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Versions: (draft-eddy-idr-flowspec-packet-rate) 00 01

Inter-Domain Routing (IDR)                                       W. Eddy
Internet-Draft                                                 J. Dailey
Intended status: Standards Track                                G. Clark
Expires: June 5, 2017                                        MTI Systems
                                                        December 2, 2016


               BGP Flow Specification Packet-Rate Action
                 draft-ietf-idr-flowspec-packet-rate-01

Abstract

   This document defines a new type of traffic filtering action for the
   BGP flow specification.  The new packet-rate action allows specifying
   a rate-limit in number of packets per second.  This is intended to be
   used in combatting some types of denial of service attacks where the
   packet rate is more important than the raw bitrate of the attack
   traffic.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on June 5, 2017.

Copyright Notice

   Copyright (c) 2016 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
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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of



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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Packet Rate Action  . . . . . . . . . . . . . . . . . . . . .   2
   3.  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The existing BGP flow specification [RFC5575] standard supports
   traffic-rate limits conveyed in bytes per second.  In some cases, it
   may be easier, faster, or more relevant to perform accounting and
   decision-making based on quantities of packets per second.  It is
   desirable to specify rate limits in terms of the number of packets
   per second, and not just the number of bytes per second.

   As an example use case, there are several types of denial of service
   attacks that do not require large amounts of bandwidth, but operate
   based on a cadence of packets over time.  TCP SYN flooding attacks
   are one well-known example [RFC4987], along with common packet-rate
   limits applied to ICMP messages and packets to unknown UDP ports.

1.1.  Requirements Language

   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 RFC 2119 [RFC2119].

2.  Packet Rate Action

   The traffic filtering actions pertaining to a matched flow
   specification are indicated using BGP extended communities [RFC7153].
   Particular extended community values are defined in RFC 5575 for a
   number of possible actions.  New types of actions can be defined
   using additional extended community values.  The value 0x8006 has
   been defined as the "traffic-rate" action, and specifies a rate-limit
   in a quantity of bytes per second.  The new packet-rate extended




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   community described in this draft is similar, except the quantity is
   interpreted as packets per second.

    +------+--------------------+-------------------------------------+
    | type | extended community | encoding                            |
    +------+--------------------+-------------------------------------+
    | TBD  | packet-rate        | 2-byte ASN, 4-byte unsigned integer |
    +------+--------------------+-------------------------------------+

                                  Table 1

   Packet-rate:  The packet-rate extended community is a transitive
      extended community across the autonomous-system boundary and uses
      following extended community encoding:

         The first two octets carry the 2-octet id, which can be
         assigned from a 2-byte AS number.  When a 4-byte AS number is
         locally present, the 2 least significant bytes of such an AS
         number can be used.  This value is purely informational and
         should not be interpreted by the implementation.

         The remaining 4 octets carry the rate information as an
         unsigned integer in network byte order, with packets per second
         as the unit represented.  A packet-rate of 0 should result on
         all traffic for the particular flow to be discarded.

   Note that this is a transitive community type, as explained in RFC
   7153 and not a non-transitive type as mentioned narratively in the
   RFC 5575 description of the traffic-rate action.

   The packet-rate action SHOULD NOT be used together with a traffic-
   rate action within the same flow specification, due to unclear
   semantics.  Implementations MUST be robust to receiving both actions
   and may choose to honor either one or the other, or the combination
   of both, depending on local implementation capabilities.

3.  Discussion

   Interaction between multiple actions in a flow specification is a
   matter of ongoing work in the IETF.  There are potential semantic
   conflicts when a traffic-rate action is combined with a packet-rate
   action.  This is legal syntactically, but devices are not universally
   capable of honoring both a packet per second and a bit per second
   rate limit, resulting in inability to meet the operator intention if
   both are used within a flow specification.  Resolving this is
   potential future work, however, the present guidance is for
   implementations to avoid sending such flow specifications, while




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   still behaving in some reasonable manner when receiving them (e.g.
   honoring one or the other limit if it is not possible to honor both).

   The traffic-rate action is specified as a floating point value.
   There can be discrepancies between what is configured and what is
   encoded, due to loss of precision in the floating point
   representation, which would be annoying for operators.  Based on
   discussions in the IDR working group, for the packet-rate action, an
   unsigned integer value is used, which allows unambiguous packet per
   second rates to be specified.  This limits rates represented to under
   4.3 Gpps (4.3 billion packets per second), which is believed to be
   sufficient for the present and foreseeable future networks.

4.  Acknowledgements

   The initial idea to add a packet rate action was encouraged by
   comments from Donald Smith at a DHS meeting in 2015.  The content of
   this document was shaped by discussion on the IETF IDR mailing list,
   including comments from Aseem Choudhary, Acee Lindem, Jeff Haas, John
   Schiel, Robert Raszuk, Kirill Kasavchenko.  Special thanks go to the
   IDR chairs Sue Hares, and John Scudder for their leadership and
   shepherding of the many other BGP enhancements concurrently underway.

5.  IANA Considerations

   If accepted for publication, IANA will need to allocate a BGP
   extended community value for the "packet-rate" action from the
   "Generic Transitive Experimental Use Extended Community Sub-Types"
   registry.

6.  Security Considerations

   No security considerations are raised by this document.

7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC5575]  Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
              and D. McPherson, "Dissemination of Flow Specification
              Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
              <http://www.rfc-editor.org/info/rfc5575>.




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   [RFC7153]  Rosen, E. and Y. Rekhter, "IANA Registries for BGP
              Extended Communities", RFC 7153, DOI 10.17487/RFC7153,
              March 2014, <http://www.rfc-editor.org/info/rfc7153>.

7.2.  Informative References

   [RFC4987]  Eddy, W., "TCP SYN Flooding Attacks and Common
              Mitigations", RFC 4987, DOI 10.17487/RFC4987, August 2007,
              <http://www.rfc-editor.org/info/rfc4987>.

Authors' Addresses

   Wesley Eddy
   MTI Systems

   Email: wes@mti-systems.com


   Justin Dailey
   MTI Systems

   Email: justin@mti-systems.com


   Gilbert Clark
   MTI Systems

   Email: gclark@mti-systems.com























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