DMM Working Group D. Moses Internet-Draft W. Feng Intended status: Standards Track Intel Expires: December 20, 2017 A. Yegin June 18, 2017 DHCPv6 Extension for On Demand Mobility exposure draft-moses-dmm-dhcp-ondemand-mobility-06 Abstract Applications differ with respect to whether or not they need IP session continuity and/or IP address reachability. Networks providing the same type of service to any mobile host and any application running on the host yields inefficiencies. This document describes extensions to the DHCPv6 protocol to enable mobile hosts to indicate the required mobility service type associated with a requested IP prefix and to allow networks to indicate the type of mobility service associated with the allocated IP prefix in return. 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 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 December 20, 2017. Copyright Notice Copyright (c) 2017 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 Moses, et al. Expires December 20, 2017 [Page 1] Internet-Draft DHCPv6 On-Demand Mobility Extension June 2017 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 . . . . . . . . . . . . . . . . . . . 3 3. IPv6 Continuity Service Option . . . . . . . . . . . . . . . 3 4. Anchor Preference Option . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction [I-D.ietf-dmm-ondemand-mobility] defines different types of mobility- associated services provided by access networks to mobile hosts with regards to maintaining IPv6 prefix continuity after an event of the host moving between locations with different points of attachments within the IP network topology. It further specifies means for applications to convey to the IP stack in the mobile host, their requirements regarding these services. This document defines extensions to the DHCPv6 protocol ([RFC3315]) in the form of a new DHCP option that specifies the type of mobility services associated with an IPv6 prefix. The IP stack in a mobile host uses the DHCP client to communicate the type of mobility service it wishes to receive from the network. The DHCP server in the network uses this option to convey the type of service that is guaranteed with the assigned IPv6 prefix in return. This new option also extends the ability of mobile routers to specify desired mobility service in a request for IPv6 prefixes (as specified in [RFC3633]), and enable delegating routers to convey the type of mobility service that is committed with the allocated IPv6 prefixes in return. In a distributed mobility management environment, there are multiple Mobility Anchors (as specified in [I-D.ietf-dmm-distributed-mobility-anchoring]). In some use-cases, mobile hosts may wish to indicate to the network, their preference of the serving Mobility Anchor. This document specifies a new DHCPv6 option that is used by DHCPv6 clients to convey this preference. Moses, et al. Expires December 20, 2017 [Page 2] Internet-Draft DHCPv6 On-Demand Mobility Extension June 2017 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. IPv6 Continuity Service Option The IPv6 Continuity Service option is used to specify the type of continuity service associated with a source IPv6 prefix. The IPv6 Continuity Service option must be encapsulated in the IAprefix- options field of the IA_PD prefix option. The format of the IPv6 Continuity Service option is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_IPv6_CONTINUITY_SERVICE| option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | service-type | +-+-+-+-+-+-+-+-+ option-code OPTION_IPv6_CONTINUITY_SERVICE (TBD) option-len 1 service-type one of 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) Anytype - Anyone of the above (0) The definition of these service types is available in [I-D.ietf-dmm-ondemand-mobility]. Moses, et al. Expires December 20, 2017 [Page 3] Internet-Draft DHCPv6 On-Demand Mobility Extension June 2017 All other values (5-255) are reserved for future use. If the OPTION_IPv6_CONTINUITY_SERVICE option is received and its service- type is equal to one of the reserved values, the option should be ignored. When a message is sent from a client to a server, the value of the IPv6 Continuity Service option indicates the type of continuity service required for the IPv6 prefix requested by the client. When a message is sent from a server to a client, the value of the IPv6 Continuity Service option indicates the type of continuity service committed by the network for the associated IPv6 prefix. The value 'AnyType' can only appear in the message sent from the client to the server to indicate that the client has no specific preference. However, it cannot appear in a message sent from the server. Once an IPv6 prefix type is requested and 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. If a server receives a request to assign an IPv6 prefix with a specified IPv6 Continuity service, but cannot fulfill the request, it must reply with the NoAddrsAvail status. A server that does not support this option will discard it as well as the IA_PD Prefix option that had this option encapsulated in one of its IAprefix-options field. If a client does not receive the requested prefix, it must resend the request without the desired IPv6 Continuity Service option since it is not supported by the server. In this case, the requesting device (host or router) cannot assume any IP continuity service behaviour for that prefix. A server must not include the IPv6 Continuity Service option in the IAprefix-options field of an IA_PD Prefix option, if not specifically requested previously by the client to which it is sending a message. If a client receives an IA_PD Prefix option from a server with the IPv6 Continuity Service option in the IAprefix-options field, without initially requesting a specific service using this option, it must discard the received IPv6 prefix. If the mobile device (host or router) has no preference regarding the type of continuity service it uses the 'AnyType' value as the specified type of continuity service. The Server will allocate an IPv6 prefix with some continuity service and must specify the type in Moses, et al. Expires December 20, 2017 [Page 4] Internet-Draft DHCPv6 On-Demand Mobility Extension June 2017 IPv6 Continuity Service option encapsulated in the IAprefix-options field of the IA_PD Prefix option. The method for selecting the type of continuity service is outside the scope of this specification. 4. Anchor Preference Option In a distributed mobility management environment that deploys multiple Mobility Anchors, each Mobility Anchor may have a set of IPv6 prefixes that is being used when assigning Session-lasting or Fixed source IPv6 prefixes to hosts. The selection of the Mobility Anchor that will serve a mobile host is performed by the network at various events like, the event of initial attachment of a mobile host to a network. The Anchor Preference option enables a host to express its desire to receive a specific source IPv6 prefix. This is useful when the mobile host wishes to indicate to the network which Mobility Anchor should be used for anchoring its traffic and ensuring service continuity in the event of handoff between LANs with different IPv6 prefixes. The network MAY respect this request but is not required to do so. The format of the Anchor Preference option is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_ANCHOR_PREFERENCE | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | preferred-lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | prefix6len | ipv6-prefix | +-+-+-+-+-+-+-+-+ (variable length) | . . |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IAanchor_preference-options | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code OPTION_ANCHOR_PREFERENCE (TBD) option-len 5 + length of ipv6-prefix field + length of anchor_preference-options field Moses, et al. Expires December 20, 2017 [Page 5] Internet-Draft DHCPv6 On-Demand Mobility Extension June 2017 preferred-lifetime The preferred lifetime of the IPv6 address whose prefix is requested, expressed in units of seconds prefix-length The length in bits of the ipv6-prefix. Typically allowed values are 0 to 128. IPv6 prefix This is a variable length field that specifies the desired ipv6 prefix. The length is (prefix6len + 7) / 8. This field is padded with 0 bits up to the nearest octet boundary when prefix6len is not divisible by 8. IAanchor_preference-option Options associated with this request An IPv6 prefix is requested only when the mobile host wishes to be anchored by a specific mobility anchor. The client must also indicate the type of mobility service it requires using the IPv6 Continuity Service option encapsulated in the IAanchor_preference- options field of the IA_PD Prefix Option. When requesting a specific IPv6 prefix, the 'Non-Persistent' type must not be used since these prefixes are not anchored and there is no need to request a specific anchor. If a server receives a request to use a specific IPv6 prefix and an IPv6 Continuity Service type, but cannot assign an IPv6 prefix with that specified IPv6 Continuity Service it must reply with the NoAddrsAvail status. A server that does not support this option will discard it. A server is not required to respect the prefix request. It can assign a different prefix as long as it fulfills the IP Continuity Service request. If a client does not receive any prefix, it must assume that the the option is not supported by the server and should not use this option in subsequent requests. 5. Security Considerations There are no specific security considerations for this option. 6. IANA Considerations TBD Moses, et al. Expires December 20, 2017 [Page 6] Internet-Draft DHCPv6 On-Demand Mobility Extension June 2017 7. References 7.1. 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, . 7.2. Informative References [I-D.ietf-dmm-distributed-mobility-anchoring] Chan, A., Wei, X., Lee, J., Jeon, S., Petrescu, A., and F. Templin, "Distributed Mobility Anchoring", draft-ietf-dmm- distributed-mobility-anchoring-05 (work in progress), May 2017. [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-10 (work in progress), January 2017. [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, . [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, . [RFC7934] Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi, "Host Address Availability Recommendations", BCP 204, RFC 7934, DOI 10.17487/RFC7934, July 2016, . Authors' Addresses Danny Moses Intel Petah Tikva Israel Moses, et al. Expires December 20, 2017 [Page 7] Internet-Draft DHCPv6 On-Demand Mobility Extension June 2017 Wu-chi Feng Intel Hillsboro USA Email: wu-chix.feng@intel.com Alper Yegin Istanbul Turkey Email: alper.yegin@yegin.org Moses, et al. Expires December 20, 2017 [Page 8]