Network Working Group                                           D. Lewis
Internet-Draft                                                  D. Meyer
Intended status: Experimental                                  V. Fuller
Expires: November 2, 2008                            Cisco Systems, Inc.
                                                             May 1, 2008

                             LISP EID Block

Status of this Memo

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   This Internet-Draft will expire on November 2, 2008.


   This is a direction to IANA to allocate a /8 IPv6 prefix for use with
   the Locator/ID Separation Protocol (LISP) and LISP Alternative
   Topology (LISP+ALT) mapping system.

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Table of Contents

   1.  Requirements Notation . . . . . . . . . . . . . . . . . . . . . 3
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Definition of Terms . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 6
   Intellectual Property and Copyright Statements  . . . . . . . . . . 7

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1.  Requirements Notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

2.  Introduction

   This is a direction to IANA to allocate a /8 IPv6 prefix for use with
   the Locator/ID Separation Protocol (LISP) [LISP] and LISP Alternative
   Topology (LISP+ALT) [LISP+ALT] mapping system.  This block will be
   used as global Endpoint ID (EID) space (Section 3) for the LISP+ALT
   mapping system.

   It is proposed that the IANA allocate 0100::/8 for this purpose.

3.  Definition of Terms

   LISP+ALT operates on two name spaces and introduces a new network
   element, the LISP+ALT Router (see below).  This section provides
   high-level definitions of the LISP+ALT name spaces, network elements,
   and message types.

   The LISP Alternative Topology (LAT):  The virtual overlay network
      made up of Generic Routing Encapsulation (GRE) tunnels between EID
      Prefix Aggregators.  The Border Gateway Protocol (BGP) runs
      between LISP+ALT routers and is used to carry reachability
      information for EID prefixes.

   Legacy Internet:  The portion of the Internet which does not run LISP
      and does not participate in LISP+ALT.

   LISP+ALT Router:  The devices which run on the LAT.  The LAT is a
      static network built with GRE tunnels.  LISP+ALT routers are
      deployed in a hierarchy which matches the EID prefix allocation
      hierarchy.  LISP+ALT routers at each level in the this hierarchy
      are responsible for aggregating all EID prefixes learned from
      LISP+ALT routers logically "below" them and advertising summary
      prefixes to the LISP+ALT routers logically "above" them.  All
      prefix learning and propagation between levels is done using BGP.
      LISP+ALT routers at the lowest level, or "edge", of the LAT learn
      EID prefixes either over a BGP or LISP TCP session to ETRs.

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      The primary function of LISP+ALT routers is to provide a
      lightweight forwarding infrastructure for LISP control-plane
      messages (Map-Request and Map-Reply), and to transport data
      packets when the packet has the same destination address in both
      the inner (encapsulating) destination and outer destination
      addresses ((i.e., a Data Probe packet).

    Endpoint ID (EID):  A 32- or 128-bit value used in the source and
      destination fields of the first (most inner) LISP header of a
      packet.  A packet that is emitted by a system contains EIDs in its
      headers and LISP headers are prepended only when the packet
      reaches an Ingress Tunnel Router (ITR) on the data path to the
      destination EID.

      In LISP+ALT, EID-prefixes MUST BE assigned in a hierarchical
      manner (in power-of-two) such that they can be aggregated by LISP+
      ALT routers.  In addition, a site may have site-local structure in
      how EIDs are topologically organized (subnetting) for routing
      within the site; this structure is not visible to the global
      routing system.

   EID-Prefix Aggregate:  A set of EID-prefixes said to be aggregatable
      in the [RFC4632] sense.  That is, an EID-Prefix aggregate is
      defined to be a single contiguous power-of-two EID-prefix block.
      Such a block is characterized by a prefix and a length.

   Routing Locator (RLOC):  An IP address of an egress tunnel router
      (ETR).  It is the output of a EID-to-RLOC mapping lookup.  An EID
      maps to one or more RLOCs.  Typically, RLOCs are numbered from
      topologically-aggregatable blocks that are assigned to a site at
      each point to which it attaches to the global Internet; where the
      topology is defined by the connectivity of provider networks,
      RLOCs can be thought of as Provider Aggregatable (PA) addresses.
      Note that in LISP+ALT, RLOCs are not carried by LISP+ALT routers.

    EID-to-RLOC Mapping:  A binding between an EID and the RLOC-set that
      can be used to reach the EID.  The term "mapping" refers to an
      EID-to-RLOC mapping.

    EID Prefix Reachability:  An EID prefix is said to be "reachable" if
      one or more of its locators are reachable.  That is, an EID prefix
      is reachable if the ETR (or its proxy) that is authoritative for a
      given EID-to-RLOC mapping is reachable.

    Default Mapping:  A Default Mapping is a mapping entry for EID-
      prefix  It maps to a locator-set used for all EIDs in
      the Internet.  If there is a more specific EID-prefix in the
      mapping cache it overrides the Default Mapping entry.  The Default

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      Mapping route can be learned by configuration or from a Map-Reply

    Default Route:  A Default Route in the context of LISP+ALT is a EID-
      prefix value of which is advertised by BGP on top of the
      LAT.  The Default Route is used to realize a path for Data Probe
      and Map-Request packets.

4.  Security Considerations

   This document introduces no new security considerations.

5.  Acknowledgments

   Marla Azinger, Chris Morrow, and Peter Schoenmaker all made
   insightful comments on early versions of this draft.

6.  IANA Considerations

   This document instructs the IANA to allocate a /8 IPv6 prefix for
   LISP and LISP+ALT deployment.  It is proposed that the IANA allocate
   0100::/8 for this purpose.

7.  References

7.1.  Normative References

   [LISP]     Farinacci, D., Fuller, V., Oran, D., and D. Meyer,
              "Locator/ID Separation Protocol (LISP)",
              draft-farinacci-lisp-07 (work in progress), Apr 2008.

   [LISP+ALT] Farinacci, D., Fuller, V., and D. Meyer, "LISP
              Alternative Topology (LISP+ALT)",
              draft-fuller-lisp-alt-02 (work in progress), Apr

   [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
              E. Lear, "Address Allocation for Private Internets",
              BCP 5, RFC 1918, February 1996.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4632]  Fuller, V. and T. Li, "Classless Inter-domain Routing

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              (CIDR): The Internet Address Assignment and Aggregation
              Plan", BCP 122, RFC 4632, August 2006.

7.2.  Informative References

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC2993]  Hain, T., "Architectural Implications of NAT", RFC 2993,
              November 2000.

Authors' Addresses

   Darrel Lewis
   Cisco Systems, Inc.


   David Meyer
   Cisco Systems, Inc.


   Vince Fuller
   Cisco Systems, Inc.


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