Negative-acknowledgment (NACK)-Oriented Reliable Multicast (NORM) Protocol
RFC 3940
Document | Type |
RFC - Experimental
(November 2004; No errata)
Obsoleted by RFC 5740
Was draft-ietf-rmt-pi-norm (rmt WG)
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Authors | Carsten Bormann , Joseph Macker , Brian Adamson , Mark Handley | ||
Last updated | 2013-03-02 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3940 (Experimental) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Allison Mankin | ||
Send notices to | lorenzo@cisco.com, rogerkermode@msn.com |
Network Working Group B. Adamson Request for Comments: 3940 NRL Category: Experimental C. Bormann Universitaet Bremen TZI M. Handley UCL J. Macker NRL November 2004 Negative-acknowledgment (NACK)-Oriented Reliable Multicast (NORM) Protocol Status of this Memo This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2004). Abstract This document describes the messages and procedures of the Negative- acknowledgment (NACK) Oriented Reliable Multicast (NORM) protocol. This protocol is designed to 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 repair and other IETF reliable multicast transport (RMT) building blocks in its design. Adamson, et al. Experimental [Page 1] RFC 3940 NORM Protocol November 2004 Table of Contents 1. Introduction and Applicability. . . . . . . . . . . . . . . . 3 1.1. NORM Delivery Service Model. . . . . . . . . . . . . . . 4 1.2. NORM Scalability . . . . . . . . . . . . . . . . . . . . 6 1.3. Environmental Requirements and Considerations. . . . . . 7 2. Architecture Definition . . . . . . . . . . . . . . . . . . . 7 2.1. Protocol Operation Overview. . . . . . . . . . . . . . . 9 2.2. Protocol Building Blocks . . . . . . . . . . . . . . . . 10 2.3. Design Tradeoffs . . . . . . . . . . . . . . . . . . . . 11 3. Conformance Statement . . . . . . . . . . . . . . . . . . . . 12 4. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 13 4.1. NORM Common Message Header and Extensions. . . . . . . . 14 4.2. Sender Messages. . . . . . . . . . . . . . . . . . . . . 16 4.2.1. NORM_DATA Message . . . . . . . . . . . . . . . . 16 4.2.2. NORM_INFO Message . . . . . . . . . . . . . . . . 24 4.2.3. NORM_CMD Messages . . . . . . . . . . . . . . . . 26 4.3. Receiver Messages. . . . . . . . . . . . . . . . . . . . 43 4.3.1. NORM_NACK Message . . . . . . . . . . . . . . . . 43 4.3.2. NORM_ACK Message. . . . . . . . . . . . . . . . . 50 4.4. General Purpose Messages . . . . . . . . . . . . . . . . 52 4.4.1. NORM_REPORT Message . . . . . . . . . . . . . . . 52 5. Detailed Protocol Operation . . . . . . . . . . . . . . . . . 52 5.1. Sender Initialization and Transmission . . . . . . . . . 54 5.1.1. Object Segmentation Algorithm . . . . . . . . . . 55 5.2. Receiver Initialization and Reception. . . . . . . . . . 57 5.3. Receiver NACK Procedure. . . . . . . . . . . . . . . . . 57 5.4. Sender NACK Processing and Response. . . . . . . . . . . 59 5.4.1. Sender Repair State Aggregation . . . . . . . . . 60 5.4.2. Sender FEC Repair Transmission Strategy . . . . . 61 5.4.3. Sender NORM_CMD(SQUELCH) Generation . . . . . . . 62 5.4.4. Sender NORM_CMD(REPAIR_ADV) Generation. . . . . . 62 5.5. Additional Protocol Mechanisms . . . . . . . . . . . . . 63 5.5.1. Greatest Round-trip Time Collection . . . . . . . 63 5.5.2. NORM Congestion Control Operation . . . . . . . . 64 5.5.3. NORM Positive Acknowledgment Procedure. . . . . . 72Show full document text