autoconf Working Group Jaehwoon Lee Internet Draft Dongguk University Expires: January 6, 2009 Sanghynn Ahn University of Seoul Younghan Kim Soongsil University Yuseon Kim Sangeon Kim KT July 7, 2008 Address Autoconfiguration for the subordinate MANET with Multiple MBRs draft-jaehwoon-autoconf-mmbr-00.txt Status of this Memo 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 becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 December 31, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Jaehwoon Lee, et al. Expires January 6, 2009 [Page 1] Internet-Draft Address Autoconfiguration for multiple MBRs July 7, 2008 Abstract In order to allow the subordinate MANET to be connected to the external network, the MANET border router (MBR) has been defined. For providing scalability and reliability to the subordinate MANET, multiple MBRs may be deployed. One of the issues on the subordinate MANET with multiple MBRs is which network prefixes are to be advertised by MBRs. In the case when MBRs advertise different network prefixes, if a MANET node changes its default MBR to a new one, the node may have to transmit packets via non-optimal paths to keep using the existing connection to the previous MBR, or change its address by using the network prefix information from the new MBR. In the latter case, on-going sessions can be terminated because of the address change. In this draft, we define a PMIPv6 based address autoconfiguration mechanism that enables MANET nodes to operate properly when all MBRs advertise the same network prefix in the subordinate MANET. Table of Contents 1. Introduction..................................................3 2. Terminology...................................................4 3. Message format................................................4 3.1 Registration Request message..............................4 3.2 Registration Confirmation message.........................4 4. Protocol operation............................................4 5. Security Considerations.......................................6 6. IANA Considerations...........................................6 References.......................................................6 Author's Addresses...............................................7 Intellectual Property and Copyright Statements ..................8 Jaehwoon Lee, et al. Expires January 6, 2009 [Page 2] Internet-Draft Address Autoconfiguration for multiple MBRs July 7, 2008 1. Introduction The mobile ad hoc network (MANET) enables mobile nodes to communicate via multiple wireless hops without the need of any wired infrastructure. In a MANET, two nodes not within their transmission range have to deliver data to each other through other intermediate nodes. For forwarding packets destined to other nodes, each node must have the routing capability, i.e., the mechanism for establishing data delivery routes between any pair of source and destination nodes. The IETF MANET working group has defined route setup mechanisms for delivering data between MANET nodes. Especially for an ad hoc network such as the MANET, the mechanism that can allow nodes to configure their addresses autonomically is more desirable than the static address configuration mechanism since the former has less configuration and management overhead by not incurring manual intervention. The MANET can be classified into the subordinate MANET or the autonomous MANET depending on whether it is connected to the external network or not[1]. The MANET border router (MBR) which is a gateway device connecting the MANET with the external network has been defined for the subordinate MANET. As the number of nodes in the MANET increases, the amount of traffic between the MANET and the Internet increases, so the MBR gets overloaded, resulting in the overall network performance degradation. To overcome this problem, multiple MBRs can be used for the Internet connectivity [2]. Mechanisms in which each MBR advertises a different network prefix have been proposed for the MANET with multiple MBRs[3-4]. However, in these mechanisms, if a node moves to another place, it sends packets via non-optimal paths to maintain its connection to the previous MBR, or it changes its address by using the network prefix from the new MBR. In the latter case, an on-going session may get terminated because of the address change. In this draft, we define a PMIPv6 based address autoconfiguration mechanism that enables MANET nodes to operate properly in the case when all MBRs advertise the same network prefix. 2. Terminology TBD. Jaehwoon Lee, et al. Expires January 6, 2009 [Page 3] Internet-Draft connected MANET Address Autoconfiguration July 7, 2008 3. Message Format 3.1 Registration Request (RR) Message TBD 3.2 Registration Confirmation (RC) Message TBD 4. Protocol Operation MR MBR1(MAG1) MBR2(MAG2) LMA (internet) CN | | | | | |<----------| | | | |SMF message| | | | (Configure IPv6 address to MANET interface) | | |<--------->| | | | (DHCP with prefix delegation) | | | |---------->| | | | |RR message | | | | | |---------------------------------->| | | | PBU message (Create Binding Cache Entry) | | |<----------------------------------| | | | PBAck message | | |<----------| | | | |RC message | | | | |<--------->|<=================================>|<------------>| | Data packet transfer between MR and CN via MBR1 and LMA | (MR changes its default gateway from MBR1 to MBR2) | | |<---------------------------| | | | SMF message | | | |--------------------------->| | | | RR message | | | | | |----------------->| | | | | PBU message | | | | | (Update Binding Cache Entry | | | |<-----------------| | | | | PBAck message | | |<---------------------------| | | | RC message | | | |<-------------------------->|<================>|<------------>| | Data packet transfer between MR and CN via MBR2 and LMA | | | | | | Figure 1: Message exchange scenario Jaehwoon Lee, et al. Expires January 6, 2009 [Page 4] Internet-Draft Address Autoconfiguration for multiple MBRs July 7, 2008 The message exchange procedure among network components considered in this draft is shown in figure 1. The network is composed of an external network such as the global Internet, a PMIPv6 domain and a MANET. In the PMIPv6 network, there exists a local mobility anchor (LMA) which acts like a home agent (HA) within the PMIPv6 domain[5]. The MANET is connected to the PMIPv6 domain by using multiple MBRs, and each MBR acts as a mobility access gateway (MAG) within the PMIPv6 domain. To the MANET, a single network prefix is assigned, and each MBR periodically advertises the same network prefix and the IPv6 address assigned to its MANET interface by using the simplified multicast forwarding (SMF) message defined in [6]. SMF messages transmitted by MBRs have the same network prefix and the prefix length. A MANET node consists of a MANET router (MR) and (virtual) hosts[7]. A MR has a MANET interface for connecting to the MANET and a host interface for connecting to hosts. When a MR connects to the MANET for the first time, it waits for SMF messages from MBRs for some time duration which is determined by a given timer value. If the MR receives SMF messages from multiple MBRs, it selects the MBR which can be reached via the minimum number of hops. If more than one MBRs can be reached via the minimum hops, it selects one at random or based on some other metrics. Let the MBR firstly chosen by the MR be MBR1. The MR configures the IPv6 address of its MANET interface by using the stateless address autoconfiguration mechanism based on the network prefix included in the SMF message from MBR1 and its MAC address, and sets MBR1 as its default gateway. Then, the MR obtains a network prefix by using the DHCP with prefix delegation. The MR with the delegated network prefix allocates an IPv6 address belonging to the delegated network prefix to the hosts connected to itself. Also, the MR sends a Registration Request (RR) message with the delegated network prefix information to MBR1. The format of the RR message is defined in the section 2. From the received RR message, MBR1 stores the binding information of the network prefix and the address assigned to the MANET interface of the MR, and sends a proxy binding update (PBU) message to the LMA. Then, the LMA stores the binding information of the received network prefix and the MBR1 address. The packets from hosts in the external network to the hosts connected to the MR are delivered to the LMA, first, and, then, the LMA forwards the received packets to MBR1 via the tunnel, and then, MBR1 forwards them to the MR. Jaehwoon Lee, et al. Expires January 6, 2009 [Page 5] Internet-Draft Address Autoconfiguration for multiple MBRs July 7, 2008 If the MR moves and receives a SMF message which has been broadcast by another MBR (i.e., MBR2) and the difference between the number of hops from MBR1 and that from MBR2 is larger than a given threshold, the MR changes its default gateway address information from MBR1 to MBR2. After that, the MR sends a RR message to MBR2. Upon receiving the RR message, MBR2 stores the binding information of the network prefix and the IPv6 address assigned to the MANET interface of the MR, and sends a PBU message to the LMA. Upon receiving the PBU message, the LMA changes the binding information of the network prefix information in the PBU message from MBR1 to MBR2. Then, the packets from hosts in the external network to the MR are delivered to MBR2 via the LMA through the tunnel. And, MBR2 forwards the received packets to the MR. 5. Security Consideration TBD. 6. IANA Considerations TBD. References [1] E. Baccelli et al., "Address Autoconfiguration for MANET: Terminology and Problem Statement", draft-ietf-autoconf- statement-04, Work in progress, Feb. 2008. [2] S. Ruffino, P. Stupar and T. Clausen, "Autoconfiguration in a MANET: connectivity scenarios and technical issues", draft- ruffino-manet-autoconf-scenarios-00, work in progress, Oct. 2004. [3] S. Ruffino and P. Stupar, "Automatic configuration of IPv6 addresses for MANET with multiple gateways (AMG)", draft-ruffino-manet-autoconf-multigw-03, work in progress, June 2006. [4] C. Jelger, T. Noel and A. Frey, "Gateway and address autoconfiguration for IPv6 adhoc networks", draft-jelger-manet- gateway-autoconf-v6-02, work in progress, apr. 2004. Jaehwoon Lee, et al. Expires January 6, 2009 [Page 6] Internet-Draft Address Autoconfiguration for multiple MBRs July 7, 2008 [5] S. Gundavelli, K. Leung, V. Devarapalli, K. Chowdhury and B. Patil, "Proxy Mobile IPv6", draft-ietf-netlmm-proxymip6-18, work in progress, May 2008. [6] J. Macker, "Simplified Multicast Forwarding for MANET", draft-ietf-manet-smf-07, Work in progress, Feb. 2008. [7] I. Chakeres, J. Macker and T. Clausen, "Mobile Ad hoc Network Architecture", draft-ietf-autoconf-manetarch-07, Work in progress, Nov. 2007. Author's Addresses Jaehwoon Lee Dongguk University 26, 3-ga Pil-dong, Chung-gu Seoul 100-715, KOREA Email: jaehwoon@dongguk.edu Sanghyun Ahn University of Seoul 90, Cheonnong-dong, Tongdaemun-gu Seoul 130-743, KOREA Email: ahn@uos.ac.kr Younghan Kim Soongsil University 11F Hyungnam Engineering Bldg. 317, Sangdo-Dong, Dongjak-Gu, Seoul 156-743 Korea E-main: yhkim@dcn.ssu.ac.kr Yuseon Kim KT 17 Woomyeon-dong, Seocho-gu Seoul 137-792, KOREA Email: yseonkim@kt.co.kr Sangeon Kim KT 17 Woomyeon-dong, Seocho-gu Seoul 137-792, KOREA Email: sekim@kt.co.kr Jaehwoon Lee, et al. Expires January 6, 2009 [Page 7] Internet-Draft Address Autoconfiguration for multiple MBRs July 7, 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). 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, THE IETF TRUST 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. Intellectual Property 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 to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Jaehwoon Lee, et al. Expires January 6, 2009 [Page 8]