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Versions: 01 rfc2546                                       Informational
INTERNET DRAFT                                                  Alain Durand
NGTRANS WG                                                              IMAG
Expires 20 November, 1998                                    Bertrand Buclin
Category: Informational                                     AT&T Labs Europe
                                                                    May 1998

                            6Bone Routing Practice


Status of this Memo

   This document is an Internet Draft. Internet Drafts are working documents
   of the Internet Engineering Task Force (IETF), its Areas, and its Working
   Groups. Note that other groups may also distribute working documents as
   Internet Drafts.

   Internet Drafts are draft documents valid for a maximum of six months.
   Internet Drafts may be updated, replaced, or obsoleted by other documents
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   Please check the 1id-abstracts.txt listing contained in the internet-drafts
   Shadow Directories on nic.ddn.mil, nnsc.nsf.net, nic.nordu.net,
   ftp.nisc.sri.com, or munnari.oz.au  to learn the current status of any
   Internet Draft.

   This memo provides information for the Internet community. This memo does
   not specify an Internet standard of any kind. Distribution of this memo is

   This draft expires October 30, 1998.

Copyright Notice

   Copyright (C) The Internet Society (date). All Rights Reserved.

1 Introduction

   The 6Bone is an environment supporting experimentation with the IPv6
   protocols and products implementing it. As the network grows, the need for
   common operation rules emerged. In particular, operation of the 6Bone
   backbone is a challenge due to the frequent insertion of bogus routes by
   leaf or even backbone sites.

   This memo identifies guidelines on how 6Bone sites might operate, so that
   the 6Bone can remain a quality experimentation environment and to avoid
   pathological situations that have been encountered in the past. It defines
   the 'best current practice' acceptable in the 6Bone for the configuration
   of both Interior Gateway Protocols (such as RIPng [RFC 2080]) and Exterior
   Gateway Protocols (like BGP4+ [RFC 2283]).

Bertrand Buclin                                                       [Page 1]

draft-ietf-ngtrans-6bone-routing-01.txt   6Bone Routing Practice   1 June 1998

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

2 Basic principles

   The 6Bone is structured as a hierarchical network with pseudo Top Level
   Aggregator (pTLA) sites, pseudo Next Level Aggregator (pNLA) sites and
   leaf sites. This topology supports the IPv6 address aggregation
   architecture as described in [1]. The 6Bone backbone is made of a mesh
   interconnecting pTLAs only. pNLAs connect to one or more pTLAs and provide

   transit service for leaf sites.

   pTLA sites MUST use BGP4+ [RFC 2283] as the mandatory routing protocol for
   exchanging routing information among them.

   Multi-homed sites or pNLAs SHOULD also use BGP4+. Regular sites MAY use a
   simple default route to their ISP.

3 Common Rules

   This section details common rules governing the routing on the 6Bone. They
   are derived from issues encountered on the 6Bone, with respect to the
   routes advertised, handling of special  addresses,  and aggregation:

    1) link local prefixes

    2) site local prefixes

    3) loopback prefix & unspecified prefix

    4) multicast prefixes

    5) IPv4-compatible prefixes

    6) IPv4-mapped prefixes

    7) default routes

    8) Yet undefined unicast prefixes (from a different /3 prefix)

    9) Inter site links issues

    10) aggregation & advertisement issues

 3.1 Link-local prefix

   The link-local prefix (FE80::/10) MUST NOT be advertised through either an
   IGP or an EGP.

   By definition, the link-local prefix has a scope limited to a specific
   link. Since the prefix is the same on all IPv6 links, advertising it in any
   routing protocol does not make sense and, worse, may introduce nasty error

   Well known cases where link local prefixes could be advertised by mistake

Bertrand Buclin                                                       [Page 2]

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   - a router advertising all directly connected network prefixes including
     the link-local one.

   - Subnetting of the link-local prefix.

   In such cases, vendors should be urged to correct their code.

 3.2 Site-local prefixes

   Site local prefixes (in the FEC0::/10 range) MAY  be advertized by IGPs or
   EGPs within a site. The precise definition of a site is ongoing work
   discussed in the IPng working group.

   Site local prefixes MUST NOT be advertised to transit pNLAs or pTLAs.

 3.3 Loopback and unspecified prefixes

   The loopback prefix (::1/128) and the unspecified prefix (::0/128) MUST NOT
   be advertised by any routing protocol.

 3.4 Multicast prefixes

   Multicast prefixes MUST NOT be advertised by any unicast routing protocol.
   Multicast routing protocols are designed to respect the semantics of
   multicast and MUST therefore be used to  route packets with multicast
   destination addresses (in the range FF00::/8).

   Multicast address scopes MUST be respected on the 6Bone. Only global scope
   multicast addresses MAY be routed across transit pNLAs and pTLAs. There is
   no requirement on a pTLA to route multicast packets.

   Organization-local multicasts (in the FF08::/16 or FF18::/16 ranges) MAY be
   routed across a pNLA to its leaf sites.

   Site-local multicasts MUST NOT be routed toward transit pNLAs or pTLAs.

   Obviously, link-local multicasts and node-local multicasts MUST NOT be
   routed at all.

 3.5 IPv4-compatible prefixes

   Sites may choose to use IPv4 compatible addresses (::a.b.c.d) internally.
   As there is no real rationale today for doing that, these addresses SHOULD

   NOT be used in the 6Bone.

   The ::/96 IPv4-compatible prefixes MAY be advertised by IGPs.

   IPv4-compatible prefixes MUST NOT be advertised by EGPs to transit pNLAs or

 3.6 IPv4-mapped prefixes

   IPv4-mapped prefixes (::FFFF:a.b.c.d where a.b.c.d is an IPv4 address) MAY
   be advertised by IGPs within a site. It may be useful for some IPv6 only

Bertrand Buclin                                                       [Page 3]

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   nodes within a site to have such a route pointing to a translation device.

   IPv4-mapped prefixes MUST NOT be advertised by EGPs.

 3.7 Default routes

   6Bone core pTLA routers MUST be default-free.

   pTLAs MAY advertise a default route to their pNLAs. Transit pNLAs MAY do
   the same for their leaf sites.

 3.8 Yet undefined unicast prefixes

   Yet undefined unicast prefixes from a format prefix other than 2000::/3
   MUST NOT be advertised by any routing protocol in the 6Bone. In particular,
   RFC1897 test addresses MUST NOT be advertised on the 6Bone.

   Routing of global unicast prefixes outside of the 6Bone range (3FFE::/16)
   is discussed in section 4, Routing policies, below.

 3.9 Inter-site links

   Global IPv6 addresses MUST be used for the end points of the inter-site
   links. In particular, IPv4 compatible addresses MUST NOT be used for

   Prefixes for those links MUST NOT be injected in the global routing tables.

 3.10 Aggregation & advertisement issues

   Route aggregation MUST be performed by any border router.

   Sites or pNLAs MUST only advertise to their upstream provider the prefixes
   assigned by that ISP unless otherwise agreed.

   Site border router MUST NOT advertise prefixes more specific than the /48
   ones allocated by their ISP.

   pTLA MUST NOT advertise prefixes longer than 24 to other pTLAs unless
   special peering agreements are implemented. When such special peering
   agreements are in place between any two or more pTLAs, care MUST be taken
   not to leak the more specific prefixes to other pTLAs not participating
   in the peering agreement.

4 Routing policies

   6Bone backbone sites maintain the mesh into the backbone and provide an as
   reliable as possible service, granted the 6Bone is an experimentation tool.
   To achieve their mission, 6Bone backbone sites MUST maintain peerings with
   at least 3 (three) other back bone sites.

   The peering agreements across the 6Bone are by nature non-commercial, and
   therefore SHOULD allow transit traffic through.

   Eventually, the Internet registries will assign other TLAs than the 6Bone
   one (currently 3FFE::/16). The organizations bearing those TLAs will

Bertrand Buclin                                                       [Page 4]

draft-ietf-ngtrans-6bone-routing-01.txt   6Bone Routing Practice   1 June 1998

   establish a new IPv6 network, parallel to the 6Bone. The 6Bone MIGHT
   interconnect with this new IPv6 Internet, b ut transit across the 6Bone
   will not be guaranteed. It will be left to each 6Bone backbone site to
   decide whether it will carry traffic to or from the IPv6 Internet.

5 The 6Bone registry

   The 6Bone registry is a RIPE-181 database with IPv6 extensions used to
   store information about the 6Bone. Each 6Bone site MUST maintain the
   relevant entries in the 6Bone registry (whois.6bone.net). In particular,
   the following objects MUST be present:

   - IPv6-site: site description

   - Inet6num: prefix delegation

   - Mntner: coordinate of site maintenance staff

   Other objects MAY be maintained at the discretion of the sites, such as
   routing policy descriptors, person or role objects. The Mntner object MUST
   make reference to a role or person object, but those must not necessarily
   reside in the 6Bone registry, they can be stored within any of the
   Internet registry databases (RIPE, InterNIC, APNIC, ...).

6 Guidelines for new sites joining the 6Bone

   New sites joining the 6Bone should seek to connect to a transit pNLA or a
   pTLA within their region, and preferably as close as possible to their
   existing IPv4 physical and routing path for Internet service. The 6Bone
   registry is available to find out candidate ISPs.

   Any site connected to the 6Bone MUST maintain a DNS server for forward name
   looking and reverse address translation. The joining site MUST maintain the
   6Bone registry objects relative to its site, and in particular the IPv6-
   site and the MNTNER objects.

   The upstream ISP MUST delegate the reverse address translation zone in DNS
   to the joining site. The ISP MUST also create 6Bone registry  objects
   reflecting the delegated address space (inet6num:).

   Up to date information about how to join the 6Bone is available on the
   6Bone Web site at http://www.6bone.net.

7 Guidelines for 6Bone pTLA sites

   6Bone pTLA sites are altogether forming the backbone of the 6Bone. In order
   to ensure the highest level possible of availability and stability for the
   6Bone environment, a few constraints are placed onto sites wishing to
   become or stay a 6Bone pTLA:

   1. The site MUST have experience with IPv6 on the 6Bone, at least as
      a leaf site and preferably as a transit pNLA under an existing pTLA.

   2. The site MUST have the ability and intent to provide "production-
      like" 6Bone backbone service to provide a robust and operationally

Bertrand Buclin                                                       [Page 5]

draft-ietf-ngtrans-6bone-routing-01.txt   6Bone Routing Practice   1 June 1998

      reliable 6Bone backbone.

   3. The  site MUST have a potential "user community" that  would  be
      served by becoming a pTLA, e.g., the requester is a major player in a
      region, country or focus of interest.

   4. Must commit to abide by the 6Bone backbone operational rules and
      policies as defined in the present document.

   When a candidate site seeks to become a pTLA site, it will apply for it to
   the 6Bone Operations group (see below) by bringing evidences it meets the
   above criteria.

8 6Bone Operations group

   The 6Bone Operations group is the body in charge of monitoring the
   adherence to the present rules, and will take the appropriate actions to
   correct deviations. Membership in the 6Bone Operations group is mandatory

   for, and restricted to, any site connecte d to the 6Bone.

   The 6Bone Operations group is currently defined by those members of the
   existing 6Bone mailing list, i.e., 6bone@isi.edu, who represent sites
   participating on the 6Bone. Therefore it is incumbent on relevant site
   contacts to join the mailing list. Instructions on how to join the list are
   maintained on the 6Bone web site at http://www.6bone.net.

9 Common rules enforcement

   Participation in the 6Bone is a voluntary and benevolent undertaking.
   However, participating sites are expected to adhere to the rules described
   in this document, in order to maintain the 6Bone as quality tool for
   experimenting with the IPv6 protocols and products implementing them.

   The following processes are proposed to help enforcing the 6Bone rules:

   - Each pTLA site has committed when requesting their pTLA to implement the
     rules, and to ensure they are respected by sites within their
     administrative control (i.e. those to who prefixes have been delegated).

   - When a site detects an issue, it will first use the 6Bone registry to
     contact the site maintainer and work the issue.

   - If nothing happens, or there is disagreement on what the right solution
     is, the issue can be brought to the 6Bone Operations group.

   - When the problem is related to a product issue, the site(s) involved is
     responsible for contact the product vendor and work toward its resolution.

   - When an issue causes major operational problems, backbone sites may
     decide to temporarily set filters in order to restore service.

10 Security considerations

   The result of bogus entries in routing tables is usually unreachable sites.
   Having guidelines to aggregate or reject routes will clean up the routing

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draft-ietf-ngtrans-6bone-routing-01.txt   6Bone Routing Practice   1 June 1998

   tables. It is expected that using these guidelines, routing  on the 6Bone
   will be less sensitive to denial of service attacks due to misleading

   The 6Bone is a test network. Therefore, denial of service, packet
   disclosure,... are to be expected.

11 Acknowledgements

   This document is the result of shared experience on the 6Bone. Special
   thanks go to Bob Fink for the hard work make to date to direct the 6Bone
   effort, to David Kessens for the 6Bone registry, and to Guy Davies for his
   insightful contributions.

12 References

   [1]        R. Hinden, S. Deering, "IP Version 6 Addressing Architecture",
              January 1998, internet draft, work in progress,

   [RFC 1897] R. Hinden & J. Postel., IPv6 Testing Address Allocation.
              January 1996. (Status: OBSOLETE)

   [RFC 2080] Malkin, G., Minnear, R., "RIPng for IPv6", January 1997.

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

   [RFC 2283] T. Bates, R. Chandra, D. Katz, Y. Rekhter, "Multiprotocol
              Extensions for BGP-4", March 98

   [RIPE-181] T.  Bates, E.  Gerich, L. Joncheray, J-M. Jouanigot, D.
              Karrenberg, M.  Terpstra, and J.  Yu.  Representation of IP
              Routing Policies in a Routing Registry.  Technical Report ripe-
              181, RIPE, RIPE NCC, Amsterdam, Netherlands, October 1994.

13   Author address

        Alain Durand
        Institut d'Informatique et de Mathematiques Appliquees de Grenoble
        IMAG BP 53
        38041 Grenoble CEDEX 9 France
        Phone : +33 4 76 63 57 03
        Fax   : +33 4 76 51 49 64
        E-Mail: Alain.Durand@imag.fr

        Bertrand Buclin
        AT&T International S.A.
        Route de l'aeroport 31, CP 72
        CH-1215 Geneve 15 (Switzerland)
        Phone : +41 22 929 37 40
        Fax   : +41 22 929 39 84
        E-Mail: Bertrand.Buclin@ch.att.com

Bertrand Buclin                                                       [Page 7]

draft-ietf-ngtrans-6bone-routing-01.txt   6Bone Routing Practice   1 June 1998

14 Full Copyright Statement

         "Copyright (C) The Internet Society (date).  All Rights Reserved.

         This document and translations of it may be copied and furnished
         to others, and derivative works that comment on or otherwise
         explain it or assist in its implmentation may be prepared, copied,
         published and distributed, in whole or in part, without
         restriction of any kind, provided that the above copyright notice
         and this paragraph are included on all such copies and derivative
         works.  However, this document itself may not be modified in any
         way, such as by removing the copyright notice or references to the
         Internet Society or other Internet organizations, except as needed
         for the purpose of developing Internet standards in which case the
         procedures for copyrights defined in the Internet Standards
         process must be followed, or as required to translate it into
         languages other than English.

         The limited permissions granted above are perpetual and will not
         be revoked by the Internet Society or its successors or assigns.

         This document and the information contained herein is provided on

Bertrand Buclin                                                       [Page 8]