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Versions: 00 01 02 03 RFC 5072

IPv6 Working Group                             S.Varada (Editor)
Internet-Draft                               Transwitch
Obsoletes: RFC 2472 (if approved)             D.Haskins
Category: Standards track                      Ed Allen
Expires: November 2007                         May 2007

                           IP Version 6 over PPP
                   <draft-ietf-ipv6-over-ppp-v2-03.txt>

Status of this Memo

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      BCP 79.

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Copyright Notice

      Copyright (C) The IETF Trust (2007).

Abstract

      The Point-to-Point Protocol (PPP) provides a standard method of
      encapsulating Network Layer protocol information over
      point-to-point links.  PPP also defines an extensible Link Control
      Protocol, and proposes a family of Network Control Protocols
      (NCPs) for establishing and configuring different network-layer
      protocols.

      This document defines the method for sending IPv6 packets over PPP
      links, the NCP for establishing and configuring the IPv6 over PPP
      and the method for forming IPv6 link-local addresses on PPP links.


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      It also specifies the conditions for performing Duplicate Address
      Detection on IPv6 global unicast addresses configured for PPP
      links either through stateful or stateless address
      autoconfiguration.

      This document obsoletes RFC 2472.

Table of Contents

   1. Introduction...................................................2
      1.1 Specification of Requirements..............................3
   2. Sending IPv6 Datagrams.........................................3
   3. A PPP Network Control Protocol for IPv6........................3
   4. IPV6CP Configuration Options...................................4
      4.1 Interface-Identifier.......................................5
   5. Stateless Autoconfiguration and Link-Local Addresses..........10
   6. Security Considerations.......................................11
   7. IANA Considerations...........................................12
   8. Acknowledgments...............................................12
   9. References....................................................12
      9.1 Normative References......................................12
      9.2 Informative references....................................13
   Appendix A:  Global Scope Addresses..............................13
   Appendix B:  Changes from RFC-2472...............................14
   Authors' Addresses...............................................14
   IPR Notice  .....................................................14
   Copyright Notice and Disclaimer..................................15


1. Introduction

      PPP has three main components:

      1) A method for encapsulating datagrams over serial links.

      2) A Link Control Protocol (LCP) for establishing, configuring,
         and testing the data-link connection.

      3) A family of Network Control Protocols (NCPs) for establishing
         and configuring different network-layer protocols.

      In order to establish communications over a point-to-point link,
      each end of the PPP link must first send LCP packets to
      configure and test the data link.  After the link has been
      established and optional facilities have been negotiated as
      needed by the LCP, PPP must send NCP packets to choose and
      configure one or more network-layer protocols.  Once each of the
      chosen network-layer protocols has been configured, datagrams
      from each network-layer protocol can be sent over the link.


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      In this document, the NCP for establishing and configuring the
      IPv6 over PPP is referred as the IPv6 Control Protocol (IPV6CP).

      The link will remain configured for communications until
      explicit LCP or NCP packets close the link down, or until some
      external event occurs (power failure at the other end, carrier
      drop, etc.).

      This document obsoletes the earlier specification from RFC 2472
      [8]. Changes from RFC 2472 are listed in Appendix B.

1.1 Specification of Requirements

      In this document, several words are used to signify the
      requirements of the specification.

      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 [7].

2. Sending IPv6 Datagrams

      Before any IPv6 packets may be communicated, PPP MUST reach the
      Network-Layer Protocol phase, and the IPv6 Control Protocol MUST
      reach the Opened state.

      Exactly one IPv6 packet is encapsulated in the Information field
      of PPP Data Link Layer frames where the Protocol field indicates
      Type hex 0057 (Internet Protocol Version 6).

      The maximum length of an IPv6 packet transmitted over a PPP link
      is the same as the maximum length of the Information field of a
      PPP data link layer frame.  PPP links supporting IPv6 MUST allow
      the information field at least as large as the minimum link MTU
      size required for IPv6 [2].

3. A PPP Network Control Protocol for IPv6

      The IPv6 Control Protocol (IPV6CP) is responsible for
      configuring, enabling, and disabling the IPv6 protocol modules
      on both ends of the point-to-point link.  IPV6CP uses the same
      packet exchange mechanism as the LCP. IPV6CP packets may not be
      exchanged until PPP has reached the Network-Layer Protocol phase.
      IPV6CP packets received before this phase is reached should be
      silently discarded.




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      The IPv6 Control Protocol is exactly the same as the LCP [1] with
      the following exceptions:

        Data Link Layer Protocol Field

            Exactly one IPV6CP packet is encapsulated in the
            Information field of PPP Data Link Layer frames where the
            Protocol field indicates type hex 8057 (IPv6 Control
            Protocol).

        Code field

            Only Codes 1 through 7 (Configure-Request, Configure-Ack,
            Configure-Nak, Configure-Reject, Terminate-Request,
            Terminate-Ack and Code-Reject) are used.  Other Codes
            should be treated as unrecognized and should result in
            Code-Rejects.

        Timeouts

             IPV6CP packets may not be exchanged until PPP has reached
             the Network-Layer Protocol phase.  An implementation
             should be prepared to wait for Authentication and Link
             Quality Determination to finish before timing out waiting
             for a Configure-Ack or other response.  It is suggested
             that an implementation give up only after user
             intervention or a configurable amount of time.

        Configuration Option Types

             IPV6CP has a distinct set of Configuration Options.

4. IPV6CP Configuration Options

      IPV6CP Configuration Options allow negotiation of desirable IPv6
      parameters.  IPV6CP uses the same Configuration Option format
      defined for LCP [1] but with a separate set of Options.  If a
      Configuration Option is not included in a Configure-Request
      packet, the default value for that Configuration Option is
      assumed.

      Up-to-date values of the IPV6CP Option Type field are specified
      in the on-line database of "Assigned Numbers" maintained at
      IANA [4].  Current value is assigned as follows:

         1 Interface-Identifier

      The only IPV6CP option defined in this document is the Interface
      Identifier.  Any other IPV6CP configuration options that can be


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      defined over time are to be defined in separate documents.

4.1 Interface-Identifier

      Description

      This Configuration Option provides a way to negotiate an unique
      64-bit interface identifier to be used for the address
      autoconfiguration [3] at the local end of the link (see
      section 5).  A Configure-Request MUST contain exactly one
      instance of the Interface-Identifier option [1].  The interface
      identifier MUST be unique within the PPP link; i.e. upon
      completion of the negotiation different Interface-Identifier
      values are to be selected for the ends of the PPP link.  The
      interface identifier may also be unique over a broader scope.

      Before this Configuration Option is requested, an implementation
      chooses its tentative Interface-Identifier.  The non-zero value of
      the tentative Interface-Identifier SHOULD be chosen such that the
      value is unique to the link and, preferably, consistently
      reproducible across initializations of the IPV6CP finite state
      machine (administrative Close and reOpen, reboots, etc).  The
      rationale for preferring a consistently reproducible unique
      interface identifier to a completely random interface identifier
      is to provide stability to global scope addresses (see Appendix A)
      that can be formed from the interface identifier

      Assuming that interface identifier bits are numbered from 0 to
      63 in canonical bit order where the most significant bit is
      the bit number 0, the bit number 6 is the "u" bit (universal/local
      bit in  IEEE EUI-64 [5] terminology) which indicates whether or
      not the interface identifier is based on a globally unique IEEE
      identifier (EUI-48 or EUI-64[5])(see the case 1 below).  It is set
      to one (1) if a globally unique IEEE identifier is used to derive
      the interface-identifier, and it is set to zero (0) otherwise.

      The following are methods for choosing the tentative Interface
      Identifier in the preference order:

        1)If an IEEE global identifier (EUI-48 or EUI-64) is
          available anywhere on the node, it should be used to
          construct the tentative Interface-Identifier due to its
          uniqueness properties.  When extracting an IEEE global
          identifier from another device on the node, care should be
          taken that the extracted identifier is presented in
          canonical ordering [14].

          The only transformation from an EUI-64 identifier is to invert
          the "u" bit (universal/local bit in IEEE EUI-64 terminology).


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          For example, for a globally unique EUI-64 identifier of the
          form:

   most-significant                                    least significant
   bit                                                               bit
   |0              1|1              3|3              4|4              6|
   |0              5|6              1|2              7|8              3|
   +----------------+----------------+----------------+----------------+

   |cccccc0gcccccccc|cccccccceeeeeeee|eeeeeeeeeeeeeeee|eeeeeeeeeeeeeeee|
   +----------------+----------------+----------------+----------------+

            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 group/individual bit, and "e" are the bits
           of the extension identifier, the IPv6 interface identifier
           would be of the form:

   most-significant                                    least-significant
   bit                                                               bit
   |0              1|1              3|3              4|4              6|
   |0              5|6              1|2              7|8              3|
   +----------------+----------------+----------------+----------------+

   |cccccc1gcccccccc|cccccccceeeeeeee|eeeeeeeeeeeeeeee|eeeeeeeeeeeeeeee|
   +----------------+----------------+----------------+----------------+

           The only change is inverting the value of the
           universal/local bit.

           In the case of a EUI-48 identifier, it is first converted
           to the EUI-64 format by inserting two bytes, with
           hexa-decimal 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).  For example, for a globally
           unique 48 bit EUI-48 identifier of the
           form:

      most-significant                   least-significant
      bit                                              bit
      |0              1|1              3|3              4|
      |0              5|6              1|2              7|
      +----------------+----------------+----------------+
      |cccccc0gcccccccc|cccccccceeeeeeee|eeeeeeeeeeeeeeee|
      +----------------+----------------+----------------+

           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 group/individual bit, and "e" are the bits


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           of the extension identifier, the IPv6 interface identifier
           would be of the form:

   most-significant                                    least-significant
   bit                                                               bit
   |0              1|1              3|3              4|4              6|
   |0              5|6              1|2              7|8              3|
   +----------------+----------------+----------------+----------------+

   |cccccc1gcccccccc|cccccccc11111111|11111110eeeeeeee|eeeeeeeeeeeeeeee|
   +----------------+----------------+----------------+----------------+

        2) If an IEEE global identifier is not available, a different
           source of uniqueness should be used.  Suggested sources of
           uniqueness include link-layer addresses, machine serial
           numbers, et cetera.  In this case, the "u" bit of the
           interface-identifier MUST be set to zero (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
           zero (0).

      Good sources [1] of uniqueness or randomness are required for
      the Interface-Identifier negotiation to succeed.  If neither an
      unique number or a random number can be generated, it is
      recommended that a zero value be used for the Interface
      Identifier transmitted in the Configure-Request.  In this case
      the PPP peer may provide a valid non-zero Interface-Identifier
      in its response as described below. Note that if at least one of
      the PPP peers is able to generate separate non-zero numbers for
      itself and its peer, the identifier negotiation will succeed.

      When a Configure-Request is received with the Interface
      Identifier Configuration Option and the receiving peer
      implements this option, the received Interface-Identifier is
      compared with the Interface-Identifier of the last
      Configure-Request sent to the peer. Depending on the result of the
      comparison an implementation MUST respond in one of the
      following ways:

      If the two Interface-Identifiers are different but the received
      Interface-Identifier is zero, a Configure-Nak is sent with a
      non-zero Interface-Identifier value suggested for use by the
      remote peer.  Such a suggested Interface-Identifier MUST be
      different from the Interface-Identifier of the last
      Configure-Request sent to the peer.  It is recommended that the
      value suggested be consistently reproducible across
      initializations of the IPV6CP finite state machine (administrative


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      Close and reOpen, reboots, etc). The "u" (universal/local) bit of
      the suggested identifier MUST be set to zero (0) regardless of its
      source unless the globally unique EUI-48/EUI-64 derived
      identifier is provided for the exclusive use by the remote peer.

      If the two Interface-Identifiers are different and the received
      Interface-Identifier is not zero, the Interface-Identifier MUST be
      acknowledged, i.e.  a Configure-Ack is sent with the requested
      Interface-Identifier, meaning that the responding peer agrees with
      the Interface-Identifier requested.

      If the two Interface-Identifiers are equal and are not zero,
      Configure-Nak MUST be sent specifying a different non-zero
      Interface-Identifier value suggested for use by the remote peer.
      It is recommended that the value suggested be consistently
      reproducible across initializations of the IPV6CP finite state
      machine (administrative Close and reOpen, reboots, etc).  The "u"
      (universal/local) bit of the suggested identifier MUST be set to
      zero (0) regardless of its source unless the globally unique
      EUI-48/EUI-64 derived identifier is provided for the exclusive use
      by the remote peer.

      If the two Interface-Identifiers are equal to zero, the Interface
      Identifiers negotiation MUST be terminated by transmitting the
      Configure-Reject with the Interface-Identifier value set to zero.
      In this case a unique Interface-Identifier can not be negotiated.

      If a Configure-Request is received with the Interface-Identifier
      Configuration Option and the receiving peer does not implement
      this option, Configure-Rej is sent.

      A new Configure-Request SHOULD NOT be sent to the peer until
      normal processing would cause it to be sent (that is, until a
      Configure-Nak is received or the Restart timer runs out [1]).

      A new Configure-Request MUST NOT contain the Interface-Identifier
      option if a valid Interface-Identifier Configure-Reject is
      received.

      Reception of a Configure-Nak with a suggested Interface-Identifier
      different from that of the last Configure-Nak sent to the peer
      indicates an unique Interface-Identifier.  In this case a new
      Configure-Request MUST be sent with the identifier value suggested
      in the last Configure-Nak from the peer.  But if the received
      Interface-Identifier is equal to the one sent in the last
      Configure-Nak, a new Interface-Identifier MUST be chosen.  In this
      case, a new Configure-Request SHOULD be sent with the new
      tentative Interface-Identifier.  This sequence (transmit
      Configure-Request, receive Configure-Request, transmit


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      Configure-Nak, receive Configure-Nak) might occur a few times, but
      it is extremely unlikely to occur repeatedly.  More likely, the
      Interface-Identifiers chosen at either end will quickly diverge,
      terminating the sequence.

      If negotiation of the Interface-Identifier is required, and the
      peer did not provide the option in its Configure-Request, the
      option SHOULD be appended to a Configure-Nak.  The tentative value
      of the Interface-Identifier given must be acceptable as the remote
      Interface-Identifier; i.e.  it should be different from the
      identifier value selected for the local end of the PPP link.  The
      next Configure-Request from the peer may include this option.  If
      the next Configure-Request does not include this option the peer
      MUST NOT send another Configure-Nak with this option included.  It
      should assume that the peer's implementation does not support this
      option.

      By default, an implementation SHOULD attempt to negotiate the
      Interface-Identifier for its end of the PPP connection.

      A summary of the Interface-Identifier Configuration Option format
      is shown below.  The fields are transmitted from left to right.


      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     | Interface-Identifier (MS Bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                           Interface-Identifier (cont)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Interface-Identifier (LS Bytes) |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

        Type

          1

        Length

          10
        Interface-Identifier

          The 64-bit Interface-Identifier, which is very likely to be
          unique on the link, or zero if a good source of uniqueness
          can not be found.





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        Default

          If no valid interface identifier can be successfully
          negotiated, no default Interface-Identifier value should be
          assumed. The procedures for recovering from such a case are
          unspecified.  One approach is to manually configure the
          interface identifier of the interface.

5. Stateless Autoconfiguration and Link-Local Addresses

      The Interface-Identifier of IPv6 unicast addresses [6] of a PPP
      interface, SHOULD be negotiated in the IPV6CP phase of the PPP
      connection setup (see section 4.1).  If no valid Interface
      Identifier has been successfully negotiated, procedures for
      recovering from such a case are unspecified.  One approach is to
      manually configure the Interface-Identifier of the interface.

      The negotiated Interface-Identifier is used by the local end of
      the PPP link to autoconfigure IPv6 link-local unicast address for
      the PPP interface.  However, it SHOULD NOT be assumed that the
      same Interface-Identifier is used in configuring global unicast
      addresses for the PPP interface using IPv6 stateless address
      autoconfiguration [3].  The PPP peer MAY generate one or more
      Interface Identifiers, for instance, using a method described in
      [9], to autoconfigure one or more global unicast addresses.

      As long as the Interface-Identifier is negotiated in the IPV6CP
      phase of the PPP connection setup, it is redundant to perform
      duplicate address detection (DAD) as a part of the IPv6 Stateless
      Address Autoconfiguration protocol [3] on the IPv6 link-local
      address generated by the PPP peer.  It may also be redundant to
      perform DAD on any global unicast addresses configured (using an
      Interface-Identifier that is either negotiated during IPV6CP or
      generated, for instance, as per [9]) for the interface as part of
      the IPv6 Stateless Address Autoconfiguration protocol [3] provided
      that the following two conditions are met:

     1) The prefixes advertised, through the Router Advertisement
        messages, by the access router terminating the PPP link are
        exclusive to the PPP link.

      2) The access router terminating the PPP link does not
         autoconfigure any IPv6 global unicast addresses from the
         prefixes that it advertises.

      Therefore, it is RECOMMENDED that for PPP links with the IPV6CP
      Interface-Identifier option enabled and satisfying the
      aforementioned two conditions, the default value of the
      DupAddrDetectTransmits autoconfiguration variable [3] is set to


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      zero by the system management. 3GPP2 networks are an example of a
      technology that uses PPP to enable a host to obtain an IPv6 global
      unicast address and satisfies the aforementioned two conditions
      [10]. 3GPP networks are another example [11] & [13].

      Link-local addresses

      Link-local addresses of PPP interfaces have the following
      format:

   | 10 bits  |        54 bits         |          64 bits            |
   +----------+------------------------+-----------------------------+
   |1111111010|           0            |    Interface-Identifier     |
   +----------+------------------------+-----------------------------+

      The most significant 10 bits of the address is the Link-Local
      prefix FE80::.  54 zero bits pad out the address between the
      Link-Local prefix and the Interface-Identifier fields.

6. Security Considerations

      Lack of link security, such as authentication, trigger the
      security concerns raised in [3] when stateless address auto-
      configuration method is employed for the generation of global
      unicast IPv6 addresses out of interface identifiers that are
      either negotiated through the IPV6CP or generated, for instance,
      using a method described in [9]. Thus, the mechanisms that are
      appropriate for ensuring PPP link security are addressed below
      together with the reference to a generic threat model.

      The mechanisms that are appropriate for ensuring PPP link
      Security are: 1) Access Control Lists that apply filters on
      traffic received over the link for enforcing admission policy, 2)
      an Authentication protocol that facilitates negotiations between
      peers [15] to select an authentication method (e.g., MD5 [16])
      for validation of the peer, and 3) an Encryption protocol that
      facilitates negotiations between peers to select encryption
      algorithms (or, crypto-suites) to ensure data confidentiality
      [17]).

      There are certain threats associated with peer interactions on a
      PPP link even with one or more of the above security measures in
      place. For instance, using MD5 authentication method [16] exposes
      one to replay attack, where in which, an attacker could intercept
      and replay a station's identity and password hash to get access to


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      a network. The user of this specification is advised to refer to
      [15], which presents a generic threat model, for an understanding
      of the threats posed to the security of a link. The reference
      [15] also gives framework to specify requirements for the
      selection of an authentication method for a given application.

7. IANA Considerations

      The editor has no specific recommendations for the IANA on the
      assignment of a value for the Type field of IPv6 datagram
      Interface-Identifier option specified in this specification. The
      current assignment is up-to-date at [4]. However, the reference
      to the RFC number needs to be updated.

8. Acknowledgments

      This document borrows from the Magic-Number LCP option and as such
      is partially based on previous work done by the PPP working group.

      The editor is grateful for the input provided by members of the
      IPv6 community in the spirit of updating the RFC 2472. Thanks, in
      particular, go to Pete Barany and Karim El-malki for their
      technical contributions.  Also, thanks to Alex Conta, for a
      thorough reviewing, Stephen Kent, for helping with security
      aspects, Spencer Dawkins and Pekka Savola for the nits. Finally,
      the author is grateful to Jari Arkko, for his initiation to bring
      closure to this specification.

9. References

9.1 Normative References

   [1]   Simpson, W., "The Point-to-Point Protocol," STD 51, RFC
         1661, July 1994.

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

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

   [4]   IANA, "Assigned Numbers," http://www.iana.org/numbers.html

   [5]   IEEE, "Guidelines for 64-bit Global Identifier (EUI-64)
         Registration Authority", April 2004.




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   [6]   Hinden, R., and S. Deering, "IP Version 6 Addressing
         Architecture", RFC 4291, February 2006.

   [7]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels," BCP 14, RFC 2119, March 1997.

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

   [9]   Narten T., et. al., " Privacy Extensions for Stateless Address
         Autoconfiguration in IPv6," draft-ietf-ipv6-privacy-addrs-v2-
         05, August 2006.

9.2 Informative references

   [10]  3GPP2 X.S0011-002-C v1.0, "cdma2000 Wireless IP Network
         Standard: Simple IP and Mobile IP Access Services," September
         2003.

   [11]  3GPP TS 29.061 V6.4.0, "Interworking between the Public Land
         Mobile Network (PLMN) Supporting packet based services and
         Packet Data Networks (PDN) (Release 6)," April 2005.

   [12]  Droms, E., et al., "Dynamic Host Configuration Protocol for
         IPv6 (DHCPv6)," RFC 3315, July 2003.

   [13]  3GPP TS 23.060 v6.8.0, "General Packet Radio Service (GPRS);
         Service description; Stage 2 (Release 6)," March 2005.

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

   [15]  Aboba, R., et. al., "Extensible Authentication Protocol," RFC
         3748, June 2004.

   [16]  Rivest, R., "The MD5 Message-Digest Algorithm," RFC 1321, April
         1992.

   [17]  Meyer, G., "The PPP Encryption Control Protocol (ECP)," RFC
         1968, June 1996.

Appendix A:  Global Scope Addresses

      A node on the PPP link MUST create global unicast addresses either
      through stateless or stateful address auto-configuration
      mechanisms.  In the stateless address auto-configuration [3], the
      node relies on sub-net prefixes advertised by the router via the


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      Router Advertisement messages to obtain global unicast addresses
      from an interface identifier.  In the stateful address auto-
      configuration, the host relies on a Stateful Server, like, DHCPv6
      [12], to obtain global unicast addresses.

Appendix B:  Changes from RFC-2472

      The following changes were made from RFC-2472 "IPv6 over PPP":

      -  Minor updates to sections 3 and 4

      -  Updated the text in section 4.1 to include the reference to
         Appendix A and minor text clarifications.

      -  Removed the section 4.2 on IPv6-Compression-Protocol, based on
         the IESG recommendation, and created a new standards track
         draft to cover the negotiation of IPv6 datagram compression
         protocol using IPV6CP.

      -  Updated the text in Section 5 to: (a) allow the use of one or
         more Interface-Identifiers generated by a peer, in addition to
         the use of Interface-identifier negotiated between peers of the
         link, in the creation of global unicast addresses for the local
         PPP interface, and (b) identify cases against the DAD of
         created non-link-local addresses.

      -  Added new and updated references.

      -  Added the Appendix A

Authors' Addresses

      Dimitry Haskin
      Ed Allen

      Srihari Varada (Editor)
      TranSwitch Corporation
      3 Enterprise Dr.
      Shelton, CT 06484. US.

      Phone: +1 203 929 8810
      EMail: varada@txc.com

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                  draft-ietf-ipv6-over-ppp-v2-03.txt          May 2007


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