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Versions: (draft-ietf-sidr-route-server-rpki-light) 00 01 02

Network Working Group                                            T. King
Internet-Draft                                                   D. Kopp
Intended status: Standards Track                                  DE-CIX
Expires: October 12, 2017                                A. Lambrianidis
                                                                  AMS-IX
                                                              A. Fenioux
                                                               France-IX
                                                          April 10, 2017


Signaling Prefix Origin Validation Results from a Route Server to Peers
             draft-ietf-sidrops-route-server-rpki-light-02

Abstract

   This document defines the usage of the BGP Prefix Origin Validation
   State Extended Community [RFC8097] to signal prefix origin validation
   results from a route server to its peers.  Upon reception of prefix
   origin validation results peers can use this information in their
   local routing decision process.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
   be interpreted as described in [RFC2119] only when they appear in all
   upper case.  They may also appear in lower or mixed case as English
   words, without normative meaning.

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 October 12, 2017.






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Copyright Notice

   Copyright (c) 2017 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  BGP Prefix Origin Validation State Utilized at Route-Servers    3
   3.  Signaling Prefix Origin Validation Results from a Route
       Server to Peers . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Operational Recommendations . . . . . . . . . . . . . . . . .   4
     4.1.  Local Routing Decision Process  . . . . . . . . . . . . .   4
     4.2.  Route Server Receiving the BGP Prefix Origin Validation
           State Extended Community  . . . . . . . . . . . . . . . .   4
     4.3.  Information about Validity of a BGP Prefix Origin Not
           Available at a Route-Server . . . . . . . . . . . . . . .   5
     4.4.  Error Handling at Peers . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   RPKI-based prefix origin validation [RFC6480] can be a significant
   operational burden for BGP peers to implement and adopt.  In order to
   boost acceptance and usage of prefix origin validation and ultimately
   increase the security of the Internet routing system, IXPs may
   provide RPKI-based prefix origin validation at the route server
   [RFC7947].  The result of this prefix origin validation is signaled
   to peers by using the BGP Prefix Origin Validation State Extended
   Community as introduced in [RFC8097].

   Peers receiving the prefix origin validation result from the route
   server(s) can use this information in their local routing decision



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   process for acceptance, rejection, preference, or other traffic
   engineering purposes of a particular route.

2.  BGP Prefix Origin Validation State Utilized at Route-Servers

   A route server that is aware of a BGP Prefix Origin Validation state
   for a certain route can handle this information in one of the
   following modes of operation:

   Simple Tagging:  The prefix origin validation state is tagged to the
       route as described in Section 3.
       This mode of operation is like the tradional way route servers
       work, however, the prefix origin validation state information is
       additionally available for peers.

   Dropping and Tagging:  Routes for which the prefix origin validation
       state is "invalid" (according to [RFC6811]) are dropped by the
       route server.  Routes which show a prefix origin validation state
       of "not found" and "valid" (according to [RFC6811]) are tagged
       accordingly to Section 3.
       Security is higher rated than questionable reachability of a
       prefix by this mode of operation.

   Prioritizing and Tagging:  If the route server learned for a
       particular prefix more than one route it removes firstly the set
       of "invalid" routes and secondly the "not found" routes unless
       the set of routes is empty.  Based on the set of routes left over
       the BGP best path section algorithm is executed.  The selected
       route is marked accordinly to Section 3.
       The BGP best path selection algorithm is changed by this mode of
       operation in such a way that "valid" routes are preferred even if
       they are unfavorable by the traditional best path selection
       algorithm.  This puts prefix origin validation on top of the best
       path selection.


   A route server MUST support the Simple Tagging mode of operation.
   Other modes of operation are OPTIONAL.  The mode of operation MAY be
   configured by the route server operator for a route server instance
   or for each BGP session with a peer seperately.

   These mode of operations might be used in combination with [RFC7911]
   in order to allow a peer to receive all routes and take the routing
   decision by itself.







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3.  Signaling Prefix Origin Validation Results from a Route Server to
    Peers

   The BGP Prefix Origin Validation State Extended Community (as defined
   in [RFC8097]) is utilized for signaling prefix origin validation
   result from a route server to peers.

   [RFC8097] proposes an encoding of the prefix origin validation result
   [RFC6811] as follows:

                  +-------+-----------------------------+
                  | Value | Meaning                     |
                  +-------+-----------------------------+
                  |   0   | Lookup result = "valid"     |
                  |   1   | Lookup result = "not found" |
                  |   2   | Lookup result = "invalid"   |
                  +-------+-----------------------------+

                                  Table 1

   This encoding is re-used.  Route servers providing RPKI-based prefix
   origin validation set the validation state according to the prefix
   origin validation result (see [RFC6811]).

4.  Operational Recommendations

4.1.  Local Routing Decision Process

   A peer receiving prefix origin validation results from the route
   server MAY use the information in its own local routing decision
   process.  The local routing decision process SHOULD apply to the
   rules as described in section 5 [RFC6811].

   A peer receiving a prefix origin validation result from the route
   server MAY redistribute this information within its own AS.

4.2.  Route Server Receiving the BGP Prefix Origin Validation State
      Extended Community

   An IXP route server receiving routes from its peers containing the
   BGP Prefix Origin Validation State Extended Community MUST remove the
   extended community before the route is re-distributed to its peers.
   This is required regardless of whether the route server is executing
   prefix origin validation or not.

   Failure to do so would allow opportunistic peers to advertise routes
   tagged with arbitrary prefix origin validation results via a route




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   server, influencing maliciously the decision process of other route
   server peers.

4.3.  Information about Validity of a BGP Prefix Origin Not Available at
      a Route-Server

   In case information about the validity of a BGP prefix origin is not
   available at the route server (e.g., error in the ROA cache, CPU
   overload) the route server MUST NOT add the BGP Prefix Origin
   Validation State Extended Community to the route.

4.4.  Error Handling at Peers

   A route sent by a route server SHOULD only contain none or one BGP
   Prefix Origin Validation State Extended Community.

   A peer receiving a route from a route server containing more than one
   BGP Prefix Origin Validation State Extended Community SHOULD only
   consider the largest value (as described in Table 1) in the
   validation result field and disregard the other values.  Values
   larger than two in the validation result field MUST be disregarded.

5.  IANA Considerations

   None.

6.  Security Considerations

   All security considerations described in RFC RFC6811 [RFC6811] fully
   apply to this document.

   Additionally, threat agents polluting ROA cache server(s) run by IXP
   operators could cause significant operational impact, since multiple
   route server clients could be affected.  Peers should be vigilant as
   to the integrity and authenticity of the origin validation results,
   as they are provided by a third party, namely the IXP operator
   hosting both the route server as well as any ROA cache server(s).

   Therefore, a route server could be misused to spread malicious prefix
   origin validation results.  However, peers already trust the route
   server for the collection, filtering (e.g.  IRR database filtering),
   and redistribution of BGP routing information to other peers.  So, no
   change in the trust level is needed for this proposal.

   To facilitate trust and help with peers establishing appropriate
   controls in mitigating the risks mentioned above, IXPs SHOULD provide
   out-of-band means for peers to ensure that the ROA validation process
   has not been compromised or corrupted.



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   While beeing under DDoS attacks, it is a common practice for peers
   connected to an IXP to make use of blackholing services (see
   [RFC7999]).  Peers are using blackholing to drop traffic, typically
   by announcing a more specific prefix, which is under attack.  A peer
   SHOULD make sure that this prefix is covered by an appropriate ROA.

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>.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
              February 2006, <http://www.rfc-editor.org/info/rfc4360>.

   [RFC6811]  Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
              Austein, "BGP Prefix Origin Validation", RFC 6811,
              DOI 10.17487/RFC6811, January 2013,
              <http://www.rfc-editor.org/info/rfc6811>.

   [RFC7911]  Walton, D., Retana, A., Chen, E., and J. Scudder,
              "Advertisement of Multiple Paths in BGP", RFC 7911,
              DOI 10.17487/RFC7911, July 2016,
              <http://www.rfc-editor.org/info/rfc7911>.

   [RFC8097]  Mohapatra, P., Patel, K., Scudder, J., Ward, D., and R.
              Bush, "BGP Prefix Origin Validation State Extended
              Community", RFC 8097, DOI 10.17487/RFC8097, March 2017,
              <http://www.rfc-editor.org/info/rfc8097>.

7.2.  Informative References

   [RFC6480]  Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
              February 2012, <http://www.rfc-editor.org/info/rfc6480>.

   [RFC7947]  Jasinska, E., Hilliard, N., Raszuk, R., and N. Bakker,
              "Internet Exchange BGP Route Server", RFC 7947,
              DOI 10.17487/RFC7947, September 2016,
              <http://www.rfc-editor.org/info/rfc7947>.







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   [RFC7999]  King, T., Dietzel, C., Snijders, J., Doering, G., and G.
              Hankins, "BLACKHOLE Community", RFC 7999,
              DOI 10.17487/RFC7999, October 2016,
              <http://www.rfc-editor.org/info/rfc7999>.

Authors' Addresses

   Thomas King
   DE-CIX Management GmbH
   Lichtstrasse 43i
   Cologne  50825
   DE

   Email: thomas.king@de-cix.net


   Daniel Kopp
   DE-CIX Management GmbH
   Lichtstrasse 43i
   Cologne  50825
   DE

   Email: daniel.kopp@de-cix.net


   Aristidis Lambrianidis
   Amsterdam Internet Exchange
   Frederiksplein 42
   Amsterdam  1017 XN
   NL

   Email: aristidis.lambrianidis@ams-ix.net


   Arnaud Fenioux
   France-IX
   88 Avenue Des Ternes
   Paris  75017
   FR

   Email: afenioux@franceix.net










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