Internet Engineering Task Force J. Haas, Ed. Internet-Draft Juniper Networks Updates: 5575 (if approved) November 5, 2013 Intended status: Standards Track Expires: May 9, 2014 Clarification of the Flowspec Redirect Extended Community draft-haas-idr-flowspec-redirect-rt-bis-00 Abstract This document clarifies the formatting of the the BGP Flowspec Redirect Extended Community, originally documented in RFC 5575. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on May 9, 2014. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 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. Haas Expires May 9, 2014 [Page 1]
Internet-Draft draft-haas-idr-flowspec-redirect-rt-bis November 2013 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4 5. Normative References . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5 Haas Expires May 9, 2014 [Page 2]
Internet-Draft draft-haas-idr-flowspec-redirect-rt-bis November 2013 1. Introduction Dissemination of Flow Specification Rules [RFC5575], commonly known as BGP Flowspec, provided for a BGP Extended Community [RFC4360] that served to redirect traffic to a VRF routing instance that matched the flow specification NLRI. In that RFC, the Redirect Extended Community was documented as follows: : +--------+--------------------+--------------------------+ : | type | extended community | encoding | : +--------+--------------------+--------------------------+ : | 0x8008 | redirect | 6-byte Route Target | : +--------+--------------------+--------------------------+ : : [...] : : Redirect: The redirect extended community allows the traffic to be : redirected to a VRF routing instance that lists the specified : route-target in its import policy. If several local instances : match this criteria, the choice between them is a local matter : (for example, the instance with the lowest Route Distinguisher : value can be elected). This extended community uses the same : encoding as the Route Target extended community [RFC4360]. : [...] : : 11. IANA Considerations : [...] : : The following traffic filtering flow specification rules have been : allocated by IANA from the "BGP Extended Communities Type - : Experimental Use" registry as follows: : [...] : : 0x8008 - Flow spec redirect The IANA registry of BGP Extended Communities clearly identifies communities of specific formats. For example, "Two-octet AS Specific Extended Community" [RFC4360], "Four-octet AS Specific Extended Community" [RFC5668] and "IPv4 Address Specific Extended Community" [RFC4360]. Route Targets [RFC4360] identify this format in the high- order (Type) octet of the Extended Community and set the value of the low-order (Sub-Type) octet to 0x02. The Value field of the Route Target Extended Community is intended to be interpreted in the context of its format. Since the Redirect Extended Community only registered a single code- point in the IANA BGP Extended Community registry, a common interpretation of the Redirect Extended Community's "6-byte Route Haas Expires May 9, 2014 [Page 3]
Internet-Draft draft-haas-idr-flowspec-redirect-rt-bis November 2013 Target" has been to look for any matching Route Target sharing the same Value portion of its Extended Community. Thus, multiple Route Targets provisioned in a router's VRFs might match even though the format was different. This "Value wildcard" behavior does not matched deployed implementations of BGP Flowspec. Deployed implementations of BGP Flowspec use the following formatting for the Redirect Extended Community: +--------+--------------------+-------------------------------------+ | type | extended community | encoding | +--------+--------------------+-------------------------------------+ | 0x8008 | redirect AS-2byte | 2-octet AS, 4-octet Value | | 0x8108 | redirect IPv4 | 4-octet IPv4 Address, 2-octet Value | | 0x8208 | redirect AS-4byte | 4-octet AS, 2-octet Value | +--------+--------------------+-------------------------------------+ It should be noted that the low-order nybble of the Redirect's Type field corresponds to the Route Target Extended Community format field (Type). (See [RFC4360], Secs. 3.1, 3.2 and [RFC5668], Sec. 2.) The low order octet (Sub-Type) of the Redirect Extended Community remains 0x08, contrasted to 0x02 for Route Targets. 2. IANA Considerations IANA is requested to update the "BGP Extended Communities Type - Experimental Use" registry as follows: 0x8008 - Flow spec redirect AS-2byte 0x8108 - Flow spec redirect IPv4 0x8208 - Flow spec redirect AS-4byte 3. Security Considerations This document introduces no additional security considerations than those already covered in [RFC5575]. 4. Acknowledgements The contents of this document was raised as part of implementation discussions of BGP Flowspec with the following individuals: Haas Expires May 9, 2014 [Page 4]
Internet-Draft draft-haas-idr-flowspec-redirect-rt-bis November 2013 Andrew Karch (Cisco) Robert Raszuk (NTT I3) Adam Simpson (Alcatel-Lucent) Matthieu Texier (Arbor Networks) Kaliraj Vairavakkalai (Juniper) 5. Normative References [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended Communities Attribute", RFC 4360, February 2006. [RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J., and D. McPherson, "Dissemination of Flow Specification Rules", RFC 5575, August 2009. [RFC5668] Rekhter, Y., Sangli, S., and D. Tappan, "4-Octet AS Specific BGP Extended Community", RFC 5668, October 2009. Author's Address Jeffrey Haas (editor) Juniper Networks 1194 N. Mathida Ave. Sunnyvale, CA 94089 US Email: jhaas@juniper.net Haas Expires May 9, 2014 [Page 5]