Network Working Group S. Daniel Park Internet-Draft M. Lee Expires: October 12, 2005 SAMSUNG Electronics April 13, 2005 Link Characteristic Information for Mobile IP draft-daniel-mip-link-characteristic-00.txt Status of this Memo By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, and any of which I 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 October 12, 2005. Copyright Notice Copyright (C) The Internet Society (2005). All Rights Reserved. Abstract This document introduces a new model for link characteristic information that is sent by the mobile node to let the correspondent node know which link is being used for communication between them. This utility allows the correspondent node to forward its ongoing traffics within the bandwidth of the mobile node while the mobile node changes its link. This model can be applicable for Mobile IPv4 as well as Mobile IPv6. Park & Lee Expires October 12, 2005 [Page 1] Internet-Draft Link Characteristic Infomation for MIP April 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Link Characteristic Information Option for Mobile IPv6 . . . . 4 4. Operational Considerations . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1 Normative References . . . . . . . . . . . . . . . . . . . . 6 8.2 Informative References . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . 8 Park & Lee Expires October 12, 2005 [Page 2] Internet-Draft Link Characteristic Infomation for MIP April 2005 1. Introduction Mobile IP [RFC3344], [RFC3775] allows an IP node to be mobile when changing its location and still maintain existing connections. When the mobile node changes its location, it might also change its link. After attaching to a new link, the mobile node sustains its connection with the previous node (called correspondent node) continuously via specific operation as binding update which sent by the mobile node that is away from home to update another node with its new address (care-of address). Mobile Nodes are more and more equipped with several interfaces of different L2 technologies. As such they may be reachable through multiple links at the same time or alternatively use each interface depending on the network environment. Mobile IP scheme, however, does not provide which link is attached to the mobile node, but maintain its existing connection. It means the correspondent node recognize that the mobile node is still attached to the same link. It can cause some trouble to communicate between them. For example, in some case (i.e.,vertical handover), if the mobile node is attached to the CDMA (low bandwidth link) from the 802.11b Wireless LAN (high bandwidth link), the mobile node needs to receive a traffic within its limited bandwidth not overwhelmed traffic from the correspondent node, however the correspondent node will send its traffic to the mobile node as if the 802.11b bandwidth is still guranteed. Ratio of packet loss will eventually be increased. This document introduces a new model for link characteristic information that is sent by the mobile node to let the correspondent node know which link is being used for communication between them. A new option called Link Characteristic Information Option is defined in this document to provide link characteristic information (i.e., current link bandwidth, link type, and others information will be expanded later if required) to the mobile node while doing a binding update. This option is recommendable to be included in the Binding Update Message as well as Binding Acknowledgement Message when attaching to a new link which is different from the previous link. In wireless environment, all link is not able to support the same bandwidth to the mobile node while attaching to the new link. If the mobile node which is currently attached to the 802.11b link is being moved to the new 802.11b link, the available link bandwidth is may different between them. So link characteristic information can be adoptable for the same link change including new extended messages. To illustrate this model easily, Mobile IPv6 [RFC3775]is only described in this document, Mobile IPv4 [RFC3344] will be able to be defined following the Type-Length-Value format for Mobile IP Park & Lee Expires October 12, 2005 [Page 3] Internet-Draft Link Characteristic Infomation for MIP April 2005 Extension. 2. Requirements 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 [RFC2119]. 3. Link Characteristic Information Option for Mobile IPv6 The Mobile Node Link Characteristic Information Option is a new optional data field that is carried in the Mobile IPv6 defined messages which includes the mobility header (Binding Update and Binding Acknowledgement). Various type and bandwidth of link can be delivered to the correspondent node from the mobile node. The subtype field in the option defined the specific link type and current bandwidth of the mobile node. This option is recommendable to be carried in the Binding Update and Binding Acknowledgement message while changing its subnet. The subtype field in the option is used to interpret the specific link type and link current bandwidth of the mobile node. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Option Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Subtype | Link Characteristic Information... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ o Option Type: To be defined by IANA o Option Length: 8-bit unsigned integer, representing the length in octets of the Subtype and Link Characteristic Information fields. o Subtype: Subtype field defines the link type of the mobile node included in the Link Characteristic Information field. Subtype Link Type ---------------------------------------------- 1 WLAN (802.11b) Park & Lee Expires October 12, 2005 [Page 4] Internet-Draft Link Characteristic Infomation for MIP April 2005 2 WLAN (802.11a) 3 WLAN (802.11g) 4 WLAN (802.11n) 5-9 Reserved for WLAN Extension 10 CDMA 11-20 Reserved for Cellular Networks 21-30 802.15 Family Networks 31-40 802.16 Family Networks 41- Reserved ---------------------------------------------- o Link Characteristic Information: A variable length of link available bandwidth as specified link type by the subtype field of this option. This option does not have any alignment requirements. 4. Operational Considerations The binding cache is a table maintained by each correspondent node and home agent that contains the current bindings for mobile nodes. To store link characteristic information on the correspondent node, one entry SHOULD be contained in the binding cache. Also the correspondent node MUST recognize this option. Otherwise, this option is silently discarded by the correspondent node. Link characteristic information MUST be provided by the mobile node while attaching a new link via Binding Update message. When the correspondent node sends Binding Acknowledgement message, Link Characteristic Information Option which is copied from the Binding Update message MUST be included. Once taking an available bandwidth of the mobile node, the correspondent node SHOULD guarantee the bandwidth when forwarding the traffics to the mobile node. For example, The ongoing traffic requires 10Mbps bandwidth, but the available bandwidth of the mobile node is at most 1Mbps, then the correspondent node SHOULD reduce its forwarding traffic amount. In vertical handover, the mobile node can be moved to various links such as wireless pan area, wireless lan are and cellular area and each link has its own specific cnaracteristic information. This option can be more valuable model for vertical handover environment than horizontal handover. This document only define the bandwidth information as link characteristic, but there is no restriction to add other available Park & Lee Expires October 12, 2005 [Page 5] Internet-Draft Link Characteristic Infomation for MIP April 2005 information which will be newly defined as new subtype and link characteristic information when anyone requires a specific information. 5. Security Considerations Attacker can use this option to reduce the current bandwidth regardless of link type of the mobile node. Several mechanisms can be adoptable for this vulnerability. Encrypting traffic at link layer such that other users on the same link do not see the link characteristic information. This mechanism does not help against attackers on the rest of the path between the mobile node and the correspondent node. Encrypting the whole packet, such as when using IPsec to protect the communications with the correspondent node [RFC3776]. 6. IANA Considerations IANA should record a value for Link Characteristic Option including subtype (Mobile IPv4 Extension and Mobile IPv6 Option. 7. Acknowledgements Understanding Mobile IPv6 whitepaper written by Microsoft on April 2004 is referred to illustrate what Mobile IPv6 is in this document. Thanks their good summary. Specially thanks Rajeev Koodli, Bongkyo Moon, Pyungsoo Kim and Junghoon Jee for their useful comments. 8. References 8.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 8.2 Informative References [RFC3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344, August 2002. [RFC3775] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [RFC3776] Arkko, J., Devarapalli, V. and F. Dupont, "Using IPsec to Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents", RFC 3776, June 2004. Park & Lee Expires October 12, 2005 [Page 6] Internet-Draft Link Characteristic Infomation for MIP April 2005 Authors' Addresses Soohong Daniel Park Mobile Platform Laboratory, SAMSUNG Electronics. 416 Maetan-3dong, Yeongtong-gu Suwon, Gyeonggi-do 443-742 KOREA Phone: +82 31 200 4508 EMail: soohong.park@samsung.com Minho Lee Mobile Platform Laboratory, SAMSUNG Electronics. 416 Maetan-3dong, Yeongtong-gu Suwon, Gyeonggi-do 443-742 KOREA Phone: +82 31 200 3697 EMail: minho03.lee@samsung.com Park & Lee Expires October 12, 2005 [Page 7] Internet-Draft Link Characteristic Infomation for MIP April 2005 Intellectual Property Statement 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. Disclaimer of Validity 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. Copyright Statement 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Park & Lee Expires October 12, 2005 [Page 8]