Internet Draft Jaehoon Paul Jeong Jung-Soo Park ETRI Kenichi Mase Niigata University Youn-Hee Han SAMSUNG Sait Badis Hakim LRI laboratory Jean-Marie Orset Telecom INT draft-jeong-manet-addr-autoconf-reqts-01.txt Expires: August 2004 14 February 2004 Requirements for Ad Hoc IP Address Autoconfiguration Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 except that the right to produce derivative works is not granted [1]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract Ad hoc network has no built-in infra-structure for communication among mobile nodes and operates in a stand-alone fashion, or may be connected to the public Internet. All the nodes in ad hoc network have the capability to maintain all the resources of the network in a distributed fashion. One of the most important resources is the set Jeong, et al. Expires - August 2004 [Page 1] Internet-Draft MANET Address Autoconf Requirements February 2004 of IP addresses configured with an addressing scheme. When a new node joins a network, it has to be assigned an IP address as part of its initialization. Since ad hoc network's topology may change unpredictably, it is important to provide a resilient method for providing IP address autoconfiguration. This document specifies the requirements for IP address autoconfiguration in ad hoc networks which have dynamic network topology. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [2]. Table of Contents 1. Terminology...................................................2 2. Introduction..................................................2 3. Scenarios.....................................................3 3.1 Join and Departure of Mobile Nodes........................3 3.2 Network Partitioning and Merging..........................4 3.3 Internet Connectivity.....................................4 4. Requirements for Ad Hoc IP Address Autoconfiguration..........5 5. IPv6 Considerations...........................................6 6. Security Considerations.......................................6 7. Open Issues...................................................7 8. Copyright.....................................................8 9. References....................................................8 10. Authors' Addresses...........................................9 1. Terminology Two new terms are defined below: Mobile Ad Hoc Network (MANET) A network where mobile nodes can communicate with one another without preexisting communication infrastructure such as base station or access point. Autoconfiguration (Autoconf) Automatic configuration or self-configuration. 2. Introduction IP address configuration is a prerequisite for all the IP networking. In ad hoc networks, such configuration should be performed in every Jeong, et al. Expires - August 2004 [Page 2] Internet-Draft MANET Address Autoconf Requirements February 2004 mobile node, either manually or automatically. For convenience sake, automatic configuration is needed in MANET [3]. In ad hoc networks, having dynamic network topology and being multi- hop, the current automatic address configuration schemes used in the Internet are difficult to adopt, such as DHCP and IPv6 stateless address autoconfiguration. Also, MANET is an unadministered network where there exists no network administrator who provides network configuration information to users. In this environment, mobile node should be able to self-configure its IP address. This document specifies the requirements for IP address autoconfiguration, considering MANET where there happen the network partitioning and merging very often. Also, it considers the global connectivity between the MANET and Internet. 3. Scenarios There are the scenarios that should be considered in ad hoc IP address autoconfiguration. Address autoconf protocol needs to deal with the following aspects of the ad hoc environment. 3.1 Join and Departure of Mobile Nodes When a mobile node joins a new MANET, an unused IP address is allocated to or configured in the mobile node. When the mobile node leaves the MANET, its address may become free for another. Requirements: o Address autoconf protocol MUST support timely autoconfiguration of IP address for a mobile node. o Address autoconf protocol MAY support mechanisms to probe whether a mobile node moves into another MANET. o Mobile nodes using address autoconf protocol MUST validate allocated IP addresses when powering up or rebooting. o Mobile nodes using address autoconf protocol MAY validate allocated IP addresses when moving into a new network. Implication: o The information needed to autoconfigure IP address must be collected or predefined in the MANET. Jeong, et al. Expires - August 2004 [Page 3] Internet-Draft MANET Address Autoconf Requirements February 2004 3.2 Network Partitioning and Merging Inevitably, a single MANET will be divided into two or more MANET partitions. Also, these two or more MANET partitions, using the same address autoconf protocol, will be connected together, creating a single merged MANET. Prior to the merging, each partition has independently allocated or configured addresses. After merging, two nodes in the merged network may end up using the same address, thus potentially creating address conflict. Therefore, this network merging must be perceived by mobile node. If address conflicts exist, they should be resolved. Implication: o The detection and resolution of address conflicts are the indispensable part of address autoconf protocol operation. Requirements: o Ad hoc address autoconf protocol MUST detect and resolve address conflicts in a timely manner and on an ongoing basis. o Ad hoc address autoconf protocol MUST allow conflicted address replaced with another. o Ad hoc address autoconf protocol SHOULD minimize the damage, such as loss of delivered packets, due to address replacement. o Addresses SHOULD be allocated or autoconfigured in a way that minimizes the probability that two or more nodes will have the same address. o In order to detect duplicate addresses, ad hoc address autoconf protocol MAY get the aid of ad hoc routing protocol. Through address autoconf protocol that detects and resolves the conflicts on an ongoing basis, mobile nodes will benefit from preventing misrouting due to duplicate addresses, and can be provided consistent routing. 3.3 Internet Connectivity A mobile node can want to communicate with a node placed in the Internet. In such case, an Internet gateway providing the Internet connectivity can exist in the MANET [4]. Requirements: Jeong, et al. Expires - August 2004 [Page 4] Internet-Draft MANET Address Autoconf Requirements February 2004 o MANET MAY allow configuration of zero or more gateways for the global connectivity to the Internet. Implication: o For host DNS name resolution, DNS information, such as the address of recursive DNS server, should be delivered together with gateway information. 4. Requirements for Ad Hoc IP Address Autoconfiguration Ad hoc IP address autoconfiguration always includes the configuration of an IP address and netmask (or prefix information in IPv6); it may include some routing information (such as default route or Internet gateway), considering the global connectivity to the Internet. IP address autoconfiguration must take place before an IP packet can be sent from one node to another. This section requires that sufficient information be provided by an ad hoc address autoconf protocol to allow IP packets to be sent to a unicast destination IP address within a connected MANET partition, consisting of multi hops. Requirements: An ad hoc address autoconf protocol o MUST configure an appropriate netmask or prefix information. o MUST allocate or autoconfigure unique IP addresses within an connected MANET partition. o MAY allow configuration of zero or more gateways for the global connectivity to the Internet. The following requirements are derived from applying Section 3.1 and Section 3.2 to IP interface configuration. Requirements: An ad hoc address autoconf protocol o MUST be capable of providing IP address in a reasonable delay. o MUST be capable of discovering whether an IP address is currently in use. o MUST detect and resolve IP address conflicts in a timely manner and on an ongoing basis. o MUST timely validate autoconfigured IP addresses when powering up or rebooting. Jeong, et al. Expires - August 2004 [Page 5] Internet-Draft MANET Address Autoconf Requirements February 2004 o MAY timely validate autoconfigured IP addresses when moving into a new network. o SHOULD be able to process the address conflict due to manual address configuration. o SHOULD minimize the influence of autoconf traffic on the ongoing MANET communication performance. o MAY get the aid of ad hoc routing protocol so as to detect duplicate addresses. o SHOULD minimize the modification of existing MANET routing protocol. o MAY get the aid of ad hoc routing protocol so as to minimize the probability that two or more nodes will have the same address. o When MANET partitions merge, ad hoc address autoconf protocol SHOULD be performed in the way it avoids congestion caused by messages sent for the purpose of duplicate address detection. o SHOULD minimize the damage, such as loss of delivered packets, due to address replacement for supporting the survivability of upper-layer sessions, such as TCP. o SHOULD allocate IP addresses to mobile nodes in a way that minimizes the probability that two or more nodes will have the same address. o The reclamation of the addresses unused any more MAY be considered. An IP address is assigned only for the duration the node stays in the network. When the node departs the network, its IP address MAY become available for assignment to other nodes. In this case, address autoconf protocol SHOULD NOT immediately reuse the released IP addresses as soon as they become available, in order to reduce address conflicts. 5. IPv6 Considerations IPv6 provides a mechanism that allows a host to generate a link-local IP address Autoconfiguration [5][6]. Thus, this mechanism can be extended to be suitable for MANET [7] or another can be redesigned separately [8][9]. Also, it is necessary to discuss how to use IPv6 link-local address in a MANET which is logically one subnet. 6. Security Considerations Jeong, et al. Expires - August 2004 [Page 6] Internet-Draft MANET Address Autoconf Requirements February 2004 Ad hoc IP address autoconf protocol MUST NOT be any less secure than current IETF-Standard protocols related to IP address autoconfiguration. Because of their lack of infrastructure and their strong mobility, mobile ad hoc networks are vulnerable to lots of security attacks. Especially, address autoconf protocol is likely to be a good target for attackers. For example, it can be the victim of Denial of Service attacks in which a malicious node monopolizes all the addresses or sends the response messages to create address conflicts in the network. Consequently, an ad hoc IP address autoconf protocol SHOULD, as much as possible, prevent such attacks. Requirements: An ad hoc address autoconf protocol o SHOULD prevent malicious nodes from monopolizing all addresses of a network. o SHOULD prevent malicious nodes from voluntarily creating IP conflicts. o SHOULD be able to identify nodes which belong to the network. o SHOULD make sure that only authorized nodes are configured and granted access to network resources. Implication: o A node SHOULD be able to prove at every moment, its membership of the network. 7. Open Issues There are some open issues about ad hoc address autoconfiguration as follows: o Is there any need to categorize requirements into some classes? Most of the ad hoc address autoconf protocols proposed until now can be categorized into two classes: a) Stateless address autoconf protocol and b) Stateful address autoconf protocol. We need to discuss if we should specify the respective requirements according to each class. o Should we make ad hoc address autoconf protocol completely independent of ad hoc routing protocol or able to get the aid of ad hoc routing protocol? o Should we consider address conflict in the overlapped MANETs with Jeong, et al. Expires - August 2004 [Page 7] Internet-Draft MANET Address Autoconf Requirements February 2004 two or more ad hoc routing protocols? o Should we consider the coexistence of the address autoconf protocol using authentication mechanism and that not using authentication mechanism? 8. Copyright The following copyright notice is copied from RFC 2026 [Bradner, 1996], Section 10.4, and describes the applicable copyright for this document. Copyright (C) The Internet Society July 12, 2001. All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assignees. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 9. References [1] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [3] A. Williams, "Requirements for Automatic Configuration of IP Jeong, et al. Expires - August 2004 [Page 8] Internet-Draft MANET Address Autoconf Requirements February 2004 Hosts", draft-ietf-zeroconf-reqts-12.txt, September 2002. [4] Ryuji Wakikawa et al., "Global connectivity for IPv6 Mobile Ad Hoc Networks", draft-wakikawa-manet-globalv6-01.txt, July 2002. [5] T. Narten, E. Nordmark and W. Simpson, "Neighbour Discovery for IP version 6", RFC 2461, December 1998. [6] S. Thomson and T. Narten, "IPv6 Stateless Address Autoconfiguration", RFC 2462, December 1998. [7] Charles E. Perkins, Jari T. Malinen, Ryuji Wakikawa, Elizabeth M. Belding-Royer and Yuan Sun, "IP Address Autoconfiguration for Ad Hoc Networks", draft-ietf-manet-autoconf-01.txt, November 2001. [8] Jaehoon Jeong et al., "Ad Hoc IP Address Autoconfiguration", draft-jeong-adhoc-ip-addr-autoconf-02.txt, February 2004. [9] Jaehoon Jeong et al., "Ad Hoc IP Address Autoconfiguration for AODV", draft-jeong-manet-aodv-addr-autoconf-00.txt, February 2004. 10. Authors' Addresses Jaehoon Paul Jeong ETRI / PEC 161 Gajeong-dong, Yuseong-gu Daejon 305-350 Korea Phone: +82-42-860-1664 EMail: paul@etri.re.kr Jung-Soo Park ETRI / PEC 161 Gajeong-dong, Yuseong-gu Daejon 305-350 Korea Phone: +82-42-860-6514 EMail: pjs@etri.re.kr Kenichi Mase Niigata University 2-8050 Ikarashi, Niigata-shi, 950-2181 Japan Jeong, et al. Expires - August 2004 [Page 9] Internet-Draft MANET Address Autoconf Requirements February 2004 Phone: +81-25-262-7446 EMail: mase@ie.niigata-u.ac.jp Youn-Hee Han Samsung Advanced Institute of Technology 111, Suwon 440-600 Korea Phone: +82-31-280-9577 EMail: yhhan@sait.samsung.co.kr Badis Hakim LRI Laboratory University of Paris-XI 91405 Orsay cedex France Phone: 01-69-15-65-91 EMail: Hakim.Badis@lri.fr Jean-Marie Orset Institut National des Telecommunications 9, rue Charles Fourier 91 011 Evry France Phone: 01-60-76-44-75 EMail: jean-marie.orset@int-evry.fr Jeong, et al. Expires - August 2004 [Page 10]