[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 RFC 5072

Internet Draft                                 S.Varada (Transwitch)
Document: draft-ietf-ipv6-over-ppp-v2-01.txt  D.Haskins
Expires: December 2004                         Ed Allen
                                              June 2004


                           IP Version 6 over PPP
                   <draft-ietf-ipv6-over-ppp-v2-01.txt>


Status of this Memo

      By submitting this Internet-Draft, I certify that any applicable
      patent or other IPR claims of which I am aware have been
      disclosed, and any of which I become aware will be disclosed, in
      accordance with RFC 3668.

      Internet-Drafts are working documents of the Internet Engineering
      Task Force (IETF), its areas, and its working groups.  Note that
      other groups may also distribute working documents as
      Internet-Drafts.

      Internet-Drafts are draft documents valid for a maximum of six
      months and may be updated, replaced, or obsoleted by other
      documents at any time.  It is inappropriate to use Internet-Drafts
      as reference material or to cite them other than as "work in
      progress."

      The list of current Internet-Drafts can be accessed at
      http://www.ietf.org/ietf/1id-abstracts.txt.

      The list of Internet-Draft Shadow Directories can be accessed at
      http://www.ietf.org/shadow.html.

Copyright Notice

      Copyright (C) The Internet Society (2004).  All Rights Reserved.

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.



Varada et al.                                                 [Page 1]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


      This document defines the method for transmission of IP Version 6
      packets over PPP links as well as the NCP for establishing and
      configuring the IPv6 over PPP. It also specifies the method of
      forming IPv6 link-local addresses on PPP links.

      This document is an update to RFC 2472 and, hence, obsoletes it.

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
      4.2 IPv6-Compression-Protocol.................................10
   5. Stateless Autoconfiguration and Link-Local Addresses..........11
   6. Security Considerations.......................................12
   7. Acknowledgments...............................................12
   8. Normative References..........................................13
   9. Informative references........................................13
   Appendix A:  Global Scope Addresses..............................13
   Appendix B:  Changes from RFC-2472...............................14
   Authors' Addresses...............................................14
   IPR Disclosure...................................................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.


Varada et al.               December 2004                    [Page 2]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004



      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.).

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.

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




Varada et al.               December 2004                    [Page 3]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


        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 values are assigned as follows:

          1       Interface-Identifier
          2       IPv6-Compression-Protocol

      The only IPV6CP options defined in this document are Interface
      Identifier and IPv6-Compression-Protocol.  Any other IPV6CP
      configuration options that can be defined over time are to be
      defined in separate documents.


Varada et al.               December 2004                    [Page 4]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004



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 [8].

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



Varada et al.               December 2004                    [Page 5]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


          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


Varada et al.               December 2004                    [Page 6]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


           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


Varada et al.               December 2004                    [Page 7]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


      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).

      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


Varada et al.               December 2004                    [Page 8]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


      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.



Varada et al.               December 2004                    [Page 9]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004



        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.

4.2 IPv6-Compression-Protocol

      Description

      This Configuration Option provides a way to negotiate the use of a
      specific IPv6 packet compression protocol.  The
      IPv6-Compression-Protocol Configuration Option is used to indicate
      the ability to receive compressed packets.  Each end of the link
      must separately request this option if bi-directional compression
      is desired.  By default, compression is not enabled.

      IPv6 compression negotiated with this option is specific to IPv6
      datagrams and is not to be confused with compression resulting
      from negotiations via Compression Control Protocol (CCP), which
      potentially effect all datagrams.

      A summary of the IPv6-Compression-Protocol 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     |   IPv6-Compression-Protocol   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Data ...
      +-+-+-+-+

        Type

          2

        Length

          >= 4






Varada et al.               December 2004                   [Page 10]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


        IPv6-Compression-Protocol

         The IPv6-Compression-Protocol field is two octets and indicates
         the compression protocol desired.  Values for this field are
         always the same as the PPP Data Link Layer Protocol field
         values for that same compression protocol.

         No IPv6-Compression-Protocol field values are currently
         assigned. Specific assignments will be made in documents that
         define specific compression algorithms.

        Data

         The Data field is zero or more octets and contains additional
         data as determined by the particular compression protocol.

        Default

          No IPv6 compression protocol enabled.

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 cannot 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 created (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:



Varada et al.               December 2004                   [Page 11]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


     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 that satisfy the
      aforementioned two conditions, the default value of the
      DupAddrDetectTransmits autoconfiguration variable [3] be zero.
      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].


      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

      The IPv6 Control Protocol extension to PPP can be used with all
      defined PPP authentication and encryption mechanisms.


7. 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
      contributions.  Also, thanks to Alex Conta for a thorough
      reviewing.


Varada et al.               December 2004                   [Page 12]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004



8. 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.

   [6]   Hinden, R., and S. Deering, "IP Version 6 Addressing
         Architecture", RFC 3513, July 1998.

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

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

   [9]   Narten T., and R. Draves, "Privacy Extensions for Stateless
         Address Autoconfiguration in IPv6,ö RFC 3041, January 2001.

9.Informative references

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

   [11]  3GPP TS 29.061 V5.8.0, "Interworking between the Public Land
         Mobile Network (PLMN) Supporting packet based services and
         Packet Data Networks (PDN) (Release 5),ö January 2004.

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


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


Varada et al.               December 2004                   [Page 13]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


      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 "IP Version 6 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.

      -  Updated the text in Section 5 to: (a) option the use of one or
         more Interface-Identifiers generated, other than the IPV6CP
         negotiated, in the creation of global unicast addresses, 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.

      EMail: varada@txc.com

IPR Disclosure

      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.

IPR Notice

      The IETF takes no position regarding the validity or scope of any
      Intellectual Property Rights or other rights that might be claimed
      to pertain to the implementation or use of the technology


Varada et al.               December 2004                   [Page 14]

                  draft-ietf-ipv6-over-ppp-v2-01.doc         June 2004


      described in this document or the extent to which any license
      under such rights might or might not be available; nor does it
      represent that it has made any independent effort to identify any
      such rights.  Information on the procedures with respect to rights
      in RFC documents can be found in BCP 78 and BCP 79.

      Copies of IPR disclosures made to the IETF Secretariat and any
      assurances of licenses to be made available, or the result of an
      attempt made to obtain a general license or permission for the use
      of such proprietary rights by implementers or users of this
      specification can be obtained from the IETF on-line IPR repository
      at http://www.ietf.org/ipr.

      The IETF invites any interested party to bring to its attention
      any copyrights, patents or patent applications, or other
      proprietary rights that may cover technology that may be required
      to implement this standard.  Please address the information to the
      IETF at ietf-ipr@ietf.org.

Copyright Notice and Disclaimer

      Copyright (C) The Internet Society (2004).  This document is
      subject to the rights, licenses and restrictions contained in BCP
      78, and except as set forth therein, the authors retain all their
      rights.

      This document and the information contained herein are provided
      on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
      REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND
      THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES,
      EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT
      THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR
      ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
      PARTICULAR PURPOSE.

















Varada et al.               December 2004                   [Page 15]


Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/