Internet-Draft J. Jeong (ed.) ETRI/University of Minnesota Expires: August 2005 18 February 2005 Requirements for Ad Hoc IP Address Autoconfiguration draft-jeong-manet-addr-autoconf-reqts-04.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. 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. This Internet-Draft will expire on August 17, 2005. Copyright Notice Copyright (C) The Internet Society (2005). All Rights Reserved. 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. The nodes in ad hoc network need Jeong, et al. Expires - August 2005 [Page 1] Internet-Draft MANET Address Autoconf Requirements February 2005 to have the capability to maintain or share all the resources of the network in a distributed fashion. One of the most important resources is the set of IP addresses configured with an addressing scheme. When a new node joins an ad hoc network, it has to be assigned a unique IP address or autoconfigure its own 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 mobile nodes with such an IP address autoconfiguration in distributive environments. 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 [3]. Table of Contents 1. Introduction..................................................2 2. Terminology...................................................3 3. Scenarios of Ad Hoc IP Address Autoconfiguration..............3 3.1. Join and Departure of Mobile Nodes.......................3 3.2. Network Partitioning and Merging.........................4 3.3. Internet Connectivity....................................5 4. Requirements for Ad Hoc IP Address Autoconfiguration..........5 5. IPv6 Considerations...........................................7 6. IANA Considerations...........................................7 7. Security Considerations.......................................8 8. Open Issues...................................................8 9. Acknowledgements..............................................9 10. Normative References.........................................9 11. Informative References.......................................9 12. Authors' Addresses..........................................10 13. Intellectual Property Statement.............................11 Full Copyright Statement........................................12 Acknowledgement.................................................12 1. Introduction IP address configuration is a prerequisite for all the IP networking. In ad hoc networks, such a configuration should be performed in every mobile node, either manually or automatically. For convenience sake, automatic configuration is needed in mobile ad hoc network. In ad hoc networks, having dynamic network topology and being multi- hop, the current automatic address configuration schemes used in the Jeong, et al. Expires - August 2005 [Page 2] Internet-Draft MANET Address Autoconf Requirements February 2005 Internet are difficult to adopt, such as DHCP and IPv6 stateless address autoconfiguration that are based on wired network. Also, mobile ad hoc network is a kind of an unadministered network where there exists no network administrator who provides network configuration information for users. In this environment, a mobile node needs to be able to self-configure its IP address by itself. This document specifies the requirements for IP address autoconfiguration, considering mobile ad hoc network where there happen the network partitioning and merging frequently. Also, it considers the addressing for the global connectivity between the mobile ad hoc network and Internet. 2. 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. 3. Scenarios of Ad Hoc IP Address Autoconfiguration 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 needs to be 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 SHOULD support timely autoconfiguration of IP address for a mobile node. o Mobile nodes using address autoconf protocol MUST verify the uniqueness of IP addresses allocated when rebooting or moving into a new network. o Address autoconf protocol MAY support mechanisms to probe Jeong, et al. Expires - August 2005 [Page 3] Internet-Draft MANET Address Autoconf Requirements February 2005 whether a mobile node moves into another MANET. o Address autoconf protocol 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. Implication: o The information needed to autoconfigure IP address must be collected or predefined in the MANET. 3.2. Network Partitioning and Merging Inevitably, a single MANET will be divided into two or more MANET partitions according to the movement of mobile nodes. 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 or more nodes in the merged network may happen to have the same address and as a result address conflict may occur potentially. Therefore, this network merging must be perceived by mobile node. In the case where some address conflicts exist, such conflicts should be resolved. Implication: o The detection and resolution of address conflicts is regarded as indispensable in address autoconf protocol operation. Requirements: o Ad hoc address autoconf protocol SHOULD detect and resolve address conflicts in a timely manner and on an ongoing basis. o Ad hoc address autoconf protocol SHOULD allow conflicted address to be 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 in a way that minimizes the probability that two or more nodes will have the same address if the autoconf protocol is stateful. o In order to detect duplicate addresses while taking part in routing, ad hoc address autoconf protocol MAY get the aid of ad Jeong, et al. Expires - August 2005 [Page 4] Internet-Draft MANET Address Autoconf Requirements February 2005 hoc routing protocol. Through address autoconf protocol that detects and resolves the conflicts on an ongoing basis, mobile nodes will benefit from preventing packets from being misrouted due to duplicate addresses, and can be provided consistent routing. 3.3. Internet Connectivity A mobile node may want to communicate with a node placed in the Internet. In such a case, an Internet gateway providing the Internet connectivity can exist in the MANET [4]. Requirements: o MANET SHOULD be connected with one or more gateways providing the information for the global connectivity to the Internet, such as gateway address, global network prefix and host IP address for mobile node. o Mobile node that desires Internet connectivity SHOULD be assigned a globally routable IP address from gateway or be able to autoconfigure its own IP address that is globally unique. o Mobile node MAY use its MANET address to communicate with some nodes in the same MANET, and use its global address to communicate with some nodes in the Internet. o Mobile node MAY use its global address such as MIP home address and care-of address to communicate with some nodes in the same MANET [9][10]. Implication: o For host DNS name resolution, DNS information, such as the address of recursive DNS server, may be delivered to mobile node 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 network 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. The sufficient information should be provided by an ad hoc address autoconf protocol Jeong, et al. Expires - August 2005 [Page 5] Internet-Draft MANET Address Autoconf Requirements February 2005 to allow IP packets to be sent to a unicast destination IP address within a connected MANET partition, consisting of multi hops. The following requirements are derived from the scenarios of Section 3. Requirements: An ad hoc address autoconf protocol o MUST configure an appropriate netmask or network prefix information, manually or automatically. o SHOULD be capable of providing IP address for mobile node in a reasonable delay. o SHOULD be capable of discovering whether an IP address is currently being used by other nodes in a limited range of network. o SHOULD detect and resolve IP address conflicts in a timely manner and on an ongoing basis. o MUST timely verify the uniqueness of IP addresses autoconfigured when rebooting or moving into a new network. o SHOULD be able to deal with address conflict due to manual address configuration. o SHOULD minimize the influence of autoconf traffic on the ongoing MANET communication performance. For example, when some MANET partitions merge, there may happen broadcast storm by autoconf traffic for duplicate address detection. 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. A free address should be selected by using the busy address information obtained from the routing protocol when a new address is given to a new node without address. o MAY get the aid of ad hoc routing protocol so as to detect duplicate addresses while taking part in routing. This is an on-going Duplicate Address Detection (DAD) requirement. o SHOULD minimize the modification of existing MANET routing protocol for the support of ad hoc address autoconf. o MAY allocate IP addresses to mobile nodes in a way that minimizes the probability that two or more nodes will have the same address in the same MANET partition if the autoconf protocol is stateful. Jeong, et al. Expires - August 2005 [Page 6] Internet-Draft MANET Address Autoconf Requirements February 2005 o SHOULD minimize the damage, such as loss of delivered packets, due to address replacement. o SHOULD support the survivability of upper-layer sessions, such as TCP, in order to allow the sessions to continue to be maintained. o SHOULD support the reclamation of addresses unused any more if the autoconf protocol is stateful. A unique IP address is assigned to each mobile node only while it 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 reuse the released IP addresses for another node, minimizing the possibility of address conflict. o SHOULD obtain from one or more gateways the information for the global connectivity to the Internet, such as gateway address, global network prefix and host IP address for mobile node. o SHOULD allocate to a mobile node desiring Internet connectivity a globally routable IP address from some gateways or allow it to autoconfigure its own IP address that is globally unique by providing network prefix for it. o MAY let mobile node use its MANET address to communicate with some nodes in the same MANET, and use its global address to communicate with some nodes in the Internet. o MAY allow mobile node to use its global address such as MIP home address and care-of address to communicate with some nodes in the same MANET [9][10]. 5. IPv6 Considerations IPv6 provides a mechanism that allows a host to generate a link-local IP address according to IPv6 stateless address autoconfiguration [5][6]. Thus, this mechanism can be extended to be suitable for MANET [7] or another can be redesigned separately [8]. Also, it is necessary to discuss how to use IPv6 link-local address in a MANET which is logically one subnet consisting of multiple links since the usage of IPv6 link-local address is limited in a link. 6. IANA Considerations A unique local address should be used for MANET. For such a unique local address allocation or configuration, some MANET network prefixes are needed [7][8][11]. For IPv6 address, a link-local address may be kept as it is in IPv6. Jeong, et al. Expires - August 2005 [Page 7] Internet-Draft MANET Address Autoconf Requirements February 2005 7. Security Considerations Ad hoc IP address autoconf protocol SHOULD 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: If the security is needed in address autoconf, 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 make sure that only authorized nodes are configured to have working addresses and granted the access to network resources. Implication: o A node SHOULD be able to prove at every moment, its membership of the network if the autoconf protocol is stateful. o If there remain free addresses on the chosen subnet, the autoconf protocol SHOULD be able to always allot an address to a requesting node. 8. 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. Jeong, et al. Expires - August 2005 [Page 8] Internet-Draft MANET Address Autoconf Requirements February 2005 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? We can use ad hoc routing protocol to detect address conflict. o Should we consider address conflict in the overlapped MANETs with two or more ad hoc routing protocols, such as AODV and OLSR? o Should we consider the possibility to make two different autoconf protocols coexist in the same network (e.g., after the mergence of two networks)? o Should we consider the coexistence of the address autoconf protocol using authentication mechanism and that not using authentication mechanism? 9. Acknowledgements This draft has greatly benefited from inputs by Charles E. Perkins and Kilian Weniger. The authors appreciate their contributions. 10. Normative References [1] S. Bradner, "Intellectual Property Rights in IETF Technology", RFC 3668, February 2004. [2] S. Bradner, "IETF Rights in Contributions", RFC 3667, February 2004. [3] S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 11. Informative References [4] R. Wakikawa et al., "Global connectivity for IPv6 Mobile Ad Hoc Networks", draft-wakikawa-manet-globalv6-03.txt, November 2002, Work in Progress. [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. Jeong, et al. Expires - August 2005 [Page 9] Internet-Draft MANET Address Autoconf Requirements February 2005 [7] C. Perkins et al., "IP Address Autoconfiguration for Ad Hoc Networks", draft-ietf-manet-autoconf-01.txt, November 2001, Work in Progress. [8] J. Jeong et al., "Ad Hoc IP Address Autoconfiguration", draft-jeong-adhoc-ip-addr-autoconf-04.txt, February 2005, Work in Progress. [9] C. Perkins, "IP Mobility Support", RFC 2002, October 1996. [10] D. Johnson, C. Perkins and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [11] R. Hinden and B. Haberman, "Unique Local IPv6 Unicast Addresses", draft-ietf-ipv6-unique-local-addr-09.txt, January 2004, Work in Progress. 12. Authors' Addresses Jaehoon Paul Jeong, Editor ETRI/University of Minnesota at Twin Cities 117 Pleasant Street SE Minneapolis, MN 55455 USA Phone: +1 651 587 7774 EMail: jjeong@cs.umn.edu Jung-Soo Park ETRI / PEC 161 Gajeong-dong, Yuseong-gu Daejeon 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 Phone: +81 25 262 7446 EMail: mase@ie.niigata-u.ac.jp Youn-Hee Han Samsung Advanced Institute of Technology Jeong, et al. Expires - August 2005 [Page 10] Internet-Draft MANET Address Autoconf Requirements February 2005 111, Suwon 440-600 Korea Phone: +82 31 280 9577 EMail: yh21.han@samsung.com 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 13. Intellectual Property Statement The following intellectual property notice is copied from RFC 3668, Section 5. The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required Jeong, et al. Expires - August 2005 [Page 11] Internet-Draft MANET Address Autoconf Requirements February 2005 to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Full Copyright Statement The following copyright notice is copied from RFC 3667, Sections 5.4 and 5.5. It describes the applicable copyright for this document. Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Jeong, et al. Expires - August 2005 [Page 12]