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Internet Protocol Version 6 over MAPOS (Multiple Access Protocol Over SONET/SDH)
RFC 3572

Document Type RFC - Informational (July 2003)
Updated by RFC 8064
Authors Toshiaki Yoshida , Tsuyoshi Ogura , Mitsuru Maruyama
Last updated 2015-10-14
RFC stream Independent Submission
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IESG Responsible AD Dr. Thomas Narten
Send notices to (None)
RFC 3572
Network Working Group                                          J. Schaad
Request for Comments: 4211                       Soaring Hawk Consulting
Obsoletes: 2511                                           September 2005
Category: Standards Track

               Internet X.509 Public Key Infrastructure
               Certificate Request Message Format (CRMF)

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document describes the Certificate Request Message Format (CRMF)
   syntax and semantics.  This syntax is used to convey a request for a
   certificate to a Certification Authority (CA), possibly via a
   Registration Authority (RA), for the purposes of X.509 certificate
   production.  The request will typically include a public key and the
   associated registration information.  This document does not define a
   certificate request protocol.

Schaad                      Standards Track                     [Page 1]
RFC 4211                  Internet X.509 CRMF             September 2005

Table Of Contents

   1. Introduction and Terminology ....................................3
   2. Overview ........................................................3
      2.1. Changes since RFC 2511 .....................................4
   3. CertReqMessage Syntax ...........................................4
   4. Proof-of-Possession (POP) .......................................5
      4.1. Signature Key POP ..........................................7
      4.2. Key Encipherment Keys ......................................9
           4.2.1. Private Key Info Content Type ......................11
           4.2.2. Private Key Structures .............................12
           4.2.3. Challenge-Response Guidelines ......................13
      4.3. Key Agreement Keys ........................................14
      4.4. Use of Password-Based MAC .................................14
   5. CertRequest syntax .............................................16
   6. Controls Syntax ................................................18
      6.1. Registration Token Control ................................18
      6.2. Authenticator Control .....................................19
      6.3. Publication Information Control ...........................19
      6.4. Archive Options Control ...................................21
      6.5. OldCert ID Control ........................................23
      6.6. Protocol Encryption Key Control ...........................23
   7. RegInfo Controls ...............................................23
      7.1. utf8Pairs .................................................23
      7.2. certReq ...................................................24
   8. Object Identifiers .............................................24
   9. Security Considerations ........................................25
   10. References ....................................................26
      10.1. Normative References .....................................26
      10.2. Informative References ...................................27
   11. Acknowledgements ..............................................28
   Appendix A.  Use of RegInfo for Name-Value Pairs ..................29
      A.1.  Defined Names ............................................29
      A.2.  IssuerName, SubjectName, and Validity Value Encoding .....29
   Appendix B.  ASN.1 Structures and OIDs ............................32
   Appendix C.  Why do Proof-of-Possession (POP) .....................38

Schaad                      Standards Track                     [Page 2]
RFC 4211                  Internet X.509 CRMF             September 2005

1.  Introduction and Terminology

   This document describes the Certificate Request Message Format
   (CRMF).  A Certificate Request Message object is used within a
   protocol to convey a request for a certificate to a Certification
   Authority (CA), possibly via a Registration Authority (RA), for the
   purposes of X.509 certificate production.  The request will typically
   include a public key and the associated registration information.

   The certificate request object defined in this document is not a
   stand-alone protocol.  The information defined in this document is
   designed to be used by an externally defined Certificate Request
   Protocol (CRP).  The referencing protocol is expected to define what
   algorithms are used, and what registration information and control
   structures are defined.  Many of the requirements in this document
   refer to the referencing Certificate Request Protocol (CRP).

   Certificate requests may be submitted by an RA requesting a
   certificate on behalf of a Subject, by a CA requesting a cross-
   certificate from another CA, or directly by an End Entity (EE).

   The key words "MUST", "REQUIRED", "SHOULD", "RECOMMENDED", and "MAY"
   in this document (in uppercase, as shown) are to be interpreted as
   described in RFC 2119 [RFC2119].

2.  Overview

   Construction of a certification request involves the following steps:

   a)  A CertRequest object is constructed.  This object may include the
       public key, all or a portion of the Subject name, other requested
       certificate fields, and additional control information related to
       the registration process.  Depending on the CRP, this information
       can be specified by the Subject and potentially modified by an
       RA, or specified by the RA based on knowledge of the Subject or
       documentation presented by the Subject.

   b)  If required, a proof-of-possession (of the private key
       corresponding to the public key for which a certificate is being
       requested) value is calculated.

   c)  Additional registration information can be combined with the
       proof-of-possession value and the CertRequest structure to form a
       CertReqMessage.  Additional registration information can be added
       by both the Subject and an RA.

Schaad                      Standards Track                     [Page 3]
RFC 4211                  Internet X.509 CRMF             September 2005

   d)  The CertReqMessage is securely communicated to a CA.  Specific
       means of secure transport are to be specified by each CRP that
       refers to this document.

2.1.  Changes since RFC 2511

   1.  Addition of an introduction section.

   2.  Addition of the concept of a CRP and language relating to CRPs.

   3.  In section 6.2, changed regToken to authenticator.

   4.  Add information describing the contents of the EncryptedValue
       structure.

   5.  Changed name and contents of OID {id-regInfo 1}.

   6.  Added text detailing what goes into the fields of the different
       structures defined in the document.

   7.  Replaced Appendix A with a reference to [RFC2875].  The only
       difference is that the old text specified to use subject alt name
       instead of subject name if subject name was empty.  This is not
       possible for a CA certificate issued using PKIX.  It would
       however be useful to update RFC 2875 to have this fallback
       position.

   7.  Insert Appendix C describing why POP is necessary and what some
       of the different POP attacks are.

   8.  pop field in the CertReqMsg structure has been renamed to popo to
       avoid confusion between POP and pop.

   9.  The use of the EncryptedValue structure has been deprecated in
       favor of the EnvelopedData structure.

   10.  Add details on how private keys are to be structured when
       encrypted.

   11.  Allow for POP on key agreement algorithms other than DH.

3.  CertReqMessage Syntax

   A certificate request message is composed of the certificate request,
   an optional proof-of-possession field, and an optional registration
   information field.

Schaad                      Standards Track                     [Page 4]
RFC 4211                  Internet X.509 CRMF             September 2005

   MSB           LSB
                      +-+-+-+-+-+-+-+-+
                      | |           | |
                      |1|D(6) - D(1)|1|
                      | |           | |
                      +-+-+-+-+-+-+-+-+
                       ^             ^
                       |             |
                       |             EA bit (always 1)
                       1 (multicast)

       Figure 2. Address mapping in multicasting (MAPOS version 1).

   MAPOS 16:

   The address field of the MAPOS 16 frame header contains the 16-bit-
   wide destination HDLC address [2].  The LSB of the first octet must
   always be 0 to indicate the continuation of this field, and the LSB
   of the second octet must always be 1 to indicate the end of this
   field.  The MSB of the first octet is used to indicate whether the
   frame is a unicast or a multicast frame.

   In the case of an IPv6 multicast, the MSB of the first octet is 1 to
   indicate that the frame is multicast.  As described above, the LSB of
   the first octet is 0 and the LSB of the second octet is 1.  The other
   13 bits of the address field must contain the lowest-order 13 bits of
   the IPv6 multicast address.  Figure 3 shows the address field of the
   MAPOS 16 frame header in the case of an IPv6 multicast, where D(1)
   through D(13) represent the lowest-order 13 bits of the IPv6
   multicast address.  Exceptions arise when these 13 bits are either
   all zeros or all ones.  In these cases, the address field should be
   0xFEFD (hexadecimal).

          MSB                           LSB
          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          | |           | |             | |
          |1|D(13)-D(8) |0|  D(7)-D(1)  |1|
          | |           | |             | |
          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           ^             ^               ^
           |             |               |
           |             |               +-- EA bit (always 1)
           |             +-- EA bit (always 0)
           1 (multicast)

           Figure 3. Address mapping in multicasting (MAPOS 16).

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3.  Interface Identifier

   This section specifies the method of forming the interface identifier
   [7].

   A node that has one or more MAPOS interfaces must create one or more
   EUI-64 [8] based interface identifiers.  Here, it should be noted
   that deriving interface identifiers from HDLC addresses of MAPOS
   interfaces is undesirable for the following reasons.

   1. When a node is connected to a frame switch, an HDLC address is
      assigned to the interface of the node from the frame switch via
      NSP [6].  (In the remainder of this document, the term "MAPOS
      address" is used to refer to the address.)  The value of the MAPOS
      address assigned to the interface depends on the combination of
      the switch number of the frame switch and the port number of the
      frame switch to which the interface is connected.  The switch
      number is required to be unique only within a MAPOS multi-switch
      environment [6]; that is, there can be frame switches that have
      the same switch number in different MAPOS multi-switch environment
      separated by IP routers.  Therefore, the uniqueness of a MAPOS
      address is guaranteed only within a MAPOS multi-switch
      environment.

      Furthermore, if an implementation ensures that the link between
      the interface of the node and the port of the frame switch is
      hot-swappable, the port number of the frame switch or the frame
      switch connected to the interface of the node can be changed, so
      the MAPOS address assigned to the interface can also be changed
      without performing a system re-start of the node.

      In short, the global uniqueness of a MAPOS address is not
      guaranteed, and a MAPOS address is not a built-in address but can
      be changed without performing a system re-start.  Thus, if an
      interface identifier were derived from a MAPOS address, it could
      also be changed without a system re-start.  This would not follow
      the recommendation in [7].

   2. In the case of a point-to-point connection between two nodes, the
      same MAPOS address is assigned to each interface.  Specifically,
      in the case of MAPOS version 1, the assigned address is 0x03 [6],
      and in the case of MAPOS 16, the assigned address is 0x0003 [2].
      It is not easy to achieve link-locality of the interface
      identifier in a strict manner using the same Link-layer address.

      For the above reasons, nodes with MAPOS interfaces must not derive
      their interface identifiers from their MAPOS addresses.

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      The following are methods of forming an interface identifier in
      the order of preference.  These are almost the same as the methods
      described in [9] except that a MAPOS address must not be used as a
      source of uniqueness when an IEEE global identifier is
      unavailable.

   1) If an IEEE global identifier (EUI-48 or EUI-64) is available
      anywhere on the node, it should be used to construct the interface
      identifier due to its uniqueness.  When extracting an IEEE global
      identifier from another device on the node, care should be taken
      to ensure that the extracted identifier is presented in canonical
      ordering [10].

      The only transformation from an EUI-64 identifier is to invert the
      "u" bit (universal/local bit in IEEE EUI-64 terminology).  For
      example, for a globally unique EUI-64 identifier as shown in
      Figure 4:

   MSB                                                               LSB
   |0              1|1              3|3              4|4              6|
   |0              5|6              1|2              7|8              3|
   +----------------+----------------+----------------+----------------+
   |cccccc0gcccccccc|cccccccceeeeeeee|eeeeeeeeeeeeeeee|eeeeeeeeeeeeeeee|
   +----------------+----------------+----------------+----------------+

               Figure 4. Globally unique EUI-64 identifier.

      where "c" are the bits of the assigned company_id, "0" is the
      value of the universal/local bit to indicate global scope, "g" is
      the group/individual bit, and "e" are the bits of the extension
      identifier, the IPv6 interface identifier would be as shown in
      Figure 5.  The only change is inverting the value of the
      universal/local bit.

   MSB                                                               LSB
   |0              1|1              3|3              4|4              6|
   |0              5|6              1|2              7|8              3|
   +----------------+----------------+----------------+----------------+
   |cccccc1gcccccccc|cccccccceeeeeeee|eeeeeeeeeeeeeeee|eeeeeeeeeeeeeeee|
   +----------------+----------------+----------------+----------------+

   Figure 5. IPv6 interface identifier derived from a globally unique
             EUI-64 identifier.

      In the case of an EUI-48 identifier, it is first converted to the
      EUI-64 format by inserting two octets, with hexadecimal values of
      0xFF and 0xFE, in the middle of the 48-bit MAC (between the
      company_id and extension-identifier portions of the EUI-48 value).

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      For example, for a globally unique 48-bit EUI-48 identifier as
      shown in Figure 6:

   MSB                                              LSB
   |0              1|1              3|3              4|
   |0              5|6              1|2              7|
   +----------------+----------------+----------------+
   |cccccc0gcccccccc|cccccccceeeeeeee|eeeeeeeeeeeeeeee|
   +----------------+----------------+----------------+

       Figure 6. Globally unique EUI-48 identifier.

      where "c" are the bits of the assigned company_id, "0" is the
      value of the universal/local bit to indicate global scope, "g" is
      the group/individual bit, and "e" are the bits of the extension
      identifier, the IPv6 interface identifier would be as shown in
      Figure 7.

   MSB                                                               LSB
   |0              1|1              3|3              4|4              6|
   |0              5|6              1|2              7|8              3|
   +----------------+----------------+----------------+----------------+
   |cccccc1gcccccccc|cccccccc11111111|11111110eeeeeeee|eeeeeeeeeeeeeeee|
   +----------------+----------------+----------------+----------------+

   Figure 7. IPv6 interface identifier derived from a globally unique
             EUI-48 identifier.

   2) If an IEEE global identifier is not available, a different source
      of uniqueness should be used.  Suggested sources of uniqueness
      include machine serial numbers, etc.  MAPOS addresses must not be
      used.

      In this case, the "u" bit of the interface identifier must be set
      to 0.

   3) If a good source of uniqueness cannot be found, it is recommended
      that a random number be generated.  In this case the "u" bit of
      the interface identifier must be set to 0.

4.  Duplicate Address Detection

   Immediately after the system start-up, the MAPOS address has not yet
   been assigned to a MAPOS interface.  The assignment is not completed
   until the adjacent frame switch, or adjacent node in the case of a
   point-to-point connection between two nodes, has delivered the MAPOS
   address to the interface via NSP [6].  Until then, no data
   transmission can be performed on the interface.  Thus, a node must

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   conduct duplicate address detection [11] on all unicast addresses of
   MAPOS interfaces after the MAPOS address assignment has been
   completed by NSP.

5.  Source/Target Link-layer Address Option

   As specified in [5], the Source/Target Link-layer Address option is
   one of the options included in Neighbor Discovery messages.  In [5],
   the length of the Source/Target Link-layer Address option field is
   specified in units of 8 octets.  However, in the case of MAPOS, the
   length of the address field is 2 octets (MAPOS 16) or 1 octet (MAPOS
   version 1)[1][2].  Thus, if the exact form of the address field is
   embedded in the Link-layer Address field of the Source/Target Link-
   layer Address option field, the total length of the option field is 4
   octets (MAPOS 16) or 3 octets (MAPOS version 1), both of which are
   shorter than 8 octets.

   For the above reason, in the case of MAPOS, the Link-layer Address
   field of the Source/Target Link-layer Address option must be extended
   with zeros in order to extend the length of the option field to 8
   octets, and the Length field must be set to 1 as shown below.

   MAPOS version 1:

    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     |             All 0             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     All 0     |    Address    |             All 0             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Fields:

   Type:                   1 for Source link-layer address.
                           2 for Target link-layer address.

   Length:                 1 (in units of 8 octets).

   Address:                MAPOS version 1 8-bit address.

   Figure 8. Format of the Source/Target Link-layer Address option
             field (MAPOS version 1).

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   MAPOS 16:

    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     |             All 0             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Link-layer Address        |             All 0             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Fields:

   Type:                   1 for Source link-layer address.
                           2 for Target link-layer address.

   Length:                 1 (in units of 8 octets).

   Link-layer Address:     MAPOS 16 16-bit address.

   Figure 9. Format of the Source/Target Link-layer Address option
             field (MAPOS 16).

6.  Security Considerations

   In MAPOS, a link-layer address (MAPOS address) is assigned to a
   network interface by a frame switch via NSP; unlike other link-layer
   protocols such as Ethernet that use a built-in address on a network
   interface.  Security considerations derived from this are described
   in 6.1 and 6.2.  Because there is no link-layer security in MAPOS,
   the same security considerations as those of other link-layer
   protocols would be applied to other points.

6.1.  Issues concerning Link-layer Addresses

6.1.1.  Protection against fraudulent reception of traffic

   In MAPOS, a MAPOS address is assigned by a frame switch, and it
   consists of the switch number and the port number of the switch to
   which the network interface is connected.  (In the case of a point-
   to-point connection between two nodes, a fixed address is assigned to
   their network interfaces.)  This brings the following advantages.

   1. The value of the MAPOS address of a MAPOS network interface
      indicates the location of the interface in the MAPOS network.  In
      other words, the value itself of the destination address of a
      MAPOS frame defines the actual location of the network interface
      to which the frame should be finally delivered.  Therefore, as
      long as MAPOS addresses of network interfaces of nodes that have

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      been connected to the network through proper administrative
      process are held and frames are delivered only to those addresses,
      other nodes cannot receive frames unless their network interfaces
      are connected to the same ports of frame switches as those to
      which network interfaces of properly administered nodes are
      connected. This makes fraudulent reception of traffic difficult.

   2. In the case where MAPOS addresses are not administered as
      mentioned above, it is possible that a malicious node could hijack
      traffic by spoofing its IPv6 address in a response to an IPv6
      Neighbor Discovery.  Even in this case, the node must advertise
      the true MAPOS address of its network interface in the response so
      that it can receive successive frames.  This makes it easy to
      pinpoint the location of the host.

6.1.2.  Protection against improper traffic

   A MAPOS frame does not have a field for including its sender's
   address.  Therefore, in the case where a node sends one-way improper
   traffic maliciously or accidentally, there is no way to obtain the
   sender's MAPOS address from the traffic and this leads to difficulty
   in identifying the node (because source IP addresses might be
   forged).

   An effective way to alleviate the difficulty is to moderate the size
   of MAPOS multi-switch environment [6].  A common approach is to
   separate it using IP routers.  This makes it easy to identify the
   node sending improper traffic within the multi-switch environment.
   To secure the environment against improper traffic from outside it,
   boundary IP routers need to block it using packet filtering based on
   IP layer information.

6.2.  Uniqueness of Interface Identifiers

   Global uniqueness of a MAPOS address is not guaranteed, and a MAPOS
   address is not a built-in address but can be changed without
   performing a system re-start if an implementation ensures that the
   link between the network interface of the node and the port of the
   frame switch is hot-swappable.  Thus, an interface identifier must
   not be derived from a MAPOS address in order to ensure that the
   interface identifier is not changed without a system re-start.

   As a consequence, in IP Version 6 over MAPOS, the existence of
   network interfaces other than MAPOS that have IEEE global identifier
   based addresses has great importance in creating interface
   identifiers.  However, it may be common for there to be no such
   interfaces on a node, so a different source of uniqueness must be
   used.  Therefore, sufficient care should be taken to prevent

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   duplication of interface identifiers.  At present, there is no
   protection against duplication through accident or forgery.

7.  References

   [1]  Murakami, K. and M. Maruyama, "MAPOS - Multiple Access protocol
        over SONET/SDH Version 1", RFC 2171, June 1997.

   [2]  Murakami, K. and M. Maruyama, "MAPOS 16 - Multiple Access
        Protocol over SONET/SDH with 16 Bit Addressing", RFC 2175, June
        1997.

   [3]  Simpson, W., Ed., "PPP in HDLC-like Framing", STD 51, RFC 1662,
        July 1994.

   [4]  Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
        Specification", RFC 2460, December 1998.

   [5]  Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery for
        IP Version 6 (IPv6)", RFC 2461, December 1998.

   [6]  Murakami, K. and M. Maruyama, "A MAPOS version 1 Extension -
        Node Switch Protocol", RFC 2173, June 1997.

   [7]  Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6)
        Addressing Architecture", RFC 3513, April 2003.

   [8]  IEEE, "Guidelines of 64-bit Global Identifier (EUI-64)
        Registration Authority",
        http://standards.ieee.org/db/oui/tutorials/EUI64.html, March
        1997.

   [9]  Haskin, D. and E. Allen, "IP Version 6 over PPP", RFC 2472,
        December 1998.

   [10] Narten, T. and C. Burton, "A Caution On The Canonical Ordering
        Of Link-Layer Addresses", RFC 2469, December 1998.

   [11] Thompson, S. and T. Narten, "IPv6 Stateless Address
        Autoconfiguration", RFC 2462, December 1998.

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8.  Authors' Addresses

   Tsuyoshi Ogura
   NTT Network Innovation Laboratories
   3-9-11, Midori-cho
   Musashino-shi
   Tokyo 180-8585, Japan

   EMail: ogura@core.ecl.net

   Mitsuru Maruyama
   NTT Network Innovation Laboratories
   3-9-11, Midori-cho
   Musashino-shi
   Tokyo 180-8585, Japan

   EMail: mitsuru@core.ecl.net

   Toshiaki Yoshida
   Werk Mikro Systems
   250-1, Mikajiri
   Kumagaya
   Saitama 360-0843, Japan

   EMail: yoshida@peta.arch.ecl.net

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9.  Full Copyright Statement

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assignees.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS 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.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.

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