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
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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
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