Internet Engineering Task Force (IETF)                       G. Tsirtsis
Request for Comments: 6626                                       V. Park
Updates: 5177                                               V. Narayanan
Category: Standards Track                                       Qualcomm
ISSN: 2070-1721                                                 K. Leung
                                                                May 2012

Dynamic Prefix Allocation for Network Mobility for Mobile IPv4 (NEMOv4)




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


Status of This Memo


This is an Internet Standards Track document.

これはInternet Standards Trackドキュメントです。

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.

このドキュメントは、IETF(Internet Engineering Task Force)の製品です。これは、IETFコミュニティのコンセンサスを表しています。公開レビューを受け、インターネットエンジニアリングステアリンググループ(IESG)による公開が承認されました。インターネット標準の詳細については、RFC 5741のセクション2をご覧ください。

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at


Copyright Notice


Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved.

Copyright(c)2012 IETF Trustおよびドキュメントの作成者として特定された人物。全著作権所有。

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents ( 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 described in the Simplified BSD License.

この文書は、BCP 78およびこの文書の発行日に有効なIETF文書に関するIETFトラストの法的規定(の対象となります。これらのドキュメントは、このドキュメントに関するあなたの権利と制限を説明しているため、注意深く確認してください。このドキュメントから抽出されたコードコンポーネントには、Trust Legal Provisionsのセクション4.eに記載されているSimplified BSD Licenseのテキストが含まれている必要があり、Simplified BSD Licenseに記載されているように保証なしで提供されます。

Table of Contents


   1. Introduction ....................................................2
   2. Requirements Notation ...........................................2
   3. Dynamic Mobile Prefix Allocation ................................2
      3.1. Mobile Client Considerations ...............................2
      3.2. Home Agent Considerations ..................................3
   4. Security Considerations .........................................4
   5. IANA Considerations .............................................4
   6. Acknowledgements ................................................4
   7. Normative References ............................................4
1. Introduction
1. はじめに

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.

基本NEMOv4仕様[RFC5177]は、モバイルネットワーク用のモバイルIPv4 [RFC5944]の拡張を定義しています。この仕様は、ホームエージェントによるモバイルプレフィックスの動的割り当てのサポートを追加します。

2. Requirements Notation
2. 要件表記

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].

このドキュメントのキーワード「MUST」、「MUST NOT」、「REQUIRED」、「SHALL」、「SHALL NOT」、「SHOULD」、「SHOULD NOT」、「RECOMMENDED」、「MAY」、および「OPTIONAL」は、 [RFC2119]で説明されているように解釈されます。

3. Dynamic Mobile Prefix Allocation
3. 動的モバイルプレフィックス割り当て

The following extension is defined according to this specification.


3.1. Mobile Client Considerations
3.1. モバイルクライアントに関する考慮事項

According to this specification, the Prefix field of the Mobile Network Request extension MUST be set to zero to indicate that the Mobile Router requests mobile network prefix(es) 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 extensions 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].

モバイルルータが登録応答を受信すると、モバイルIPv4 [RFC5944]および[RFC5177]で定義されているようにそれを処理する必要があります。 「成功」に設定されたコードフィールドに1つ以上のネットワーク肯定応答拡張が含まれている場合、モバイルルータは、対応するプレフィックスフィールドのプレフィックスを割り当てられたプレフィックスとして扱い、[RFC5177]で定義されている適切なバインディングを作成する必要があります。

In response to a registration request with a Mobile Network Request extension with the Prefix field set to zero, if 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
3.2. ホームエージェントに関する考慮事項

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].


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. The Mobile Router may request for multiple mobile network prefixes to be assigned by the home agent. For a Mobile Network Prefix for which the assignment was unsuccessful, the Code field in the corresponding Mobile Network Acknowledgement extension should be set to 4 (MOBNET_UNASSIGNED).


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 Network Access Identifier (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.

動的プレフィックス割り当ての場合、ゼロに設定されていない場合、モバイルルーターのホームアドレスを使用してクライアントを識別できます。それ以外の場合は、モバイルIPv4 [RFC2794]のネットワークアクセス識別子(NAI)拡張[RFC2794]で定義されているように、NAI拡張を登録要求に含める必要があります。この場合、同じ拡張を使用して、モバイルルータを識別する必要があります(SHOULD)。プレフィックス割り当ての目的。

4. Security Considerations
4. セキュリティに関する考慮事項

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

この仕様は、モバイルIPv4 [RFC5944]、NAI [RFC2794]、および[RFC5177]のセキュリティ制約と要件で動作します。

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.


5. IANA Considerations
5. IANAに関する考慮事項

A new value has been assigned in the Mobile Network Acknowledgement Extension registry: 4 - Home Agent cannot assign a mobile network prefix (MOBNET_UNASSIGNED).

Mobile Network Acknowledgement Extensionレジストリに新しい値が割り当てられました。4-Home Agentはモバイルネットワークプレフィックス(MOBNET_UNASSIGNED)を割り当てることができません。

6. Acknowledgements
6. 謝辞

The authors would like to thank Pete McCann, Alexandru Petrescu, Ralph Droms, and Jari Arkko for their reviews and comments.


7. Normative References
7. 引用文献

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

[RFC2119] Bradner、S。、「要件レベルを示すためにRFCで使用するキーワード」、BCP 14、RFC 2119、1997年3月。

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

[RFC2794] Calhoun、P。およびC. Perkins、「IPv4のモバイルIPネットワークアクセス識別子拡張機能」、RFC 2794、2000年3月。

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

[RFC5177] Leung、K.、Dommety、G.、Narayanan、V。、およびA. Petrescu、「Network Mobility(NEMO)Extensions for Mobile IPv4」、RFC 5177、2008年4月。

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

[RFC5944]パーキンス、C。、「IPv4のIPモビリティサポート、改訂」、RFC 5944、2010年11月。

Authors' Addresses


George Tsirtsis Qualcomm

George Tsirtsis Qualcomm


Vincent Park Qualcomm


   Phone: +908-443-8141

Vidya Narayana Qualcomm


   Phone: +858-845-2483

Kent Leung Cisco


   Phone: +408-526-5030