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DMM Working Group                                                W. Feng
Internet-Draft                                                       PSU
Intended status: Standards Track                                D. Moses
Expires: September 18, 2018                                        Intel
                                                          March 17, 2018


         Router Advertisement Extensions for On-Demand Mobility
                    draft-feng-dmm-ra-prefixtype-02

Abstract

   Router Advertisement / Router Solicitation is one of the ways for
   hosts to establish network IPv6 connectivity configuration.  This
   document describes two approches to allowing a router to specify
   service continuity type availability to mobile hosts.  Mobile hosts
   can then configure their IP address to the preferred service
   continuity type.  Two possibilities are considered: (i) creating an
   extension to the router advertisement prefix information option to
   allow the router to specify service connectivity types, and (ii)
   specifying a new RA options that allows the router to specify the
   service connectivity types.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on September 18, 2018.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of



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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Notational Conventions  . . . . . . . . . . . . . . . . . . .   2
   3.  Router Advertisement Extensions . . . . . . . . . . . . . . .   2
     3.1.  Modifying PIO . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Adding a new RA option  . . . . . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   [I-D.ietf-dmm-ondemand-mobility] defines different types of mobility
   related network services provided by access network to mobile hosts.
   In particular, it defines different types of service continuity types
   as mobile nodes move between different points of attachments.

   This document proposes two such options to the router advertisement
   message ([RFC4861]) to allow the router to convey service continuty
   types services associated with an Ipv6 prefix.  The possibilities
   considered are: (i) creating an extension to the router advertisement
   prefix information option to allow the router to specify service
   connectivity types, and (ii) specifying a new RA options that allows
   the router to specify the service connectivity types.

2.  Notational Conventions

   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 [RFC2119].

3.  Router Advertisement Extensions

   IP prefixes are conveyed in Router Advertisement messages through the
   Prefix Information Option field ([RFC4861]).  These prefix
   information option fields are used to allow hosts to configure their
   IPv6 addresses.



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   For distributed mobility management, there is a need for a network to
   be able to convey different prefixes for different connectivity
   scenarios.  [I-D.ietf-dmm-ondemand-mobility] defines different
   service continuity requirements including: Non-Persistent, Session-
   Lasting, Fixed, and Graceful-replacement.  Currently, however, there
   is no way for a router to specify the continuity type through a
   router advertisement message.

   This document proposes two possibilities for modifying the router
   advertisement message to include service continuity options that it
   is offering to mobile hosts that are attached: (i) creating an
   extension to the router advertisement prefix information option (PIO)
   to allow the router to specify service connectivity types, and (ii)
   specifying a new RA options that allows the router to specify the
   service connectivity types.

3.1.  Modifying PIO

   The first option is to modify the PIO.  The advantages of this
   approach are that it is semantically in line with the intended
   function.  That is, specifying prefix options.  This, however,
   requires the modification of several bits in the existing PIO to
   support the specification of the service connectivity type.

   The modified prefix information option fields are shown in the
   following figure:


        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     | Prefix Length |L|A| Rsv1|SrvTp|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         Valid Lifetime                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                       Preferred Lifetime                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                           Reserved2                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       +                                                               +
       |                                                               |
       +                            Prefix                             +
       |                                                               |
       +                                                               +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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   Fields:

   Type           3

   Length         4

   Prefix Length  8-bit unsigned integer.  The number of leading bits in
                  the Prefix that are valid.  The value ranges from 0 to
                  128.

   L              1-bit on-link flag.  When set, indicates that this
                  prefix can be used for on-link determination.

   A              1-bit autonomous address-configuration flag.  When set
                  indicates that this prefix can be used for stateless
                  address configuration.

   Rsv1           3-bit unused field.  It MUST be initialized to zero by
                  the sender and MUST be ignored by the receiver.

   SrvTp          3-bit field that specifies the service type.  The
                  field can have the following values:



                  Non-Persistent -   a non-persistent IP prefix (1)

                  Session-Lasting -   a session-lasting IP prefix (2)

                  Fixed -        a fixed IP prefix (3)

                  Graceful-replacement -   a graceful-replacement IP
                                 prefix (4)

   The definition of these service types is available in
   [I-D.ietf-dmm-ondemand-mobility].

   0 is reserved and should not be used.  All other values (5-7) are
   reserved for future use.

   The value of the Service Type indicates the type of continuity
   service committed by the network for the associated IPv6 prefix.

   Once an IPv6 prefix type is provided, any subsequent messages
   involving this prefix (lease renewal - for example) must include the
   IPv6 Continuity Service option with the same service type that was
   assigned by the server during the initial allocation.




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   Given the list of IPv6 prefixes and their associated service
   connectivity type, the mobile host can then configure its IP address
   to the appropriate service required by the application

   Mobile hosts that do not support this new option should ignore the
   prefix information option.

   Routers should also send an additional prefix information option
   without the session-type field from time to time for hosts that do
   not support this new format.

3.2.  Adding a new RA option

   The second approach is to add a new RA option alongside the existing
   PIO (and other RA options).  The advantage of this approach are that
   it leaves the existing PIO untouched.  Furthermore, hosts that
   receive this option with the type that they do not understand can
   simply disregard it.

   The new RA option specification is shown in the following figure:


        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     | Prefix Length |L|A| Rsv1|SrvTp|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         Valid Lifetime                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                       Preferred Lifetime                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                           Reserved2                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       +                                                               +
       |                                                               |
       +                            Prefix                             +
       |                                                               |
       +                                                               +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Fields:

   Type           Need to define new Type #

   Length         4




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   Prefix Length  8-bit unsigned integer.  The number of leading bits in
                  the Prefix that are valid.  The value ranges from 0 to
                  128.

   L              1-bit on-link flag.  When set, indicates that this
                  prefix can be used for on-link determination.

   A              1-bit autonomous address-configuration flag.  When set
                  indicates that this prefix can be used for stateless
                  address configuration.

   Rsv1           3-bit unused field.  It MUST be initialized to zero by
                  the sender and MUST be ignored by the receiver.

   SrvTp          3-bit field that specifies the service type.  The
                  field can have the following values:



                  Non-Persistent -   a non-persistent IP prefix (1)

                  Session-Lasting -   a session-lasting IP prefix (2)

                  Fixed -        a fixed IP prefix (3)

                  Graceful-replacement -   a graceful-replacement IP
                                 prefix (4)

   The definition of these service types is available in
   [I-D.ietf-dmm-ondemand-mobility].

   0 is reserved and should not be used.  All other values (5-7) are
   reserved for future use.

   The value of the Service Type indicates the type of continuity
   service committed by the network for the associated IPv6 prefix.

   Once an IPv6 prefix type is provided, any subsequent messages
   involving this prefix (lease renewal - for example) must include the
   IPv6 Continuity Service option with the same service type that was
   assigned by the server during the initial allocation.

   Given the list of IPv6 prefixes and their associated mobility service
   type, the mobile host can then configure its IP address to the
   appropriate service required by the application

   Mobile hosts that do not support this new option should ignore the
   prefix information option.



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   Routers should also send an additional prefix information option
   without the session-type field from time to time for hosts that do
   not support this new format.

4.  Security Considerations

   There are no specific security considerations for this option.

5.  IANA Considerations

   TBD

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

6.2.  Informative References

   [I-D.ietf-dmm-distributed-mobility-anchoring]
              Chan, A., Wei, X., Lee, J., Jeon, S., and C. Bernardos,
              "Distributed Mobility Anchoring", draft-ietf-dmm-
              distributed-mobility-anchoring-08 (work in progress),
              March 2018.

   [I-D.ietf-dmm-ondemand-mobility]
              Yegin, A., Moses, D., Kweon, K., Lee, J., Park, J., and S.
              Jeon, "On Demand Mobility Management", draft-ietf-dmm-
              ondemand-mobility-13 (work in progress), January 2018.

   [RFC3315]  Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
              C., and M. Carney, "Dynamic Host Configuration Protocol
              for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
              2003, <https://www.rfc-editor.org/info/rfc3315>.

   [RFC3633]  Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
              Host Configuration Protocol (DHCP) version 6", RFC 3633,
              DOI 10.17487/RFC3633, December 2003,
              <https://www.rfc-editor.org/info/rfc3633>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007,
              <https://www.rfc-editor.org/info/rfc4861>.



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   [RFC7934]  Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi,
              "Host Address Availability Recommendations", BCP 204,
              RFC 7934, DOI 10.17487/RFC7934, July 2016,
              <https://www.rfc-editor.org/info/rfc7934>.

Authors' Addresses

   Wu-chi Feng
   Portland State Univ.
   Hillsboro
   USA

   Email: wuchi@pdx.edu


   Danny Moses
   Intel
   Petah Tikva
   Israel

   Email: danny.moses@intel.com






























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