DMM Working Group Z. Yan Internet-Draft G. Geng Intended status: Standards Track CNNIC Expires: March 22, 2020 J. Lee Sangmyung University H. Chan Huawei Technologies September 19, 2019 Mobility Capability Negotiation and Protocol Selection draft-yan-dmm-man-05 Abstract Based on different requirements, multiple mobility management protocols have been developed. Different protocols have different functional requirements on the network element or the host and then a scheme should be used in order to support the negotiation and selection of adopted mobility management protocol when a host accesses to a new network. In this draft, this issue is analyzed. 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 March 22, 2020. Copyright Notice Copyright (c) 2019 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 publication of this document. Please review these documents Yan, et al. Expires March 22, 2020 [Page 1] Internet-Draft MCN-PS September 2019 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. Motivations . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Possible Cases . . . . . . . . . . . . . . . . . . . . . . . 4 4. Principles and Possible Procedure . . . . . . . . . . . . . . 9 5. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 12 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.1. Normative References . . . . . . . . . . . . . . . . . . 12 8.2. Informative References . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction In order to clearly analyze the possible cases, the following category labels of the mobility management protocols are defined: o Mobile IPv6 (MIPv6) protocol: the mobility management scheme based on [RFC6275]. o Proxy Mobile IPv6 (PMIPv6) protocol: the mobility management scheme based on [RFC5213]. o MIPv6 suit protocols: based on MIPv6, there are multiple extension protocols have been standardized. These protocols can be classified into two types: protocols for the function extension and protocols for the performance enhancement. The protocols for the function extension are proposed to support some specific scenarios or functions, such as Dual-stack Mobile IPv6 (DSMIPv6) [RFC5555] for mobility of the dual-stack nodes, Multiple Care-of- address (MCoA) [RFC5648] for hosts with multiple access interfaces and Network Mobility (NEMO) [RFC3963] for mobility of sub-network. The other type is proposed to enhance the performance of the mobility management, such as Fast Mobile IPv6 (FMIP6) [RFC5268] for fast handover, Hierarchical Mobile IPv6 (HMIPv6) [RFC5380] for hierarchical mobility optimization. In the MIPv6 suit protocols, location update is initiated by the host and the tunnel is also terminated at the host. o PMIPv6 suit protocols: in order to reduce the protocol cost and enhance the handover performance further, the network-based mobility management protocols were proposed and PMIPv6 was standardized as a basis. Based on PMIPv6, a series of its Yan, et al. Expires March 22, 2020 [Page 2] Internet-Draft MCN-PS September 2019 extensions were proposed, such as Dual-stack Proxy Mobile IPv6 (DS-PMIPv6) [RFC5844], and Distributed Mobility Management Proxy Mobile IPv6 (DMM-PMIPv6) [RFC7333]. Be different from the MIPv6 suit protocols, the location update in PMIPv6 suit protocols is triggered by the network entity and the tunnel is established between network entities. Then the host needs to do nothing about the signaling exchange during the movement, particularly, the mobility is transparent to the IP layer of the host. o Network-based protocols: generally, it means the mobility management protocols which do not require the involvement of the mobile node in order to accomplish mobility. It includes PMIPv6 suit protocols and other network-based solutions, such as GPRS Tunnelling Protocol (GTP) [TS.29274][TS.29281]. o Host-based protocols: generally, the mobility management protocols which require the involvement of the mobile node in order to accomplish mobility. It includes MIPv6 suit protocols and other host-based solutions, such as Host Identity Protocol (HIP) [RFC7401] and IKEv2 Mobility and Multihoming Protocol (MOBIKE) [RFC4555]. Figure 1 illustrates the scopes of the above different category labels. +----------------+ +----------------+ | Network-based | | Host-based | |+--------------+| |+--------------+| ||PMIPv6 suit || ||MIPv6 suit || ||+------------+|| ||+------------+|| |||PMIPv6 ||| |||MIPv6 ||| ||+------------+|| ||+------------+|| |+--------------+| |+--------------+| +----------------+ +----------------+ Figure 1: Scopes of different protocol category labels In reality, the host-based protocols and network-based protocols will be co-existing and multiple protocol deamons will be configured on the network entities or host. That means a scheme is needed to support the negotiation and selection of mobility management protocol when the host accesses into a new access network initially or handover happens [Paper-CombiningMobilityStandards]. This document tries to present the principles for the protocol selection and analyze the possible scenarios which should be supported by the further solution. Yan, et al. Expires March 22, 2020 [Page 3] Internet-Draft MCN-PS September 2019 2. Motivations As illustrated above, these protocols may co-exist in reality and simultaneously be used in an access network or even the same entity. Due to their different requirements on the network entity or host, a scheme is needed to support the negotiation and selection of adopted mobility management protocol when the host accesses to a new network. Generally, two problems should be solved: o What principles should be followed for the protocol negotiation and selection? o What procedure should be adopted for the protocol negotiation and selection? This scheme is needed because network entity and host may have different capabilities and preferences (may be decided by the capability and mobility pattern of the host). This scheme aims to guarantee that the optimum and most suitable protocol will be used. 3. Possible Cases From both host and network aspects, their capacities of mobility management may have multiple cases as shown in Figure 2. We mainly analyze that host and network support single protocol, if multiple protocols are supported simultaneously by the host or network side, multiple cases exist at the same time but the logic is same as that in the case with single protocol supported. Specifically, the following cases should be considered. 1) Network supports network-based protocol, host supports network- based protocol In this case, there are the following sub-cases: a) Host supports PMIPv6 suit protocol, Network supports PMIPv6 suit protocol o if host supports PMIPv6 and network supports PMIPv6, PMIPv6 is selected. o if host supports PMIPv6 and network supports extended PMIPv6 protocol, extended PMIPv6 protocol is selected if no host involvement is needed, otherwise the plain PMIPv6 is selected (we assume that the extension protocols are backward-compatible with the related plain protocol). o if host supports extended PMIPv6 protocol and network supports PMIPv6, PMIPv6 is selected (we assume that the extension protocols are backward-compatible with the related plain protocol). Yan, et al. Expires March 22, 2020 [Page 4] Internet-Draft MCN-PS September 2019 o if host supports extended PMIPv6 protocol and network supports extended PMIPv6 protocol, the identical extension protocol is selected, otherwise, PMIPv6 is selected (we assume that the extension protocols are backward-compatible with the related plain protocol). +-------------+-----------+--------------------------- + | | |PMIPv6 | | | |-----------------+----------+ |Network-based|PMIPv6 suit| |DS-PMIPv6 | | | | +----------+ | | |PMIPv6 extensions|FPMIPv6 | | | | +----------+ | | | |DMM-PMIPv6| | | | +----------+ | | | |... | | |-----------+-----------------+----------+ | | Others |GTP | | | |----------------------------+ | | |... | +-------------+-----------+----------------------------+ | | |MIPv6 | | | |-----------------+----------+ |Host-based |MIPv6 suit | |DS-MIPv6 | | | | +----------+ | | | |FMIPv6 | | | | +----------+ | | |MIPv6 extensions |HMIPv6 | | | | +----------+ | | | |NEMO | | | | +----------+ | | | |DMM-MIPv6 | | | | +----------+ | | | |... | | |-----------+-----------------+----------+ | | Others |HIP | | | |----------------------------+ | | |MOBIKE | | | |----------------------------+ | | |... | +-------------+-----------+----------------------------+ Figure 2: Possible capacities of host and network b) Host supports PMIPv6 suit protocol, Network supports other network-based protocol Yan, et al. Expires March 22, 2020 [Page 5] Internet-Draft MCN-PS September 2019 o if host supports PMIPv6 and network supports other network-based protocol, other network-based protocol is selected if no host involvement is needed, otherwise failure. o if host supports extended PMIPv6 protocol and network supports other network-based protocol, other network-based protocol is selected if no host involvement is needed, otherwise failure. c) Host supports other network-based protocol, Network supports PMIPv6 suit protocol o if host supports other network-based protocol and network supports PMIPv6, PMIPv6 is selected. o if host supports other network-based protocol and network supports extended PMIPv6 protocol, extended PMIPv6 protocol is selected if no host involvement is needed, otherwise failure. d) Host supports other network-based protocol, Network supports other network-based protocol o the identical protocol is selected, otherwise follow network capability if the protocols are different. 2) Network supports network-based protocol, host supports host-based protocol In this case, there are the following sub-cases: a) Host supports PMIPv6 suit protocol, Network supports MIPv6 suit protocol o if host supports PMIPv6 and network supports MIPv6, failure. o if host supports PMIPv6 and network supports extended MIPv6 protocol, failure. o if host supports extended PMIPv6 protocol and network supports MIPv6, failure. o if host supports extended PMIPv6 protocol and network supports extended MIPv6 protocol, failure. b) Host supports PMIPv6 suit protocol, Network supports other host- based protocol o if host supports PMIPv6 and network supports other host-based protocol, failure. o if host supports extended PMIPv6 protocol and network supports other host-based protocol, failure. c) Host supports other network-based protocol, Network supports MIPv6 suit protocol Yan, et al. Expires March 22, 2020 [Page 6] Internet-Draft MCN-PS September 2019 o if host supports other network-based protocol and network supports MIPv6, failure. o if host supports other network-based protocol and network supports extended MIPv6 protocol, failure. d) Host supports other network-based protocol, Network supports other host-based protocol o failure. 3) Network supports host-based protocol, host supports network-based protocol In this case, there are the following sub-cases: a) Host supports MIPv6 suit protocol, Network supports PMIPv6 suit protocol o if host supports MIPv6 and network supports PMIPv6, PMIPv6 is selected in default and MIPv6 is selected if host prefers it. o if host supports MIPv6 and network supports extended PMIPv6 protocol, extended PMIPv6 is selected in default, then PMIPv6 is selected with the lower priority and MIPv6 is selected if host prefers it. o if host supports extended MIPv6 protocol and network supports PMIPv6, PMIPv6 is selected in default, then extended MIPv6 protocol is selected if host prefers it and network also supports, otherwise MIPv6 is selected with the lowest priority. o if host supports extended MIPv6 protocol and network supports extended PMIPv6 protocol, extended PMIPv6 protocol is selected in default, then PMIPv6 is selected, then extended MIPv6 protocol is selected if host prefers and network also supports, otherwise MIPv6 is selected with the lowest priority. b) Host supports MIPv6 suit protocol, Network supports other network- based protocol o if host supports MIPv6 and network supports other network-based protocol, other network-based protocol is selected if no host involvement is needed, otherwise failure. o if host supports extended MIPv6 protocol and network supports other network-based protocol, other network-based protocol is selected if no host involvement is needed, otherwise failure. c) Host supports other host-based protocol, Network supports PMIPv6 suit protocol Yan, et al. Expires March 22, 2020 [Page 7] Internet-Draft MCN-PS September 2019 o if host supports other host-based protocol and network supports PMIPv6, PMIPv6 is selected in default, otherwise failure. o if host supports other host-based protocol and network supports extended PMIPv6 protocol, extended PMIPv6 protocol is selected if no host involvement is needed, otherwise failure. d) Host supports other host-based protocol, Network supports other network-based protocol o other network-based protocol is selected if no host involvement is needed, otherwise failure. 4) Network supports host-based protocol, host supports host-based protocol In this case, there are the following sub-cases: a) Host supports MIPv6 suit protocol, Network supports MIPv6 suit protocol o if host supports MIPv6 and network supports MIPv6, MIPv6 is selected. o if host supports MIPv6 and network supports extended MIPv6 protocol, MIPv6 is selected. o if host supports extended MIPv6 protocol and network supports MIPv6, MIPv6 is selected. o if host supports extended MIPv6 protocol and network supports extended MIPv6 protocol, the identical protocol is selected, otherwise MIPv6 is selected. b) Host supports MIPv6 suit protocol, Network supports other host- based protocol o if host supports MIPv6 and network supports other host-based protocol, failure. o if host supports extended MIPv6 protocol and network supports other host-based protocol, failure. c) Host supports other host-based protocol, Network supports MIPv6 suit protocol o if host supports other host-based protocol and network supports MIPv6, failure. o if host supports other host-based protocol and network supports extended MIPv6 protocol, failure. d) Host supports other host-based protocol, Network supports other host-based protocol Yan, et al. Expires March 22, 2020 [Page 8] Internet-Draft MCN-PS September 2019 o the identical other host-based protocol is selected, otherwise failure. 5) Network supports host-based protocol and network-based protocol, host supports host-based protocol and network-based protocol o follow the network based protocol in default if the host can support, otherwise select the protocol both network and host can support if host prefers. 4. Principles and Possible Procedure Two different schemes may be used for the protocol negotiation and selection: host-initiated and network-initiated. Within the MIPv6/ PMIPv6 protocols, the priority of the function-extension protocols should be higher than the performance-enhancement protocols. Generally, the following principles should be followed: o In default: Network based scheme if it can be supported o Priority 1: Follow network capability o Priority 2: Follow host preference o Priority 3: Support the functional extensions o Priority 4: Support the performance enhancements And the general procedure for the protocol selection should be: o During initiation, network-based protocol may be used as a default mobility management protocol once the network supports it. o If the host prefers host-based protocols, a negotiation is executed to handover from network-based protocol to host-based protocol. o After initial attachment, a profile will be generated in the management store to record the selected or preferred protocol of this host. o When the handover happens, the network will check the selected or preferred protocol during the authentication process. But the network also needs to notify the host if the selected protocol cannot be supported herein. 5. Extensions In order to fulfill the above principles, some extensions should be supported, for example: 1) Extended negotiation messages The protocol negotiation may be included in the MN_ATTACH Function [MN-AR.IF] and the implementation may be based on a new signaling Yan, et al. Expires March 22, 2020 [Page 9] Internet-Draft MCN-PS September 2019 message or extended messages (e.g., ICMPv6, Diameter, and RADIUS). Besides these, some other protocols may also be used in some specified scenarios, such as extended IEEE 802.21 primitives. As a possible solution, a new option under ICMPv6 is proposed in this draft in order to support the protocol negotiation when the mobile terminal initially accesses the network or hands over to a different network. In the RA and Router Solicitation (RS) message headers, a one-bit flag (C) is used to illustrate that mobility capability negotiation is needed and a Mobility Capability (MC) option is included in the message body. The format of MC option is shown in Figure 3. 0 78 1516 2324 31 +---------+---------+---------+---------+ | Type | Length | p |Reserved | +---------------------------------------+ | Protocol 1 | ...... | +---------------------------------------+ | Protocol p | Protocol p+1 | +---------------------------------------+ | ...... | Protocol s | +---------------------------------------+ Figure 3: The format of Mobility Capability option "Type" indicates that this option is of the type Mobility Capability. "p" is the number of preferred protocols. "Protocol 1" to "Protocol s" is a list of s supported protocols, which can be selected. Out of the s supported protocols, the first p protocols are ones preferred by the network and the terminal, listed in the order of preference, whereas no preference is indicated in the remaining protocols from p+1 to s. How to code the protocol types with the 16-bit space is implementation-depended. "Length" is the number of octets in this option excluding option type and option length, and it can be seen that Length = 2x(s+1). "Reserved" is for future use. It is noted that when p = 0, preference is not indicated in the entire list of supported protocols, and when p = s, preference is indicated in all the supported protocols. Based on this extension, when the mobile terminal receives the RA message with the "C" flag set to 1 and "p" in MC option is at least one, it means that the access network has selected the first supported protocol (protocol 1) as the default protocol for the Yan, et al. Expires March 22, 2020 [Page 10] Internet-Draft MCN-PS September 2019 terminal. Based on the previous principles, the terminal should follow this selected protocol if it is able to. If the terminal is not capable to use the first supported protocol, it will use the second supported protocol (protocol 2) if it is able to. If it is still not capable of using the second supported protocol, it will try the third one and so on. If the terminal is not capable of using any of the p supported protocols, it will try to use any of the remaining protocols. When the mobile terminal receives the RA message with the "C" flag set to 1 and "Preferred protocol" in MC option is null, it means that the access network has not selected the default protocol for the terminal but illustratesed to the terminal about the supported protocols from the network side. Then based on the previous principles, the terminal should select one protocol and notify it to the network with the MC option in RS message. The network should acknowledge it with a new re-formatted RA message. In this new RA message, the protocol selected by terminal is included in the "Preferred protocol" of MC option. After the choice has been made, the terminal may inform the network of the choice by sending a message with MC option in which p = s = 1, and the protocol field is the selected protocol. When the network receives the RS message with the "C" flag set to 1 and "p" in MC option is zero, it means that the terminal only lists its supported mobility management protocols but does not have any preference. The network will then select one based on the principles and notify the selected protocol to the terminal with a RA message containing the MC option in which p=1 and "protocol 1" is the selected protocol. When the network receives the RS message with the "C" flag set to 1 and "p" in MC option is at least one, it means that the terminal tries to negotiate the mobility management protocol and has included the preferred protocols listed in the order of preference. The network will try one by one to select from protocol 1 to protocol p until it has find one it supports. If the network is not capable of supporting all the p protocols, it will try the remaining s-p protocols. 2) Extended management store When the host accesses to the network, an authentication should be executed before the mobility management service is provided. In order to support the mobility management protocol selection, a new information should be recorded by the network after the successful authentication during the initial attachment. The newly introduced information shows the selected mobility management protocol and should be updated when the used protocol changes. Yan, et al. Expires March 22, 2020 [Page 11] Internet-Draft MCN-PS September 2019 6. Security Considerations Generally, this function will not incur additional security issues. The detailed influence should be analyzed in the future. 7. IANA Considerations A new ICMP option or authentication option or other signaling message may be used with a new code number. 8. References 8.1. Normative References [MN-AR.IF] Laganier, J., Narayanan, S., and P. McCann, "Interface between a Proxy MIPv6 Mobility Access Gateway and a Mobile Node", draft-ietf-netlmm-mn-ar-if-03, February 2008. [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, "Network Mobility (NEMO) Basic Support Protocol", RFC 3963, DOI 10.17487/RFC3963, January 2005, . [RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol (MOBIKE)", RFC 4555, DOI 10.17487/RFC4555, June 2006, . [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, DOI 10.17487/RFC5213, August 2008, . [RFC5268] Koodli, R., Ed., "Mobile IPv6 Fast Handovers", RFC 5268, DOI 10.17487/RFC5268, June 2008, . [RFC5380] Soliman, H., Castelluccia, C., ElMalki, K., and L. Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility Management", RFC 5380, DOI 10.17487/RFC5380, October 2008, . [RFC5555] Soliman, H., Ed., "Mobile IPv6 Support for Dual Stack Hosts and Routers", RFC 5555, DOI 10.17487/RFC5555, June 2009, . Yan, et al. Expires March 22, 2020 [Page 12] Internet-Draft MCN-PS September 2019 [RFC5648] Wakikawa, R., Ed., Devarapalli, V., Tsirtsis, G., Ernst, T., and K. Nagami, "Multiple Care-of Addresses Registration", RFC 5648, DOI 10.17487/RFC5648, October 2009, . [RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010, . [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 2011, . [RFC7333] Chan, H., Ed., Liu, D., Seite, P., Yokota, H., and J. Korhonen, "Requirements for Distributed Mobility Management", RFC 7333, DOI 10.17487/RFC7333, August 2014, . [RFC7401] Moskowitz, R., Ed., Heer, T., Jokela, P., and T. Henderson, "Host Identity Protocol Version 2 (HIPv2)", RFC 7401, DOI 10.17487/RFC7401, April 2015, . [TS.29274] "3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3", 3GPP TS 29.274 8.10.0, June 2011. [TS.29281] "General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)", 3GPP TS 29.281 10.3.0, September 2011. 8.2. Informative References [Paper-CombiningMobilityStandards] Oliva, A., Soto, I., Calderon, M., Bernardos, C., and M. Sanchez, "The costs and benefits of combining different IP mobility standards", Computer Standards and Interfaces, February 2013. Authors' Addresses Yan, et al. Expires March 22, 2020 [Page 13] Internet-Draft MCN-PS September 2019 Zhiwei Yan CNNIC No.4 South 4th Street, Zhongguancun Beijing 100190 China Email: yan@cnnic.cn Guanggang Geng CNNIC No.4 South 4th Street, Zhongguancun Beijing 100190 China Email: ggg@cnnic.cn Jong-Hyouk Lee Sangmyung University 31, Sangmyeongdae-gil, Dongnam-gu Cheonan Republic of Korea Email: jonghyouk@smu.ac.kr H. Anthony Chan Huawei Technologies 5340 Legacy Dr. Building 3 Plano, TX 75024 USA Email: h.a.chan@ieee.org Yan, et al. Expires March 22, 2020 [Page 14]