Mobile IP Working Group Alpesh Patel INTERNET DRAFT Kent Leung 14 October, 2003 Cisco Systems Experimental Message, Extension and Error Codes for Mobile IPv4 draft-patel-mobileip-experimental-messages-02.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 Mobile IPv4 message types range from 0 to 255. This document reserves a message type for use by an individual, company, or organization for experimental purpose, to evaluate enhancements to Mobile IPv4 messages before formal standards proposal. Mobile IPv4 defines a general Extension mechanism to allow optional information to be carried by Mobile IP control messages. Extensions are not skippable, if defined in range [0- 127] and skippable, if defined in range [128-255]. This document reserves extension types in both the skippable and non-skippable range for experimental use. Also, Mobile IPv4 defines error codes for use by FA [64-127] and HA [128-192]. This document reserves an error code in both these ranges for experimental use. Patel, Leung Expires 25 January, 2004 [Page 1] Internet Draft Experimental Message, Extension & Error Codes October 2003 Table of Contents 1. Introduction..............................................2 2. Terminology...............................................3 3. Experimental Message......................................3 4. Experimental Extensions...................................4 4.1 Non-skippable Experimental Extension.....................4 4.2 Skippable Experimental Extension.........................5 5. Experimental Error Codes..................................6 6. Mobility Entity Considerations............................6 7. IANA Considerations.......................................6 8. Security Considerations...................................6 9. Backward Compatibility Considerations.....................6 10. Intellectual Property Rights.............................7 11. Acknowledgements.........................................7 12. References...............................................7 13. Contact Information......................................8 Full Copyright Statement.....................................8 1. Introduction Mobile IPv4 message types range from 0 to 255. This document reserves a message type for experimental purpose, to evaluate enhancements to Mobile IPv4 messages before formal standards proposal. Without experimental message capability, one would have to select a type value from the range defined for IANA assignment, which may result in collision. Also, Mobile IP defines a general Extension mechanism to allow optional information to be carried by Mobile IP control messages. Extensions are not skippable, if defined in range [0- 127] and skippable, if defined in range [128-255]. This document reserves extension types in both the skippable and non-skippable range for experimental use. Mobile IPv4 defines error codes for use by FA [64-127] and HA [128-192]. This document reserves an error code in both these ranges for experimental use. Patel, Leung Expires March 13, 2004 [Page 2] Internet Draft Experimental Message, Extension & Error Codes October 2003 2. Terminology 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 [1]. EXP-MSG-TYPE: A message in the range [0-255] to be assigned by IANA for experimental use. EXP-SKIP-EXT-TYPE: Extension in the range [128-255] to be assigned by IANA for experimental use. EXP-NONSKIP-EXT-TYPE: Extension in the range [0-127] to be assigned by IANA for experimental use. EXP-HA-ERROR-CODE: Error code in the range [128-192] for use by HA in reply messages to indicate error condition. EXP-FA-ERROR-CODE: Error code in the range [64-127] for use by FA in reply messages to indicate error condition. 3. Experimental Message Since the nature and purpose of an experimental message cannot be known in advance, the structure is defined as opaque payload. Entities implementing the message can interpret the message as per their implementation. One suggestion is to interpret based on extensions present in the message. These messages will be used between the mobility entities (Home Agent, Foreign Agent, and Mobile Node). Experimental messages SHOULD be authenticated using any of the authentication mechanism defined for Mobile IP ([2], [5]). This message MAY contain extensions defined in Mobile IP, including vendor specific extensions [4]. IP fields: Source Address Typically the interface address from which the message is sent. Destination Address The address of the agent or the Mobile Node. UDP fields: Source Port variable Patel, Leung Expires March 13, 2004 [Page 3] Internet Draft Experimental Message, Extension & Error Codes October 2003 Destination Port 434 Mobile IP fields shown below follow the UDP header: 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 | Opaque... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type EXP-MSG-TYPE (To be assigned by IANA) Opaque The Opaque is zero or more octets. Once an experimental message has been tested and shown to be useful, a permanent number could be obtained through the normal assignment procedures. A single experimental message type is recommended since this message can contain extensions based on which the message can be interpreted. 4. Experimental Extensions This document reserves extensions in both skippable and non- skippable range for experimental purposes. The long extension format (for non-skippable extensions) and short extension format (for skippable extensions), as defined [2] are used for experimental extensions. 4.1 Non-skippable Experimental Extension This format is applicable for non-skippable extensions, which carry information more than 256 bytes. 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 | Sub-Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Opaque ą +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Patel, Leung Expires March 13, 2004 [Page 4] Internet Draft Experimental Message, Extension & Error Codes October 2003 Type EXP-NONSKIP-EXT-TYPE (to be assigned by IANA) is the type, which describes an experimental extension. Sub-Type is a unique number given to each member in the aggregated type. Length indicates the length (in bytes) of the data field within this Extension. It does NOT include the Type, Sub-Type and Length bytes. Opaque The Opaque is zero or more octets. Since the length field is 16 bits wide, the extension data can exceed 256 bytes in length. 4.2 Skippable Experimental Extension This format is applicable for skippable extensions, which carry information less than 256 bytes. 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 | Sub-Type | Opaque ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type EXP-SKIP-EXT-TYPE (to be assigned by IANA) is the type, which describes an experimental extension. Length indicates the length (in bytes) of the data field within this Extension. It does NOT include the Type and Length bytes. Sub-Type is a unique number given to each member in the aggregated type. Opaque The Opaque is zero or more octets. Since the length field is 8 bits wide, the extension data cannot exceed 256 bytes in length. Patel, Leung Expires March 13, 2004 [Page 5] Internet Draft Experimental Message, Extension & Error Codes October 2003 5. Experimental Error Codes This document reserves reply error code EXP-FA-ERROR-CODE, in the range [64-127], for use by FA. This document also reserves reply error code EXP-HA-ERROR-CODE, in the range [128-192], for use by HA. These experimental error codes may be included in registration reply messages. It is recommended that experimental error code must be included in experimental messages or messages containing at-least one experimental extension. 6. Mobility Entity Considerations Mobility entities can send and receive experimental messages. Implementations that don't understand the message type SHOULD silently discard the message. Experimental extensions can be carried in experimental messages and standards defined messages. In the later case, it is suggested that experimental extensions MUST not be used in deployed products and usage be restricted to experimentations only. 7. IANA Considerations IANA services are required for this draft. Since a new message type is needed to be reserved as experimental, a value must be assigned for EXP-MSG-TYPE from Mobile IP control message space. Also, values for EXP-NONSKIP-EXT-TYPE and EXP-SKIP-EXT-TYPE must be assigned for experimental extensions. Also, values for EXP-HA-ERROR-CODE and EXP-FA-ERROR-CODE must be assigned for experimental error code. 8. Security Considerations Like all Mobile IP control messages, the experimental messages SHOULD be authenticated with at least one authenticator. Messages without a valid authenticator SHOULD be discarded. 9. Backward Compatibility Considerations Mobility entities that donĘt understand the experimental message MUST silently discard it. Patel, Leung Expires March 13, 2004 [Page 6] Internet Draft Experimental Message, Extension & Error Codes October 2003 Mobility entities that donĘt understand the experimental skippable extensions MUST ignore them. Mobility entities that donĘt understand the non-skippable experimental extensions MUST silently discard the message containing them. FA and HA SHOULD include experimental error code in reply message only if they have a general indication that the receiving entity would be able to parse it. An indication of this is if the request message was of type EXP-MSG-TYPE or contained at-least one experimental extension. 10. Intellectual Property Rights The IETF takes no position regarding the validity or scope of any intellectual property 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; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication 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 implementors or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. 11. Acknowledgements The authors would like to acknowledge Henrik Levkowetz for his detailed review of the draft and suggestion to incorporate experimental extensions in this draft. The authors would also like to acknowledge Thomas Narten for his initial review of the draft and reference to draft-narten- iana-experimental-allocations-03.txt for general guidelines. 12. References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Patel, Leung Expires March 13, 2004 [Page 7] Internet Draft Experimental Message, Extension & Error Codes October 2003 Levels", BCP 14, RFC 2119, March 1997. [2] Perkins, C., "IP Mobility Support", RFC 3344, August 2002. [3] Reynolds, J. and J. Postel, "Assigned Numbers", STD 2, RFC 1700, October 1994. [4] G. Dommety, K. Leung, "Mobile IP Vendor/Organization-Specific Extensions" RFC 3115, April 2001 [5] C. Perkins, P. Calhoun, "Mobile IPv4 Challenge/Response Extensions", RFC 3012, November 2000 13. Contact Information Questions and comments about this draft should be directed at the Mobile IPv4 working group: mip4@ietf.org Questions and comments about this draft may also be directed to the authors: Alpesh Patel Kent Leung Cisco Systems Cisco Systems 170 W. Tasman Drive, 170 W. Tasman Drive, San Jose, CA 95134 San Jose, CA 95134 USA USA Email: alpesh@cisco.com Email: kleung@cisco.com Phone: +1 408-853-9580 Phone: +1 408-526-5030 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. 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