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Versions: 00 01 02 03 04 rfc2725                                        
Internet Engineering Task Force                        Curtis Villamizar
INTERNET-DRAFT                                                       ANS
draft-ietf-rps-auth-01                              Cengiz Alaettinoglu
                                                                    ISI
                                                         David M. Meyer
                                                   University of Oregon
                                                           Sandy Murphy
                                                                    TIS
                                                           Carol Orange
                                                                   RIPE
                                                           May 15, 1998


                      Routing Policy System Security





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
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  To view the entire list of current Internet-Drafts, please check
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  (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu
  (US West Coast).


Abstract


  The RIPE database specifications [2] and RPSL language [1] define
  languages used as the basis for representing information in a routing
  policy system.  A repository for routing policy system information is
  known as a routing registry.  A routing registry provides a means of
  exchanging information needed to address many issues on importance to
  the operation of the Internet.  The implementation and deployment of a
  routing policy system must maintain some degree of integrity to be of

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  any operational use.  This document addresses the need to assure
  integrity of the data by providing an authentication and authorization
  model.



1  Overview


  The Internet Routing Registry (IRR) has evolved to meet a need for
  Internet-wide coordination.  This need was described in RFC-1787, an
  informational RFC prepared on behalf of the IAB [18].  The following
  summary appears in Section 7 of RFC-1787.



     While ensuring Internet-wide coordination may be more and more
     difficult, as the Internet continues to grow, stability and con-
     sistency of the Internet-wide routing could significantly benefit
     if the information about routing requirements of various organi-
     zations could be shared across organizational boundaries.  Such
     information could be used in a wide variety of situations ranging
     from troubleshooting to detecting and eliminating conflicting
     routing requirements.  The scale of the Internet implies that the
     information should be distributed.  Work is currently underway to
     establish depositories of this information (Routing Registries),
     as well as to develop tools that analyze, as well as utilize this in-
     formation.


  A routing registry must maintain some degree of integrity to be of any
  use.  The degree of integrity required depends on the usage of the
  routing policy system.

  An initial intended usage of routing policy systems such as the RIPE
  database had been in an advisory capacity, documenting the intended
  routing policies for the purpose of debugging.  In this role a very
  weak form of authentication was deemed sufficient.

  The IRR is increasingly used for purposes that have a stronger
  requirement for data integrity and security.  This document addresses
  issues of data integrity and security that is consistent with the
  usage of the IRR and which avoids compromising data integrity and se-
  curity even if the IRR is distributed among less trusted repositories.



2  Background


  An early routing policy system used in the T3--NSFNET, the policy
  routing database (PRDB), provided a means of determining who was

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  authorized to announce specific prefixes to the NSFNET backbone.  The
  need for a policy database was recognized as far back as 1989 [6, 4].
  By 1991 the database was in place [5].  Authentication was
  accomplished by requiring confirmation and was a manually intensive
  process.  This solved the problem for the NSFNET, but was oriented
  toward holding the routing policy of a single organization.

  The problem since has become more difficult.  New requirements have
  emerged.



 1.  The need to represent the routing policies of many organizations,

 2.  CIDR and overlapping prefixes, the increasing complexity of routing
     policies and the needs of aggregation,
 3.  the need to assure integrity of the data and delegate authority for
     the data representing specifically allocated resources to multiple
     persons or organizations,

 4.  the need to assure integrity of the data and distribute the storage
     of data subsets to multiple repositories.



  The RIPE effort specificly focused on the first issue [2].  Its
  predecessor, the PRDB, addressed the needs of a single organization,
  while the RIPE database was initially intended to address the needs of
  the European Internet community.  The RIPE database formats as
  described in [2] are the basis of current IRR.

  Routing protocols themselves provide no assurance that the origination
  of a route is legitimate and can actually reach the stated
  destination.  The nature of CIDR allows more specific prefixes to
  override less specific prefixes [9, 19, 8].  Even with signed route
  origination, there is no way to determine if a more specific prefix is
  legitimate and should override a less specific route announcement
  without a means of determining who is authorized to announce specific
  prefixes.  Failing to do so places no assurance of integrity of global
  routing information and leaves an opportunity for a very effective
  form of denial of service attack.

  The Routing Policy System Language (RPSL) [1, 15, 14] was a fairly
  substantial evolutionary step in the data representation which was
  largely targeted at addressing the second group of needs.  The PRDB
  accommodated CIDR in 1993 [13] and the RIPE database accommodated the
  entry of CIDR prefixes from inception, but RPSL provides many needed
  improvements including explicit support for aggregation.  Transition
  of the IRR to RPSL is expected to occur in late 1988 [12].

  This document addresses the third group of needs identified above.


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  While the current implementation supporting weak authentication
  doesn't guarantee integrety of the data, it does provide extensive
  mechanisms to make sure that all involved parties get notified when a
  change is made to the database, whether the change was malicious or
  intended.  This provides inaddequate protection against additions.
  Since the software is increasingly used to configure the major parts
  of the Internet infrastructure, it is not considered to be adequate
  anymore to know about and have the ability roll back unintended
  changes.  Therefore, more active security mechanism need to be
  developed to prevent such problems before they happen.

  A separate document addressing the fourth group of needs is also being
  written.



3  Implicit Policy Assumptions


  The authorization model encodes certain policies for allocation of
  address numbers, AS numbers, and for the announcement of routes.
  Implicit to the authorization model are a very limited number of
  policy assumptions.



 1.  Address numbers are allocated hierachically.  The IANA delegates
     portions of the address space to the regional registries (currently
     ARIN, APNIC and RIPE), which in turn delegate address space to
     their members, who can assign addresses to their customers.
 2.  AS numbers are allocated either singly or in small blocks by
     registries.  Registries are allocated blocks of AS numbers, thereby
     making the allocation hierarchical.

 3.  Routes should only be anounced with the consent of the holder of
     the origin AS number of the announcement and with the consent of
     the holder of the address space.

 4.  AS numbers and IP address registries may be different entities from
     routing registries.


  For subsets of any of these three allocation spaces, network
  addresses, AS numbers, and routes, these restrictions may be loosened
  or disabled by specifying a very weak authorization method or an
  authentication method of ``none''.  However, even when no
  authentication mechanism is used, all involved parties can be notified
  about the changes that occurred through use of the existing ``notify''
  attribute.




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4  Organization of this Document


  Familiarity with RIPE-181 [2] and RPSL [1] is assumed throughout this
  document.  Goals are described in Section 5.  Section 6 through
  Section 8 provide descriptions of the changes and discussion.
  Section 9 provides a concise summary of data formats and semantics.
  Appendix A through Appendix C provide additional technical discussion,
  examples, and deployment considerations.



     Goals and Requirements Section 5 provides a more detailed
     description of the issues and identifies specific problems that
     need to be solved, some of which require a degree of cooperation in
     the Internet community.

     Data Representation Section 6 provides some characteristics of RPSL
     and formats for external representations of information.

     Authentication Model Section 7 describes current practice, proposes
     additional authentication methods, and describes the extension
     mechanism if additional methods are needed in the future.

     Authorization Model Section 8 describes the means of determining
     whether a transaction contains the authorization needed to add,
     modify, or delete specific data objects, based on stated
     authentication requirements in related data objects.

     Data Format Summaries Section 9 provides a concise reference to the
     data formats and steps in transaction processing.

     Technical Discussion Section A contains some discussion of
     technical tradeoffs.

     Common Operational Cases Section B provides some examples drawn
     from past operational experience with the IRR.

     Deployment Considerations Section C describes some deployment
     issues and discusses possible means of resolution.



5  Goals and Requirements


  The Internet is an open network.  This openness and the large scale of
  the Internet can present operational problems.  Technical weaknesses
  that allow misconfiguration or errant operation in part of the network
  to propagate globally or which provide potentials for simple denial of
  service attacks should be eliminated to the extent that it is
  practical.  The integrity of routing information is critical in

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  assuring that traffic goes where it is supposed to.

  An accidental misconfiguration can direct traffic toward routers that
  cannot reach a destination for which they are advertising reachabil-
  ity.  This is commonly caused by misconfigured static routes though
  there are numerous other potential causes.  Static routes are often
  used to provide constant apparent reachability to single homed desti-
  nations.  Some of the largest ISPs literally have thousands of static
  routes in their networks.  These are often entered manually by opera-
  tors.  Mistyping can divert traffic from a completely unrelated desti-
  nation to a router with no actual reachability to the advertised des-
  tination.  This can happen and does happen somewhat regularly.  In ad-
  dition, implementation bugs or severe misconfigurations that result in the
  loss of BGP AS path information or alteration of prefix length can result
  in the advertisement of large sets of routes.  Though considerably more
  rare, on a few occasions where this has occurred the results were catas-
  trophic.

  Where there is the potential for an accidental misconfiguration in a
  remote part of the Internet affecting the global Internet there is
  also the potential for malice.  For example, it has been demonstrated
  by accident that multiple hour outages at a major institution can be
  caused by a laptop and a dial account if proper precautions are not
  taken.  The dial account need not be with the same provider used by
  the major institution.

  The potential for error is increased by the CIDR preference for more
  specific routes [8].  If an institution advertises a single route of a
  given length and a distant router advertises a more specific router
  covering critical hosts, the more specific route, if accepted at all,
  is preferred regardless of administrative weighting or any routing
  protocol attributes.

  There is a need to provide some form of checks on whether a route
  advertisement is valid.  Today checks are typically made against the
  border AS advertising the route.  This prevents accepting routes from
  the set of border AS that could not be legitimately advertise the
  route.  Theses checks rely on the use of information registered in the
  IRR to generate lists of prefixes that could be advertised by a
  specific border AS. Checks can also be made against the origin AS. If
  policy information were sufficiently populated, checks could be made
  against the entire AS path, but this is not yet feasible.

  The use of a routing registry can also make it more difficult for
  prefixes to be used without authorization such as unallocated prefixes
  or prefixes allocated to another party.

  In summary, some of the problems being addressed are:



  o  Localizing the impact of accidental misconfiguration made by

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     Internet Providers to that provider's networks only.

  o  Eliminating the potential for an Internet provider's customer to
     use malicious misconfiguration of routing as a denial of service
     attack if the provider router filters their customers and
     localizing the denial of service to that Internet provider only if
     the immediate Internet service provider does not route filter their
     customers but other providers route filter the route exchange at
     the inter-provider peering.

  o  Eliminating the unauthorized use of address space.


  If the data within a routing registry is critical, then the ability to
  change the data must be controlled.  Centralized authorities can
  provide control but centralization can lead to scaling problems (and
  is politically distasteful).

  Address allocation and name allocation is already delegated.  Since
  delegation can be to outside registries it is at least somewhat
  distributed [11].  Autonomous System (AS) numbers are allocated by the
  same authorities.  It makes sense to delegate the routing number space
  in a manner similar to the address allocation and AS number
  allocation.  The need for this delegation of authority to numerous
  registries increases the difficulty of maintaining the integrity of
  the body of information as a whole.

  As a first step, the database can be somewhat centrally administered
  with authority granted to many parties to change the information.
  This is the case with the current IRR. There are a very small number
  of well trusted repositories and a very large number of parties
  authorized to make changes.  Control must be exercised over who can
  make changes and what changes they can make.  The distinction of who
  vs what separates authentication from authorization.



  o  Authentication is the means to determine who is attempting to make
     a change.

  o  Authorization is the determination of whether a transaction passing
     a specific authentication check is allowed to perform a given
     operation.



  Different portions of the database will require different methods of
  authentication.  Some applications will require authentication based
  on strong encryption.  In other cases software supporting strong
  encryption may not be necessary or may not be legally available.  For
  this reason multiple authentication methods must be supported,
  selected on a per object basis.  The authentication methods may range

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  from very weak data integrity checks to cryptographicly strong
  signatures.  The authorization model must insure that the use of weak
  integrity checks in parts of the database does not compromise the
  overall integrity of the database.

  Additional requirements are placed on the authorization model if the
  database is widely distributed with delegations made to parties that
  may not be trustworthy or whose security practices may be lacking.
  This problem must be addressed in the authorization model in order to
  enable later evolution to a more distributed routing registry.

  Autonomous system numbers can be delegated in blocks and subdelegated
  as needed and then individual AS numbers assigned.  Address allocation
  is a simple numeric hierarchy.  Route allocation is somewhat more
  complicated.  The key attributes in a route object (key with regard to
  making it unique) contains both an address prefix and an AS number,
  known as the origin AS. The addition of a route object must be
  validated against both the authorization criteria for the AS and the
  address prefix.  Route objects may exist for the same prefix with mul-
  tiple origin AS values due to a common multihoming practice that does
  not require a unique origin AS. There is often no correlation between
  the origin AS of a prefix and the origin AS of overlapping more specific
  prefixes.

  There are numerous operational cases that must be accommodated.  Some
  of the more common are listed below.  These are explored in greater
  detail in Appendix B with discussion of technical tradeoffs in
  Appendix A.



  o  simple hierarchical address allocation and route allocation

  o  aggregation and multihomed more specific routes
  o  provider independent addresses and multiple origin AS

  o  changing Internet service providers

  o  renumbering grace periods


  The authorization model must accommodate a variety of policies
  regarding the allocation of address space and cannot mandate the use
  of any one model.  There is no standardization of address allocation
  policies though guidelines do exist [11, 20].  Whether authorization
  allows the recovery of address space must be selectable on a per
  object basis and may differ in parts of the database.  This issue is
  discussed further in Appendix A.





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6  Data Representation


  RPSL provides a complete description of the contents of a routing
  repository [1].  Many RPSL data objects remain unchanged from the RIPE
  and RPSL references the RIPE-181 specification as recorded in RFC-1786
  [2].  RPSL provides external data representation.  Data may be stored
  differently internal to a routing registry.

  Some database object types or database attributes must be added to
  RPSL to record the delegation of authority and to improve the
  authentication and authorization mechanisms.  These additions are very
  few and are described in Section 7 and Section 8.

  Some form of encapsulation must be used to exchange data.  The
  de-facto encapsulation has been the one which the RIPE tools accept, a
  plain text file or plain text in the body of an RFC-822 formatted mail
  message with information needed for authentication derived from the
  mail headers or the body of the message.  Merit has slightly modified
  this using the PGP signed portion of a plain text file or PGP signed
  portion of the body of a mail message.  These very simple forms of
  encapsulation are suitable for the initial submission of a database
  transaction.

  The encapsulation of registry transaction submissions, registry
  queries and registry responses and exchanges between registries is
  outside the scope of this document.



7  Authentication Model


  The maintainer objects serve as a container to hold authentication
  filters.  A reference to a maintainer within another object defines
  authorization to perform operations on the object or on a set of
  related objects.  The maintainer is typically referenced by name in
  mnt-by attributes of objects.  Further details on the use of
  maintainers are provided in Section 8.1.

  The maintainer contains one or more ``auth'' attributes.  Each
  ``auth'' attribute begins with a keyword identifying the
  authentication method followed by the authentication information
  needed to enforce that method.  For example, where the method is
  identified by the keyword ``pgp-key'' the authentication information
  is the PGP public key block in ASCII radix-64 format.

  Authentication methods currently supported include the following.
  Note that pgp-from is being replaced by the pgp-key (see Section 9).




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  mail-from  This is a very weak authentication check and is
     discouraged.  The authentication information is a regular
     expression over ASCII characters.  The maintainer is authenticated
     if the from or reply-to fields in RFC-822 mail headers are matched
     by this regular expression.  Since mail forgery is quite easy, this
     is a very weak form of authentication.

  crypt-pw  This is another weak form of authentication.  The
     authentication information is a fixed encrypted password in UNIX
     crypt format.  The maintainer is authenticated if the transaction
     contains the clear text password of the maintainer.  Since the
     password is in clear text in transactions, it can be captured by
     snooping.  Since the encrypted form of the password is exposed, it
     is subject to password guessing attacks.

  pgp-from  This format is being replaced by the ``pgp-key'' so that the
     public key certificate will be available to remote repositories.
     This is Merit's PGP extension.  The authentication information is a
     signature identity pointing to an external public key ring.  The
     maintainer is authenticated if the transaction (currently PGP
     signed portion of a mail message) is signed by the corresponding
     private key.
  pgp-key  The authentication information is a PGP public key block in
     ASCII radix-64 format.  The maintainer is authenticated if the
     transaction is signed by the corresponding private key.



  Repositories may elect to disallow the addition of ``auth'' attributes
  specifying weaker forms of authentication and/or disallow their use in
  local transaction submissions.  Repositories are encouraged to
  disallow the addition of ``auth'' attributes with the depricated
  ``pgp-from'' method.

  Any digital signature technique can be used for authentication.
  Transactions should be signed using multiple digital signature
  techniques to allow repositories or mirrors that only use a subset of
  the techniques to verify at least one of the signatures.  Any digital
  signature techniques would be applicable.  One that may be supported
  in the in the future is DSA [16, 17].  Numerous digital signature
  algorithms are described in [22].



8  Authorization Model


  The authorization model must accommodate the requirements outlined in
  Section 5.  A key feature of the authorization model is the
  recognition that authorization for the addition of certain types of
  data objects must be derived from related data objects.


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  With multiple repositories, objects not found in RPSL are needed to
  control AS delegations and new attributes are needed in existing
  objects to control subdelegation.  Objects are also needed to provide
  query information for other repositories.

  A root repository must be agreed upon.  Ideally such a repository
  would contain only top level delegations and pointers to other
  repositories used in these delegations.  It would be wise to allow
  only cryptographically strong transactions in the root repository.
  The following might be used to identify a repository (for formal
  description, see 9).



    repository:         RIPE
    query-address:      whois.ripe.net 43
    response-auth-type: rsa-pubkey some-incredibly-long-public-key
    response-auth-type: none
    remarks:            you can request rsa signature on queries
    submit-address:     mailto://auto-dbm@ripe.net
    submit-address:     rps-query://whois.ripe.net:43
    submit-auth-type:   pgp-key crypt-pw mail-from
    remarks:            these are the authentication types supported
    mnt-by:             maint-ripe-db
    refresh:            3600
    expire:             14400
    remarks:            refresh and expire same as in DNS SOA
    ...
    remarks:            admin and technical contact, etc
    source:             IANA



  In each repository there should be a special repository object named
  ROOT. This should point to the root repository or to a higher level
  repository.  This is to allow queries to be directed to the local
  repository but refer to the full set of registries for resolution of
  hierarchically allocated objects.

  The ``repository'' object and its usage is described in greater detail
  in Section 9.



8.1  Maintainer Objects

  The maintainer objects serve as a container to hold authentication
  filters.  The authentication methods are described in Section 7.  The
  maintainer can be referenced by name in other objects, most notably in
  the mnt-by attributes of those objects.



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  Maintainers themselves contain mnt-by attributes.  In some cases the
  mnt-by in a maintainer will reference the maintainer itself.  In this
  case, authorization to modify the maintainer is provided to a (usually
  very limited) set of identities.  A good practice is to create a
  maintainer containing a long list of identities authorized to make
  specific types of changes but have the maintainer's mnt-by attribute
  reference a far more restrictive maintainer more tightly controlling
  changes to the maintainer object itself.

  The mnt-by attribute is mandatory in all objects.  Some data already
  exists without mnt-by attributes.  A missing mnt-by attribute is
  interpreted as the absence of any control over changes.  This is
  highly inadvisable and most repositories will no longer allow this.

  The ``mnt-routes'' attribute are needed to reference maintainer
  objects to provide specific permissions related to the object.  This
  is an extensions to RPSL and RIPE-181 proposed in this document and
  are described in detail in Section 9.

  A mnt-routes attribute in an aut-num object allows addition of route
  objects with that AS number as the origin to the maintainers listed.
  A mnt-routes attribute in an inetnum object allows addition of route
  objects with exact matching or more specific prefixes.  A mnt-routes
  attribute in a route object allows addition of route objects with
  exact matching or more specific prefixes.  A mnt-routes attribute does
  not allow changes to the aut-num, inetnum, or route object where they
  appear.  A mnt-routes may optionally be constrained to only apply to a
  subset of more specific routes.



8.2  The reclaim and no-reclaim attributes

  A reclaim attribute is needed in as-block, inetnum and route objects.
  The reclaim attribute allows a control to be retained over more
  specific AS, address or route space by allowing modify and delete
  privileges regardless of the mnt-by in the object itself.

  The reclaim and no-reclaim attributes contain contain lists of objects
  subject to the reclaim and no-reclaim.  See Section 9 for a full
  description of the reclaim and no-reclaim attributes.

  The reclaim attribute provides the means to enforce address lending.
  It allows cleanup in cases where entities cease to exist or as a last
  resort means to correct errors such as parties locking themselves out
  of access to their own objects.  To allow finer control a set of
  prefixes can be specified.

  A no-reclaim attribute can be used to provide explicit exceptions.  A
  reclaim attribute can only be added to an existing object if the
  addition of the reclaim attribute does not remove autonomy of existing


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  more specific objects that are covered by the new reclaim attribute.



 1.  A reclaim attribute can be added to an existing object if there are
     no existing exact matches or more specific objects overlapped by
     the new reclaim attribute, or

 2.  if the submitter is listed in the maintainer pointed to be the
     mnt-by of the objects which are overlapped, or
 3.  if any overlapped object is listed in a no-reclaim attribute in the
     object where the reclaim is being added.



  Similarly a no-reclaim attribute cannot be deleted unless there are no
  overlapped objects for which the submitter is not listed in the
  maintainer pointed to be the mnt-by of the overlapped object.


8.3  AS-block and aut-num objects


  An ``as-block'' object is needed to delegate a range of AS numbers to
  a given repository.  This is needed for authorization and it is needed
  to avoid having to make an exhaustive search of all repositories to
  find a specific AS. This search would not be a problem now but would
  be if a more distributed routing repository is used.

  The ``as-block'' object also makes it possible to separate AS number
  allocation from registration of AS routing policy.



    as-block:        AS1321 - AS1335
    delegated:       ANS
    ...



  The ``aut-num'' describes the routing policy for an AS and is critical
  for router configuration of that AS and for analysis performed by
  another AS. For the purpose of this document it is sufficient to
  consider the aut-num solely as a place holder identifying the
  existence of an AS and providing a means to associate authorization
  with that AS for the purpose of adding ``route'' objects.

  The ``as-block'' object is proposed here solely as a means of record-
  ing the delegation of blocks of AS numbers to alternate registries and
  in doing so providing a means to direct queries and a means to support
  hierarchical authorization across multiple repositories.


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8.4  inetnum objects


  A delegation attribute is needed in the inetnum and route object.
  This will accommodate the delegation of address space from IANA to
  regional IP registries.  When the routing registry becomes more widely
  distributed a delegation attribute is needed to support any
  subdelegations to more localized registries or delegations to Internet
  provider operated registries or organizations who may prefer to run
  their own routing registry.  The delegation attribute for an inetnum
  or a route object can be multi-valued and refers to all registries in
  which more specific route objects can be found.



    inetnum:        193.0.0.0 - 193.0.0.255
    delegated:      RIPE
    ...
    source:         IANA



  This inetnum simply delegates the storage of any more specific inetnum
  objects overlapping the stated range to the RIPE repository.  An exact
  match of this inetnum may exist in the RIPE repository to provide
  hooks for the attributes referencing maintainer objects.

  The ``inetnum'' exists to support address allocation.  For external
  number registries, such as those using ``[r]whoisd[++]'' the
  ``inetnum'' can serve as a secondary record that is added when an
  address allocation is made in the authoritative database.  Such
  records could be added by a address registry such as ARIN as a
  courtesy to the corresponding routing registry.


8.5  route objects


  Currently there are a quite few route objects in more than one
  registry.  Quite a few are registered with origin AS for which they
  have never been announced.  There is a legitimate reason to be in more
  than one origin AS. With the previous authorization restrictions, this
  could result in a route object for the same prefix in more than one
  database.  The example below is a route registered differently in two
  databases (and registered incorrectly).  This would now require a
  delegation attribute.



    route:          128.32.0.0/16
    delegated:      MCI RADB


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  The ``delegated'' attribute should be single valued for all objects
  except those that are granfathered due to addition prior to the use of
  these authorization rules.  This is to prevent race conditions
  involving mutually exclusive additions with the same origin AS in
  different repositories.

  The ``route'' object is used to record routes which may appear in the
  global routing table.  Explicit support for aggregation is provided.
  Route objects exist both for the configuration of routing information
  filters used to contain incidents of erroneous route announcements
  (Section 5) and to support network problem diagnosis.



8.6  Other Objects

  Many of the RPSL ancillary objects have no natural hierarchy the way
  AS numbers, Internet addresses and routes have a numeric hierarchy.
  Some examples are ``maintainers'', ``people'' and ``role'' objects.
  For these objects, lack of any hierarchy leads to two problems.



 1.  There is no hierarchy that can be exploited to direct queries to
     alternate registries.  At some point the query strategy of
     searching all known registries becomes impractical.

 2.  There is no hierarchy on which authorizations of additions can be
     based.


  The first problem can be addressed by considering the name space for
  each of the ancillary objects to be unique only within the local
  database and to use explicit references to an external repository
  where needed.  A possible syntax is to precede the object key with the
  name of the repository and a delimiter.  For example, the delimiter
  ``::''  can be used to form the NIC handle ``RIPE::CO19''.  Currently
  there is a desire to keep NIC handles unique so the naming convention
  of appending a dash and the repository name is used.  Prepending the
  repository name provides the unique name space since an object in the
  RIPE database referencing ``CO19'' would be interpreted as
  ``RIPE::CO19'' by default, but it would still be possible to query or ref-
  erence ``IANA::CO19''.  There is no possibility of accidentally forget-
  ting to adhere to the conventions when making an addition and the exist-
  ing objects are accommodated, including cases where name conflicts have
  already occurred.

  The second problem can be partially addressed by using a referral
  system for the addition of maintainers and requiring that any other
  object be submitted by a registered maintainer.  The referral system
  would allow any existing maintainer to add another maintainer.  This


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  can be used in parallel with the addition of other object types to
  support the maintenance of those objects.  For example, when adding a
  subdomain to the ``domain'' hierarchy (in the RIPE repository where
  domains are also handled), even when adding a new domain to a rela-
  tively flat domain such as ``com'', there is already a maintainer for
  the existing domain.  The existing maintainer can add the maintainer
  that will be needed for the new domain in addition to adding the new do-
  main and giving the new maintainer the right to modify it.

  An organization gaining a presence on the Internet for the first time
  would be given a maintainer.  This maintainer may list a small number
  of very trusted employees that are authorized to modify the maintainer
  itself.  The organization itself can then add another maintainer
  listing a larger set of employees but listing the more restrictive
  maintainer in the mnt-by attributes of the maintainers themselves.
  The organization can then add people and role objects as needed and
  any other objects as needed and as authorization permits.



8.7  Query Processing

  A query may have to span multiple repositories.  All queries should be
  directed toward a local repository which may mirror the root
  repository and others.  Currently each IRR repository mirrors all
  others repositories.  In this way, the query may be answered by the
  local repository but draw data from others.

  For object types that have a natural hierarchy, such as aut-num,
  inetnum, and route, the search begins at the root database and follows
  the hierarchy.  For objects types that have no natural hierarchy, such
  as maintainers, people, and roles, the search is confined to a default
  database unless a database is specified.  The default database is the
  same database as an object from which a reference is made if the query
  is launched through the need to follow a reference.  Otherwise the
  default is generally the local database or a default set by the
  repository.  The default can be specified in the query itself.

  In searching for an AS, the AS blocks can be consulted, moving the
  search to data from other repositories.  Eventually the AS is either
  found or the search fails.

  The search for an inetnum is similar.  Less specific inetnums may
  refer the search to other databases.  Eventually the most specific
  inetnum is found and its status can be determined and assignment
  determined if it is assigned.

  The search for a route is similar except the search may branch to more
  than one repository.  The most specific route in one repository may be
  more specific than the most specific in another.  In looking for a
  route object it makes sense to return the most specific route that is


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  not more specific than the query requests regardless of which
  repository that route is in rather than return one route from each
  repository that contains a less specific overlap.



8.8  Adding to the Database

  The root repository must be initially populated at some epoch with a
  few entries.  An initial maintainer is needed to add more maintainers.
  The referral-by and referral-in attribute can be set to refer to
  itself in this special case (Section 9 describes the referral-by and
  referral-in).  When adding an inetnum or a route object an existing
  exact match or a less specific overlap must exist.  A route object may
  be added based on an exact match or a less specific inetnum.  The root
  repository must be initially populated with the allocation of an
  inetnum covering the prefix 0/0, indicating that some address
  allocation authority exists.  Similarly an initial as-block is needed
  covering the full AS number range.

  When adding an object with no natural hierarchy, the search for an
  existing object follows the procedure outlined in Section 8.7.

  When adding an aut-num (an AS), the same procedure used in a query is
  used to determine the appropriate repository for the addition and to
  determine which maintainer applies.  The sequence of AS-block objects
  and repository delegations is followed.  If the aut-num does not
  exist, then the submission must match the authentication specified in
  the maintainer for the most specific AS-block in order to be added.

  The procedure for adding an inetnum is similar.  The sequence of
  inetnum blocks is followed until the most specific is found.  The
  submission must match the authentication specified in the maintainer
  for the most specific inetnum overlapping the addition.

  Adding a route object is somewhat more complicated.  The route object
  submission must satisfy two authentication criteria.  It must match
  the authentication specified in the aut-num and the authentication
  specified in either a route object or if no applicable route object is
  found, then an inetnum.

  An addition is submitted with an AS number and prefix as its key.  If
  the object already exists, then the submission is treated as a modify
  (see Section 8.9).  If the aut-num does not exist on a route add, then
  the addition is rejected (see Section A for further discussion of
  tradeoffs).  If the aut-num exists then the submission is checked
  against the applicable maintainer.  A search is then done for the
  prefix first looking for an exact match.  If the search for an exact
  match fails, a search is made for the longest prefix match that is
  less specific than the prefix specified.  If this search succeeds it
  will return one or more route objects.  The submission must match an


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  applicable maintainer in at least one of these route objects for the ad-
  dition to succeed.  If the search for a route object fails, then a search
  is performed for an inetnum that exactly matches the prefix or for the most
  specific inetnum that is less specific than the route object submission.
  The search for an inetnum should never fail but it may return an unallo-
  cated or reserved range.  The inetnum status must be ``allocated'' and the
  submission must match the maintainer.

  Having found the AS and either a route object or inetnum, the
  authorization is taken from these two objects.  The applicable
  maintainer object is any referenced by the mnt-routes attributes.  If
  one or more mnt-routes attributes are present in an object, the mnt-by
  attributes are not considered.  In the absence of a mnt-routes
  attribute in a given object, the mnt-by attributes are used for that
  object.  The authentication must match one of the authorizations in
  each of the two objects.

  If the addition of a route object or inetnum contains a reclaim
  attribute, then any more specific objects of the same type must be
  examined.  The reclaim attribute can only be added if there are no
  more specific overlaps or if the authentication on the addition is
  present in the authorization of a less specific object that already
  has a reclaim attribute covering the prefix range, or if the
  authentication on the addition is authorized for the modification of
  all existing more specific prefixes covered by the addition.



8.9  Modifying or Deleting Database Objects

  When modifying or deleting any existing object a search for the object
  is performed as described in Section 8.7.  If the submission matches
  an applicable maintainer for the object, then the operation can
  proceed.  An applicable maintainer for a modification is any
  maintainer referenced by the mnt-by attribute in the object.  For
  route and inetnum objects an applicable maintainer may be listed in a
  less specific object with a reclaim attribute.

  If the submission is for a route object, a search is done for all less
  specific route objects and inetnums.  If the submission is for an
  inetnum, a search is done for all less specific inetnums.  If the
  submission fails the authorization in the object itself but matches
  the reclaim attribute in any of the less specific objects, then the
  operation can proceed.  Section A contains discussion of the rationale
  behind the use of the reclaim attribute.

  A modification to an inetnum object that adds a reclaim attribute or
  removes a no-reclaim attribute must be checked against all existing
  inetnums that are more specific.  The same check of the reclaim
  attribute that is made during addition must be made when a reclaim
  attribute is added by a modification (see Section 8.8).


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  A deletion is considered a special case of the modify operation.  The
  deleted object may remain in the database with a ``deleted'' attribute
  in which case the mnt-by can still be consulted to remove the
  ``deleted'' attribute.



9  Data Format Summaries


  RIPE-181 [2] and RPSL [1] data is represented externally as ASCII
  text.  Objects consist of a set of attributes.  Attributes are name
  value pairs.  A single attribute is represented as a single line with
  the name followed by a colon followed by whitespace characters (space,
  tab, or line continuation) and followed by the value.  Within a value
  all whitespace is equivalent to a single space.  Line continuation is
  supported by a backslash at the end of a line or the following line
  beginning with whitespace.  When transferred, externally attributes
  are generally broken into shorter lines using line continuation though
  this is not a requirement.  An object is externally represented as a
  series of attributes.  Objects are separated by blank lines.

  There are about 80 attribute types in the current RIPE schema and
  about 15 object types.  Some of the attributes are mandatory in
  certain objects.  Some attributes may appear multiple times.  One or
  more attributes may form a key.  Some attributes or sets of attributes
  may be required to be unique across all repositories.  Some of the
  attributes may reference a key field in an object type and may be
  required to be a valid reference.  Some attributes may be used in
  inverse lookups.

  A review of the entire RIPE or RPSL schema would be too lengthy to
  include here.  Only the differences in the schema are described.


9.1  Changes to the RIPE/RPSL Schema


  Two object types are added to the RIPE/RPSL schema.  A few attributes
  are added to existing object types.  There are significant changes to
  the rules which determine if the addition of an object is authorized.
  Additional keywords representing new authentication types are added to
  the semantics of the existing ``auth'' attribute.

  The new object types are listed below.  The first attribute listed is
  the key attribute and also serves as the name of the object type.



    repository      key  mandatory  single    unique
    query-address        mandatory  multiple


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    response-auth-type   mandatory  multiple
    submit-address       mandatory  multiple
    submit-auth-type     mandatory  multiple
    refresh              optional   single
    expire               mandatory  single
    descr                optional   multiple
    remarks              optional   multiple
    admin-c              mandatory  multiple
    tech-c               mandatory  multiple
    notify               optional   multiple
    mnt-by               mandatory  multiple
    changed              mandatory  multiple
    source               mandatory  single

    as-block        key  mandatory  single    unique
    delegated            optional   single
    descr                optional   multiple
    remarks              optional   multiple
    admin-c              mandatory  multiple
    tech-c               mandatory  multiple
    notify               optional   multiple
    mnt-by               mandatory  multiple
    changed              mandatory  multiple
    source               mandatory  single



  In the above object types only a small number of the attribute types
  are new.  These are:



  repository  This attribute provides the name of the repository.  This
     is the key field for the object and is single and must be globally
     unique.  This is the same name used in the source attribute of all
     objects in that repository.
  query-address  This attribute provides a host name and a port number
     used to direct queries.  Optional fields may follow the port number
     at a later time and should be ignored.  Alternately a URL format
     may be used.  The special protocol identified ``rps-query'' can be
     used in URL format.

  response-auth-type  This attribute provides the authentication types
     that may be used by the repository when responding to queries.
  submit-address  This attribute provides a host name and a port number
     used to submit objects to the repository.  Optional fields may
     follow the port number at a later time and should be ignored.
     Alternately a URL format may be used.  The special protocol
     identified ``rps-query'' can be used in URL format.

  submit-auth-type  This attribute provides the authentication types
     that may be used by the repository when responding to queries.

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  refresh  Near real time flooding of repository updates is recommended
     as a method of distributing database changes.  The refresh suggests
     a time interval for processing updates.  Time is in seconds if
     expressed as an integer.  Alternately, the letters ``h'', ``m'', or
     ``s'' can be used to indicate hours, minutes, and seconds.

  expire  If near real time flooding is temporarily not operational,
     objects should be considered non-authoritative after this interval,
     and cannot be used for authorization purposes.

  as-block  This attribute provides the AS number range for an
     ``as-block'' object.
  delegated  This attribute indicates that further searches for object
     in the hierarchy must be made in one or more alternate
     repositories.  The current repository may be listed.



  In order to support stronger authentication, the following keywords
  are added to the ``auth'' attribute:



  pgp-from  The remainder of the attribute gives the string identifying
     a PGP identity whose public key is held in an external keyring.
     The use of this method is depricated in favor of the ``pgp-key''
     method.
  pgp-key  The remainder of the attribute provides a PGP public key
     block in ASCII radix-64 format.



  In order to disable authentication and give permission to anyone, the
  authentication method ``none'' is added.  It has no arguments.

  An additional change is the ``auth'' attribute is allowed to exist in
  a ``person'' or ``role'' object.  The ``auth'' method ``role'' or
  ``person'' can be used to refer to a role or person object and take
  the ``auth'' fields from those objects.  Care must be taken in
  implementations to detect circular references and terminate expansion
  or the references already visited.

  A few attributes are added to the schema.  These are:



  mnt-routes  The mnt-routes attribute may appear in an aut-num,
     inetnum, or route object.  This attribute references a maintainer
     object which is used in determining authorization for the addition
     of inetnum and route objects.  If a mnt-routes object is absent,
     the mnt-by attribute is used for this purpose.  The mnt-routes
     attribute is optional and multiple.  the format is identical the

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     the exiting ``mnt-by'' but has an additional optional range
     preceeding the authorization information.  The syntax for the range
     is the word ``range'' followed by a
     prefix lists (as defined in RPSL) in curly braces (``{\and \}") asused
     elsewherein RPSL.

  reclaim  Thereclaim attributemay appearinas-block, aut-num,inetnum, orroute objects. Any
     objectof thesame typebelow inthe hierarchymay bemodified ordeleted bythe maintainerof
     theobject containinga reclaimattribute. Thevalue of theattribute isa setor rangeof objects
     ofthe sametype wherethe syntaxof theset orrange isas definedin RPSL. SeeSection 8.2for
     restrictionson addingreclaim attributes.

  no-reclaim  Theno-reclaim attribute is usedwith the reclaimattribute.  Theno-reclaim at-
     tributenegates any reclaimattribute it overlaps. See Section8.2 for restrictions ondeleting
     no-reclaimattributes.
  delegated  Thedelegated attributeisallowed inany objecttype withahierarchy. This attribute
     indicatesthatfurther searchesfor objectin thehierarchy mustbe madein oneor morealternate
     repositories.The currentrepository maybe listed.

  referral-by  Thisattribute isrequired inthe maintainer object.It maynever be alteredafter
     theaddition ofthe maintainer. Thisattribute refers tothe maintainerthat created thismain-
     tainer.It maybe multiple ifmore thanone signatureappeared onthe transaction creatingthe
     object.

  referral-in  Thisattribute mayappear in amaintainer object. Itis multiple. Eachtime the
     maintainerobjectis usedto addanother maintainer,a referral-inreferencingthe newmaintainer
     isautomatically added.
  auth-override  Anauth-override attributecan beadded, deleted,or changedby a transaction
     submittedby maintainerlisted inthereferal-by. The auth-overrideattribute itselfcontains only
     thedate whenthe attributewill gointo effect whichmust beat least60 days fromthe current
     dateunless thereis alreadyauthorization tomodify themaintainer. Afterthe date inthe auth-
     overrideis reached, thoseidentified by themaintainer in thereferal-by have authorization to
     modifythe maintainer. This attribute existsas a means toclean up should theholder of a
     maintainerbecomeunresponsive andcan onlytake effectif thatmaintainer doesnot removethe
     auth-overridein responseto theautomatic notificationthat occurson changes.



  Each repository must identify itself with a ``repository'' object.
  The repository must also contain a special ``repository'' whose key is
  ``ROOT''. The root repository is where all non-local queries are
  directed, including where hierarchical object queries start.  The
  query methods listed for the root repository may actually be a subset
  of those offered by that repository if efficiency considerations and
  topologic distance make some methods less useful.

  The root repository must contain a copy of the repository objects in
  any repository considered valid.  The repository objects will be
  essential when the routing registry becomes more widely distributed.

  The existing ``mnt-by'' attribute references the ``maintainer'' object
  type.  The ``mnt-by'' attribute is now mandatory in all object types.

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  A new maintainer may be added by any existing maintainer.  The
  ``referral-by'' attribute is now mandatory in the ``maintainer''
  object to keep a record of which maintainer made the addition and can
  never be changed.  Maintainers cannot be deleted as long as they are
  referenced by a ``referral-by'' attribute elsewhere.  In order to add
  a maintainer to another database, a ``referral-in'' attribute is
  needed, containing the name of the external database.  A ``referral-
  in'' attribute cannot be deleted unless there are no ``referral-by''
  references to the maintainer in the named external databases.



A  Technical Discussion


  A few design tradeoffs exist.  Some of these tradeoffs, the selected
  solution, and the alternatives are discussed here.  Some of the issues
  are listed below.


 1.  Whether to error on the side of permissiveness and weaken
     authorization controls or risk the possibility of erecting barriers
     to registering information.

 2.  Whether to support enforcible address lending or provide the
     smaller or end user with ultimate control over the registration of
     the prefixes they are using.

 3.  What to do with older objects that either don't conform to newer
     requirements regarding minimum authorization, authentication, and
     accountability, or are of questionable validity.


A.1  Relaxing requirements for ease of registry


  If the requirement that an aut-num exists is relaxed, then it is
  possible for anyone to make use of an unassigned AS number or make use
  of an assigned AS number for which the aut-num has not been entered.
  Placing requirements on the entry of aut-num presumes cooperation of
  the Internet address allocation authority (if separate from the rout-
  ing registry).  The address allocation authority must be willing to
  field requests to populate skeleton aut-nums from the party for which
  the allocation has been made.  These aut-num must include a reference
  to a maintainer.  A request to the address allocation authority must
  therefore include a reference to an existing maintainer.

  The ability to add route objects is also tied to the existence of less
  specific route objects or inetnums.  The Internet address allocation
  authority (if separate from the routing registry) must also be willing
  to field requests to add inetnum records for the party already
  allocated the address space.

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  The Internet address allocation authority should also add inetnums and
  aut-nums for new allocations.  In order to do so, a maintainer must
  exist.  If a party is going to connect to the Internet, they can get a
  maintainer by making a request to the Internet service provider they
  will be connecting to.  Once they have a maintainer they can make a
  request for address space or an AS number.  The maintainer can contain
  a public key for a cryptographicly strong authorization method or
  could contain a ``crypt-key'' or ``mail-to'' authorization check if
  that is considered adequate by the registering party.  Furthermore an
  address allocation authority should verify that the request for an AS
  number or for address space matches the authorization criteria in the main-
  tainer.

  Currently only the registry themselves may add maintainers.  This
  becomes a problem for the registry particularly verifying public keys.
  This requirement is relaxed by allowing existing maintainers to add
  maintainers.  Unfortunately the accountability trail does not exist
  for existing maintainers.  The requirement then should be relaxed such
  that existing maintainers may remain but only existing maintainers
  that have a ``referral-by'' attribute can add maintainers.  The
  ``referral-by'' and ``referral-in'' cannot be modified.  This require-
  ment can be relax slightly so that a ``referral-by'' can be added to a
  maintainer by an existing maintainer with a ``referral-by''.  This
  will allow the accountability trail to be added to existing maintainers
  and these maintainers can then add new maintainers.

  Verifying that a party is who they claim to be on initial addition, is
  one of the problems that currently falls upon the AS number and
  address registry.  This problem is reduced by allowing existing
  maintainers to add maintainers.  This may actually make it easier to
  get maintainers and therefore easier to register.  The number
  authority still must verify that the AS or address space is actually
  needed by the party making a request.

  Authorization checks made during the addition of route objects that
  refer to AS objects and inetnum strongly rely on the cooperation of
  the Internet address allocation authorities.  The number authorities
  must register as-blocks, aut-nums, or inetnums as AS numbers or ad-
  dress space is allocated.  If only a subset of the number authorities
  cooperate, then either an inetnum or as-block can be created covering
  the space that registry allocates and essentially requiring null allo-
  cation (for example a ``crypt-pw'' authentication where the password
  is given in the remarks in the object or its maintainer) or those ob-
  taining addresses from that number authority will have trouble regis-
  tering in the routing registry.  The authorization model supports either
  option, though it would be preferable if the number authorities cooper-
  ated and the issue never surfaced in practice.

  The maintainer requirements can be relaxed slightly for existing main-
  tainers making it easier to register.  Relaxing requirements on other
  objects may defeat the authorization model, hence is not an option.


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A.2  The address lending issue


  The issue of whether lending contracts should be enforcible is an
  issue of who should ultimately be able to exercise control over allo-
  cations of address space.  The routing registry would be wise to stay
  as neutral as possible with regard to disputes between third parties.
  The ``reclaim'' and ``no-reclaim'' are designed to allow either out-
  come to the decision as to whether the holder of a less specific inet-
  num or route object can exercise control over suballocations in the
  registry.  The routing registry itself must decide whether to retain
  control themselves and if so, should very clearly state under what
  conditions the registry would intervene.  A registry could even go to
  the extreme of stating that they will intervene in such a dispute only af-
  ter the dispute has been resolved in court and a court order has been is-
  sued.

  When an allocation is made by a registry, the registry should keep a
  ``reclaim'' attribute in the less specific object and make a strong
  policy statement that the reclaim privilege will not be used except
  under very clearly defined special circumstances (which at the very
  minimum would include a court order).  If the allocation is further
  subdivided the party subdividing the allocation and the party accept-
  ing the suballocation must decide whether a ``reclaim'' can be kept by
  the holder of the less specific allocation or whether a ``no-reclaim''
  must be added transferring control to the holder of the more specific.
  The registry is not involved in that decision.  Different pairs of
  third parties may do different decisions regarding the ``reclaim'' and any
  contractual restrictions on its use that may be expressed outside of the
  registry in the form of a legal contract and ultimately resolved by the
  courts in the event of a bitter dispute.

  By retaining ``reclaim'' rights the registry retains the ability to
  abide by a court order.  This may only truly become an issue in a
  distributed registry environment where registries will be rechecking
  the authorization of transactions made elsewhere and may fail to
  process the attempt of another registry to abide by a court order by
  overriding normal authorization to change the registry contents if a
  reclaim is not present.


A.3  Dealing with non-conformant or questionable older data


  Some of the newer requirements include requiring that all objects
  reference a maintainer object responsible for the integrity of the
  object and requiring accountability for the creation of maintainers to
  be recorded in the maintainer objects so that accountability can be
  traced back from an unresponsive maintainer.  In the event that
  contact information is absent or incorrect from objects and there is
  any question regarding the validity of the objects, the maintainer can


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  be contacted.  If the maintainer is unresponsive, the maintainer that
  authorized the addition of that maintainer can be contacted to either
  update the contact information on the maintainer or confirm that the
  entity no longer exists or is no longer actively using the Internet or the
  registry.

  Many route objects exist for which there are no maintainers and for
  which inetnum and AS objects do not exist.  Some contain the now
  obsoleted guardian attribute rather than a mnt-by.

  It is not practical to unconditionally purge old data that does not
  have maintainers or does not conform to the authorization hierarchy.
  New additions must be required to conform to the new requirements
  (otherwise the requirements are meaningless).  New requirements can be
  phased in by requiring modifications to conform to the new
  requirements.

  A great deal of questionable data exists in the current registry.  The
  requirement that all objects have maintainers and the requirements for
  improved accountability in the maintainers themselves may make it
  easier to determine contact information even where the objects are not
  updated to reflect contact information changes.

  It is not unreasonable to require valid contact information on
  existing data.  A great deal of data appears to be unused, such as
  route objects for which no announcement has been seen in many months
  or years.  An attempt should be made to contact the listed contacts in
  the object, in the maintainer if there is one, then up the maintainer
  referral-by chain if there is one, and using the number registry or
  origin AS contact information if there is no maintainer accountability
  trail to follow.  Experience so far indicates that the vast majority
  of deletions identified by comparing registered prefixes against route
  dumps will be positively confirmed (allowing the deletion) or there
  will be no response due to invalid contact information (in many cases the
  IRR contact information points to nsfnet-admin@merit.edu).

  By allowing the registry to modify (or delete) any objects which are
  disconnected from the maintainer accountability trail, cleanup can be
  made possible (though mail header forging could in many cases have the
  same effect it is preferable to record the fact that the registry
  itself made the cleanup).  Similarly, a mechanism may be needed in the
  future to allow the maintainer in the referral-by to override
  maintainer privileges in a referred maintainer if all contacts have
  become unresponsive for a maintainer.  The referral-by maintainer is
  allowed to add an ``auth-override'' attribute which becomes usable as
  an ``auth'' within 60 days from the time of addition.  The maintainer
  themselves would be notified of the change and could remove the ``auth-
  override'' attribute before it becomes effective and inquire as to why it
  was added and correct whatever problem existed.  This can be supported im-
  mediately or added later if needed.



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B  Common Operational Cases


  In principle address allocation and route allocation should be
  hierarchical with the hierarchy corresponding to the physical
  topology.  In practice this is often not the case for numerous
  reasons.  The primary reasons are the topology is not strictly tree
  structured and the topology can change.  More specificly:



 1.  The Internet topology is not strictly tree structured.

     o At the top level the network more closely resembles a moderately
       dense mesh.
     o Near the bottom level many attachments to the Internet are
       multihomed to more than one Internet provider.

 2.  The Internet topology can and does change.
     o Many attachments switch providers to obtain better service or
       terms.

     o Service providers may modify adjacencies to obtain better transit
       service or terms.
     o Service providers may disappear completely scattering attachments
       or merge.



  Renumbering is viewed as a practical means to maintain a strict
  numeric hierarchy [20].  It is also acknowledged that renumbering IPv4
  networks can be difficult [20, 3, 21].  We examine first the simple
  case where hierarchy still exists.  We then examine the operational
  cases where either initial topology is not tree structured or cases
  where topology changes.


B.1  simple hierarchical address allocation and route allocation


  This is the simplest case.  Large ranges of inetnums are assigned to
  address registries.  These registries in turn assign smaller ranges
  for direct use or to topologically large entities where allocations
  according to topology can reduce the amount of routing information
  needed (promote better route aggregation).

  AS objects are allocated as topology dictates the need for additional
  AS [10].  Route objects can be registered by those with authorization
  given by the AS and by the address owner.  This is never an issue
  where the maintainer of the AS and the inetnum are the same.  Where
  they differ, either the provider can give permission to add route
  objects for their AS, or the party allocated the address space can

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  give the provider permission to add router objects for their address
  space, or both parties can sign the transaction.  Permission is
  provided by adding to maintainer attributes.



B.2  aggregation and multihomed more specific routes

  Aggregation is normally not a problem if a provider is aggregating
  address space allocated to the provider and then suballocated
  internally and/or to customers.  In fact, the provider would be
  expected to do so.  This is not a problem even if the route object for
  the aggregation is added after the more specific route objects since
  only less specific objects are considered.

  Aggregation is potentially a problem if a provider or a set of
  providers plan to aggregate address space that was never explicitly
  allocated as a block to those providers but rather remains the
  allocation of a address registry.  These large aggregations can be
  expected to be uncommon, but relatively easily dealt with.
  Superaggregates of this type will generally be formed by topologically
  close entities who have also managed to draw adjacent address
  allocations.  In effect, the registry must give permission to form
  such as superaggregate by either giving permission to do so in an
  inetnum or by signing the submission along with the other parties.

  A more common case is where a more specific route object must be
  registered with a different AS than the aggregate due to the prefix
  being multihomed.  In this case, the maintainer of the aggregate can
  create a more specific route object with their own AS marked withdrawn
  so as not to be routable.  The new AS can be included in the
  maintainer solely for the purpose of allowing them to create a new
  route object with their own AS. Again, alternately both parties can
  sign the submission for the addition with the new AS.



B.3  provider independent addresses and multiple origin AS


  Provider independent addresses and multihoming arrangement using
  multiple origin AS present a similar problem to multihoming.  The
  maintainer of the address space and the maintainer of the AS is not
  the same.  Permission can be granted using additions to the maintainer
  or multiple signatures can appear on the submission.


B.4  change in Internet service provider


  A change in Internet service providers is similar to multihoming.  A
  minor difference is that the AS for the more specific route will be

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  the AS of the new provider rather than the AS of the multihomed
  customer.  A provider may be hesitant to give permissions to their
  competitor to make additions with their AS. There is no potential for
  harm in giving permission to a withdrawn exact match of the more
  specific so the maintainer of the aggregate could more easily in
  effect grant permission to the maintainers of the new AS.



B.5  renumbering grace periods

  Renumbering grace periods allow a provider who wants to keep an
  address allocation intact to allow a customer who has chosen to go to
  another provider to renumber their network gradually and then return
  the address space after renumbering is completed.  The issue of
  whether to require immediate renumbering or offer renumbering grace
  periods and how long they should be or whether they should be
  indefinite has been topic of bitter disputes.  The authorization model
  can support no renumbering grace period, a finite renumbering grace
  period, or an indefinite renumbering grace period.  The ``reclaim''
  attribute described in Section 8.1 provides a means to end the grace
  period.



C  Deployment Considerations


  This section describes deployment considerations.  The intention is to
  raise issues and discuss approaches rather than to provide a
  deployment plan.

  The use of routing registries is not yet universally accepted.  There
  still remain Internet providers who see no reason to provide the added
  assurance of accurate routing information described in Section 5.
  More accurately, these benefits are viewed as being insufficient to
  justify the cost.  This has been largely caused an inability of a very
  major router vendor up until recently to handle prefix lists of the
  size needed to specify routing policy on a per prefix basis.  Another
  reason cited is that filtering on a prefix basis in an environment
  where routing registry is incomplete or inaccurate can interfere with
  connectivity.

  There clearly is a critical mass issue with regard to the use of
  routing registries.  A minority of providers use the existing IRR to
  filter on a per prefix basis.  Another minority of providers do not
  support the IRR and generally fail to register prefixes until
  connectivity problems are reported.  The majority of providers
  register prefixes but do not implement strict prefix filtering.

  Deploying new authentication mechanisms has no adverse consequences.


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  This has been proven with Merit's deployment of PGP.

  In deploying new authorization mechanisms, a major issue is dealing
  with existing data of very questionable origin.  A very large number
  of route objects refer to prefixes that have not been announced for
  many years.  Other route objects refer to prefixes that are no longer
  announced with the origin AS that they are register with (some were
  incorrectly registered to start with).  There are many causes for
  this.



 1.  During the transition from the NSFNET PRDB to the RADB a large
     number of prefixes were registered with an origin AS corresponding
     to the border AS at which the NSFNET had once heard the route
     announcements.  The PRDB did not support origin AS, so border AS
     was used.  Many of these routes were no longer in use at the time
     and are now routed with a submitter listed as
     ``nsfnet-admin@merit.edu''.

 2.  As CIDR was deployed, aggregates replaced previously separately
     announced more specific prefixes.  The route objects for the more
     specific prefixes were never withdrawn from the routing registries.
 3.  Some prefixes are simply no longer in use.  Some networks have been
     renumbered.  Some network no longer exist.  Often the routing
     registry information is not withdrawn.

 4.  As provider AS adjacencies changed and as end customers switched
     providers often the actual origin AS changed.  This was often not
     reflected by a change in the routing registry.


  Inaccuracies will continue to occur due to the reasons above, except
  the first.  The hierarchical authorization provides greater
  accountability.  In the event that the contacts for specific objects
  become unresponsive traversal up the authorization hierarchy should
  help identify the parties having previous provided authorization.
  These contacts may still have sufficient authorization to perform the
  necessary cleanup.  This issue is discussed in Section A.

  A great deal of information is currently missing in the IRR. Quite a
  few AS have no aut-num.  Quite a lot of data has no maintainer and the
  vast majority of maintainers use only the weakest of authentication
  methods.  Very little can be done by the registries to correct this.
  The defaults in the cases of missing objects needed for authorization
  has to be to make no authentication checks at all.

  The transition can be staged as follows:



 1.  Add and make use of stronger authorization models.

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 2.  Make schema modifications necessary to support delegations.

 3.  Add delegation objects needed for query traversal.

 4.  Base query traversal on delegations rather than search of all known
     registries.
 5.  Obtain the cooperation of the address registries for the purpose of
     populating the ``inetnum'' entries on an ongoing basis.

 6.  Add hierarchical authorization support for critical object types,
     ``aut-num'', ``inetnum'' and ``route''.

 7.  Add the requirement that database object either be in use or have
     valid contact information and if queries are made by the registry a
     response from a contact indicating that the object serves a purpose
     if it is not clear what its use is.
 8.  Begin to purge data which is clearly not in use and for which there
     is no valid contact information or no response from the contacts.



  Deployment of hierarchical authorization requires cooperation among
  the existing routing registries.  New code will have to be deployed.
  In some cases very little development resources are available and
  substantial inertia exists due to the reliance on the current
  repository and the need to avoid disruption.

  If hierarchical authorization of route objects depends on the
  existence of address registration information, minimal cooperation of
  the currently separate address registries is required.  The extent of
  the cooperation amounts to sending cryptographically signed
  transactions from the address registry to the number registry as
  address allocations are made or providing equivalent access to new
  address allocations.

  Currently most registries returns query results from all of the known
  repositories using their mirrored copies.  Cross registry
  authorizations are not yet implemented.  Minimal schema changes have
  to be made to support the ability to delegate objects for which there
  is an authorization hierarchy and the support queries and references
  to other repositories.  In the case of AS delegations, ``as-block''
  need to be created solely for the purpose of traversal.



Acknowledgments


  This document draws ideas from numerous discussions and contributions
  of the IETF Routing Policy System Work Group and RIPE Routing Work
  Group.


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Security Considerations


  @@ This entire document is about security but at some point we need to
  figure out what belongs here in this case.  Maybe the Area Directors
  can provide some advice.



Author's Addresses


  Curtis Villamizar
  ANS Communications
  <curtis@ans.net>



  Cengiz Alaettinoglu
  ISI
  <cengiz@ISI.EDU>



  David M. Meyer
  University of Oregon
  <meyer@uoregon.edu>



  Sandy Murphy
  Trusted Information Systems
  <sandy@tis.com>



  Carol Orange
  RIPE NCC
  <orange@ripe.net>














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