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Network Working Group                                          A. DurandRequest for Comments: 2546                                          IMAGCategory: Informational                                        B. Buclin                                                        AT&T Labs Europe                                                              March 1999                         6Bone Routing PracticeStatus of this Memo   This memo provides information for the Internet community.  It does   not specify an Internet standard of any kind.  Distribution of this   memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (1999).  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]).   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].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.Durand & Buclin              Informational                      [Page 1]

RFC 2546                 6Bone Routing Practice               March 1999   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 issues3.1  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 conditions.   Well known cases where link local prefixes could be advertised by   mistake include:Durand & Buclin              Informational                      [Page 2]

RFC 2546                 6Bone Routing Practice               March 1999   - 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.Durand & Buclin              Informational                      [Page 3]

RFC 2546                 6Bone Routing Practice               March 1999   The ::/96 IPv4-compatible prefixes MAY be advertised by IGPs.   IPv4-compatible prefixes MUST NOT be advertised by EGPs to transit   pNLAs or pTLAs.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 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,RFC 2471 test addresses MUST NOT be advertised on the   6Bone.   Routing of global unicast prefixes outside of the 6Bone range   (3FFE::/16) is discussed insection 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 tunnels.   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.Durand & Buclin              Informational                      [Page 4]

RFC 2546                 6Bone Routing Practice               March 1999   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 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,Durand & Buclin              Informational                      [Page 5]

RFC 2546                 6Bone Routing Practice               March 19996.  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 athttp://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      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.Durand & Buclin              Informational                      [Page 6]

RFC 2546                 6Bone Routing Practice               March 19998.  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 connected 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 athttp://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.Durand & Buclin              Informational                      [Page 7]

RFC 2546                 6Bone Routing Practice               March 199910.  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 tables. It is expected that using these     guidelines, routing on the 6Bone will be less sensitive to denial     of service attacks due to misleading routes.     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]        Hinden, R. and S. Deering, "IP Version 6 Addressing              Architecture",RFC 2373, July 1998.   [RFC 2471] Hinden, R., Fink, R. and J. Postel (deceased), "IPv6              Testing Address Allocation",RFC 2471, December 1998.   [RFC 2080] Malkin, G. and R. Minnear, "RIPng for IPv6",RFC 2080,              January 1997.   [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate              Requirement  Levels",BCP 14,RFC 2119, March 1997.   [RFC 2283] Bates, T., Chandra, R., Katz, D. and Y. Rekhter,              "Multiprotocol Extensions for BGP-4",RFC 2283, March              1998.   [RIPE-181] Bates, T., Gerich, E., Joncheray, L., Jouanigot, J.,              Karrenberg, D., Terpstra, M. and J.  Yu,  Representation              of IP Routing Policies in a Routing Registry.  Technical              Report ripe-181, RIPE, RIPE NCC, Amsterdam, Netherlands,              October 1994.Durand & Buclin              Informational                      [Page 8]

RFC 2546                 6Bone Routing Practice               March 199913.  Authors' Addresses   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   EMail: 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   EMail: Bertrand.Buclin@ch.att.comDurand & Buclin              Informational                      [Page 9]

RFC 2546                 6Bone Routing Practice               March 199914.  Full Copyright Statement   Copyright (C) The Internet Society (1999).  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 implementation 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 an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Durand & Buclin              Informational                     [Page 10]