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Versions: 00 01 02 03 04 05                                             
autoconf                                                    C. Bernardos
Internet-Draft                                               M. Calderon
Expires: January 12, 2006                                           UC3M
                                                           July 11, 2005


      Survey of IP address autoconfiguration mechanisms for MANETs
                draft-bernardos-manet-autoconf-survey-00

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
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   This Internet-Draft will expire on January 12, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This Internet Draft aims at describing some of the already proposed
   mechanisms for the autoconfiguration of IP addresses in MANET
   networks, trying to provide a useful reference in the standardisation
   process.  Solutions proposed in research papers and submitted as I-Ds
   are presented and classified by a simple criteria.  The analysis of
   the solutions includes a brief description of the mechanism and also
   a summary of the key characteristics.




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Table of Contents

   1.  Introduction and problem statement . . . . . . . . . . . . . .  4
   2.  IP address auto-configuration protocols  . . . . . . . . . . .  6
     2.1   Conflict-detection allocation mechanisms . . . . . . . . .  6
       2.1.1   IP address Autoconfiguration for Ad Hoc Networks
               (Perkins et al.) . . . . . . . . . . . . . . . . . . .  7
       2.1.2   IPv6 Autoconfiguration in Large Scale Mobile
               Ad-Hoc Networks (Weniger et al.) . . . . . . . . . . .  8
       2.1.3   Weak Duplicate Address Detection in Mobile Ad Hoc
               Networks (Vaidya)  . . . . . . . . . . . . . . . . . .  9
       2.1.4   Global connectivity for IPv6 Mobile Ad Hoc
               Networks (Wakikawa et al.) . . . . . . . . . . . . . . 10
       2.1.5   Ad Hoc IP Address Autoconfiguration (Jeong et al.) . . 10
       2.1.6   Automatic configuration of IPv6 addresses for
               nodes in a MANET with multiple gateways (Ruffino
               et al.)  . . . . . . . . . . . . . . . . . . . . . . . 11
       2.1.7   Address autoconfiguration in Optimized Link State
               Routing Protocol (Adjih et al.)  . . . . . . . . . . . 12
       2.1.8   MANETconf: Configuration of Hosts in a Mobile Ad
               Hoc Network (Nesargi et al.) . . . . . . . . . . . . . 12
       2.1.9   Extended Support for Global Connectivity for IPv6
               Mobile Ad Hoc Networks (Cha et al.)  . . . . . . . . . 13
     2.2   Conflict-free allocation mechanisms  . . . . . . . . . . . 14
       2.2.1   Prophet Address Allocation for Large Scale MANETs
               (Zhou et al.)  . . . . . . . . . . . . . . . . . . . . 15
       2.2.2   Self-Configuring Networks. DRCP and DAAP (McAuley
               et al.)  . . . . . . . . . . . . . . . . . . . . . . . 15
         2.2.2.1   DRCP . . . . . . . . . . . . . . . . . . . . . . . 16
         2.2.2.2   DAAP . . . . . . . . . . . . . . . . . . . . . . . 16
       2.2.3   Autoconfiguration, Registration, and Mobility
               Management for Pervasive Computing. DDCP (Misra et
               al.) . . . . . . . . . . . . . . . . . . . . . . . . . 17
       2.2.4   IP Address Assignment in a Mobile Ad Hoc Network
               (Mohsin et al.)  . . . . . . . . . . . . . . . . . . . 17
       2.2.5   An address assignment for the automatic
               configuration of mobile ad hoc networks (Tayal et
               al.) . . . . . . . . . . . . . . . . . . . . . . . . . 18
       2.2.6   Simple MANET Address Autoconfiguration (Clausen et
               al.) . . . . . . . . . . . . . . . . . . . . . . . . . 18
       2.2.7   Gateway and address autoconfiguration for IPv6
               adhoc networks (Jelger et al.) . . . . . . . . . . . . 19
   3.  Conclusions  . . . . . . . . . . . . . . . . . . . . . . . . . 20
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 21
   5.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 22
     5.1   Normative References . . . . . . . . . . . . . . . . . . . 22
     5.2   Informative References . . . . . . . . . . . . . . . . . . 23
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 24



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       Intellectual Property and Copyright Statements . . . . . . . . 25


















































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1.  Introduction and problem statement

   A group of mobile wireless nodes capable of spontaneously forming a
   network and support multi-hop communications constitutes a Mobile Ad
   Hoc Network (MANET).  This kind of multi-hop network presents some
   interesting advantages, such as not requiring any infrastructure to
   work, e.g., allowing the extension of coverage areas or providing
   connectivity to nodes that not have the suitable access technologies.
   Several manet routing protocol specifications have been developed by
   the IETF MANET WG.  In order to enable these networks to support IP
   services, address configuration of the nodes is a requirement.
   However, currently there is no standard specification that can be
   used by manet nodes to autoconfigure their IP addresses.

   Existing solutions for IP infrastructure-based networks (e.g., RFCs
   2461, 2462, 3315 etc.) cannot be directly used by nodes constituting
   an ad hoc network.  These protocols assume the availability of a
   multicast capable link for signalling, but there is not such a link
   in ad-hoc multi-hop networks.

   The main goal of the AUTOCONF group is to develop solutions for IPv4
   and IPv6 address auto-configuration (both manet-local and global
   scoped).  The group has identified three possible scenarios of MANET
   where IP address auto-configuration is required:

   o  Stand-alone ad hoc network: ad hoc networks not connected to any
      external network, such as conference networks, battlefield
      networks, surveillance networks, etc.  In this scenario, nodes may
      be added or removed randomly.  Besides, most likely no pre-
      established nor reliable address or prefix allocation agency will
      be present in the network.

   o  Ad hoc network at the edge of an infra-structure network: Stand-
      alone network connected to the Internet via one or more Internet
      gateways (i.e., nodes that have connectivity to both an
      infrastructure access network and the ad hoc network, providing
      connectivity to the nodes attached to the latter).  These Internet
      gateways may be used in the auto-configuration address mechanisms,
      e.g., by providing prefix information to the MANET nodes.

   o  Hybrid networks: ad hoc network that may be stand-alone for most
      of the time but temporarily connected to the infrastructure
      network (e.g., a car network connected while parked and
      disconnected otherwise).

   Ad hoc networks present a particular characteristic that should be
   taken into account when designing address auto-configuration
   protocols: two or more ad hoc network may get merged (the problem of



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   having two or more nodes with the same IP address may arise) or
   single ad hoc network may get partitioned into two or more separate
   networks, at any moment of time.

   This Internet Draft aims at describing some of the already proposed
   mechanisms for the autoconfiguration of IP addresses in MANET
   networks, trying to provide a useful reference in the standardisation
   process.  Solutions proposed in research papers and submitted as I-Ds
   are presented and classified by a simple criteria.  The analysis of
   the solutions includes a brief description of the mechanism and also
   a summary of the key characteristics.








































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2.  IP address auto-configuration protocols

   In this section we briefly describe some of the existing proposals
   for IP address autoconfiguration, classifying them into two different
   categories: conflict-detection and conflict-free allocation.  Some of
   the mechanisms included in this document are not complete
   autoconfiguration protocols, but just pieces (e.g., Duplicate Address
   Detection in the MANET) required in a more general autoconfiguration
   protocol.  We also include them for completeness.

2.1  Conflict-detection allocation mechanisms

            -----------------------------
            |                           |
            |         Pool of           |
            |        addresses          |
            |                           |
            |                           |
            |  addrX                    |
            |    A                      |
            -----+-----------------------            -----
                 |                                   |   |
             (1) | Node x picks an             ----->| z |
                 | address (addrX)            /      |   |
                 V                           /       -----
               -----                  ----- / (2) is addrX OK?
               |   |      (2)         |   |/
       Node x  | x |----------------->| y |\
   (3) waits   |   |  is addrX OK?    |   | \ (2) is addrX OK?
       for an  -----                  -----  \       -----
       answer     \                     A     \      |   |
                   \                    |      ----->| t |
   (2) is addrX OK? \                 _/             |   |
                     |             __/               -----
                     V          __/
                   -----     __/
                   |   |  __/    (2) is addrX OK?
                   | w |_/
                   |   |
                   -----

              Figure 1: Conflict-detection allocation scheme

   These methods are based on picking an IP address from a pool of
   available addresses, configuring it as tentative address and asking
   the rest of the nodes of the network, checking the address uniqueness
   and requesting for approval from all the nodes of the network.  In
   case of conflict (e.g., the address has been already configured by



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   another node), the node should pick a new address and repeat the
   procedure (sort-of "trial and error" method).  An example of
   conflict-detection allocation general mechanism is shown in Figure 1.

2.1.1  IP address Autoconfiguration for Ad Hoc Networks (Perkins et al.)

   This ad hoc address autoconfiguration mechanism, proposed in [1] and
   [14], basically consists in choosing an address randomly belonging to
   a network prefix available to the MANET and performing a Duplicate
   Address Detection procedure within the MANET (that we can called
   MANET-DAD to avoid confusing it with the DAD performed in IPv6
   single-hop networks).  The mechanism is defined both for IPv4 ([14],
   [1]) and IPv6 ([1]).

   This mechanism works (for IPv4) as follows: when a node requires a
   unique IP address, it first selects a random host ID from the range
   [2048, (2^(32-n)-1)], where n is the number of significant bits in
   the network prefix available for the MANET.  The node then appends
   that host ID to the prefix, thus forming the tentative IP address for
   which it performs MANET-DAD.  The node also selects a random host ID
   in the range [0, 2047] and appends this value to the available
   network prefix, forming an address that is used as a temporary source
   IP address for the short period while the node performs MANET-DAD.
   The MANET-DAD is performed by creating an Address Request (AREQ)
   message, including its tentative IP address, which is broadcasted to
   its neighbours (using the randomly selected source address).  When a
   node receives an AREQ message, it creates a reverse route entry for
   the node indicated by the random originator IP address.  If the
   tentative address contained in the AREQ message does not match the
   address of the receiving node, it rebroadcasts the message to its
   neighbours.  If the IP address of the receiving node matches the
   tentative address contained in the AREQ message it sends an Address
   Reply (AREP) message to the sender, indicating that the address is
   already in use.  The route created by the AREQ messages is used to
   route the message back to the source node.

   A requesting node sends an AREQ message, waits for the reception of
   an AREP message during a timer and retries the process several times.
   If no AREP is received, it assumes that the tentative address
   included in the AREQ messages is not in use and takes it for its own.
   If an AREP message is received, then it picks up a different host ID
   and begins the MANET-DAD process again.

   For IPv6, the mechanism is similar.  The tentative address belongs to
   a non-link-local prefix (a prefix obtained by other means or a
   default MANET_PREFIX reserved for MANET autoconfiguration).  The
   source address belongs to a different non-overlapping prefix (or part
   of the prefix, if the same prefix is used for both tentative and



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   source addresses).  The protocol is basically the same, but using
   different message formats.  For IPv4, ICMP messages are used, whereas
   in IPv6 modified Neighbour Solicitation and Advertisement messages
   are used.

   In [15] some limitations of this solution are presented.

   Summary of some other characteristics:

   o  Suitable for IPv4 and IPv6.

   o  Not restricted to any particular ad hoc routing solution, but it
      is best suited for reactive routing protocols such as AODV.

   o  It does not support partition/merging.


2.1.2  IPv6 Autoconfiguration in Large Scale Mobile Ad-Hoc Networks
       (Weniger et al.)

   The solution described in [16] extends the Neighbour Discovery and
   IPv6 Stateless Address Autoconfiguration mechanisms to work in multi-
   hop wireless networks.  To do so, some modifications are needed:

   o  The Neighbour Solicitation message is modified to allow it to be
      broadcasted to a bounded area of radius r_s hops (instead of only
      a single hop).  In addition, a new option for Neighbour Discovery
      is defined (called MANET option) which contains a Random Source ID
      (RS-ID) field, that is used to distinguish different nodes.  Nodes
      use the all-nodes multicast address instead of the solicited-node
      multicast address.  This mechanism guarantees link-local addresses
      to be unique within the scope (limited by r_s) of each node.

   o  To enable the configuration of unique site-local (note: this is
      not described in the paper, but this method could be also used to
      configure global addresses) addresses, a hierarchy is established
      by special nodes (called leader nodes) that configure a group of
      nodes by issuing Router Advertisements (RA) within their scope,
      containing the subnet ID (i.e., network prefix) and its link-local
      address as source address.  The subnet ID has to be unique for
      each leader node, so MANET-DAD has to be performed between the
      leader nodes within the entire Ad hoc network.  An algorithm is
      provided for the election of leader nodes.

   It should be noted that because of the nature of the solution, it
   would be possible to have multihomed nodes (if a node is within the
   scope of more than one leader node).




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   Summary of some other characteristics:

   o  Intended to IPv6.

   o  Not restricted to any particular ad hoc routing solution, but it
      may be advantageous if it follows an hierarchical structure.
      Besides, it is also preferable that nodes move in logical groups.

   o  It supports partition/merging.


2.1.3  Weak Duplicate Address Detection in Mobile Ad Hoc Networks
       (Vaidya)

   The mechanism described in [17] is not by itself an IP address
   autoconfiguration protocol, but a mechanism to ensure that packets
   ``meant for'' one node are not routed to another node, even if the
   two nodes have chosen the same address.

   The authors follow an approach to solve the IP address
   autoconfiguration problem in ad Hoc networks, that is pretty common.
   The node just picks a tentative address randomly and performs a
   MANET-DAD procedure to detect if that address is already in use.
   Typically, these MANET-DAD mechanisms make use of timeouts and the
   author of [17] says that message delays cannot be bounded in an ad
   hoc network (or if possible, determining the delays is non-trivial).
   Therefore, he proposes a 'weak' DAD, that prevents a packet to be
   delivered to a ``wrong'' destination node (even if two nodes have the
   same IP address).  To do that, it is assumed that each node is pre-
   assigned a unique ``key'' (MAC addresses can be used as keys if they
   are guaranteed to be unique).  Information about {IP address, key}
   pairs is included in the routing protocols (they assume that it is
   not possible to embed the key in the IP address), so address
   duplication can be detected.  The authors describe how to do that
   with Link State Routing (proactive routing protocol) and Dynamic
   Source Routing (reactive routing protocol).  The weak DAD cannot be
   used when flooding is used as the routing protocol.

   Summary of some other characteristics:

   o  Intended to IPv4.  It would be also possible to use this mechanism
      in IPv6.

   o  Restricted to particular ad hoc routing solutions.  It is
      described how the mechanism works with LSR and DSR.

   o  It supports partition/merging.




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2.1.4  Global connectivity for IPv6 Mobile Ad Hoc Networks (Wakikawa et
       al.)

   This mechanism [2] is similar to [3] from the point of view of how
   IPv6 addresses are configured.  Global prefix information is obtained
   from Internet gateways.  They propose two methods for the Internet
   gateway discovery: one method periodically disseminates gateway
   advertisements to all nodes in the MANET; the other method utilises
   solicitation and advertisement signalling between a MANET node and
   the gateway.  Extended router solicitation and advertisements of the
   Neighbour Discovery Protocol (NDP) or extended control message of
   each MANET routing protocol can be used for this signalling.  The
   proposed methods target all MANET protocols regardless of whether
   they are reactive and proactive.  Internet gateways supply their own
   global prefix information and IPv6 global address to MANET nodes
   somehow, either proactively or reactively.  In this way, the reactive
   and proactive route discovery features of each MANET routing protocol
   are not disturbed.

   Once the MANET node has obtained the prefix information from the
   Internet gateway, it uses the 64-bit interface ID in order to
   construct a valid address with the acquired prefix.  It is assumed
   than before configuring a global IPv6 address, the node has
   configured a link local address, and MANET-DAD has been performed for
   that link-local address (using the mechanism defined in [1] and
   [14]), so it is assumed that the global address would be also unique.
   If not, the node may perform another MANET-DAD for this global
   address.

   Summary of some other characteristics:

   o  Intended to IPv6.

   o  Not restricted to any particular ad hoc routing solution.


2.1.5  Ad Hoc IP Address Autoconfiguration (Jeong et al.)

   The IP address autoconfiguration mechanism described in [4] is
   comprised of three steps:

   1.  Selection of a random address.

   2.  Verification of the address uniqueness.

   3.  Assignment of the address to the network interface.

   The MANET-DAD procedure follows an hybrid approach, consisting of two



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   phases:

   o  Strong DAD: based on [1].  Strong DAD is done in the
      initialisation in order to check if there is an address
      duplication or not. [4] describes the message format for IPv4 and
      IPv6, using ICMP messages (new types are defined). [5] describes
      the message format for AODV.

   o  Weak DAD: based on [17].  During ad hoc routing, weak DAD is used
      to find out whether address duplication, due to merging, has
      occurred or not.  The concept of ``Virtual IP address'', which is
      the combination of ''IP address'' and ``Key'', is used.

   Summary of some other characteristics:

   o  Suitable for IPv4 and IPv6.

   o  Not restricted to any particular ad hoc routing solution.

   o  It supports partition/merging.


2.1.6  Automatic configuration of IPv6 addresses for nodes in a MANET
       with multiple gateways (Ruffino et al.)

   This mechanism [6] describes a mechanism to enable nodes of a MANET
   connected to the infrastructure - by means of one or more gateways -
   to configure IP addresses.

   Each of the gateways available at the MANET has a global IPv6 prefix
   that is announced using a new OSLR message type, called Prefix
   Advertisement (PA).  The nodes of the MANET can configure addresses
   belonging to each of the prefixes received (a generic MANET DAD
   procedure, such as [1], has to performed in order to verify
   uniqueness of MANET-local and global addresses).

   The mechanism basically works as follows: at boostrap, a node
   configures a Primary Address (PADD) that is MANET-scoped and is used
   as main address in OLSR messages.  The node then is able to start
   participating to OLSR and receiving topology information.  With the
   prefix information received in the PA messages, the node is able to
   build a set of global IPv6 addresses (called Secondary Addresses:
   SADDs).  Among them, the node chooses the "best" prefix and starts
   using the address formed from this prefix (called, Designated
   Secondary Address: DSADD).  The node introduces all (or a subset) of
   the SADDs (including the DSADD) in OLSR messages and starts
   broadcasting them, enabling these addresses to be routable and
   reachable within the MANET.



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   Summary of some other characteristics:

   o  Intended for IPv6.

   o  Restricted to OLSR.

   o  It supports partition/merging.


2.1.7  Address autoconfiguration in Optimized Link State Routing
       Protocol (Adjih et al.)

   This draft [7] describes a mechanism to perform MANET-DAD by
   extending the OLSR routing protocol.  Basically, the MANET-DAD
   algorithm uses an special control packet called ``Multiple Address
   Declaration'' (MAD), that includes the node address and a node
   identifier (that must be globally unique).  This packet is broadcast
   in the network, so all the nodes receive this packet.  If a node
   receives a MAD message containing an address that matches its own
   address and a node identifier that does not, this implies that the
   address is duplicated.  To spare the channel bandwidth, it is
   proposed to send MAD packets using the MPR (Multi-Point Relay)
   flooding.

   Summary of some other characteristics:

   o  Intended to IPv6.

   o  The mechanism is specified as an extension to OLSR.


2.1.8  MANETconf: Configuration of Hosts in a Mobile Ad Hoc Network
       (Nesargi et al.)

   Nesargi et al. propose in [15] a Distributed Dynamic Host
   Configuration Protocol (DDHCP) designed to configure nodes in a
   MANET.

   It basically operates as follows: a node proposes a candidate IP
   address for assignment to a newly arriving node.  If the proposal is
   accepted by all the nodes that are part of the MANET, the proposed
   address is assigned to the newly arrived node.  Otherwise, another
   candidate IP address is chosen and the process is repeated.

   When a node (called requester) joins the MANET it broadcasts a
   request message to all its neighbours, waiting for a reply from a
   node willing to act as the initiator for the assignment of an IP
   address to the requester.  If it is the first node of the MANET (no



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   replies are received) it configures itself an IP address and the
   MANET its initialised.  If the requester receives a reply message (or
   more than one), it then selects one of the reachable nodes that
   answered as the initiator, which will be the one that performs the
   address allocation on its behalf.  All other nodes know a route to
   the initiator and can forward their responses to it.  Ultimately, the
   initiator conveys the result of the address allocation operations to
   the requester.

   The proposed protocol has some other interesting features, such as
   releasing unused IP addresses, soft state maintenance, concurrent IP
   address allocation and partition/merging support.

   Summary of some other characteristics:

   o  Intended to IPv4.

   o  It assumes (for simplicity) that the IP address block from which
      nodes are to be assigned their IP address is known in advance.

   o  Not restricted to any particular ad hoc routing solution.

   o  Intended for standalone MANETs.  Nevertheless, it seems that it
      could be used for connected MANETs.


2.1.9  Extended Support for Global Connectivity for IPv6 Mobile Ad Hoc
       Networks (Cha et al.)

   [8] describes how to provide enhanced Internet connectivity to mobile
   ad-hoc networks.  The protocol is devised as an extension to AODV,
   but the concept may be applicable to other proactive routing
   protocols.

   The protocol basically consists in nodes requesting global addresses
   to a gateway (GW), which assigns a non-used address to the requesting
   node.  More details can be found in [8].

   Summary of some other characteristics:

   o  Intended to IPv6.

   o  Although the protocol is devised as an extension to AODV, it could
      be applicable to any proactive routing protocol.







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2.2  Conflict-free allocation mechanisms

   These methods assume that the addresses that are delegated are not
   being used by any node in the network.  This can be achieved, for
   example, by ensuring that the nodes that participate in the
   delegation have disjoint address pools.  In this way, there is no
   need of performing MANET-DAD.  An example of a conflict-free
   allocation general mechanism is shown in Figure 2.

            ------------------------------
            |                            |
            |          Pool of           |
            |         addresses          |
            |                            |
            -----+------------------------
                 |
             (1) | Node x (first node) picks the
                 | pool and configures its interfaces
                 |
                -+---                     -----
                |   | (3) Node y requests |   | (2) Node y joins
                | x |<--------------------| y |     the network
                |   |     some addresses  |   |
                -+---                     ---+-
                 |  \                     ^  |
                 |   \___________________/   |
                 |                           |
                 |   (4) Node x gives half   |
                 |       its pool of         |
                 |       addresses           |
                 |                           |
          -------+-------        ------------+--
          |             |        |             |
          |   Pool of   |        |   Pool of   |
          |   Node x    |        |   Node y    |
          |             |        |             |
          ---------------        ---------------

             (5) Both Node x and Node y      ?
                 can give addresses to     --+--
                 new arriving nodes that   |   |
                 request IP addresses      | z |
                                           |   |
                                           -----

                 Figure 2: Conflict-free allocation scheme





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2.2.1  Prophet Address Allocation for Large Scale MANETs (Zhou et al.)

   The mechanism defined in [18] is based on using an stateful function
   f(n) (where the initial state of f(n) is the seed) that produces as
   output an integer sequence of numbers.  Different seeds lead to
   different sequences, and the state of f(n) is updated.  This function
   can be used to derive IP addresses if it satisfies certain
   properties:

   o  The interval between two occurrences of the same number in a
      sequence is extremely long.

   o  The probability of more than one occurrence of the same number in
      a limited number of different sequences initiated by different
      seeds during some interval is extremely low.

   This properties may be satisfied if the space of available addresses
   is large, so it is easier to achieve in IPv6 than in IPv4.

   The mechanism basically work as follows: the first node chooses a
   random number as its IP address and uses a random or default state
   value as the seed for its f(n).  When a different node approaches,
   the first node uses its f(n) to obtain a different number and state.
   This number is used by the second node as its IP address, and the
   state is used as the seed for its f(n).  After that both nodes are
   able to assign IP addresses to other nodes.

   Summary of some other characteristics:

   o  Suitable for IPv4 and IPv6.

   o  Not restricted to any particular ad hoc routing solution.

   o  It supports partition/merging.


2.2.2  Self-Configuring Networks. DRCP and DAAP (McAuley et al.)

   In [19] the Dynamic Registration and Configuration Protocol (DRCP)
   and Dynamic Address Allocation Protocol (DAAP) are described.  These
   two protocols together may provide autoconfiguration to entire
   networks.  The authors state that their proposal is concerned with
   registration and autoconfiguration in 'quasi-dynamic networks'.  They
   define quasi-dynamic networks as those that require rapid deployment,
   but are relatively stable except for some incremental deployment and
   losses.

   Their goal is to allow all hosts and routers in the quasi-dynamic



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   domain to be plug and play, being the only restriction on the number
   of nodes the size of the address space (paper focused in IPv4, but
   solution would be also applicable to IPv6).

2.2.2.1  DRCP

   The Dynamic Registration and Configuration Protocol (DRCP) is heavily
   based on DHCP, but aims at being faster and more suited to the quasi-
   dynamic network scenario (e.g., by using efficiently the scarce
   wireless bandwidth).

   DRCP adds some new messages to DHCP.  It uses a client-server model.
   The server sends periodic ADVERTISEMENT messages.  The client
   transmits DISCOVER (or REQUEST) messages - requesting an IP address -
   until it gets an OFFER message - that carries a configuration message
   - (or ACK).  The server keeps retransmitting the OFFER (or ACK)
   message until it gets an ACCEPT or DECLINE message.

2.2.2.2  DAAP

   The Dynamic Address Allocation Protocol (DAAP) is a new protocol that
   basically distributes address-pools among nodes in a domain.  This
   allows any node to act as a new DRCP server, using a part of the
   addresses of the pool for allocation to new arriving nodes.  The
   protocol is very simple and defines only two messages: one to request
   an address pool (POOL_REQUEST) and one to convey the response
   (POOL_RESPONSE).

   The combination of DRCP and DAAP allows a rapid configuration of IP
   addresses in a network.  Basically the first node has configured, by
   some other means (e.g., statically), an address pool.  It then
   configures its interfaces using DRCP.  After that, it starts sending
   DRCP ADVERTISEMENT messages.  When a new node arrives, and discover
   the server, it configures an IP address in the interface that
   connects to that server, using DRCP.  Then, it requests an address
   pool using DAAP.  The initial node sends to the new node half of its
   address pool.  The new node configures then the rest of its
   interfaces using DRCP and may start acting as a new DRCP server on
   the network.

   Summary of some other characteristics:

   o  Intended to IPv4, but it could be applicable to IPv6.

   o  Aimed for quasi-dynamic networks, so it is not a general MANET IP
      address autoconfiguration solution.





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   o  Not restricted to any particular ad hoc routing solution, as it is
      not even restricted to ad hoc.


2.2.3  Autoconfiguration, Registration, and Mobility Management for
       Pervasive Computing. DDCP (Misra et al.)

   The Dynamic Configuration Distribution Protocol (DDCP) proposed in
   [20] is quite similar to the DAAP proposal [19].  Actually DDCP just
   automates the distribution of address pools to other nodes, that can
   then run any link configuration protocol (LCP), like DHCP or DRCP to
   configure addresses of incoming nodes.  The main difference with DAAP
   is that DDCP provides also autoconfiguration of additional IP-related
   parameters and capabilities, such as the location of DNS and SIP
   servers.  Another difference is that DDCP explicitly states that
   nodes, when requested, split their address pools into two parts,
   forwarding the second part to the requester node (in DAAP, there is
   not such detail about how the address pool has to be split, although
   in the examples, the pool is halved in two as well).

   Summary of some other characteristics:

   o  Intended to IPv4.

   o  Not restricted to any particular ad hoc routing solution, as it is
      not even restricted to ad hoc.


2.2.4  IP Address Assignment in a Mobile Ad Hoc Network (Mohsin et al.)

   The solution described in [21] is based on the concept of binary
   split, but address also the issue of partitioning, merging and abrupt
   departure of nodes from the MANET.  This is done by associating a
   Partition ID, which should be universally unique, to every partition.
   If a MANET gets partitioned into two, as long as they do not run out
   of IP addresses, they do not generate new Partition IDs, so if they
   merge later there is no duplicated address.  If one of the portions
   runs out of addresses, it generates a new Partition ID and acquires
   the IP address block that belongs to the other portion.  If this
   portions merge later (the case of two MANETs that had not been
   previously part of the same MANET is analogous), one of the portions
   has to give up its IP address block.  In this mechanism, the one with
   the larger address block is the one that gives up it addresses and
   has to acquire a new one.

   Summary of some other characteristics:





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   o  Suitable for IPv4 and IPv6.

   o  Not restricted to any particular ad hoc routing solution.

   o  It supports partition/merging.


2.2.5  An address assignment for the automatic configuration of mobile
       ad hoc networks (Tayal et al.)

   The solution described in [22] is very similar to the previous one
   ([21]), sharing the idea (also used by others) of having nodes
   assigning half of their address pools to newly arrived nodes that
   request IP addresses.

   Summary of some other characteristics:

   o  Suitable for IPv4 and IPv6.

   o  Not restricted to any particular ad-hoc routing solution.

   o  It supports partition/merging.


2.2.6  Simple MANET Address Autoconfiguration (Clausen et al.)

   This draft [9] defines a simple autoconfiguration mechanism, based on
   partitioning a local scoped address space among the nodes of the
   MANET.  This address space is used for assigning ``temporary
   addresses'' (also called ``local'').  The nodes periodically signals
   their address space in ADDR_BEACON messages, in order to detect and
   solve conflicts.

   When a new arriving node wants to configure a global IPv6 address, it
   first has to acquire a temporary address.  To do this, it first
   listens to ADDR_BEACON messages sent by those nodes that may act as
   'configuring nodes'.  The new node selects a node as its configuring
   node and sends to it an ADDR_CONFIG message in order to request a
   local address.  The configuring node, upon the reception of this
   request, assigns a local address to the new node and signals this
   assignment trough another ADDR_CONFIG message (additionally, this
   address is marked as ``used'' in the ADDR_BEACON messages it sends
   afterwards).  Once the new node has configured a local address it can
   start participating in the routing protocol and it can start
   acquiring a global IP address.  The configuring node is in charge of
   acting on behalf of the new node, and different mechanisms may be
   used, as acting as a proxy DHCP server and transmitting a request to
   an existing DHCP server or consulting the topology table (in case of



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   proactive routing protocols as OLSR) and picking an non-used address.

   Summary of some other characteristics:

   o  Intended to IPv6.

   o  The mechanism is specified as an extension to OLSR, but nothing
      prevents the mechanism to work with other routing protocols.


2.2.7  Gateway and address autoconfiguration for IPv6 adhoc networks
       (Jelger et al.)

   This solution [3], combines the problem of IP address configuration
   and gateway discovery (needed to obtain global connectivity).

   Basically, each gateway (it could be more than one in the same MANET)
   sends periodically GW_INFO messages to its one-hop neighbours.  This
   information includes its IPv6 global address and prefix length.  If a
   receiving node decides to use this information, it has to forward
   this message (updating some fields) to its neighbours (this leads to
   the so-called 'prefix continuity': any node A that selected a given
   prefix P has at least one neighbour on its path to the selected
   gateway G).  The prefix information obtained from these GW_INFO
   messages is used in the creation of the global IPv6 address of the
   node, by adding the EUI64 of the interface from which the GW_INFO
   message has been received (padding with zeros if needed). [3] states
   that the MANET-DAD procedure must not be performed.

   Summary of some other characteristics:

   o  Intended to IPv6.

   o  Not restricted to any particular ad hoc routing solution.

















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3.  Conclusions

   This draft has presented some of the solutions for the problem of the
   autoconfiguration of IP addresses in Mobile Ad Hoc Networks that have
   been proposed so far.  This document tries to provide a reference
   that could help in the discussions of the AUTOCONF group, just
   presenting the already available mechanisms that tackle the
   autoconfiguration problem.

   A detailed analysis of the characteristics (i.e., complexity,
   communication overhead, latency, scalability, network requirements,
   etc.) of each proposal, as well as a more extensive problem
   statement, are not included yet.






































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4.  Security Considerations

   This documents does not raise any security issue.  The possible
   security considerations of the described proposals have not been
   addressed in this I-D.














































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5.  References

5.1  Normative References

   [1]   Perkins, C., Wakikawa, R., Malinen, J., Belding-Royer, E., and
         Y. Suan, "IP Address Autoconfiguration for Ad Hoc Networks",
         draft-ietf-manet-autoconf-01.txt (work in progress),
         November 2001.

   [2]   Wakikawa, R., "Global Connectivity for IPv6 Mobile Ad Hoc
         Networks", draft-wakikawa-manet-globalv6-03 (work in progress),
         October 2003.

   [3]   Jelger, C., "Gateway and address autoconfiguration for IPv6
         adhoc networks", draft-jelger-manet-gateway-autoconf-v6-02
         (work in progress), April 2004.

   [4]   Jeong, J., "Ad Hoc IP Address Autoconfiguration",
         draft-jeong-adhoc-ip-addr-autoconf-04 (work in progress),
         February 2005.

   [5]   Jeong, J., "Ad Hoc IP Address Autoconfiguration for AODV",
         draft-jeong-manet-aodv-addr-autoconf-01 (work in progress),
         July 2004.

   [6]   Ruffino, S. and P. Stupar, "Automatic configuration of IPv6
         addresses for nodes in a MANET with multiple  gateways",
         draft-ruffino-manet-autoconf-multigw-00 (work in progress),
         June 2005.

   [7]   Laouiti, A., "Address autoconfiguration in Optimized Link State
         Routing Protocol", draft-laouiti-manet-olsr-address-autoconf-00
         (work in progress), February 2005.

   [8]   Cha, H., Park, J., and H. Kim, "Extended Support for Global
         Connectivity for IPv6 Mobile Ad Hoc Networks",
         draft-cha-manet-extended-support-globalv6-00 (work in
         progress), October 2003.

   [9]   Clausen, T. and E. Baccelli, "Simple MANET Address
         Autoconfiguration", draft-clausen-manet-address-autoconf-00
         (work in progress), February 2005.

   [10]  Jeong, J., "Requirements for Ad Hoc IP Address
         Autoconfiguration", draft-jeong-manet-addr-autoconf-reqts-04
         (work in progress), February 2005.

   [11]  Ruffino, S., Stupar, P., and T. Clausen, "Autoconfiguration in



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         a MANET: connectivity scenarios and technical issues",
         draft-ruffino-manet-autoconf-scenarios-00 (work in progress),
         October 2004.

   [12]  Ruffino, S., "Connectivity Scenarios for MANET",
         draft-ruffino-conn-scenarios-00 (work in progress),
         February 2005.

   [13]  Wakikawa, R., "IPv6 Support on Mobile Ad-hoc Network",
         draft-wakikawa-manet-ipv6-support-00 (work in progress),
         February 2005.

5.2  Informative References

   [14]  Suan, Y., Belding-Royer, E., and C. Perkins, "Internet
         Connectivity for Ad hoc Mobile Networks", International Journal
         of Wireless Information Networks special issue on 'Mobile Ad
         Hoc Networks (MANETs): Standards, Research, Applications' ,
         2002.

   [15]  Nesargi, S. and R. Prakash, "MANETconf: Configuration of Hosts
         in a Mobile Ad Hoc Network", IEEE INFOCOM 2002 , 2002.

   [16]  Weniger, K. and M. Zitterbart, "IPv6 Autoconfiguration in Large
         Scale Mobile Ad-Hoc Networks", European Wireless 2002 , 2002.

   [17]  Vaidya, N., "Weak Duplicate Address Detection in Mobile Ad Hoc
         Networks", MOBIHOC'02 , 2002.

   [18]  Zhou, H., Ni, L., and M. Mutka, "Prophet Address Allocation for
         Large Scale MANETs", Proceedings of INFOCOM 2003 , 2003.

   [19]  McAuley, A. and K. Manousakis, "Self-Configuring Networks",
         21st Century Military Communications Conference Proceedings ,
         2000.

   [20]  Misra, A., Das, S., McAuley, A., and S. Das,
         "Autoconfiguration, Registration, and Mobility Management for
         Pervasive Computing", IEEE Personal Communications , 2001.

   [21]  Mohsin, M. and R. Prakash, "IP Address Assignment in a Mobile
         Ad Hoc Network", MILCOM 2002 , 2002.

   [22]  Tayal, A. and L. Patnaik, "An address assignment for the
         automatic configuration of mobile ad hoc networks", Personal
         Ubiquitous Computing , 2004.

   [23]  Zhou, Z. and A. Seneviratne, "A Survey of Zero and Auto



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         Configurations for Wireless Networks", ATNAC 2003 , 2003.


Authors' Addresses

   Carlos J. Bernardos
   Universidad Carlos III de Madrid
   Av. Universidad, 30
   Leganes, Madrid  28911
   Spain

   Phone: +34 91624 8859
   Email: cjbc@it.uc3m.es


   Maria Calderon
   Universidad Carlos III de Madrid
   Av. Universidad, 30
   Leganes, Madrid  28911
   Spain

   Phone: +34 91624 8780
   Email: maria@it.uc3m.es




























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