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Internet Engineering Task Force (IETF)                           K. RazaRequest for Comments: 7506                           Cisco Systems, Inc.Updates:4379                                                   N. AkiyaCategory: Standards Track                            Big Switch NetworksISSN: 2070-1721                                             C. Pignataro                                                     Cisco Systems, Inc.                                                              April 2015IPv6 Router Alert Optionfor MPLS Operations, Administration, and Maintenance (OAM)AbstractRFC 4379 defines the MPLS Label Switched Path (LSP) Ping/Traceroute   mechanism in which the Router Alert Option (RAO) MUST be set in the   IP header of the MPLS Echo Request messages and may conditionally be   set in the IP header of the MPLS Echo Reply messages depending on the   Reply Mode used.  While a generic "Router shall examine packet"   Option Value is used for the IPv4 RAO, there is no generic RAO value   defined for IPv6 that can be used.  This document allocates a new,   generic IPv6 RAO value that can be used by MPLS Operations,   Administration, and Maintenance (OAM) tools, including the MPLS Echo   Request and MPLS Echo Reply messages for MPLS in IPv6 environments.   Consequently, it updatesRFC 4379.   The initial motivation to request an IPv6 RAO value for MPLS OAM   comes from the MPLS LSP Ping/Traceroute.  However, this value is   applicable to all MPLS OAM and not limited to MPLS LSP Ping/   Traceroute.Status of This Memo   This is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   Internet Standards is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc7506.Raza, et al.                 Standards Track                    [Page 1]

RFC 7506               MPLS OAM IPv6 Router Alert             April 2015Copyright Notice   Copyright (c) 2015 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 78 and the IETF Trust's Legal   Provisions Relating to IETF Documents   (http://trustee.ietf.org/license-info) in effect on the date of   publication of this document.  Please review these documents   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.Table of Contents1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .22.  Specification of Requirements . . . . . . . . . . . . . . . .33.  IPv6 RAO Value for MPLS OAM . . . . . . . . . . . . . . . . .34.  Updates toRFC 4379 . . . . . . . . . . . . . . . . . . . . .35.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .46.  Security Considerations . . . . . . . . . . . . . . . . . . .47.  References  . . . . . . . . . . . . . . . . . . . . . . . . .47.1.  Normative References  . . . . . . . . . . . . . . . . . .47.2.  Informative References  . . . . . . . . . . . . . . . . .5   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .5   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .61.  Introduction   A commonly deployed MPLS OAM tool is specified in [RFC4379],   "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures",   which is used to diagnose MPLS network data planes.  This   specification, often referred to as "MPLS LSP Ping/Traceroute"   [RFC4379], requires the use of the Router Alert Option (RAO) in the   IP header.  For example,Section 4.3 of [RFC4379] states that the IP   RAO MUST be set in the IP header of an MPLS Echo Request message.   Similarly,Section 4.5 of [RFC4379] states that the IP RAO MUST be   set in the IP header of an MPLS Echo Reply message if the Reply Mode   in the Echo Request is set to "Reply via an IPv4/IPv6 UDP packet with   Router Alert".   [RFC2113] defines a generic Option Value 0x0 for IPv4 RAO that is   used in LSP Ping and LSP Traceroute for MPLS in IPv4 environments.   This IPv4 RAO value of 0x0 is assigned to "Router shall examine   packet".  However, currently there is no generic IPV6 RAO value   defined that can be used in LSP Ping and LSP Traceroute for MPLS inRaza, et al.                 Standards Track                    [Page 2]

RFC 7506               MPLS OAM IPv6 Router Alert             April 2015   IPv6 environments.  Specifically, [RFC2711] defined the Router Alert   for a general IPv6 purpose but required the Value field in the RAO to   indicate a specific reason for using the RAO.  Because there is no   defined value for MPLS LSP Ping/Traceroute use or for general use, it   is not possible for MPLS OAM tools to use the IPv6 Router Alert   mechanism.   As vendors are starting to implement MPLS on the IPv6 control plane   (e.g., [LDP-IPV6]), there is a need to define and allocate such an   Option Value for IPv6 in order to comply with [RFC4379].  This   document defines a new IPv6 RAO value that can be used by MPLS OAM   tools, including the MPLS Echo Request and MPLS Echo Reply messages   for MPLS in IPv6 environments.   This document closes the gap discussed in the third paragraph ofSection 3.4.2 in [RFC7439].2.  Specification of Requirements   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this   document are to be interpreted as described in [RFC2119].3.  IPv6 RAO Value for MPLS OAM   This document defines a new Option Value (69) for the IPv6 RAO to   alert transit routers to examine the packet more closely for MPLS OAM   purposes.  This Option Value is used by any MPLS OAM application that   requires their packets to be examined by a transit router.   In the scope of this document, this Option Value will be used by the   MPLS Echo Request and MPLS Echo Reply for its IPv6 messages, as is   required by [RFC4379].4.  Updates toRFC 4379   [RFC4379] specifies the use of the RAO in the IP header.  Sections   4.3 and 4.5 of [RFC4379] are updated as follows:   For every time in which the "Router Alert IP Option" is used, the   following text is appended:      In case of an IPv4 header, the generic IPv4 RAO value 0x0      [RFC2113] SHOULD be used.  In case of an IPv6 header, the IPv6 RAO      value (69) allocated through this document for MPLS OAM MUST be      used.Raza, et al.                 Standards Track                    [Page 3]

RFC 7506               MPLS OAM IPv6 Router Alert             April 20155.  IANA Considerations   This document defines a new value (69) for the IPv6 RAO to alert   transit routers to examine the packet more closely for MPLS OAM   purposes.  IANA has assigned a new code point under its "IPv6 Router   Alert Option Values" registry defined by [RFC2711], updated by   [RFC5350], and maintained in [IANA-IPv6-RAO].  The new code point is   as follows:      Value   Description                       Reference      -----   -------------------------------   ---------------         69   MPLS OAMRFC 75066.  Security Considerations   This document introduces no new security concerns in addition to what   have already been captured in [RFC4379] and [RFC6398], the latter of   which expands the security considerations of [RFC2113] and [RFC2711].   IPv6 packets containing the MPLS OAM RAO are encapsulated with an   MPLS header and are not expected to be inspected by every label   switched hop within an MPLS LSP.  Consequently, this value of the RAO   will be processed by the appropriate router and is not subject to the   problem of being ignored, as described inSection 2.2 of [RFC7045].7.  References7.1.  Normative References   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997,              <http://www.rfc-editor.org/info/rfc2119>.   [RFC2711]  Partridge, C. and A. Jackson, "IPv6 Router Alert Option",RFC 2711, October 1999,              <http://www.rfc-editor.org/info/rfc2711>.   [RFC4379]  Kompella, K. and G. Swallow, "Detecting Multi-Protocol              Label Switched (MPLS) Data Plane Failures",RFC 4379,              February 2006, <http://www.rfc-editor.org/info/rfc4379>.   [RFC5350]  Manner, J. and A. McDonald, "IANA Considerations for the              IPv4 and IPv6 Router Alert Options",RFC 5350, September              2008, <http://www.rfc-editor.org/info/rfc5350>.   [RFC6398]  Le Faucheur, F., Ed., "IP Router Alert Considerations and              Usage",BCP 168,RFC 6398, October 2011,              <http://www.rfc-editor.org/info/rfc6398>.Raza, et al.                 Standards Track                    [Page 4]

RFC 7506               MPLS OAM IPv6 Router Alert             April 20157.2.  Informative References   [IANA-IPv6-RAO]              IANA, "IPv6 Router Alert Option Values",              <http://www.iana.org/assignments/ipv6-routeralert-values>.   [LDP-IPV6] Asati, R., Pignataro, C., Raza, K., Manral, V., and R.              Papneja, "Updates to LDP for IPv6", Work in Progress,draft-ietf-mpls-ldp-ipv6-17, February 2015.   [RFC2113]  Katz, D., "IP Router Alert Option",RFC 2113, February              1997, <http://www.rfc-editor.org/info/rfc2113>.   [RFC7045]  Carpenter, B. and S. Jiang, "Transmission and Processing              of IPv6 Extension Headers",RFC 7045, December 2013,              <http://www.rfc-editor.org/info/rfc7045>.   [RFC7439]  George, W., Ed. and C. Pignataro, Ed., "Gap Analysis for              Operating IPv6-Only MPLS Networks",RFC 7439, January              2015, <http://www.rfc-editor.org/info/rfc7439>.Acknowledgements   The authors would like to thank George Swallow, Ole Troan, Bob   Hinden, Faisal Iqbal, Mathew Janelle, and Gregory Mirsky for their   useful input.Raza, et al.                 Standards Track                    [Page 5]

RFC 7506               MPLS OAM IPv6 Router Alert             April 2015Authors' Addresses   Kamran Raza   Cisco Systems, Inc.   2000 Innovation Drive   Kanata, ON  K2K-3E8   Canada   EMail: skraza@cisco.com   Nobo Akiya   Big Switch Networks   EMail: nobo.akiya.dev@gmail.com   Carlos Pignataro   Cisco Systems, Inc.   7200-12 Kit Creek Road   Research Triangle Park, NC  27709   United States   EMail: cpignata@cisco.comRaza, et al.                 Standards Track                    [Page 6]