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Versions: 00

INTERNET DRAFT                                               M. A. Patton
Expiration Date: October 1995                                         BBN
<draft-ietf-nimrod-dns-00.txt>                                  June 1995


         DNS Resource Records for Nimrod Routing Architecture


Status of this Memo

   This document is an Internet-Draft.  Internet-Drafts are working
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   This Internet Draft expires December 1995.

Abstract

   This document describes two additional RR types for the Domain Name
   System[7,8] required to implement the Nimrod Routing Architecture[1].
   These RRs record the Nimrod Locator and an Endpoint Identifier (EID)
   associated with a given Domain Name.

Introduction

   Nimrod is a scalable internetwork routing architecture.  The Nimrod
   architecture is designed to accommodate an internetwork of arbitrary
   size and with heterogeneous service requirements and restrictions
   and to admit incremental deployment throughout an internetwork.  The
   key to Nimrod's scalability is its ability to represent and
   manipulate routing-related information at multiple levels of
   abstraction.

   To do this efficiently, Nimrod separates the identification of
   communicating entities (Endpoints) from any topological information.
   Endpoint Identifiers (EIDs) are used to specify and uniquely
   identify entities connected to the network.  Information about the
   topological location of an endpoint in the network is given by a
   Locator, which may change as the network topology changes.

   During the initial deployment of the Nimrod system the mapping will
   be stored in the existing DNS system as two additional RRs on the
   Domain Name of the Endpoint.  This document describes the two new
   RR types required to record this information.

   Nimrod uses a hierarchy of abstract maps of (parts of) the network.
   A Locator is a topologically significant "name" for a Nimrod node,
   indicating where in the map hierarchy it can be found.  Because it
   reflects location in the network, a node's Locator will change when
   the network topology changes.  An EID is a short identifier for the
   endpoint of a communication (e.g. a host system) and has no
   structure or significance other than global uniqueness.  An
   endpoint can retain the same EID forever, no matter where in the
   network it is located.  Any given system has exactly one EID to
   identify it, but may have more than one Locator if it appears in
   multiple maps.

   Updates of the EID and the Locator information will almost always
   be done through a Dynamic Update[2] protocol, triggered by normal
   Nimrod protocol operations.  Except during testing, these will not
   be done by manual editing of a master file, which means that human
   readability is not a major concern.

1. definition of the RR types

   Both of the RR types described in this document encode numbers
   whose structure (if any) is not meaningfully interpreted by the DNS
   system.  Thus each is encoded as an uninterpreted string of octets.
   The interpretation of the values is described in the Nimrod
   protocol spec [[[TBD]]].

1.1. The EID (Endpoint Identifier) RR

   The EID (Endpoint IDentifier) RR is defined with mnemonic "EID" and
   TYPE code 31 (decimal) and is used to map from domain names
   to EIDs.  The EIDs declared in this RR may be used by any system
   that uses Endpoint Identifiers, but the initial use is intended for
   the Nimrod Routing system.  EIDs are short, fixed length strings of
   octets whose content is meaningful to the Nimrod routing system.
   Since the top level RR format and semantics as defined in Section
   3.2.1 of RFC 1035 include a length indicator, the Domain Name
   System is not required to understand any internal structure.

   An Endpoint can only have one unique identifier, so multiple
   different EID RRs at the same DNS name is an error.  There are
   three ways to interpret such a condition when returned.  If the
   conflict occurs when a reply is received from the authoritative
   server, that should be used and the existing (cached) RR should be
   discarded.  The simplest, but less sure, way to deal with
   non-authoritative conflict is to ignore the RRs with the smaller
   TTL and use the one with the longest remaining Time To Live.
   Secondly, the query can be retried at the authoritative server,
   with the result replacing the erroneous info as per the first item.
   Any caching server which is cognizant of EIDs should retain at most
   one EID RR as determined above, but legacy servers may not handle
   this requirement, so any system that needs to make use of EIDs must
   handle the conflict resolution described.

   The format of an Endpoint IDentifier (EID) RR is:

                                            1  1  1  1  1  1
              0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                                               |
           /                                               /
           /                        NAME                   /
           |                                               |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                    TYPE = EID                 |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                    CLASS = IN                 |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                        TTL                    |
           |                                               |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                      RDLENGTH                 |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           /                       RDATA                   /
           /                                               /
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

   where:

   *  NAME: an owner name, i.e., the name of the DNS node to which this
      resource record pertains.

   *  TYPE: two octets containing the EID RR TYPE code of 31 (decimal).

   *  CLASS: two octets containing the RR IN CLASS code of 1.

   *  TTL: a 32 bit signed integer that specifies the time interval in
      seconds that the resource record may be cached before the source
      of the information should again be consulted.

   *  RDLENGTH: an unsigned 16 bit integer that specifies the length in
      octets of the RDATA field.

   *  RDATA: a string of octets containing the Endpoint Identifier.
      The value is the binary encoding of the Identifier, meaningful
      only to the system utilizing it.

1.2. The NIMLOC (Nimrod Locator) RR

   The NIMLOC (Nimrod Locator) RR is defined with mnemonic "NIMLOC"
   and TYPE code 32 (decimal) and is used to map from domain
   names to Nimrod Locators.  Nimrod Locators are possibly variable
   length strings of octets whose content is only meaningful to the
   Nimrod routing system.  Since the top level RR format and semantics
   as defined in Section 3.2.1 of RFC 1035 include a length indicator,
   the Domain Name System is not required to understand any internal
   structure.

   A Nimrod system may have any number of Locators associated with it.
   They are in this sense like A and AAAA RRs for IPv4 and IPv6
   addresses.  Multiple NIMLOC RRs with the same NAME, CLASS and RDATA
   are the same and can be merged in a cache, retaining only the
   highest TTL.

   The format of a Nimrod Locator (NIMLOC) RR is:

                                            1  1  1  1  1  1
              0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                                               |
           /                                               /
           /                        NAME                   /
           |                                               |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                    TYPE = NIMLOC              |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                    CLASS = IN                 |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                        TTL                    |
           |                                               |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                      RDLENGTH                 |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           /                       RDATA                   /
           /                                               /
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

   where:

   *  NAME: an owner name, i.e., the name of the DNS node to which this
      resource record pertains.

   *  TYPE: two octets containing the NIMLOC RR TYPE code of 32 (decimal).

   *  CLASS: two octets containing the RR IN CLASS code of 1.

   *  TTL: a 32 bit signed integer that specifies the time interval in
      seconds that the resource record may be cached before the source
      of the information should again be consulted.

   *  RDLENGTH: an unsigned 16 bit integer that specifies the length in
      octets of the RDATA field.

   *  RDATA: a variable length string of octets containing the Nimrod
      Locator.  The value is the binary encoding of the Locator
      specified in the Nimrod protocol[[[ref to be supplied]]].

2. Additional Section Processing

   DNS servers cognizant of EID and NIMLOC type RRs should return
   these records in the Additional Section of any response including
   an A or AAAA type RR.  These could be in response to either A or
   AAAA type queries, or some other query (e.g. NS) that specifies A
   and/or AAAA records in the Additional Section.  This is not
   required for operation of the Nimrod system, as additional queries
   can always be made, but, in general, any time an A or AAAA RR will
   be used by a Nimrod agent, it will also need the EID and Locator
   info.

3. Master File Format

   The format of NIMLOC and EID RRs follows all the rules of RFC 1035,
   Section 5, "Master Files."  The RDATA portion of both the NIMLOC
   and EID records contains uninterpreted binary data.  The
   representation in the text master file is an even number of hex
   characters (0 to 9, a to f), case is not significant.

   Example master file with NIMLOC and EID RRs (based on the example
   in RFC1035):

   @   IN  SOA     VENERA      Action\.domains (
                                    20     ; SERIAL
                                    7200   ; REFRESH
                                    600    ; RETRY
                                    3600000; EXPIRE
                                    60)    ; MINIMUM

           NS      A.ISI.EDU.
           NS      VENERA
           NS      VAXA
           MX      10      VENERA
           MX      20      VAXA

   A       A       26.3.0.103
           EID     E32C6F78163A9348
           NIMLOC  32251A030067

   VENERA  A       10.1.0.52
           A       128.9.0.32
           EID     813F4B7CDAB34217
           NIMLOC  3227450A010034
           NIMLOC  75234159EAC457800920

   VAXA    A       10.2.0.27
           A       128.9.0.33
           EID     3141592653589793
           NIMLOC  75234159EAC457800921



4. Acknowledgements

   I'd like to thank the members of the DNS and Nimrod mailing lists
   for their comments and suggestions, and to the Nimrod Architects
   for the documents on which this is based.  I'd also like to thank
   Arnt Gulbrandsen for his collected list of DNS RFCs and permission
   to use it as the basis for the References section and Bill Manning,
   the author of RFC1348, for unwittingly supplying the boilerplate
   and diagrams I used as a basis for this document.

   Specific thanks to Robert Elz, Masataka Ohta, and Martha Steenstrup
   for their helpful comments on early drafts.

   [[[ more? ]]].

5.  Security Considerations

   Security issues are not discussed in this memo.

6. References

   [1]  draft-ietf-nimrod-routing-arch-00.txt: I. Castineyra,
             J. N. Chiappa, M. Steenstrup, "The Nimrod Routing
             Architecture", March 1995

   [2]  draft-ietf-dnsind-dynDNS-01.txt: S. Thomson, Y. Rekhter,
             J. Bound, "Dynamic Updates in the Domain Name System",
             March 1995

   [3]  RFC 1536: A. Kumar, J. Postel, C. Neuman, P. Danzig, S. Miller,
             "Common DNS Implementation Errors and Suggested Fixes.",
             10/06/1993.

   [4]  RFC 1348: B. Manning, "DNS NSAP RRs", 07/01/1992.

   [5]  RFC 1183: R. Ullman, P. Mockapetris, L. Mamakos, C. Everhart,
             "New DNS RR Definitions", 10/08/1990.

   [6]  RFC 1101: P. Mockapetris, "DNS encoding of network names and
             other types", 04/01/1989.

   [7]  RFC 1035: P. Mockapetris, "Domain names - implementation and
             specification", 11/01/1987.

   [8]  RFC 1034: P. Mockapetris, "Domain names - concepts and
             facilities", 11/01/1987.

   [9]  RFC 1033: M. Lottor, "Domain administrators operations guide",
             11/01/1987.

   [10]  RFC 1032: M. Stahl, "Domain administrators guide", 11/01/1987.

   [11]  RFC 974: C. Partridge, "Mail routing and the domain system",
             01/01/1986.

7. Authors' Address:

   Michael A. Patton
   Bolt Beranek and Newman
   10 Moulton Street
   Cambridge, MA, 02138

   Phone: (617) 873 2737
   FAX:   (617) 873 3457
   Email: map@bbn.com


This Internet Draft expires December 1995


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