RFC 3940 · EXPERIMENTAL · 2004

Negative-acknowledgment -Oriented Reliable Multicast Protocol

Overview

RFC 3940, “Negative-acknowledgment -Oriented Reliable Multicast Protocol”, is an Experimental document published in November 2004 by B. Adamson, C. Bormann, M. Handley, J. Macker. It has been obsoleted by RFC 5740 — refer to the newer document for the authoritative version. The canonical text is published by the RFC Editor.

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. This memo defines an Experimental Protocol for the Internet community.

Abstract as published in the RFC, via rfc-editor.org.

What “Experimental” means

Describes a specification that is part of a research or development effort, published so the community can gain experience with it.

Read this RFC

The canonical text of RFC 3940 is hosted at rfc-editor.org. Available in TXT,HTML.

Relationships to other RFCs
Obsoleted by
RFC 5740
Other RFCs from 2004

Who Is Online

In total there are 52 users online: 0 registered, 46 guests and 6 bots.

Most users ever online was 1,226 on 13 Jun 2026, 3:56 am.

Bots: AhrefsBot Applebot Googlebot Other Bot SemrushBot Sogou

Users active in the past 15 minutes. Total registered members: 354