draft-ietf-mpls-deprecate-bgp-entropy-label-01.txt		draft-ietf-mpls-deprecate-bgp-entropy-label-02.txt
	Internet Engineering Task Force J. Scudder		Internet Engineering Task Force J. Scudder
	Internet-Draft K. Kompella		Internet-Draft K. Kompella
	Updates: 6790 (if approved) Juniper Networks		Updates: 6790 (if approved) Juniper Networks
	Intended status: Standards Track July 23, 2014		Intended status: Standards Track December 12, 2014
	Expires: January 24, 2015		Expires: June 15, 2015
	Deprecation of BGP Entropy Label Capability Attribute		Deprecation of BGP Entropy Label Capability Attribute
	draft-ietf-mpls-deprecate-bgp-entropy-label-01		draft-ietf-mpls-deprecate-bgp-entropy-label-02
	Abstract		Abstract
	RFC 6790 defines the BGP Entropy Label Capability attribute.		RFC 6790 defines the BGP Entropy Label Capability attribute.
	Regrettably, it has a bug: although RFC 6790 mandates that Entropy		Regrettably, it has a bug: although RFC 6790 mandates that Entropy
	Label-incapable routers must remove the attribute, in practice this		Label-incapable routers must remove the attribute, in practice this
	requirement can't be guaranteed to be fulfilled. This specification		requirement can't be guaranteed to be fulfilled. This specification
	deprecates the attribute. A forthcoming document will propose a		deprecates the attribute. A forthcoming document will propose a
	replacement.		replacement.
	skipping to change at page 1, line 36		skipping to change at page 1, line 36
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on January 24, 2015.		This Internet-Draft will expire on June 15, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2014 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 23		skipping to change at page 2, line 23
	process entropy labels. Sadly, this requirement cannot be fulfilled		process entropy labels. Sadly, this requirement cannot be fulfilled
	with the ELCA as specified, because it is an optional, transitive		with the ELCA as specified, because it is an optional, transitive
	attribute: by definition, a node that does not support the ELCA will		attribute: by definition, a node that does not support the ELCA will
	propagate the attribute. (This is a general property of optional,		propagate the attribute. (This is a general property of optional,
	transitive attributes, see [RFC4271].) But such an ELCA-oblivious		transitive attributes, see [RFC4271].) But such an ELCA-oblivious
	node is likely to also be entropy label-incapable and is exactly the		node is likely to also be entropy label-incapable and is exactly the
	one that we desire to remove the attribute!		one that we desire to remove the attribute!
	This specification updates RFC 6790 by deprecating the version of		This specification updates RFC 6790 by deprecating the version of
	ELCA defined in Section 5.2 of that document. A forthcoming document		ELCA defined in Section 5.2 of that document. A forthcoming document
	will propose a replacement.		will propose a replacement. All other sections of RFC 6790 are
			unchanged.
	1.1. Requirements Language		1.1. Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [RFC2119].		document are to be interpreted as described in RFC 2119 [RFC2119].
	2. Deprecation of ELCA		2. Deprecation of ELCA
	This document deprecates the ELCA path attribute. This means that		This document deprecates the ELCA path attribute. This means that
	any implementation done subsequent to the publication of this		any implementation MUST NOT generate the attribute. If received it
	document MUST NOT generate the attribute. If received it MUST be		MUST be treated as any other unrecognized optional transitive
	treated as any other unrecognized optional transitive attribute as		attribute as per [RFC4271], until and unless the code point is reused
	per [RFC4271], until and unless the code point is reused by some new		by some new specification. (To the authors' best knowledge, there
	specification. (To the authors' best knowledge, there are no		are no implementations of ELCA at the time of writing.)
	implementations of ELCA at the time of writing.)
	3. IANA Considerations		3. IANA Considerations
	For the reasons given in Section 1, IANA is requested to mark		For the reasons given in Section 1, IANA is requested to mark
	attribute 28 in the "BGP Path Attributes" registry as "deprecated",		attribute 28 in the "BGP Path Attributes" registry as "deprecated"
	reference this RFC.		and reference this RFC.
	4. Security Considerations		4. Security Considerations
	ELCA as defined in [RFC6790] S. 5.2, has in common with other		ELCA as defined in [RFC6790] S. 5.2, has in common with other
	optional, transitive path attributes the property that it will be		optional, transitive path attributes the property that it will be
	"tunneled" through intervening routers that don't implement the		"tunneled" through intervening routers that don't implement the
	relevant specification. Unfortunately, as discussed elsewhere in		relevant specification. Unfortunately, as discussed elsewhere in
	this document, implementations of [RFC6790] S. 5.2 receiving such		this document, implementations of [RFC6790] S. 5.2 receiving such
	"tunneled" attributes could -- sometimes improperly -- rely on them.		"tunneled" attributes could -- sometimes improperly -- rely on them.
	The consequence of so doing could be a black hole in the forwarding		The consequence of so doing could be a black hole in the forwarding
End of changes. 6 change blocks.
	13 lines changed or deleted		13 lines changed or added
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