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Experimental Message, Extensions, and Error Codes for Mobile IPv4
draft-ietf-mip4-experimental-messages-02

The information below is for an old version of the document that is already published as an RFC.
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This is an older version of an Internet-Draft that was ultimately published as RFC 4064.
Authors Alpesh Patel , Kent Leung
Last updated 2015-10-14 (Latest revision 2004-09-14)
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
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IESG IESG state Became RFC 4064 (Proposed Standard)
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Responsible AD Dr. Thomas Narten
Send notices to mccap@lucent.com
draft-ietf-mip4-experimental-messages-02
Mobile IP Working Group                               Alpesh Patel 
   INTERNET DRAFT                                          Kent Leung 
   10 September 2004                                    Cisco Systems 
         
                                         
                 
    Experimental Message, Extension and Error Codes for Mobile IPv4 
             draft-ietf-mip4-experimental-messages-02.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. 
       
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      material or to cite them other than as "work in progress." 
       
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      This Internet-Draft will expire on March 9, 2005. 
    
    
   Copyright Notice 
    
    
      Copyright (c) The Internet Society (2004). All Rights Reserved. 
 
         
        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. 
         
         
 
     
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        Table of Contents 
    
    
        1. Introduction.............................................2 
        2. Terminology..............................................3 
        3. Experimental Message.....................................3 
        4. Experimental Extensions..................................4 
        4.1 Non-skippable Mobile IPv4 Experimental Extension........5 
        4.2 Non-skippable ICMP Router Discovery Exp. Extension......5 
        4.3 Skippable Mobile IPv4 Experimental Extension............6 
        4.4 Skippable ICMP Router Discovery Experimental Extension..7 
        5. Experimental Error Codes.................................7 
        6. Mobility Entity Considerations...........................7 
        7. IANA Considerations......................................8 
        7.1 New Message Type........................................8 
        7.2 New Extension Values....................................8 
        7.3 New Error Codes.........................................8 
        9. Backward Compatibility Considerations....................9 
        10. Acknowledgements........................................9 
        11. References..............................................9 
        11.1 Normative References..................................10 
        11.2 Informative References................................10 
        12. Authors' Addresses.....................................10 
        Intellectual Property Statement............................11 
        Disclaimer of Validity.....................................11 
        Copyright Statement........................................11 
 
 
    
1. Introduction  
 
 
        Mobile IPv4 message types range from 0 to 255. This document 
        reserves a message type for experimental purposes, 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 collisions. 
         
        Within a message, 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 
        the range [0-127] and skippable if defined in the range [128-
        255]. This document reserves extension types in both the 
        skippable and non-skippable ranges for experimental use.  
         

  
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        Mobile IPv4 defines error codes for use by the FA [64-127] and 
        HA [128-192]. This document reserves an error code in both 
        these ranges for experimental use. 
         
        The definition of experimental numbers in this document is done 
        according to the recommendation of Section 2.2 of BCP 82,  
        RFC 3692. 
         
 
 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].  
         
        In addition, this document frequently uses the following terms: 
         
        EXP-MSG-TYPE: A Mobile-IPv4 message number in the range [0-255] 
        to be assigned by IANA for experimental use. 
         
        EXP-SKIP-EXT-TYPE: A Mobile-IPv4 and ICMP router discovery 
        Agent Advertisement extension number in the range [128-255] to 
        be assigned by IANA for experimental use. 
         
        EXP-NONSKIP-EXT-TYPE: A Mobile-IPv4 and ICMP router discovery 
        Agent Advertisement extension number in the range [0-127] to be 
        assigned by IANA for experimental use. 
         
        EXP-HA-ERROR-CODE: A Mobile-IPv4 error code in the range [128-
        192] for use by HA in MIPv4 reply messages to indicate an error 
        condition. 
         
        EXP-FA-ERROR-CODE: A Mobile-IPv4 error code in the range [64-
        127] for use by FA in reply messages to indicate error 
        condition. 
         
        Mobility Entity: Entities as defined in [2] (home agent, 
        foreign agent and mobile node). 
    
    
   3. Experimental Message 
         
 
        Since the nature and purpose of an experimental message cannot 
        be known in advance, the structure is defined as having an 
        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. 
       

  
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        These messages may be used between the mobility entities (Home 
        Agent, Foreign Agent, and Mobile Node). Experimental messages 
        MUST 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        Set according to RFC 768 (variable) 
       
            Destination Port   Set to the value 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     Zero or more octets of data, with structure defined 
                    only by the particular experiment it is used for. 
         
        Once an experimental message has been tested and shown to be 
        useful, a permanent number should be obtained through the 
        normal IANA numbers assignment procedures. 
         
        A single experimental message type is defined. This message can 
        contain extensions based on which the message can be 
        interpreted.  
         
         
   4. Experimental Extensions 
         
         
        This document reserves Mobile IPv4 extensions in both the 
        skippable and non-skippable ranges for experimental purposes. 
        The long extension format (for non-skippable extensions) and 
  
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        short extension format (for skippable extensions), as defined 
        by [2], are used for Mobile IPv4 experimental extensions.  
         
        Also, ICMP router discovery extension numbers in both the 
        skippable and non-skippable ranges are reserved for 
        experimental use. 
         
         
   4.1 Non-skippable Mobile IPv4 Experimental Extension 
         
         
        This format is applicable for non-skippable extensions and may 
        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. . . 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
         
         
        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 fields. 
         
        Opaque   Zero or more octets of data, with structure defined 
                 only by the particular experiment it is used for. 
         
        Since the length field is 16 bits wide, the extension data can 
        exceed 256 bytes in length. 
         
         
   4.2 Non-skippable ICMP Router Discovery Exp. Extension 
         
         
      This format is applicable for non-skippable extensions. 
 
 
      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     |           Opaque . . .  
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
  
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        Type     EXP-NONSKIP-EXT-TYPE (to be assigned by IANA) is   
                 the type, which describes an ICMP router discovery   
                 experimental extension. 
         
        Length   Indicates the length (in bytes) of the data field  
                 within this extension.  It does NOT include the Type  
                 and Length fields. 
         
        Opaque   Zero or more octets of data, with structure defined 
                 only by the particular experiment it is used for. 
 
        A node which receives a router advertisement with this 
        extension should ignore the extension if it does not recognize 
        it.  
         
        A mobility entity which understands this extension, but does 
        not recognize it, should drop (ignore) the router 
        advertisement. 
         
         
   4.3 Skippable Mobile IPv4 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 fields. 
         
        Sub-Type is a unique number given to each member in the  
                 aggregated type. 
         
        Opaque   Zero or more octets of data, with structure defined 
                 only by the particular experiment it is used for. 
 
        Since the length field is 8 bits wide, the extension data 
        cannot exceed 256 bytes in length. 
  
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   4.4 Skippable ICMP Router Discovery Experimental Extension 
    
         
        This format is applicable for skippable ICMP router discovery 
        extensions. This extension should be ignored if an 
        implementation does not understand it. 
 
      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     |   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 fields. 
         
        Opaque   Zero or more octets of data, with structure defined 
                 only by the particular experiment it is used for. 
 
 
   5. Experimental Error Codes 
    
         
        This document reserves reply error code EXP-FA-ERROR-CODE for 
        use by the FA. This document also reserves reply error code 
        EXP-HA-ERROR-CODE for use by the HA.  
         
        These experimental error codes may be used in registration 
        reply messages.  
 
        It is recommended that experimental error codes be used 
        with experimental messages and extensions whenever none of the 
        standardized error codes are applicable. 
 
 
   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 latter case, it is 
  
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        suggested that experimental extensions MUST NOT be used in 
        deployed products and usage be restricted to experimentations 
        only. 
    
    
   7. IANA Considerations 
    
    
        This document defines a control message to be used between 
        mobility entities, two new extension formats and two new error 
        codes. To ensure correct interoperation based on this 
        specification, IANA has reserved values in the Mobile IPv4 
        number space, as defined in [2] for one new message type, two 
        new extensions and two error codes. 
         
         
   7.1 New Message Type 
 
        A new Mobile IPv4 control message using UDP port 434, type EXP-
        MSG-TYPE has been defined by IANA. This value has been taken 
        from the same number space as Mobile IP Registration Request 
        (Type = 1), and Mobile IP Registration Reply (Type = 3). (The 
        value 255 is suggested in this case). 
         
         
   7.2 New Extension Values 
 
        The following extension types are introduced by this 
        specification:  
         
        Experimental non-skippable extension: The value for EXP-
        NONSKIP-EXT-TYPE has been assigned from the numbering space for 
        non-skippable extensions, which may appear in Mobile IPv4 
        control messages.  
         
        Also, the same number, EXP-NONSKIP-EXT-TYPE has been assigned 
        from the numbering space for non-skippable extensions, which 
        may appear in ICMP router discovery messages.  (The value 127 
        is suggested in both cases.) 
 
        Experimental skippable extension: The value EXP-SKIP-EXT-TYPE 
        has been assigned from the numbering space for skippable 
        extensions, which may appear in Mobile IPv4 control messages.  
         
        Also, the same number, EXP-SKIP-EXT-TYPE has been assigned from 
        the numbering space for skippable extensions which may appear 
        in ICMP router discovery messages. (The value 255 is suggested 
        in both cases.) 
         
   7.3 New Error Codes 
 

  
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        The value EXP-HA-ERROR-CODE has been defined by IANA to be used 
        as code field in messages generated by HA. (The value 192 is 
        suggested for this code.) 
         
        Also, value EXP-FA-ERROR-CODE has been defined by IANA to be 
        used as the code field in messages generated by the FA. (The 
        value 127 is suggested for this code.) 
          
         
   8. Security Considerations 
    
         
        Like all Mobile IP control messages, the experimental messages  
        MUST be authenticated as per the requirements specified in [2] 
        or [5]. Experimental messages without a valid authenticator 
        SHOULD be discarded. 
         
 
   9. Backward Compatibility Considerations 
    
    
        Mobility entities that don't understand the experimental 
        message MUST silently discard it. 
         
        Mobility entities that don't understand the experimental 
        skippable extensions MUST ignore them. Mobility entities that 
        don't understand the non-skippable experimental extensions 
        MUST silently discard the message containing them. This 
        behavior is consistent with section 1.8 of [2]. 
         
        Foreign Agents and Home Agents SHOULD include an experimental 
        error code in a 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. 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 [6] for 
        general guidelines. 
 
    
   11. References 
    
    
  
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   11.1 Normative References 
    
    
   [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 
       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. 
    
    
   11.2 Informative References 
    
         
   [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 
    
   [6] T. Narten, "Assigning Experimental and Testing Numbers   
       Considered Useful", BCP 82, RFC 3692, January, 2004 
     
 
   12. Authors' Addresses 
    
    
        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 
         Cisco Systems 
         170 W. Tasman Drive, 
         San Jose, CA 95134 
         USA 
         Email: alpesh@cisco.com 
         Phone: +1 408-853-9580 
    
    
         Kent Leung 
         Cisco Systems 
         170 W. Tasman Drive, 
         San Jose, CA 95134 
         USA 
         Email: kleung@cisco.com 
  
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         Phone: +1 408-526-5030 
    
    
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        Copyright (C) The Internet Society (2004).  This document is 
        subject to the rights, licenses and restrictions contained in 
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   Acknowledgement 
         
        Funding for the RFC Editor function is currently provided by 
        the Internet Society. 

  
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