Internet-Draft Route Optimization for MN based on PD June 2003 Individual Submission Internet Draft Kyeong-Jin Lee Jae-Hoon Jeong Jung-Soo Park Hyoung-Jun Kim ETRI Expires: December 2003 22 June 2003 Route Optimization for Mobile Nodes in Mobile Network based on Prefix Delegation 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 This document describes how to support Route Optimization for Mobile Nodes in IPv6 Mobile Network. The support is provided by Prefix Delegation. Mobile Router gets a prefix from an access router using Prefix Delegation protocol and advertises the delegated prefix to its subnet. Each Mobile Nodes makes its care-of address from the prefix and performs binding update. It allows the Mobile Nodes to communicate with Correspondent Nodes directly, avoiding ingress filtering. Lee, Jeong, Park, Kim Expires - December 2003 [Page 1] Internet-Draft Route Optimization for MN based on PD June 2003 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 and Abbreviation..................................2 2. Introduction..................................................2 3. Protocol Overview.............................................3 4. Neighbor Discovery extension : Delegated Prefix option format.5 5. Mobile IPv6 extension : Process of Delegated Prefix option....6 6. Handover Considerations.......................................6 7. Security Considerations.......................................6 8. References....................................................6 9. Authors' Addresses............................................7 1. Terminology and Abbreviation This document uses the terminology and abbreviation of [2]-[4] on the assumption that the reader is familiar with Mobile IPv6 and NEMO terminology. In addition, the following term is used: Delegated Prefix (DP) A prefix assigned to a site by a provider, from which the site may derive link prefixes [5]. 2. Introduction NEMO Basic Support is to preserve session continuity using bidirectional tunnel between Mobile Router (MR) and MR's HA. The support is reasonable for small-scale mobile network because MR MUST encapsulate and decapsulate all packets for Mobile Network Nodes. Specially, outbound packets MUST be tunneled in order to pass ingress filtering. The purpose of this document is to enable MNs behind the MR to perform Mobile IPv6 Route Optimization. This can reduce the overhead on MR because MR considers the packets of Local Fixed Nodes in the bidirectional tunnel between MR and HA. Lee, Jeong, Park, Kim Expires - December 2003 [Page 2] Internet-Draft Route Optimization for MN based on PD June 2003 When MR detects its movement, it runs Prefix Delegation(PD) protocol such as APD, RA-PD and DHCP v6 described in [5]-[7] respectively. If MRs become placed in multiple levels, the mobile network has hierarchical architecture. Most of the current PD protocols are designed for leaf network. How to extend PD protocol for hierarchical IPv6 network is outside the scope of this specification. Even when every AR on visited network does not support PD, there SHOULD be no problem in the communication between MN and CN. If this mechanism is disabled, all the Mobile Network Nodes (MNNs) communicate with CN by NEMO Basic Support. Therefore, it can provide Route Optimization for mobile nodes within mobile network according to whether the access network allows PD. 3. Protocol Overview This document assumes that all AR and MR support PD. Otherwise, only NEMO Basic Support [8]-[9] is provided to preserve session continuity and Route Optimization is disabled. Figure 1 shows a topology before two MRs move from home link to foreign link. When the MR1 and MR2 are at home link, each MR uses 1:1:: and 2:1:: respectively as its own mobile network prefix. +---+ |CN | +-+-+ | +------+ +--+-----+ +------+ |HA-MR1|-----------|Internet|----------------|HA-MR2| +---+--+ +--+-----+ +----+-+ |1:: | 2:: | +-+-+1 +--+-+ +-+-+3 |MR1| | AR | |MR2| +-+-+2 +--+-+ +-+-+4 |1:1:: | 3:: 2:1:: | --+---+--+------+- ----+--- ---+---+--+-- | | | | | +-+-+5 +-+-+6 +-+-+7 +-+-+8 +-+-+9 |LMN| |VMN| |LFN| |LMN| |VMN| +---+ +---+ +---+ +---+ +---+ Figure 1. Mobile router at home link Lee, Jeong, Park, Kim Expires - December 2003 [Page 3] Internet-Draft Route Optimization for MN based on PD June 2003 Figure 2 shows a topology after two MRs move from home link to foreign link and each MR performs PD. First, MR1 detects movement and gets a prefix (3:1::) from AR. MR1 advertises the DP to its subnet by sending RA message with Delegated Prefix option. And then, MR2 moves to MR1's network. MR2 gets prefix (3:1:1::) from MR1 and advertises the prefix to its subnet. When each MN receives RA message with Delegated Prefix option, it processes the DP option preferentially: make CoA from the prefix and performs binding updates to HA and CN. In figure 2, CoA1 is used as a primary CoA, which is made from DP. This process is transparent to LFNs. +---+ |CN | +-+-+ | +------+ +--+-----+ +------+ |HA-MR1|-----------|Internet|----------------|HA-MR2| +---+--+ +--+-----+ +----+-+ |1:: | 2:: | +--+-+ | AR | +--+-+ | 3:: --+----+------ | +-+-+ HoA 1::1, CoA 3::1 |MR1| Delegated Prefix(DP) = 3:1:: +-+-+ Mobile Network Prefix(MNP) = 1:1:: | --+---+--+------+--------+------ | | | | +-+-+ +-+-+ +-+-+ +-+-+ HoA 2::3 |LMN| |VMN| |LFN| |MR2| CoA1 3:1::3 +---+ +---+ +---+ +-+-+ CoA2 1:1::3 CoA1 3:1::5 3:1::6 | DP = 3:1:1:: CoA2 1:1::6 ---+---+--+-- MNP = 2:1:: | | +-+-+ +-+-+ |LMN| |VMN| +-+-+ +-+-+ CoA1 3:1:1::8 3:1:1::9 CoA2 2:1::9 Figure 2. Prefix Delegation for Route Optimization Lee, Jeong, Park, Kim Expires - December 2003 [Page 4] Internet-Draft Route Optimization for MN based on PD June 2003 After the PD, the routing table of routers is updated by routing protocol. It is possible because each router has information about delegated prefix. 4. Neighbor Discovery extension : Delegated Prefix option format This specification defines the Delegated Prefix option for the Neighbor Discovery protocol of IPv6. The option format is shown in Figure 2. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Prefix Length |L|A| Reserved1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Valid Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Preferred Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Prefix + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2. Delegated Prefix Option Format for Route Optimization Fields: Type XXX [TBD: IANA] Prefix Delegated Prefix. The Prefix Length field contains the number of valid leading bits in the prefix. The bits in the prefix after the prefix length are reserved and MUST be initialized to zero by the sender and ignored by the receiver The Delegated Prefix option provides mobile nodes with on-link prefix of access network and prefix for address autoconfiguration of CoA. Lee, Jeong, Park, Kim Expires - December 2003 [Page 5] Internet-Draft Route Optimization for MN based on PD June 2003 The Delegated Prefix option appears in Router Advertisement packets and MUST be silently ignored for other messages. 5. Mobile IPv6 extension : Process of Delegated Prefix option MN scans all options in received router advertisement message. To initiate Route Optimization MN operation MUST be extended as follows: (1)Process the new RA option, Delegated Prefix option: MN forms CoA using the prefix. (2)Use the CoA as primary CoA. MN performs registration procedure according to the Mobile IPv6 protocol. There is no change of HA and CN operations. 6. Handover Considerations When a MR moves into another AR and detects movement, it SHOULD NOT return prefix delegated from the old AR immediately. It takes some time to find out whether the new AR supports PD or not. Moreover, MR can fail in PD for several reasons. Therefore, some considerations are needed for smooth handover. 7. Security Considerations Because the mechanism described in this document needs to exchange PD message between a MR and its AR, AAA MAY be used to authenticate MR. 8. References [1] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. [2] Thierry Ernst, "Network Mobility Support Terminology", draft- ietf-nemo-terminology-00.txt, May 2003. [3] D. Johnson, C. Perkins and J. Arkko, "Mobility Support in IPv6", draft-ietf-mobileip-ipv6-22.txt, May 2003. [4] J. Manner and M. Kojo, "Mobility Related Terminology", draft- ietf-seamoby-mobility-terminology-04.txt, Oct 2003. [5] Nathan Lutchansky, "IPv6 Router Advertisement Prefix Delegation Option", draft-lutchann-ipv6-delegate-option-00.txt, Aug 2002 Lee, Jeong, Park, Kim Expires - December 2003 [Page 6] Internet-Draft Route Optimization for MN based on PD June 2003 [6] B. Haberman, "Automatic Prefix Delegation Protocol for Internet Protocol Version 6 (IPv6)", draft-haberman-ipngwg-auto-prefix- 02.txt, Aug 2002 [7] O. Troan and R. Droms, "IPv6 Prefix Options for DHCPv6", draft- troan-dhcpv6-opt-prefix-delegation-00.txt, Aug 2002 [8] T.J. Kniveton, Jari T. Malinen, Vijay Devarapalli and Charles E. Perkins, "Mobile Router Tunneling Protocol", draft-kniveton- mobrtr-03.txt, May 2003 [9] Ryuji wakikawa, Keisuke Uehara, Koshiro Mitsuya and Thierry Ernst, "Basic Network Mobility Support", draft-wakikawa-nemo-basic- 00.txt, Feb 2003 9. Authors' Addresses Kyeong-Jin Lee ETRI / PEC 161 Gajong-Dong, Yusong-Gu Daejon 305-350 Korea Phone: +82 42 860 6484 EMail: leekj@etri.re.kr Jae-Hoon Jeong ETRI / PEC 161 Gajong-Dong, Yusong-Gu Daejon 305-350 Korea Phone: +82 42 860 1664 EMail: paul@etri.re.kr Jung-Soo Park ETRI / PEC 161 Gajong-Dong, Yusong-Gu Daejon 305-350 Korea Phone: +82 42 860 6514 EMail: pjs@etri.re.kr Hyoung-Jun Kim ETRI / PEC Lee, Jeong, Park, Kim Expires - December 2003 [Page 7] Internet-Draft Route Optimization for MN based on PD June 2003 161 Gajong-Dong, Yusong-Gu Daejon 305-350 Korea Phone: +82 42 860 6576 EMail: khj@etri.re.kr Lee, Jeong, Park, Kim Expires - December 2003 [Page 8]