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Versions: 00 01 02 03 04                                                
LISP Working Group                                              L. Cheng
Internet-Draft                                                    M. Sun
Intended status: Standards Track                         ZTE Corporation
Expires: April 25, 2013                                 October 22, 2012


                       draft-cheng-lisp-shdht-02
                  LISP Single-Hop DHT Mapping Overlay

Abstract

   This draft specifies the LISP Single-Hop Distributed Hash Table
   Mapping Overlay (LISP-SHDHT), a distributed mapping database which
   embodies SHDHT Nodes to maintain (Key, value) pairs for LISP
   (Locator/ID Separation Protocol)-like architecture, wherein every
   (key value) pair is according to an EID(Endpoint ID)-to-RLOC(Routing
   Locator) mapping information entry.  According to this strategy, EID
   is hashed to be a unique Resource ID which is used for locating
   destiny DHT Node who maintains mapping entry for the particular EID.
   Furthermore, adaptive hash space partition method is adopted to solve
   the load balance problem on SHDHT Nodes which is common on
   traditional DHT planes.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on April 25, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of



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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Definition of Terms  . . . . . . . . . . . . . . . . . . . . .  5
   3.  SHDHT Overview . . . . . . . . . . . . . . . . . . . . . . . .  7
     3.1.  Node ID and Partition ID . . . . . . . . . . . . . . . . .  7
     3.2.  Data Storage and Hash Assignment . . . . . . . . . . . . .  8
     3.3.  Node Routing Table . . . . . . . . . . . . . . . . . . . .  9
   4.  LISP SHDHT . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.1.  ITR Operation  . . . . . . . . . . . . . . . . . . . . . . 10
     4.2.  ETR Operation  . . . . . . . . . . . . . . . . . . . . . . 10
     4.3.  SHDHT Map Resolver Operation . . . . . . . . . . . . . . . 11
     4.4.  SHDHT Map Server Operation . . . . . . . . . . . . . . . . 11
     4.5.  Encapsulated Message Format  . . . . . . . . . . . . . . . 12
       4.5.1.  Encapsulated Map Request . . . . . . . . . . . . . . . 13
   5.  Mobility Considerations  . . . . . . . . . . . . . . . . . . . 14
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 16
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 17
     8.2.  Informational References . . . . . . . . . . . . . . . . . 17
   Appendix A.  Acknowledgments . . . . . . . . . . . . . . . . . . . 17
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17




















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1.  Introduction

   Locator/ID Separation Protocol (LISP) [I-D.ietf-lisp] specifies an
   architecture and mechanism for replacing the address currently used
   by IP with two separate name spaces: Endpoint IDs (EIDs), used within
   LISP sites, and Routing Locators (RLOCs), used on transit networks
   that make up the Internet infrastructure.  To achieve this
   separation, LISP defines protocol mechanisms for mapping from EIDs to
   RLOCs.  As a result, an efficient database is needed to store and
   propagate those mappings globally.  Several such mapping databases
   have been proposed, among them: LISP-NERD [I-D.lear-lisp-nerd], LISP-
   ALT[I-D.ietf-lisp-alt], LISP-DDT[I-D.fuller-lisp-ddt], and LISP-DHT
   [I-D.fuller-lisp-ddt].

   According to hybrid model databases such like LISP-ALT
   [I-D.ietf-lisp-alt] and LISP-DDT [I-D.fuller-lisp-ddt], architectures
   of these mapping databases are based on announcement/delegation of
   hierarchically-delegated segments of EID namespace (i.e., prefixes).
   Therefore, based on these architectures, when a roaming event occurs
   and a LISP site or a LISP MN receives new RLOCs, the site or MN has
   to anchor pre-configured map-server to register its new mapping
   information no matter where the site or MN currently locates, just in
   order to protect EID prefixes announced aggregately in the database
   [I-D.meyer-lisp-mn].

   As a DHT strategy based mapping database, LISP-DHT
   [I-D.mathy-lisp-dht] exhibits several interesting properties, such as
   self-configuration, self-maintenance, scalability and robustness that
   are clearly desirable for a EID-to-RLOC resolution service.  However,
   this database is based on multi-hop Chord DHT.  On one hand,
   inquiries of mapping information in this case need to pass through
   iterative multi-hop lookup steps which will cause relatively large
   delay time.  On the other hand, load balance between Chord nodes is
   another essential problem need to be solved.

   This draft specifies a Single-Hop Distributed Hash Table Mapping
   Overlay (LISP-SHDHT) which provides mapping information lookup
   service for sites running LISP.  Main characters of this strategy is
   that,

   1.  Each SHDHT Node maintains routing information for all other SHDHT
       Nodes.  Thus, messages interaction between SHDHT Nodes in the
       same SHDHT overlay just need one or two hops.

   2.  Traditionally, Node IDs are used to identify DHT nodes and
       represent hash space arrangement on DHT nodes.  In SHDHT
       strategy, the two roles are separated.  Partition IDs are adopted
       for hash space arrangement and a build-in load balancing solution



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       is designed.

   This draft specifies the outline of SHDHT and the basic application
   of LISP SHDHT.  In actual deployment of LISP SHDHT, mapping database
   could be maintained by operators and could be deployed as
   collaborative combination of multiple domain LISP SHDHTs.  Deployment
   of collaborative domain LISP SHDHTs is for future study, as well as
   the security strategies on/between domain LISP SHDHTs.











































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2.  Definition of Terms

   This draft uses terms defined in [I-D.ietf-lisp].  This section
   defines some new terms used in this document.

   SHDHT:  Single-Hop Distributed Hash Table Mapping Overlay.

   SHDHT Node:  Physical nodes which compose SHDHT overlay's topology.
      Each SHDHT Node has a unique Node ID and maintains multiple hash
      space segments which labeled by Partition IDs.  Each SHDHT Node
      maintains a Node Routing Table of local SHDHT Mapping Overlay.
      SHDHT Nodes locates in the same Mapping Overlay implement hash
      operation based on the same hash algorithm.  SHDHT Nodes hash data
      object to be a unique Resource ID, and perform put/get/move
      operations based on the Resource IDs.

   Node ID:  Node identifier, which is used for maintenance.  Each SHDHT
      Node has a unique Node ID.  The ring containing Node IDs indicates
      overlay's topology.

   Partition ID:  Partition identifier, which is used for hash space
      assignment.  Partition IDs and Resource IDs share the same hash
      space.  All Partition IDs in overlay are unique.  Each SHDHT Node
      could have multiple Partition IDs.  The ring containing Partition
      IDs determines how the hash space is partitioned into segments and
      how these segments are assigned to nodes.

   Resource ID:  Each data object stored in DHT overlay could be hashed
      to be a unique Resource ID.  In LISP-SHDHT strategy, data objects
      are according to the EIDs.  Resource IDs share the same hash space
      with Partition IDs.  As a result, SHDHT Nodes perform data objects
      put/get/remove operations based on these IDs.

   Node Routing Table:  Routing table of a SHDHT Mapping Overlay which
      contains all SHDHT Nodes information of this overly, including
      Node IDs, Partition IDs and Node IP addresses, etc.  Each SHDHT
      Node of this overly will maintain the Routing Table.

   SHDHT Map Server:  A SHDHT Node that also implements Map Server
      functionality (forwarding Map-Requests and/or return Map Replies
      if offering proxy Map-Reply service) for mapping entries it
      maintains.

   SHDHT Map Resolver:  A SHDHT Node that also implements Map Resolver
      functionality (accepting Map-Requests, hash the requested EID to
      be Resource ID, and then forward Map-Requests to corresponding
      SHDHT Map Server based on Resource ID).  Furthermore, in this
      document SHDHT Map Resolver could perform as proxy for Map-



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      Register.  SHDHT Map Resolver could accept register messages and
      forward them to SHDHT Map Servers.

















































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3.  SHDHT Overview

3.1.  Node ID and Partition ID

   Most of existing DHTs use node IDs for both maintenance and hash
   space arrangement.  For example, in LISP-DHT[I-D.mathy-lisp-dht],
   each chord node of the DHT ring has a unique k-bits identifier
   (ChordID).  Nodes perform operations such like put/get/remove based
   on ChordIDs.  Furthermore, ChordIDs are also used to associate nodes
   with hash space segments that the nodes responsible for.

   In SHDHT, two roles of maintenance and hash space arrangement are
   separated and a new kind identifier called Partition ID is adopted.
   Each SHDHT node has a unique Node ID which identifies the physical
   node and multiple Partition IDs which represent hash space segments.
   All Partition IDs in the overlay are also unique.  Node IDs and
   Partition IDs are mapped into two ring-shaped spaces respectively.
   The ring containing Node IDs indicates the overlay's topology.  The
   ring containing Partition IDs determines how the hash space is
   partitioned into segments and how these segments are assigned to
   nodes.  It is noteworthy that SHDHT Nodes could determine number of
   Partition IDs on them separately and could generate Partition IDs
   randomly just need to make sure that the generated Partition IDs will
   not conflict with existing Partition IDs on the SHDHT plane.

  +--------------------+                          +--------------------+
  |Node ID:      0x0123|                          |Node ID:      0x4444|
  |Partition ID: 0x1234| +-----+          +-----+ |Partition ID: 0x9000|
  |              0x7000| |Node1+----------+Node2| |              0x3234|
  +--------------------+ +--+--+          +--+--+ +--------------------+
                            |                |
                            |                |
                            |                |
                            |                |
  +--------------------+ +--+--+          +--+--+ +--------------------+
  |Node ID:      0xe000| |Node3+----------+Node4| |Node ID:      0xc000|
  |Partition ID: 0x5000| +-----+          +-----+ |Partition ID: 0xaaaa|
  |              0xeeee|                          |              0xcccc|
  +--------------------+                          +--------------------+

                      Fig.1 SHDHT Deployment Example

   As shown in Fig.1 is an example of SHDHT.  This SHDHT overlay is
   consist of four SHDHT NODEs each has a unique Node ID and maintains
   two Partition IDs.  According to this deployment, hash space is
   partitioned to be eight segments each is indexed by a Partition ID.
   From Fig. I, it could be observed that hash space segments are not
   required to be partitioned equally.  As SHDHT Nodes could general



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   Partition IDs separately, when a SHDHT Node gets all hash segments
   assignment information for other SHDHT Nodes, it will be able to
   implement the load balance of SHDHT overlay by general proper
   Partition IDs.

   In SHDHT, each SHDHT Node stores and maintains data objects.  Data
   objects are indexed by Resource IDs which share the same hash space
   with Partition IDs and will locate in the hash space segments whose
   Partition IDs are closest to their Resource IDs.

   For example, for a data object whose Resource ID is 0x8213, the
   Resource ID locates between Partition ID 0x7000 and Partition ID
   0x9000.  As Partition ID 0x9000 is closer to Resource ID 0x8213, the
   data object will be stored and maintained on Node2 who is assigned
   with the hash space segment indexed by Partition ID 0x9000.

3.2.  Data Storage and Hash Assignment

   In traditional DHTs, hash space is partitioned into segments based on
   node IDs.  As a result, data objects are always stored in their root
   nodes, whose node IDs are "closest" to data objects' Resource IDs.

   What does "closes" means?  Suppose we have three consecutive
   Partition IDs a, b and c which are the only Partition IDs in SHDHT
   for our example, then the range of each hash space segment is defined
   as follow:

      Partition ID a: [id(a)-0.5*d(c,a); id(a)+0.5*d(a,b))

      Partition ID b: [id(b)-0.5*d(a,b); id(b)+0.5*d(b,c))

      Partition ID c: [id(c)-0.5*d(b,c); id(c)+0.5*d(c,a))

      with functions

      id(x): value of Partition ID x in hash space

      d(x,y): distance between Partition ID x and y in hash space

   Replications of data objects in a particular node are always stored
   in the preceding node or successor node of the root node.  The backup
   preceding node or successor node will automatically become the new
   closest node if the root node leaves the overlay.

   In SHDHT, the whole hash space is partitioned into segments based on
   partition IDs.  The root node of a data object is the node, which has
   the closest partition ID to the data object's Resource ID.  In SHDHT,
   each node can maintain multiple hash space segments with respective



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   Partition IDs.  As the preceding Partition ID or successor Partition
   ID may be owned by the same root node.  Replication of data objects
   could still be stored in preceding node or successor node of root
   node.

3.3.  Node Routing Table

   In SHDHT, each node maintains a Node Routing Table containing routing
   information for all other SHDHT Nodes locate in the same SHDHT
   overlay.  Table I shows the Node Routing Table on SHDHT Nodes of
   Fig.1.  A Node Routing Table contains all Partition IDs and their
   associated Node IDs and node addresses.  For simplification, Node IDs
   and Partition IDs shown in the draft are only 16-bit numbers.

   When SHDHT Node receives a message points to a particular Resource
   ID, it could look up Node Routing Table and find out the Partition ID
   which is closest to the Resource ID.  Furthermore, message could be
   transferred to the corresponding SHDHT Node.

                +--------------+---------+---------------+
                | Partition ID | Node ID | Address       |
                +--------------+---------+---------------+
                | 0x1234       | 0x0123  | 10.0.0.2:2000 |
                | 0x3234       | 0x4444  | 10.0.0.3:2000 |
                | 0x5000       | 0xe000  | 10.0.0.4:2000 |
                | 0x7000       | 0x0123  | 10.0.0.2:2000 |
                | 0x9000       | 0x4444  | 10.0.0.3:2000 |
                | 0xaaaa       | 0xc000  | 10.0.0.5:2000 |
                | 0xcccc       | 0xc000  | 10.0.0.5:2000 |
                | 0xeeee       | 0xe000  | 10.0.0.4:2000 |
                +--------------+---------+---------------+

                     TABLE II SHDHT Node Routing Table

   For example, if Node 1 (ID: 0x1234) in Fig.1 needs to implement put/
   get/remove operations for a data object with Resource ID 0x8213.
   Node 1 first lookups its Node Routing Table and finds out that the
   closest Partition ID to this Resource ID is 0x9000.  Then Node 1 will
   send put/get/remove request to the node owns the Partiton ID, in
   Fig.1 is Node2, whose Node ID is 0x4444 and address is 10.0.0.3:2000.











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4.  LISP SHDHT

   LISP SHDHT is proposed to provide "EID-to-RLOC(s)" mapping
   information lookup service for sites running the Locator/ID
   Separation Protocol (LISP).

   In LISP SHDHT, mapping overlay consists of SHDHT Nodes which play
   roles of SHDHT Map Server and/or SHDHT Map Resolver.  In this draft
   SHDHT-MS and SHDHT-MR just represent function entities, and these
   entities could be collocated on the same SHDHT Node.

   All EID-to-RLOC mapping entries are stored in SHDHT Nodes as data
   objects.  Each SHDHT Node has a RLOC address.  EIDs in mapping
   entries can be hashed as Resource IDs of data objects.  All SHDHT
   Nodes in the same SHDHT overly perform hash operation based on the
   same hash algorithm.

   Data objects stored in LISP SHDHT Nodes may be in the following
   format:

          Object (lisp) = [EID prefix, (RLOC1, priority, weight),
                        ...,RLOCn, priority, weight), TTL ]

4.1.  ITR Operation

   According to LISP-MS [I-D.ietf-lisp-ms], LISP ITRs use Map Resolvers
   as proxy to send control messages, such like encapsulated Map-
   Requests and Map-Replies.

   In Scenario of LISP SHDHT, an ITR send Map-Requests directely to the
   SHDHT Node which is selected to play roles of SHDHT Map Resolver for
   the ITR.

4.2.  ETR Operation

   According to LISP-MS [I-D.ietf-lisp-ms], LISP ETRs register mapping
   information onto the Map Server by sending Map-Register messages.

   In scenario of LISP SHDHT, ETR could send Map-Register messages
   directely to the SHDHT Node which play roles of SHDHT Map Server for
   the registered EIDs.

   Alternatively, ETRs could send Map-Register messages to a nearest
   SHDHT Node who will hash registered mapping entries to be Resource
   IDs.  Then, the SHDHT Node forwards Map-Register messages to the
   corresponding SHDHT Map Servers based on Resource IDs.  This
   alternative strategy will be more efficient for roaming scenario.
   Furthermore, ETRs are no longer anchoring to fixed SHDHT Map Server



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   Nodes, and ISPs who operate mapping overlays could arrange hash space
   onto SHDHT Nodes more autonomously and could perform better load
   balance among SHDHT Nodes.

4.3.  SHDHT Map Resolver Operation

   In LISP SHDHT, when a SHDHT Map Resolver receives a Map-Request
   message from an ITR, it will perform the following operations,

   1.  SHDHT Map Resolver extracts destination EID address from the Map-
       Request message.

   2.  SHDHT Map Resolver hash the EID address to be Resource ID based
       on the shared hash algorithm.

   3.  SHDHT Map Resolver looks up Node Routing Table and find out the
       Partition ID which matches the Resource ID.

   4.  SHDHT Map Resolver forward Map-Request message to the
       Corresponding SHDHT Node.  This SHDHT Node maintains the hash
       space labeled by matched Partition ID and plays the role of SHDHT
       Map Server for the requested mapping entry.

   In LISP SHDHT, when a SHDHT Map Resolver receives a Map-Register
   message from an ETR, it will perform the following operations,

   1.  SHDHT Map Resolver extracts registered EID information of the
       Map-Register message.

   2.  SHDHT Map Resolver hash the registered EID address to be Resource
       ID based on shared hash algorithm.

   3.  SHDHT Map Resolver looks up Node Routing Table and find out the
       Partition ID which matches the Resource ID.

   4.  SHDHT Map Resolver forward Map-Register message to the
       Corresponding SHDHT Map Server.

4.4.  SHDHT Map Server Operation

   In LISP SHDHT, when a SHDHT Map Server receives a Map-Request
   message, it will perform the following operations,

   1.  SHDHT Map Server first check if it is responsible for the
       requested mapping entry, i.e. if it has a hash space whose
       Partition ID matches Resource ID of the requested EID.





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   2.  SHDHT Map Server then looks for data objects in its hash space
       according to the matched Partition ID.

   3.  If there's no data object according to the requested EID, SHDHT
       Map Server response a negative Map-Reply message.

   4.  If there's a data object according to the requested EID, SHDHT
       Map Server will forward the Map-Request to registered ETR or
       return Map-Reply message if it offers proxy Map-Reply service.

   In LISP SHDHT, when a SHDHT Map Server receives a Map-Register
   message, it will perform the following operations,

   1.  SHDHT Map Server first checks if it is responsible for the
       registered mapping entry, i.e. if it has a hash space who's
       Partition ID matches Resource ID of the requested EID.

   2.  SHDHT Map Server then store and maintain the registered mapping
       information in its hash space according to the matched Partition
       ID.

4.5.  Encapsulated Message Format

   An Encapsulated Control Message (ECM) defined in[I-D.ietf-lisp] is
   used to encapsulate control packets sent between xTRs and mapping
   database system.  At this time, only Map-Request messages are allowed
   to be encapsulated in ECM format.  When ITRs choose a SHDHT Node as
   proxy to send control messages, they could use encapsulated message
   format defined in [I-D.ietf-lisp], as shown in Fig.2.






















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        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |                       IPv4 or IPv6 Header                     |
   OH  |                      (uses RLOC addresses)                    |
     \ |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |       Source Port = xxxx      |       Dest Port = 4342        |
   UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |           UDP Length          |        UDP Checksum           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   LH  |Type=8 |S|                  Reserved                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |                       IPv4 or IPv6 Header                     |
   IH  |                  (uses RLOC or EID addresses)                 |
     \ |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |       Source Port = xxxx      |       Dest Port = yyyy        |
   UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |           UDP Length          |        UDP Checksum           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   LCM |                      LISP Control Message                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Fig.2 Encapsulated Control Message Format

4.5.1.  Encapsulated Map Request

   Suppose that the selected SHDHT Node of an ITR is Node1.

   When the ITR sends Encapsulated Map-Requests to Node1, source address
   and destination address in message OH (Outside Header) should be RLOC
   addresses of ITR and Node1 respectively.

   In the IH (Inside Header), source address is still RLOC address of
   Node1, while destination address is the inquired EID address.

   Consider Node1 is a configured Map Resolver, and then the
   configuration of Encapsulated Map-Request message has not been
   changed.











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5.  Mobility Considerations

   As specified in section 4.2 and 4.3, ITR/ETR could choose a nearest
   LISP SHDHT Node as proxy to send control messages.

   Based on LISP SHDHT, when roaming events occurs, the roamed LISP
   sites or LISP MNs are no longer need to anchor pre-configured map-
   servers.











































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6.  Security Considerations

   TBD
















































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7.  IANA Considerations

   This document makes no requests to IANA.
















































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8.  References

8.1.  Normative References

   [I-D.fuller-lisp-ddt]
              Fuller, V., Lewis, D., and V. Ermagan, "LISP Delegated
              Database Tree", March 2012.

   [I-D.ietf-lisp]
              Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
              "Locator/ID Separation Protocol (LISP)", May 2012.

   [I-D.ietf-lisp-alt]
              Fuller, V., Farinacci, D., Meyer, D., and D. Lewis, "LISP
              Alternative Topology (LISP+ALT)", December 2011.

   [I-D.mathy-lisp-dht]
              Mathy, L. and L. Iannone, "LISP-DHT: Towards a DHT to map
              identifiers onto locators,
              http://dl.acm.org/citation.cfm?id=1544073", December 2008.

   [I-D.meyer-lisp-mn]
              Farinacci, D., Lewis, D., Meyer, D., and C. White, "LISP
              Mobile Node", April 2012.

8.2.  Informational References

   [I-D.ietf-lisp-ms]
              Fuller, V. and D. Farinacci, "LISP Map Server Interface",
              March 2012.

   [I-D.lear-lisp-nerd]
              Lear, E., "NERD: A Not-so-novel EID to RLOC Database",
              April 2012.


Appendix A.  Acknowledgments

   The authors with to express their thanks to Michael Hoefling for work
   on Hash space segment of SHDHT overlay.  Thanks also go to Dino
   Farinacci and Darrel Lewis for their suggestions about database
   structure deployment.









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Internet-Draft     LISP Single-Hop DHT Mapping Overlay      October 2012


Authors' Addresses

   Li Cheng
   ZTE Corporation
   R&D Building 1, Zijinghua Road No.68
   Nanjing, Yuhuatai District  210012
   P.R.China

   Email: cheng.li2@zte.com.cn


   Mo Sun
   ZTE Corporation
   R&D Building 1, Zijinghua Road No.68
   Nanjing, Yuhuatai District  210012
   P.R.China

   Email: sun.mo@zte.com.cn

































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