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
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This Internet-Draft will expire on March 22, 2020.
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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
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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.
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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).
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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
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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
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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
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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
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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
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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
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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.
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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,
<https://www.rfc-editor.org/info/rfc3963>.
[RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, DOI 10.17487/RFC4555, June 2006,
<https://www.rfc-editor.org/info/rfc4555>.
[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, DOI 10.17487/RFC5213, August 2008,
<https://www.rfc-editor.org/info/rfc5213>.
[RFC5268] Koodli, R., Ed., "Mobile IPv6 Fast Handovers", RFC 5268,
DOI 10.17487/RFC5268, June 2008,
<https://www.rfc-editor.org/info/rfc5268>.
[RFC5380] Soliman, H., Castelluccia, C., ElMalki, K., and L.
Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility
Management", RFC 5380, DOI 10.17487/RFC5380, October 2008,
<https://www.rfc-editor.org/info/rfc5380>.
[RFC5555] Soliman, H., Ed., "Mobile IPv6 Support for Dual Stack
Hosts and Routers", RFC 5555, DOI 10.17487/RFC5555, June
2009, <https://www.rfc-editor.org/info/rfc5555>.
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[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, <https://www.rfc-editor.org/info/rfc5648>.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010,
<https://www.rfc-editor.org/info/rfc5844>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://www.rfc-editor.org/info/rfc6275>.
[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,
<https://www.rfc-editor.org/info/rfc7333>.
[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,
<https://www.rfc-editor.org/info/rfc7401>.
[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
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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
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