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Versions: 00 01 02 03 04 05 06 RFC 6626

Network Working Group                                        G. Tsirtsis
Internet-Draft                                                   V. Park
Intended status: Standards Track                            V. Narayanan
Expires: October 30, 2011                                       Qualcomm
                                                                K. Leung
                                                                   Cisco
                                                          April 28, 2011


                  Dynamic Prefix Allocation for NEMOv4
                 draft-ietf-mip4-nemov4-dynamic-05.txt

Abstract

   The base NEMOv4 specification defines extensions to Mobile IPv4 for
   mobile networks.  This specification defines a dynamic prefix
   allocation mechanism.

Status of this Memo

   This Internet-Draft is submitted to IETF 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 http://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 October 30, 2011.

Copyright Notice

   Copyright (c) 2011 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   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



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   described in the Simplified BSD License.


Table of Contents

   1.  Requirements notation  . . . . . . . . . . . . . . . . . . . .  3
   2.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Dynamic Mobile Prefix allocation . . . . . . . . . . . . . . .  5
     3.1.  Mobile Client Considerations . . . . . . . . . . . . . . .  5
     3.2.  Home Agent Considerations  . . . . . . . . . . . . . . . .  5
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . .  7
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  9
   7.  Normative References . . . . . . . . . . . . . . . . . . . . . 10
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11




































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1.  Requirements notation

   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].














































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2.  Introduction

   The base NEMOv4 specification [RFC5177] defines extensions to Mobile
   IPv4 [RFC5944] for mobile networks.  This specification adds support
   for dynamic allocation of mobile prefixes by the home agent.














































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3.  Dynamic Mobile Prefix allocation

   The following extension is defined according to this specification.

3.1.  Mobile Client Considerations

   [RFC5177] defines that the prefix field of the mobile network request
   extension can not be set to zero.  This mechanism works only in
   combination with the explicit mode of operation defined in [RFC5177].

   According to this specification, a Mobile Router MAY include one or
   more mobile network request extensions with the prefix field set to
   zero.  Such mobile network request extensions indicate that the
   Mobile Router requests mobile network prefix(es) to be assigned to it
   by the home agent.  In this case, the Mobile Router MAY set the
   prefix length field of such extensions to zero or to a length of its
   choice as a hint to the home agent.  According to this specification,
   mobile network request extensions with the prefix field set to zero
   MAY be included in a registration request message either during
   initial registration or during a subsequent registration.

   When a Mobile Router receives a registration reply it MUST process it
   as defined in Mobile IPv4 [RFC5944] and [RFC5177].  If one or more
   network acknowledgement extension are included with the Code field
   set to "Success" the Mobile Router SHOULD treat the prefixes in the
   corresponding prefix fields as allocated prefixes and create the
   appropriate bindings as defined in [RFC5177].

   If in response to a registration request with a mobile network
   request extension with the prefix field set to zero, a Mobile Router
   receives a registration reply with a network acknowledgement
   extension including Code field set to 1 "invalid prefix", it may use
   it as a hint that the home agent does not support dynamic prefix
   allocation.

3.2.  Home Agent Considerations

   A home agent receiving a mobile network request extension with the
   prefix field set to zero MAY return a mobile network acknowledgement
   extension [RFC5177] with the prefix field set to the prefix allocated
   to the Mobile Router.  The length of that prefix is at the discretion
   of the home agent.  The home agent MAY take into account the prefix
   length hint if one is included in the mobile network request
   extension.  Once the home agent allocates a prefix it MUST maintain
   the prefix registration table as defined in [RFC5177].  Alternatively
   the home agent MAY return a mobile network acknowledgement extension
   with the Code field set to one of the negative codes defined in
   [RFC5177].



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   Dynamic mobile prefix allocation as defined in this specification MAY
   be combined with dynamic home address allocation as defined in
   [RFC5177].  In other words the home address field of the registration
   request message MAY be set to zero while the message also includes
   one or more mobile network request extensions with the prefix field
   also set to zero.

   Once the home agent allocates a prefix it MUST maintain the prefix
   registration table as defined in [RFC5177].  The lifetime of the
   allocated prefix will be equal to the lifetime of the binding cache
   entry

   For dynamic prefix allocation the Mobile Router's home address MAY be
   used to identify the client if it is not set to zero.  Otherwise, as
   defined in the NAI extension [RFC2794] of Mobile IPv4 [RFC2794], the
   NAI extension needs to be included in the registration request, in
   which case the same extension SHOULD be used to identify the Mobile
   Router for prefix allocation purposes.

































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4.  Security Considerations

   This specification operates in the security constraints and
   requirements of Mobile IPv4 [RFC5944], NAI [RFC2794] and [RFC5177].

   Home agent implementations SHOULD take steps to prevent address
   exhaustion attacks.  One way to limit the effectiveness of such an
   attack is to limit the number and size of prefixes any one mobile
   router can be allocated.










































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5.  IANA Considerations

   This document has no actions for IANA
















































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6.  Acknowledgements

   The authors would like to thank Pete McCann and Alexandru Petrescu
   for their reviews and comments.















































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7.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2794]  Calhoun, P. and C. Perkins, "Mobile IP Network Access
              Identifier Extension for IPv4", RFC 2794, March 2000.

   [RFC5177]  Leung, K., Dommety, G., Narayanan, V., and A. Petrescu,
              "Network Mobility (NEMO) Extensions for Mobile IPv4",
              RFC 5177, April 2008.

   [RFC5944]  Perkins, C., "IP Mobility Support for IPv4, Revised",
              RFC 5944, November 2010.





































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Authors' Addresses

   George Tsirtsis
   Qualcomm

   Email: tsirtsis@googlemail.com


   Vincent Park
   Qualcomm

   Phone: +908-947-7084
   Email: vpark@qualcomm.com


   Vidya Narayana
   Qualcomm

   Phone: +858-845-2483
   Email: vidyan@qualcomm.com


   Kent Leung
   Cisco

   Phone: +408-526-5030
   Email: kleung@cisco.com
























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