Network Working Group                                            R. Bush
Internet-Draft                                 Internet Initiative Japan
Obsoletes: 4384 (if approved)                                E.M.J. Aben
Intended status: Best Current Practice                          RIPE NCC
Expires: 21 August 2022                                 17 February 2022


                Marking Announcements to BGP Collectors
              draft-ymbk-grow-bgp-collector-communities-02

Abstract

   When BGP route collectors such as RIPE RIS and Route Views are used
   by operators and researchers, currently one can not tell if the
   collection of paths announced to a collector represents the ISP's
   customer cone, includes internal routes, includes paths learned from
   peerings or transits.  This greatly reduces the utility of the
   collected data.  This document specifies the use of BGP communities
   to differentiate the kinds of views being presented to the
   collectors.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

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 https://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 21 August 2022.






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Copyright Notice

   Copyright (c) 2022 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 (https://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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Rationale . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Categories  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Signaling . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Alternative Signaling . . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   BGP route collectors such as RIPE RIS [ris] and Route Views [rviews]
   are used by both operators and researchers.  Unfortunately, one can
   not tell paths announced to a collector are solely from the ISP's
   customer cone (one's own prefixes and the closure of those to whom
   transit is provided; i.e. what one would announce to a peer), include
   internal routes (e.g. inter-router links), or external paths learned
   via peering or transit.  This greatly reduces the utility of the
   collected data, and has been a cause of much pain over the years.
   This document suggests the use of BGP communities to differentiate
   between these categories.

   In 2006, [RFC4384] attempted a similar goal but failed to gain
   traction in the operational community.  We believe this was due to
   its unnecessary complexity.  This document proposes two much simpler
   marking schemes and, if published, will obsolete [RFC4384].







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2.  Rationale

   When an operator uses a collector to look at an ISP's announcement of
   a prefix, it is very useful to know if the ISP also announced it to
   their customers and/or peers/transits.  Researchers want to
   differentiate similarly in order to understand expected route
   propagation.

   One usually wishes to ignore any internal-only routes, e.g.  inter-
   router point-to-point links, an ISP may announce to the collector, as
   they would not be announcing them to peers, transits, or customers.
   I.e. they would not be used operationally.

   An ISP is expected to announce customer routes to their customers,
   and announce customer routes to their external peers and transits.

   In general, one does not need to differentiate whether the ISP will
   announce to peers or transits; and the ISP may not wish to expose the
   business relationships with external providers.  So this document do
   not propose to differentiate peers from transit providers.

3.  Categories

   We consider only three categories of announcements:

   Customer Cone:  One's own prefixes and the closure of those to whom
      transit is provided including routes announced by BGP customers,
      static prefixes used for non-BGP customers, datacenter routes,
      etc.
   External Routes:  Routes learned from peers and transit providers
      which the ISP would normally announce to customers but not to
      peers.  Often, ISPs do not announce such routes to collectors.
      But, as there is no general practice, this category is important
      to mark.
   Internal Routes:  ISPs occasionally announce to the collector
      Internal point to point and other routes they would not normally
      announce to customers, peers, or transit providers.

4.  Signaling

   BGP announcements to route collectors SHOULD be marked with
   communities indicating into which category the announcement falls.
   As most collector peers already use community markings similar to
   these, but ad hoc, the additional effort should be trivial.

   The ASN in the marking SHOULD be that of the collector peer.  The
   communities were selected from community values which were unused at
   the time of this document and SHOULD be as follows:



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   ASs which do not peer with collectors MAY also choose to use these
   markings.


                      +================+===========+
                      | Category       | Community |
                      +================+===========+
                      | Customer Cone  | ASN:64994 |
                      +----------------+-----------+
                      | External Route | ASN:64995 |
                      +----------------+-----------+
                      | Internal Route | ASN:64996 |
                      +----------------+-----------+

                                 Table 1

   Community Markings

5.  Alternative Signaling

   Alternatively, should marking at the path granularity be considered
   too revealing, the collector peer could announce a single well-known
   prefix, for example 10.10.10.10/10, with one or more of the community
   markings as above, describing the set of paths being announced to the
   collector.

6.  IANA Considerations

   As the number of categories is intentionally minimal, an IANA
   registry should not be needed.

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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [ris]      "RIPE Routing Information Service (RIS)",
              <https://www.ripe.net/analyse/internet-measurements/
              routing-information-service-ris/routing-information-
              service-ris>.



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   [rviews]   "University of Oregon Route Views Project",
              <http://www.routeviews.org/>.

7.2.  Informative References

   [RFC4384]  Meyer, D., "BGP Communities for Data Collection", BCP 114,
              RFC 4384, DOI 10.17487/RFC4384, February 2006,
              <https://www.rfc-editor.org/info/rfc4384>.

Authors' Addresses

   Randy Bush
   Internet Initiative Japan
   5147 Crystal Springs
   Bainbridge Island, Washington 98110
   United States of America
   Email: randy@psg.com


   Emile Aben
   RIPE NCC
   Singel 258
   1016 AB Amsterdam
   Netherlands
   Email: emile.aben@ripe.net


























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