draft-ietf-rmt-fec-bb-revised-03.txt		draft-ietf-rmt-fec-bb-revised-04.txt
	Reliable Multicast M. Watson		Reliable Multicast M. Watson
	Internet-Draft M. Luby		Internet-Draft M. Luby
	Expires: July 24, 2006 Digital Fountain		Intended status: Informational Digital Fountain
	L. Vicisano		Expires: March 8, 2007 L. Vicisano
	Cisco Systems, Inc.		Cisco Systems, Inc.
	January 20, 2006		September 4, 2006
	Forward Error Correction (FEC) Building Block		Forward Error Correction (FEC) Building Block
	draft-ietf-rmt-fec-bb-revised-03		draft-ietf-rmt-fec-bb-revised-04
	Status of this Memo		Status of this Memo
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	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
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	This Internet-Draft will expire on July 24, 2006.		This Internet-Draft will expire on March 8, 2007.
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2006).		Copyright (C) The Internet Society (2006).
	Abstract		Abstract
	This document describes how to use Forward Error Correction (FEC)		This document describes how to use Forward Error Correction (FEC)
	codes to efficiently provide and/or augment reliability for data		codes to efficiently provide and/or augment reliability for data
	transport. This document defines a framework for the definition of		transport. This document defines a framework for the definition of
	skipping to change at page 2, line 17		skipping to change at page 3, line 7
	defining the information communication requirements associated with		defining the information communication requirements associated with
	those codes and registering them with the Internet Assigned Numbers		those codes and registering them with the Internet Assigned Numbers
	Authority (IANA) are also described. The requirements on Content		Authority (IANA) are also described. The requirements on Content
	Delivery Protocols which wish to use FEC codes defined within this		Delivery Protocols which wish to use FEC codes defined within this
	framework are also defined. The companion document titled, "The Use		framework are also defined. The companion document titled, "The Use
	of Forward Error Correction (FEC) in Reliable Multicast" describes		of Forward Error Correction (FEC) in Reliable Multicast" describes
	some applications of FEC codes for delivering content.		some applications of FEC codes for delivering content.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	2. Definitions/Abbreviations . . . . . . . . . . . . . . . . . . 4		2. Definitions/Abbreviations . . . . . . . . . . . . . . . . . . 5
	3. Requirements notation . . . . . . . . . . . . . . . . . . . . 5		3. Requirements notation . . . . . . . . . . . . . . . . . . . . 6
	4. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 6		4. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 7
	5. Applicability Statement . . . . . . . . . . . . . . . . . . . 8		5. Applicability Statement . . . . . . . . . . . . . . . . . . . 9
	6. Functionality . . . . . . . . . . . . . . . . . . . . . . . . 9		6. Functionality . . . . . . . . . . . . . . . . . . . . . . . . 10
	6.1. FEC Schemes . . . . . . . . . . . . . . . . . . . . . . . 10		6.1. FEC Schemes . . . . . . . . . . . . . . . . . . . . . . . 11
	6.2. FEC Object Transmission Information . . . . . . . . . . . 12		6.2. FEC Object Transmission Information . . . . . . . . . . . 13
	6.2.1. Transport of FEC Object Transmission Information . . . 13		6.2.1. Transport of FEC Object Transmission Information . . . 14
	6.2.2. Opacity of FEC Object Transmission Information . . . . 14		6.2.2. Opacity of FEC Object Transmission Information . . . . 15
	6.2.3. Mandatory FEC Object Transmission Information		6.2.3. Mandatory FEC Object Transmission Information
	elements . . . . . . . . . . . . . . . . . . . . . . . 14		elements . . . . . . . . . . . . . . . . . . . . . . . 15
	6.2.4. Common FEC Object Transmission Information elements . 15		6.2.4. Common FEC Object Transmission Information elements . 16
	6.2.5. Scheme-specific FEC Object Transmission		6.2.5. Scheme-specific FEC Object Transmission
	Information element . . . . . . . . . . . . . . . . . 15		Information element . . . . . . . . . . . . . . . . . 16
	6.3. FEC Payload ID . . . . . . . . . . . . . . . . . . . . . . 16		6.3. FEC Payload ID . . . . . . . . . . . . . . . . . . . . . . 17
	7. FEC scheme specifications . . . . . . . . . . . . . . . . . . 17		7. FEC scheme specifications . . . . . . . . . . . . . . . . . . 18
	8. CDP specifications . . . . . . . . . . . . . . . . . . . . . . 20		8. CDP specifications . . . . . . . . . . . . . . . . . . . . . . 21
	9. Common algorithms . . . . . . . . . . . . . . . . . . . . . . 21		9. Common algorithms . . . . . . . . . . . . . . . . . . . . . . 22
	9.1. Block partitioning algorithm . . . . . . . . . . . . . . . 21		9.1. Block partitioning algorithm . . . . . . . . . . . . . . . 22
	9.1.1. First Step . . . . . . . . . . . . . . . . . . . . . . 21		9.1.1. First Step . . . . . . . . . . . . . . . . . . . . . . 22
	9.1.2. Second step . . . . . . . . . . . . . . . . . . . . . 22		9.1.2. Second step . . . . . . . . . . . . . . . . . . . . . 23
	10. Requirements from other building blocks . . . . . . . . . . . 23		10. Requirements from other building blocks . . . . . . . . . . . 24
	11. Security Considerations . . . . . . . . . . . . . . . . . . . 24		11. Security Considerations . . . . . . . . . . . . . . . . . . . 25
	12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25		12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
	12.1. Explicit IANA Assignment Guidelines . . . . . . . . . . . 25		12.1. Explicit IANA Assignment Guidelines . . . . . . . . . . . 26
	13. Changes from RFC3452 . . . . . . . . . . . . . . . . . . . . . 27		13. Changes from RFC3452 . . . . . . . . . . . . . . . . . . . . . 28
	14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 28		14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29
	15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29		15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 30
	15.1. Normative References . . . . . . . . . . . . . . . . . . . 29		15.1. Normative References . . . . . . . . . . . . . . . . . . . 30
	15.2. Informative References . . . . . . . . . . . . . . . . . . 29		15.2. Informative References . . . . . . . . . . . . . . . . . . 30
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31
	Intellectual Property and Copyright Statements . . . . . . . . . . 31		Intellectual Property and Copyright Statements . . . . . . . . . . 32
	1. Introduction		1. Introduction
	This document describes how to use Forward Error Correction (FEC)		This document describes how to use Forward Error Correction (FEC)
	codes to provide support for reliable delivery of content within the		codes to provide support for reliable delivery of content within the
	context of a Content Delivery Protocol (CDP). This document		context of a Content Delivery Protocol (CDP). This document
	describes a building block as defined in [10]. This document is a		describes a building block as defined in [10]. This document is a
	product of the IETF RMT WG and follows the general guidelines		product of the IETF RMT WG and follows the general guidelines
	provided in [8].		provided in [8].
	skipping to change at page 14, line 47		skipping to change at page 15, line 47
	The encoding formats defined by the CDP for the Common FEC Object		The encoding formats defined by the CDP for the Common FEC Object
	Transmission Information elements are not opaque in this sense,		Transmission Information elements are not opaque in this sense,
	although it must be considered that different FEC Schemes may use		although it must be considered that different FEC Schemes may use
	different combinations of the Common FEC Object Transmission		different combinations of the Common FEC Object Transmission
	Information elements.		Information elements.
	6.2.3. Mandatory FEC Object Transmission Information elements		6.2.3. Mandatory FEC Object Transmission Information elements
	The Mandatory FEC Object Transmission Information element is:		The Mandatory FEC Object Transmission Information element is:
	FEC Encoding ID: an integer between 0 and 255 inclusive identifying a		FEC Encoding ID: an integer between 0 and 255 inclusive identifying
	specific FEC scheme (Fully-Specified or Under-Specified.)		a specific FEC scheme (Fully-Specified or Under-Specified.)
	6.2.4. Common FEC Object Transmission Information elements		6.2.4. Common FEC Object Transmission Information elements
	The Common FEC Object Transmission Information elements are described		The Common FEC Object Transmission Information elements are described
	below. Note that with the exception of the FEC Instance ID, this		below. Note that with the exception of the FEC Instance ID, this
	specification does not provide complete definitions of these fields.		specification does not provide complete definitions of these fields.
	Instead only aspects of the abstract type are defined. The precise		Instead only aspects of the abstract type are defined. The precise
	type and semantics are defined for each FEC scheme in the FEC scheme		type and semantics are defined for each FEC scheme in the FEC scheme
	specification.		specification.
	FEC Instance ID: an integer between 0 and 65535 inclusive identifying		FEC Instance ID: an integer between 0 and 65535 inclusive
	an instance of an Under-specifed FEC scheme		identifying an instance of an Under-specifed FEC scheme
	Transfer-Length: a non-negative integer indicating the length of the		Transfer-Length: a non-negative integer indicating the length of the
	object in bytes		object in bytes
	Encoding-Symbol-Length: a non-negative integer indicating the length		Encoding-Symbol-Length: a non-negative integer indicating the length
	of each encoding symbol in bytes		of each encoding symbol in bytes
	Maximum-Source-Block-Length: a non-negative integer indicating the		Maximum-Source-Block-Length: a non-negative integer indicating the
	maximum number of source symbols in a source block		maximum number of source symbols in a source block
	Max-Number-of-Encoding-Symbols: a non-negative integer indicating the		Max-Number-of-Encoding-Symbols: a non-negative integer indicating
	maximum number of encoding symbols (i.e. source plus repair		the maximum number of encoding symbols (i.e. source plus repair
	symbols in the case of a systematic code)		symbols in the case of a systematic code)
	The FEC Instance ID MUST be used by all Under-specified FEC schemes		The FEC Instance ID MUST be used by all Under-specified FEC schemes
	and MUST NOT be used by Fully-specified FEC Schemes.		and MUST NOT be used by Fully-specified FEC Schemes.
	FEC Schemes define the precise type of those of the above elements		FEC Schemes define the precise type of those of the above elements
	that they use and in particular may restrict the value range of each		that they use and in particular may restrict the value range of each
	element. FEC Schemes also define an encoding format for the subset		element. FEC Schemes also define an encoding format for the subset
	of the above elements that they use. CDPs may also provide an		of the above elements that they use. CDPs may also provide an
	encoding format for each element in which case this encoding format		encoding format for each element in which case this encoding format
	skipping to change at page 19, line 22		skipping to change at page 20, line 22
	2.2.3 Scheme-Specific <define the Scheme-specific FEC Object		2.2.3 Scheme-Specific <define the Scheme-specific FEC Object
	Transmission Information, including an encoding format, if		Transmission Information, including an encoding format, if
	required>		required>
	3. Procedures <describe any procedures which are specific to this		3. Procedures <describe any procedures which are specific to this
	FEC scheme, in particular derivation and interpretation of the		FEC scheme, in particular derivation and interpretation of the
	fields in the FEC Payload ID and FEC Object Transmission		fields in the FEC Payload ID and FEC Object Transmission
	Information.>		Information.>
	4. FEC code specification (for Fully-Specified FEC schemes		4. FEC code specification (for Fully-Specified FEC schemes only)
	only) <provide a complete specification of the FEC Code>		<provide a complete specification of the FEC Code>
	Specifications MAY include additional sections, for example,		Specifications MAY include additional sections, for example,
	examples.		examples.
	Each FEC scheme MUST be specified independently of all other FEC		Each FEC scheme MUST be specified independently of all other FEC
	schemes; for example, in a separate specification or a completely		schemes; for example, in a separate specification or a completely
	independent section of larger specification.		independent section of larger specification.
	8. CDP specifications		8. CDP specifications
	skipping to change at page 22, line 31		skipping to change at page 23, line 31
	T -- the number of source symbols in the object.		T -- the number of source symbols in the object.
	N -- The number of source blocks into which the object is		N -- The number of source blocks into which the object is
	partitioned.		partitioned.
	Output:		Output:
	I -- the number of larger source blocks.		I -- the number of larger source blocks.
	A_large -- the length of each of the larger source blocks in symbols.		A_large -- the length of each of the larger source blocks in
			symbols.
	A_small -- the length of each of the smaller source blocks in		A_small -- the length of each of the smaller source blocks in
	symbols.		symbols.
	Algorithm:		Algorithm:
	1. A_large = ceil[T/N]		1. A_large = ceil[T/N]
	2. A_small = floor[T/N]		2. A_small = floor[T/N]
	skipping to change at page 31, line 5		skipping to change at page 32, line 5
	Email: luby@digitalfountain.com		Email: luby@digitalfountain.com
	Lorenzo Vicisano		Lorenzo Vicisano
	Cisco Systems, Inc.		Cisco Systems, Inc.
	170 West Tasman Dr.		170 West Tasman Dr.
	San Jose, CA 95134		San Jose, CA 95134
	U.S.A.		U.S.A.
	Email: lorenzo@cisco.com		Email: lorenzo@cisco.com
	Intellectual Property Statement		Full Copyright Statement
			Copyright (C) The Internet Society (2006).
			This document is subject to the rights, licenses and restrictions
			contained in BCP 78, and except as set forth therein, the authors
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	Disclaimer of Validity
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	"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
	OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
	ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
	INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
	INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
	WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	Copyright Statement
	Copyright (C) The Internet Society (2006). This document is subject
	to the rights, licenses and restrictions contained in BCP 78, and
	except as set forth therein, the authors retain all their rights.
	Acknowledgment		Acknowledgment
	Funding for the RFC Editor function is currently provided by the		Funding for the RFC Editor function is provided by the IETF
	Internet Society.		Administrative Support Activity (IASA).
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