Clarification of the Flowspec Redirect Extended Community
RFC 7674

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Internet Engineering Task Force (IETF)                      J. Haas, Ed.
Request for Comments: 7674                              Juniper Networks
Updates: 5575                                               October 2015
Category: Standards Track
ISSN: 2070-1721

       Clarification of the Flowspec Redirect Extended Community

Abstract

   This document updates RFC 5575 ("Dissemination of Flow Specification
   Rules") to clarify the formatting of the BGP Flowspec Redirect
   Extended Community.

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 in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7674.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Haas                         Standards Track                    [Page 1]
RFC 7674          Flowspec Redirect Extended Community      October 2015

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  BGP Transitive Extended Community Types . . . . . . . . .   5
     2.2.  Update to BGP Generic Transitive Experimental Use
           Extended Community Sub-Types  . . . . . . . . . . . . . .   5
     2.3.  Generic Transitive Experimental Use Extended Community
           Part 2 Sub-Types  . . . . . . . . . . . . . . . . . . . .   5
     2.4.  Generic Transitive Experimental Use Extended Community
           Part 3 Sub-Types  . . . . . . . . . . . . . . . . . . . .   6
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   4.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

Haas                         Standards Track                    [Page 2]
RFC 7674          Flowspec Redirect Extended Community      October 2015

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 Virtual Routing and Forwarding (VRF)
   instance that matched the flow specification's Network Layer
   Reachability Information (NLRI).  In RFC 5575, 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