FEC

This document describes the current research outcomes in Network Coding (NC) for Content-Centric Networking (CCNx) / Named Data Networking (NDN) and clarifies the technical considerations and potential challenges for applying NC in CCNx/NDN. This document is the product of the Coding for Efficient Network Communications Research Group (NWCRG) and the Information-Centric Networking Research Group (ICNRG).

Forward Erasure Correction (FEC) is a reliability mechanism that is distinct and separate from the retransmission logic in reliable transfer protocols such as TCP. FEC coding can help deal with losses at the end of transfers or with networks having non-congestion losses. However, FEC coding mechanisms should not hide congestion signals. This memo offers a discussion of how FEC coding and congestion control can coexist. Another objective is to encourage the research community to also consider congestion control aspects when proposing and comparing FEC coding solutions in communication systems.

This document is the product of the Coding for Efficient Network Communications Research Group (NWCRG). The scope of the document is end-to-end communications; FEC coding for tunnels is out of the scope of the document.

The Real-time Transport Object delivery over Unidirectional Transport (ROUTE) protocol is specified for robust delivery of Application Objects, including Application Objects with real-time delivery constraints, to receivers over a unidirectional transport. Application Objects consist of data that has meaning to applications that use the ROUTE protocol for delivery of data to receivers; for example, it can be a file, a Dynamic Adaptive Streaming over HTTP (DASH) or HTTP Live Streaming (HLS) segment, a WAV audio clip, etc. The ROUTE protocol also supports low-latency streaming applications.

The ROUTE protocol is suitable for unicast, broadcast, and multicast transport. Therefore, it can be run over UDP/IP, including multicast IP. The ROUTE protocol can leverage the features of the underlying protocol layer, e.g., to provide security, it can leverage IP security protocols such as IPsec.

This document specifies the ROUTE protocol such that it could be used by a variety of services for delivery of Application Objects by specifying their own profiles of this protocol (e.g., by adding or constraining some features).

This is not an IETF specification and does not have IETF consensus.

This document is a product of the Coding for Efficient Network Communications Research Group (NWCRG). It conforms to the directions found in the NWCRG taxonomy (RFC 8406).

The objective is to contribute to a larger deployment of Network Coding techniques in and above the network layer in satellite communication systems. This document also identifies open research issues related to the deployment of Network Coding in satellite communication systems.

This document provides information and requirements for the use of Forward Error Correction (FEC) by WebRTC implementations.

This document defines new RTP payload formats for the Forward Error Correction (FEC) packets that are generated by the non-interleaved and interleaved parity codes from source media encapsulated in RTP. These parity codes are systematic codes (Flexible FEC, or "FLEX FEC"), where a number of FEC repair packets are generated from a set of source packets from one or more source RTP streams. These FEC repair packets are sent in a redundancy RTP stream separate from the source RTP stream(s) that carries the source packets. RTP source packets that were lost in transmission can be reconstructed using the source and repair packets that were received. The non-interleaved and interleaved parity codes that are defined in this specification offer a good protection against random and bursty packet losses, respectively, at a cost of complexity. The RTP payload formats that are defined in this document address scalability issues experienced with the earlier specifications and offer several improvements. Due to these changes, the new payload formats are not backward compatible with earlier specifications; however, endpoints that do not implement this specification can still work by simply ignoring the FEC repair packets.

This document summarizes recommended terminology for Network Coding concepts and constructs. It provides a comprehensive set of terms in order to avoid ambiguities in future IRTF and IETF documents on Network Coding. This document is the product of the Coding for Efficient Network Communications Research Group (NWCRG), and it is in line with the terminology used by the RFCs produced by the Reliable Multicast Transport (RMT) and FEC Framework (FECFRAME) IETF working groups.

The Rapid Acquisition of Multicast RTP Sessions (RAMS) solution is a method based on RTP and the RTP Control Protocol (RTCP) that enables an RTP receiver to rapidly acquire and start consuming the RTP multicast data. Upon a request from the RTP receiver, an auxiliary unicast RTP retransmission session is set up between a retransmission server and the RTP receiver, over which the reference information about the new multicast stream the RTP receiver is about to join is transmitted at an accelerated rate. This often precedes, but may also accompany, the multicast stream itself. When there is only one multicast stream to be acquired, the RAMS solution works in a straightforward manner. However, when there are two or more multicast streams to be acquired from the same or different multicast RTP sessions, care should be taken to configure each RAMS session appropriately. This document provides example scenarios and discusses how the RAMS solution could be used in such scenarios. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document defines the semantics for grouping the associated source and FEC-based (Forward Error Correction) repair flows in the Session Description Protocol (SDP). The semantics defined in this document are to be used with the SDP Grouping Framework (RFC 5888). These semantics allow the description of grouping relationships between the source and repair flows when one or more source and/or repair flows are associated in the same group, and they provide support for additive repair flows. SSRC-level (Synchronization Source) grouping semantics are also defined in this document for Real-time Transport Protocol (RTP) streams using SSRC multiplexing. [STANDARDS-TRACK]

This document describes the Asynchronous Layered Coding (ALC) protocol, a massively scalable reliable content delivery protocol. Asynchronous Layered Coding combines the Layered Coding Transport (LCT) building block, a multiple rate congestion control building block and the Forward Error Correction (FEC) building block to provide congestion controlled reliable asynchronous delivery of content to an unlimited number of concurrent receivers from a single sender. This document obsoletes RFC 3450. [STANDARDS-TRACK]

This document defines a new report block type within the framework of RTP Control Protocol (RTCP) Extended Reports (XRs). One of the initial XR report block types is the Loss Run Length Encoding (RLE) Report Block. This report conveys information regarding the individual Real-time Transport Protocol (RTP) packet receipt and loss events experienced during the RTCP interval preceding the transmission of the report. The new report, which is referred to as the Post-repair Loss RLE report, carries information regarding the packets that remain lost after all loss-repair methods are applied. By comparing the RTP packet receipts/losses before and after the loss repair is completed, one can determine the effectiveness of the loss- repair methods in an aggregated fashion. This document also defines the signaling of the Post-repair Loss RLE report in the Session Description Protocol (SDP). [STANDARDS-TRACK]

This document describes the messages and procedures of the Negative- ACKnowledgment (NACK) Oriented Reliable Multicast (NORM) protocol. This protocol can provide end-to-end reliable transport of bulk data objects or streams over generic IP multicast routing and forwarding services. NORM uses a 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 a unicast return path) between the senders and receivers. The protocol offers a 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 (forward error correction) repair and other IETF Reliable Multicast Transport (RMT) building blocks in its design. This document obsoletes RFC 3940. [STANDARDS-TRACK]

The Layered Coding Transport (LCT) Building Block provides transport level support for reliable content delivery and stream delivery protocols. LCT is specifically designed to support protocols using IP multicast, but it also provides support to protocols that use unicast. LCT is compatible with congestion control that provides multiple rate delivery to receivers and is also compatible with coding techniques that provide reliable delivery of content. This document obsoletes RFC 3451. [STANDARDS-TRACK]

The Session Description Protocol (SDP) provides mechanisms to describe attributes of multimedia sessions and of individual media streams (e.g., Real-time Transport Protocol (RTP) sessions) within a multimedia session, but does not provide any mechanism to describe individual media sources within a media stream. This document defines a mechanism to describe RTP media sources, which are identified by their synchronization source (SSRC) identifiers, in SDP, to associate attributes with these sources, and to express relationships among sources. It also defines several source-level attributes that can be used to describe properties of media sources. [STANDARDS-TRACK]

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. [STANDARDS-TRACK]

This document provides Forward Error Correction (FEC) Scheme specifications according to the Reliable Multicast Transport (RMT) FEC building block for the Compact No-Code FEC Scheme, the Small Block, Large Block, and Expandable FEC Scheme, the Small Block Systematic FEC Scheme, and the Compact FEC Scheme. This document obsoletes RFC 3695 and assumes responsibility for the FEC Schemes defined in RFC 3452. [STANDARDS-TRACK]

This document describes the motivation for the development of the Licklider Transmission Protocol (LTP) designed to provide retransmission-based reliability over links characterized by extremely long message round-trip times (RTTs) and/or frequent interruptions in connectivity. Since communication across interplanetary space is the most prominent example of this sort of environment, LTP is principally aimed at supporting "long-haul" reliable transmission in interplanetary space, but it has applications in other environments as well.

In an Interplanetary Internet setting deploying the Bundle protocol, LTP is intended to serve as a reliable convergence layer over single-hop deep-space radio frequency (RF) links. LTP does Automatic Repeat reQuest (ARQ) of data transmissions by soliciting selective-acknowledgment reception reports. It is stateful and has no negotiation or handshakes.

This document is a product of the Delay Tolerant Networking Research Group and has been reviewed by that group. No objections to its publication as an RFC were raised. This memo defines an Experimental Protocol for the Internet community.

The Licklider Transmission Protocol (LTP) is intended to serve as a reliable convergence layer over single-hop deep-space radio frequency (RF) links. LTP does Automatic Repeat reQuest (ARQ) of data transmissions by soliciting selective-acknowledgment reception reports. It is stateful and has no negotiation or handshakes. This document describes security extensions to LTP, and is part of a series of related documents describing LTP.

This document is a product of the Delay Tolerant Networking Research Group and has been reviewed by that group. No objections to its publication as an RFC were raised. This memo defines an Experimental Protocol for the Internet community.

This document specifies a payload format for generic Forward Error Correction (FEC) for media data encapsulated in RTP. It is based on the exclusive-or (parity) operation. The payload format described in this document allows end systems to apply protection using various protection lengths and levels, in addition to using various protection group sizes to adapt to different media and channel characteristics. It enables complete recovery of the protected packets or partial recovery of the critical parts of the payload depending on the packet loss situation. This scheme is completely compatible with non-FEC-capable hosts, so the receivers in a multicast group that do not implement FEC can still work by simply ignoring the protection data. This specification obsoletes RFC 2733 and RFC 3009. The FEC specified in this document is not backward compatible with RFC 2733 and RFC 3009. [STANDARDS-TRACK]

This document describes how to use Forward Error Correction (FEC) codes to efficiently provide and/or augment reliability for bulk data transfer over IP multicast. This document defines a framework for the definition of the information that needs to be communicated in order to use an FEC code for bulk data transfer, in addition to the encoded data itself, and for definition of formats and codes for communication of that information. Both information communicated with the encoded data itself and information that needs to be communicated 'out-of-band' are considered. The procedures for specifying new FEC codes, defining the information communication requirements associated with those codes and registering them with the Internet Assigned Numbers Authority (IANA) are also described. The requirements on Content Delivery Protocols that wish to use FEC codes defined within this framework are also defined. The companion document titled "The Use of Forward Error Correction (FEC) in Reliable Multicast" describes some applications of FEC codes for delivering content. This document obsoletes RFC 3452. [STANDARDS-TRACK]

This memo describes the use of Forward Error Correction (FEC) codes to efficiently provide and/or augment reliability for one-to-many reliable data transport using IP multicast. One of the key properties of FEC codes in this context is the ability to use the same packets containing FEC data to simultaneously repair different packet loss patterns at multiple receivers. Different classes of FEC codes and some of their basic properties are described and terminology relevant to implementing FEC in a reliable multicast protocol is introduced. Examples are provided of possible abstract formats for packets carrying FEC. This memo provides information for the Internet community.

This document provides advice to the designers of digital

communication equipment and link-layer protocols employing link

layer Automatic Repeat reQuest (ARQ) techniques. This document

presumes that the designers wish to support Internet protocols, but

may be unfamiliar with the architecture of the Internet and with the

implications of their design choices on the performance and

efficiency of Internet traffic carried over their links.

In RFC 2533, "A Syntax for Describing Media Feature Sets", an expression format is presented for describing media feature capabilities using simple media feature tags. This memo contains two corrections to that specification: one fixes an error in the formal syntax specification, and the other fixes an error in the rules for reducing feature comparison predicates. [STANDARDS-TRACK]