol, mainly at the scalability and reliability point of view, in two separate research areas: (a) file delivery to large user population, and (b) real-time P2P media streaming in a mobile networking environment. Multicast-based file delivery is one of the most efficient ways to deliver the same content to a large user population, but reliability becomes a concern, because multicast techniques are commonly based on unreliable transport protocols to scale up to large and massive receiver groups. As it is shown in this Thesis, FEC data carousel will be the best way to provide reliability in most cases when the total amount of data which is transmitted in the delivery system is used as a critical factor. In P2P content distribution, overlay network structure and data partitioning are very important issues from the scalability point of view. A random mesh-based overlay architecture provides flexibility for handling peer departures, but good general connectivity between peers is better achieved using for example clustered overlay architecture. In P2P delivery, a downloading client becomes a leecher peer when it has at least one complete block, so with a small enough block size the number of alternative source peers will increase faster. Data partitioning in P2P media streaming applications is even more demanding. Partitioning based on fixed byte ranges, like in P2P file delivery, is not suitable for streaming a continuous media, which is of variable bit rate nature. In contrast to file delivery where one does not care if the data parts arrive in the original order or not, since the viewing experience will be anyhow the same once the file is fully downloaded, P2P media streaming applications require that all data is received relatively close to its playback position. Good user experience is achieved by using client side buffers to eliminate the network induced delay and jitter. With bigger buffer size it is possible to smooth the variation between packet arrival times and have also time for packet loss recovery. On the other hand, the smaller the buffering time is the faster the playback can be started. The real-time P2P media streaming system presented in this Thesis contains several important improvements to enhance the mobile usage, like small ten seconds initial buffering time, ten seconds reception buffer due to the RTP usage, and the partial RTP stream concept, which allow a single media stream to be effectively received simultaneously from multiple senders

Reed-Solomon Forward Error Correction (FEC)

IETF Internet DraftThis document describes a Fully-Specified FEC scheme for the Reed-Solomon forward error correction code and its application to reliable delivery of data objects on the packet erasure channel. The Reed-Solomon codes belong to the class of Maximum Distance Separable (MDS) codes, i.e, they enable a receiver to recover the k source symbols from any set of k received symbols. The implementation described here is compatible with the IPR-free implementation from Luigi Rizzo

A MASSIVELY SCALABLE PERSISTENT CONTENT DISTRIBUTION SYSTEM

This paper proposes a novel form of peercasting system as an improved solution for IP-based mass media content delivery. Several approaches are discussed, some of which are already widely deployed, or undergoing such deployment, as homogeneous systems. In particular, IP multicast and Peer-to-Peer (P2P) overlay network techniques are described in isolation- as they form the bedrock of the new peercasting system proposal. This proposal aims to improve existing homogenous and heterogeneous systems for mass media distribution to very large user bases, with needs for timely and reliable delivery, and content persistence. Thus IP multicast has great advantages for delivery with controlled last-mile elements, both for mobile and fixed usage. However, persistence while the number of still-receiving users dwindle, and reliability at reasonable network cost, are better served by P2P techniques. The work primarily considers discrete media delivery, which is useful both alongside with streaming media and in standalone applications. The feasibility of such a combined multicast and P2P system is shown and the working prototype implementation of this proposal, Delco, is introduced