Network Working Group                                            R. Bush
Internet-Draft                                                       IIJ
Intended status: BCP                                    January 29, 2011
Expires: August 2, 2011

                 RPKI-Based Origin Validation Operation


   Deployment of the RPKI-based BGP origin validation has many
   operational considerations.  This document attempts to collect and
   present them.  It is expected to evolve as RPKI-based origin
   validation is deployed and the dynamics are better understood.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [RFC2119].

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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   This Internet-Draft will expire on August 2, 2011.

Copyright Notice

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   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document.  Please review these documents

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   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  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Suggested Reading . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  RPKI Distribution and Maintenance . . . . . . . . . . . . . . . 3
   4.  Within a Network  . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Routing Policy  . . . . . . . . . . . . . . . . . . . . . . . . 5
   6.  Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 6
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     10.1.  Normative References . . . . . . . . . . . . . . . . . . . 6
     10.2.  Informative References . . . . . . . . . . . . . . . . . . 7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 7

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1.  Introduction

   RPKI-based origin validation relies on widespread propagation of the
   Resource Public Key Infrastructure (RPKI) [I-D.ietf-sidr-arch].  How
   the RPKI is distributed and maintained globally is a serious concern
   from many aspects.

   The global RPKI has yet to be deployed, only a testbed exists, and
   some beta testing is being done by the IANA and some RIRs.  It is
   expected to be deployed incrementally over a number of years.  It is
   thought that origin validation based on the RPKI will deploy over the
   next year to five years.

   Origin validation only need be done by an AS's border routers and is
   designed so that it can be used to protect announcements which are
   originated by large providers, upstreams and downstreams, and by
   small stub/entetprise/edge routers.

   Origin validation has been designed to be deployed on current routers
   without hardware upgrade.  It should be used by everyone from large
   backbones to small stub/entetprise/edge routers.

   RPKI-based origin validation has been designed so that, with prudent
   local routing policies, there is little risk that normal Internet
   routing is threatened by unprudent deployment of the global RPKI, see
   Section 5.

2.  Suggested Reading

   It is assumed that the reader understands BGP, [RFC4271], the RPKI,
   see [I-D.ietf-sidr-arch], the RPKI Repository Structure, see
   [I-D.ietf-sidr-repos-struct], ROAs, see [I-D.ietf-sidr-roa-format],
   the RPKI to Router Protocol, see [I-D.ietf-sidr-rpki-rtr], and RPKI-
   based Prefix Validation, see [I-D.ietf-sidr-pfx-validate].

3.  RPKI Distribution and Maintenance

   The RPKI is a distributed database containing certificates, CRLs,
   manifests, ROAs, and Ghostbuster Records as described in
   [I-D.ietf-sidr-repos-struct].  Policies and considerations for RPKI
   object generation and maintenance are discussed elsewhere.

   A local valid cache containing all RPKI data may be gathered from the
   global distributed database using the rsync protocol and a validation
   tool such as rcynic.

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   Validated caches may also be created and maintained from other
   validated caches.  An operator should take maximum advantage of this
   feature to minimize load on the global distributed RPKI database.

   As RPKI-based origin validation relies on the availability of RPKI
   data, operators will likely want border routers to have one or more
   nearby caches.

   For redundancy, a router may peer with more than one cache at the
   same time.  Peering with two or more, one local and others remote, is

   If an operator or site trusts upstreams to carry their traffic, they
   might as well trust the RPKI data those upstreams cache and peer with
   of those caches.  Note that this places an obligation on those
   upstreams to maintain fresh and reliable caches.

   A transit provider or a network with peers will want to validate
   origins in announcements made by downstreams and peers.  They still
   may choose to trust the caches provided by their upstreams.

   Before issuing a ROA for a block, an operator MUST ensure that any
   sub-allocations from that block which are announced by others (e.g.
   customers) have ROAs in play.  Otherwise, issuing a ROA for the
   super-block will cause the announcements of sub-allocations with no
   ROAs to be Invalid.

   An environment where private address space is announced in eBGP MAY
   wish to have private RPKI for that space with its own trust anchor.

   Operators issuing ROAs may have 'lazy' customers who announce into
   global eBGP but who do not wish to go though the work to manage their
   own certificates and ROAs.  The operator SHOULD provision the RPKI
   data for the lazy customer just as they provision many other things
   for them.

4.  Within a Network

   Origin validation need only be done by edge routers in a network,
   those which border other networks/ASs.

   A validating router will use the result of origin validation to
   influence local policy within its network, see Section 5.  In
   deployment this policy should fit into the AS's existing policy,
   preferences, etc.  This allows a network to incrementally deploy
   validation capable border routers.

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   eBGP speakers which face more critical peers or up/downstreams would
   be candidates for the earliest deployment.  Validating more critical
   received announcements should be considered in partial deployment.

5.  Routing Policy

   Origin validation based on the RPKI merely marks a received
   announcement as having an origin which is Valid, NotFound, or
   Invalid.  See [I-D.ietf-sidr-pfx-validate].  How this is used in
   routing is specified by the operator's local policy.

   Local policy using relative preference is suggested to manage the
   uncertainty associated with a system in flux, applying local policy
   to eliminate the threat of unroutability of prefixes due to ill-
   advised certification policies and/or incorrect certification data.
   E.g. until the community feels comfortable relying on RPKI data,
   routing on Invalid origin validity, though at a low preference, will
   likely be prevalent for a long time.

   As origin validation will be rolled out incrementally, coverage will
   be incomplete for a long time.  Therefore, routing on NotFound
   validity state will be advisable for a long time.  As the transition
   moves forward, the number of BGP announcements with validation state
   NotFound should decrease.  Hence an operator's policy should not be
   overly strict, preferring Valid announcements, attaching a lower
   preference to, but still using, NotFound announcements, and giving
   very low preference to, but still using, Invalid announcements.

   Some may choose to use the large Local-Preference hammer.  Others
   might choose to let AS-Path rule and set their internal metric, which
   comes after AS-Path in the BGP decision process.

   When using a metric which is also influenced by other local policy,
   the operator should be careful not to create privilege upgrade
   vulnerabilities.  E.g. if Local Pref is set depending on validity
   state, be careful that peer community signaling can not upgrade an
   invalid announcement to valid or better.

   Announcements with Valid origins SHOULD be preferred over those with
   NotFound or Invalid origins.

   Announcements with NotFound origins SHOULD be preferred over those
   with Invalid origins.

   Announcements with Invalid origins MAY be used, but SHOULD be less
   preferred than those with Valid or NotFound.

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6.  Notes

   Like the DNS, the global RPKI presents only a loosely consistent
   view, depending on timing, updating, fetching, etc.  Thus, one cache
   or router may have different data about a particular prefix than
   another cache or router.  There is no 'fix' for this, it is the
   nature of distributed data with distributed caches.

   There is some uncertainty about the origin AS of aggregates and what,
   if any, ROA can be used.  The long range solution to this is the
   deprecation of AS-SETs, see [I-D.wkumari-deprecate-as-sets].

7.  Security Considerations

   As the BGP origin is not signed, origin validation is open to
   malicious spoofing.  It is only designed to deal with inadvertent

   Origin validation does nothing about AS-Path validation and therefore
   is open to monkey in the middle path attacks.

   The data plane may not follow the control plane.

   Be aware of the class of privilege escalation issues discussed in
   Section 5 above.

8.  IANA Considerations

   This document has no IANA Considerations.

9.  Acknowledgments

   The author wishes to thank Rob Austein, Steve Bellovin, Pradosh
   Mohapatra, Chris Morrow, Sandy Murphy, Keyur Patel, Heather and Jason
   Schiller, John Scudder, Maureen Stillman, and Dave Ward.

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.


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              Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", draft-ietf-sidr-arch-11 (work in
              progress), September 2010.

              Huston, G., Loomans, R., and G. Michaelson, "A Profile for
              Resource Certificate Repository Structure",
              draft-ietf-sidr-repos-struct-06 (work in progress),
              November 2010.

              Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
              Origin Authorizations (ROAs)",
              draft-ietf-sidr-roa-format-09 (work in progress),
              November 2010.

              Bush, R. and R. Austein, "The RPKI/Router Protocol",
              draft-ietf-sidr-rpki-rtr-07 (work in progress),
              January 2011.

              Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
              Austein, "BGP Prefix Origin Validation",
              draft-ietf-sidr-pfx-validate-00 (work in progress),
              July 2010.

10.2.  Informative References

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.

              Kumari, W., "Deprecation of BGP AS_SET, AS_CONFED_SET.",
              draft-wkumari-deprecate-as-sets-01 (work in progress),
              September 2010.

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Author's Address

   Randy Bush
   Internet Initiative Japan, Inc.
   5147 Crystal Springs
   Bainbridge Island, Washington  98110

   Phone: +1 206 780 0431 x1

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