Internet DRAFT - draft-ietf-dmm-best-practices-gap-analysis
draft-ietf-dmm-best-practices-gap-analysis
DMM D. Liu, Ed.
Internet-Draft China Mobile
Intended status: Informational JC. Zuniga, Ed.
Expires: May 8, 2015 InterDigital
P. Seite
Orange
H. Chan
Huawei Technologies
CJ. Bernardos
UC3M
November 4, 2014
Distributed Mobility Management: Current practices and gap analysis
draft-ietf-dmm-best-practices-gap-analysis-09
Abstract
This document analyzes deployment practices of existing IP mobility
protocols in a distributed mobility management environment. It then
identifies existing limitations when compared to the requirements
defined for a distributed mobility management solution.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 8, 2015.
Copyright Notice
Copyright (c) 2014 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Functions of existing mobility protocols . . . . . . . . . . 3
4. DMM practices . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. IP flat wireless network . . . . . . . . . . . . . . . . 6
4.2.1. Host-based IP DMM practices . . . . . . . . . . . . . 7
4.2.2. Network-based IP DMM practices . . . . . . . . . . . 11
4.3. Flattening 3GPP mobile network approaches . . . . . . . . 13
5. Gap analysis . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1. Distributed mobility management - REQ1 . . . . . . . . . 16
5.2. Bypassable network-layer mobility support for each
application session - REQ2 . . . . . . . . . . . . . . . 19
5.3. IPv6 deployment - REQ3 . . . . . . . . . . . . . . . . . 20
5.4. Considering existing mobility protocols - REQ4 . . . . . 20
5.5. Coexistence with deployed networks/hosts and
operability across different networks - REQ5 . . . . . . 21
5.6. Operation and management considerations - REQ6 . . . . . 21
5.7. Security considerations - REQ7 . . . . . . . . . . . . . 22
5.8. Multicast - REQ8 . . . . . . . . . . . . . . . . . . . . 22
5.9. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 23
6. Security Considerations . . . . . . . . . . . . . . . . . . . 25
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1. Normative References . . . . . . . . . . . . . . . . . . 26
8.2. Informative References . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction
Existing network-layer mobility management protocols have primarily
employed a mobility anchor to ensure connectivity of a mobile node by
forwarding packets destined to, or sent from, the mobile node after
the node has moved to a different network. The mobility anchor has
been centrally deployed in the sense that the traffic of millions of
mobile nodes in an operator network is typically managed by the same
anchor. This centralized deployment of mobility anchors to manage IP
sessions poses several problems. In order to address these problems,
a distributed mobility management (DMM) architecture has been
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proposed. This document investigates whether it is feasible to
deploy current IP mobility protocols in a DMM scenario in a way that
can fulfill the requirements as defined in [RFC7333]. It discusses
current deployment practices of existing mobility protocols and
identifies the limitations (gaps) in these practices from the
standpoint of satisfying DMM requirements. The analysis is primarily
towards IPv6 deployment, but can be seen to also apply to IPv4
whenever there are IPv4 counterparts equivalent to the IPv6 mobility
protocols.
The rest of this document is organized as follows. Section 3
analyzes existing IP mobility protocols by examining their functions
and how these functions can be configured and used to work in a DMM
environment. Section 4 presents the current practices of IP wireless
networks and 3GPP architectures. Both network- and host-based
mobility protocols are considered. Section 5 presents the gap
analysis with respect to the current practices.
2. Terminology
All general mobility-related terms and their acronyms used in this
document are to be interpreted as defined in the Mobile IPv6 base
specification [RFC6275], in the Proxy Mobile IPv6 specification
[RFC5213], and in the Distributed Mobility Management Requirements
[RFC7333]. These terms include mobile node (MN), correspondent node
(CN), home agent (HA), Local Mobility Anchor (LMA), Mobile Access
Gateway (MAG), centrally depoyed mobility anchors, distributed
mobility management, hierarchical mobile network, flatter mobile
network, and flattening mobile network.
In addition, this document also introduces some definitions of IP
mobility functions in Section 3.
In this document there are also references to a "distributed mobility
management environment." By this term, we refer to a scenario in
which the IP mobility, access network and routing solutions allow for
setting up IP networks so that traffic is distributed in an optimal
way, without relying on centrally deployed mobility anchors to manage
IP mobility sessions.
3. Functions of existing mobility protocols
The host-based Mobile IPv6 (MIPv6) [RFC6275] and its network-based
extension, Proxy Mobile IPv6 (PMIPv6) [RFC5213], as well as
Hierarchical Mobile IPv6 (HMIPv6) [RFC5380] are logically centralized
mobility management approaches addressing primarily hierarchical
mobile networks. Although these approaches are centralized, they
have important mobility management functions resulting from years of
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extensive work to develop and to extend these functions. It is
therefore useful to take these existing functions and examine them in
a DMM scenario in order to understand how to deploy the existing
mobility protocols to provide distributed mobility management.
The main mobility management functions of MIPv6, PMIPv6, and HMIPv6
are the following:
1. Anchoring Function (AF): allocation to a mobile node of an IP
address, i.e., Home Address (HoA), or prefix, i.e., Home Network
Prefix (HNP) topologically anchored by the advertising node.
That is, the anchor node is able to advertise a connected route
into the routing infrastructure for the allocated IP prefixes.
This function is a control plane function.
2. Internetwork Location Information (LI) function: managing and
keeping track of the internetwork location of an MN. The
location information may be a binding of the IP advertised
address/prefix, e.g., HoA or HNP, to the IP routing address of
the MN or of a node that can forward packets destined to the MN.
It is a control plane function.
In a client-server protocol model, location query and update
messages may be exchanged between a location information client
(LIc) and a location information server (LIs).
3. Forwarding Management (FM) function: packet interception and
forwarding to/from the IP address/prefix assigned to the MN,
based on the internetwork location information, either to the
destination or to some other network element that knows how to
forward the packets to their destination.
FM may optionally be split into the control plane (FM-CP) and
data plane (FM-DP).
In Mobile IPv6, the home agent (HA) typically provides the anchoring
function (AF); the location information server (LIs) is at the HA
whereas the location information client (LIc) is at the MN; the
Forwarding Management (FM) function is distributed between the ends
of the tunnel at the HA and the MN.
In Proxy Mobile IPv6, the Local Mobility Anchor (LMA) provides the
anchoring function (AF); the location information server (LIs) is at
the LMA whereas the location information client (LIc) is at the
mobile access gateway (MAG); the Forwarding Management (FM) function
is distributed between the ends of the tunnel at the HA and the MAG.
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In Hierarchical Mobile IPv6 (HMIPv6) [RFC5380], the Mobility Anchor
Point (MAP) serves as a location information aggregator between the
LIs at the HA and the LIc at the MN. The MAP also provides the FM
function to enable tunneling between HA and itself as well as
tunneling between MN and itself.
4. DMM practices
This section documents deployment practices of existing mobility
protocols to satisfy distributed mobility management requirements.
This description considers both IP wireless, e.g., evolved Wi-Fi
hotspots, and 3GPP flattening mobile network.
While describing the current DMM practices, the section provides
references to the generic mobility management functions described in
Section 3 as well as some initial hints on the identified gaps with
respect to the DMM requirements documented in [RFC7333].
4.1. Assumptions
There are many different approaches that can be considered to
implement and deploy a distributed anchoring and mobility solution.
The focus of the gap analysis is on certain current mobile network
architectures and standardized IP mobility solutions, considering any
kind of deployment options which do not violate the original protocol
specifications. In order to limit the scope of our analysis of DMM
practices, we consider the following list of technical assumptions:
1. Both host- and network-based solutions are considered.
2. Solutions should allow selecting and using the most appropriate
IP anchor among a set of available candidates.
3. Mobility management should be realized by the preservation of the
IP address across the different points of attachment (i.e.,
provision of IP address continuity). This is in contrast to
certain transport-layer based approaches such as Stream Control
Transmission Protocol (SCTP) [RFC4960] or application-layer
mobility.
Applications which can cope with changes in the MN's IP address do
not depend on IP mobility management protocols such as DMM.
Typically, a connection manager together with the operating system
will configure the source address selection mechanism of the IP
stack. This might involve identifying application capabilities and
triggering the mobility support accordingly. Further considerations
on application management and source address selection are out of the
scope of this document, but the reader might consult [RFC6724].
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4.2. IP flat wireless network
This section focuses on common IP wireless network architectures and
how they can be flattened from an IP mobility and anchoring point of
view using common and standardized protocols. We take Wi-Fi as an
useful wireless technology, since it is widely known and deployed
nowadays. Some representative examples of Wi-Fi deployment
architectures are depicted in Figure 1.
+-------------+ _----_
+---+ | Access | _( )_
|AAA|. . . . . . | Aggregation |----------( Internet )
+---+ | Gateway | (_ _)
+-------------+ '----'
| | |
| | +-------------+
| | |
| | +-----+
+---------------+ | | AR |
| | +--+--+
+-----+ +-----+ *----+----*
| RG | | WLC | ( LAN )
+-----+ +-----+ *---------*
. / \ / \
/ \ +-----+ +-----+ +-----+ +-----+
/ \ |Wi-Fi| |Wi-Fi| |Wi-Fi| |Wi-Fi|
MN1 MN2 | AP1 | | AP2 | | AP3 | | AP4 |
+-----+ +-----+ +-----+ +-----+
. .
/ \ / \
/ \ / \
MN3 MN4 MN5 MN6
Figure 1: IP Wi-Fi network architectures
In Figure 1, three typical deployment options are shown
[I-D.gundavelli-v6ops-community-wifi-svcs]. On the left hand side of
the figure, mobile nodes MN1 and MN2 directly connect to a
Residential Gateway (RG) at the customer premises. The RG hosts the
802.11 Access Point (AP) function to enable wireless layer-2 access
connectivity and also provides layer-3 routing functions. In the
middle of the figure, mobile nodes MN3 and MN4 connect to Wi-Fi
Access Points (APs) AP1 and AP2 that are managed by a Wireless LAN
Controller (WLC), which performs radio resource management on the
APs, domain-wide mobility policy enforcement and centralized
forwarding function for the user traffic. The WLC could also
implement layer-3 routing functions, or attach to an access router
(AR). Last, on the right-hand side of the figure, access points AP3
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and AP4 are directly connected to an access router. This can also be
used as a generic connectivity model.
IP mobility protocols can be used to provide heterogeneous network
mobility support to users, e.g., handover from Wi-Fi to cellular
access. Two kinds of protocols can be used: Proxy Mobile IPv6
[RFC5213] or Mobile IPv6 [RFC5555], with the role of mobility anchor,
e.g., Local Mobility Anchor or home agent, typically being played by
the edge router of the mobile network [SDO-3GPP.23.402].
Although this section has made use of the example of Wi-Fi networks,
there are other flattening mobile network architectures specified,
such as WiMAX [IEEE.802-16.2009], which integrates both host- and
network-based IP mobility functions.
Existing IP mobility protocols can also be deployed in a flatter
manner, so that the anchoring and access aggregation functions are
distributed. We next describe several practices for the deployment
of existing mobility protocols in a distributed mobility management
environment. The analysis in this section is limited to protocol
solutions based on existing IP mobility protocols, either host- or
network-based, such as Mobile IPv6 [RFC6275], [RFC5555], Proxy Mobile
IPv6 (PMIPv6) [RFC5213], [RFC5844] and Network Mobility Basic Support
protocol (NEMO) [RFC3963]. Extensions to these base protocol
solutions are also considered. The analysis is divided into two
parts: host- and network-based practices.
4.2.1. Host-based IP DMM practices
Mobile IPv6 (MIPv6) [RFC6275] and its extension to support mobile
networks, the NEMO Basic Support protocol (hereafter, simply referred
to as NEMO) [RFC3963] are well-known host-based IP mobility
protocols. They depend on the function of the Home Agent (HA), a
centralized anchor, to provide mobile nodes (hosts and routers) with
mobility support. In these approaches, the Home Agent typically
provides the Anchoring Function (AF), Forwarding Management (FM), and
Internetwork Location Information server (LIs) functions. The mobile
node possesses the Location Information client (LIc) function and the
FM function to enable tunneling between HA and itself. We next
describe some practices that show how MIPv6/NEMO and several other
protocol extensions can be deployed in a distributed mobility
management environment.
One approach to distribute the anchors can be to deploy several HAs
(as shown in Figure 2), and assign the topologically closest anchor
to each MN [RFC4640], [RFC5026], [RFC6611]. In the example shown in
Figure 2, the mobile node MN1 is assigned to the home agent HA1 and
uses a home address anchored by HA1 to communicate with the
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correspondent node CN1. Similarly, the mobile node MN2 is assigned
to the home agent HA2 and uses a home address anchored by HA2 to
communicate with the correspondent node CN2. Note that MIPv6/NEMO
specifications do not prevent the simultaneous use of multiple home
agents by a single mobile node. In this deployment model, the mobile
node can use several anchors at the same time, each of them anchoring
IP flows initiated at a different point of attachment. However,
there is currently no mechanism specified in IETF standard to enable
an efficient dynamic discovery of available anchors and the selection
of the most suitable one.
<-INTERNET-> <- HOME NETWORK -> <------- ACCESS NETWORK ------->
+-----+ +-----+ +--------+
| CN1 |--- ===| AR1 |=======| MN1 |
+-----+ \ +-----------+ // +-----+ |(FM,LMc)|
---| HA1 |=== +--------+
|(AF,FM,LMs)| +-----+ (anchored
+-----------+ | AR2 | at HA1)
+-----+ +-----+
| CN2 |--------------
+-----+ \ +-----+ +--------+
-------------| AR3 |-------| MN2 |
+-----------+ +-----+ |(FM,LMc)|
| HA2 | +--------+
|(AF,FM,LMs)| +-----+ (anchored
+-----------+ | AR4 | at HA2)
+-----+
CN1 CN2 HA1 HA2 AR1 AR3 MN1 MN2
| | | | | | | |
|<-------------->|<======tunnel====+=============>| | BT mode
| | | | | | | |
| |<---------------------------------+-------------->| RO mode
| | | | | | | |
Figure 2: Distributed operation of Mobile IPv6 (BT and RO) / NEMO
One goal of the deployment of mobility protocols in a distributed
mobility management environment is to avoid the suboptimal routing
caused by centralized anchoring. Here, the Route Optimization (RO)
support provided by Mobile IPv6 can be used to achieve a flatter IP
data forwarding. By default, Mobile IPv6 and NEMO use the so-called
Bidirectional Tunnel (BT) mode, in which data traffic is always
encapsulated between the MN and its HA before being directed to any
other destination. The RO mode allows the MN to update its current
location on the CNs, and then use the direct path between them.
Using the example shown in Figure 2, MN1 is using BT mode with CN1,
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while MN2 is in RO mode with CN2. However, the RO mode has several
drawbacks:
o The RO mode is only supported by Mobile IPv6. There is no route
optimization support standardized for the NEMO protocol because of
the security problems posed by extending return routability tests
for prefixes, although many different solutions have been proposed
[RFC4889].
o The RO mode requires signaling that adds some protocol overhead.
o The signaling required to enable RO involves the home agent and is
repeated periodically for security reasons [RFC4225]. Therefore
the HA remains a single point of failure.
o The RO mode requires support from the CN.
Notwithstanding these considerations, the RO mode does offer the
possibility of substantially reducing traffic through the Home Agent,
in cases when it can be supported by the relevant correspondent
nodes. Note that a mobile node can also use its care-of-address
(CoA) directly [RFC5014] when communicating with CNs on the same link
or anywhere in the Internet, although no session continuity support
would be provided by the IP stack in this case.
Hierarchical Mobile IPv6 (HMIPv6) [RFC5380] (as shown in Figure 3),
is another host-based IP mobility extension which can be considered
as a complement to provide a less centralized mobility deployment.
It allows the reduction of the amount of mobility signaling as well
as improving the overall handover performance of Mobile IPv6 by
introducing a new hierarchy level to handle local mobility. The
Mobility Anchor Point (MAP) entity is introduced as a local mobility
handling node deployed closer to the mobile node. It provides LI
intermediary function between the LI server (LIs) at the HA and the
LI client (LIc) at the MN. It also performs the FM function to
tunnel with the HA and also with the MN.
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<INTERNET> <- HOME NETWORK -> <---------- ACCESS NETWORK ---------->
LCoA anchored
at AR1
+---+ +--------+
===|AR1|==| MN1 |
+-----+ +-----------+ +----------+ // +---+ |(FM,LMc)|
| CN1 |----| HA1 |======| MAP1 |=== +--------+
+-----+ |(AF,FM,LMs)| /|(AF,FM,LM)| +---+ HoA,
+-----------+ / +----------+ |AR2| RCoA,
HoA anchored / RCoA anchored +---+ LCoA
at HA1 / at MAP1
/ +---+
/ |AR3|
+-----+ / +----------+ +---+
| CN2 |---------------- | MAP2 |
+-----+ |(AF,FM,LM)| +---+
+----------+ |AR4|
+---+
CN1 CN2 HA1 MAP1 AR1 MN1
| | | | | |
|<-------------->|<===============>|<====tunnel============>| HoA
| | | | | |
| |<-------------------------->|<====tunnel============>| RCoA
| | | | | |
Figure 3: Hierarchical Mobile IPv6
When HMIPv6 is used, the MN has two different temporary addresses:
the Regional Care-of Address (RCoA) and the Local Care-of Address
(LCoA). The RCoA is anchored at one MAP, which plays the role of
local home agent, while the LCoA is anchored at the access router
level. The mobile node uses the RCoA as the CoA signaled to its home
agent. Therefore, while roaming within a local domain handled by the
same MAP, the mobile node does not need to update its home agent,
i.e., the mobile node does not change its RCoA.
The use of HMIPv6 enables a form of route optimization, since a
mobile node may decide to directly use the RCoA as source address for
a communication with a given correspondent node, particularly if the
MN does not expect to move outside the local domain during the
lifetime of the communication. This can be seen as a potential DMM
mode of operation, though it fails to provide session continuity if
and when the MN moves outside the local domain. In the example shown
in Figure 3, MN1 is using its global HoA to communicate with CN1,
while it is using its RCoA to communicate with CN2.
Furthermore, a local domain might have several MAPs deployed,
enabling therefore a different kind of HMIPv6 deployments which are
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flattening and distributed. The HMIPv6 specification supports a
flexible selection of the MAP, including those based on the distance
between the MN and the MAP, or taking into consideration the expected
mobility pattern of the MN.
Another extension that can be used to help with distributing mobility
management functions is the Home Agent switch specification
[RFC5142], which defines a new mobility header for signaling a mobile
node that it should acquire a new home agent. [RFC5142] does not
specify the case of changing the mobile node's home address, as that
might imply loss of connectivity for ongoing persistent connections.
Nevertheless, that specification could be used to force the change of
home agent in those situations where there are no active persistent
data sessions that cannot cope with a change of home address.
There are other host-based approaches standardized that can be used
to provide mobility support. For example MOBIKE [RFC4555] allows a
mobile node encrypting traffic through IKEv2 [RFC5996] to change its
point of attachment while maintaining a Virtual Private Network (VPN)
session. The MOBIKE protocol allows updating the VPN Security
Associations (SAs) in cases where the base connection initially used
is lost and needs to be re-established. The use of the MOBIKE
protocol avoids having to perform an IKEv2 re-negotiation. Similar
considerations to those made for Mobile IPv6 can be applied to
MOBIKE; though MOBIKE is best suited for situations where the address
of at least one endpoint is relatively stable and can be discovered
using existing mechanisms such as DNS.
Extensions have been defined to the mobility protocol to optimize the
handover performance. Mobile IPv6 Fast Handovers (FMIPv6) [RFC5568]
is the extension to optimize handover latency. It defines new access
router discovery mechanism before handover to reduce the new network
discovery latency. It also defines a tunnel between the previous
access router and the new access router to reduce the packet loss
during handover. The Candidate Access Router Discovery (CARD)
[RFC4066] and Context Transfer Protocol (CXTP) [RFC4067] protocols
were standardized to improve the handover performance. The DMM
deployment practice discussed in this section can also use those
extensions to improve the handover performance.
4.2.2. Network-based IP DMM practices
Proxy Mobile IPv6 (PMIPv6) [RFC5213] is the main network-based IP
mobility protocol specified for IPv6. Proxy Mobile IPv4 [RFC5844]
defines some IPv4 extensions. With network-based IP mobility
protocols, the Local Mobility Anchor (LMA) typically provides the
Anchoring Function (AF), Forwarding Management (FM) function, and
Internetwork Location Information server (LIs) function. The mobile
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access gateway (MAG) provides the Location Information client (LIc)
function and Forwarding Management (FM) function to tunnel with LMA.
PMIPv6 is architecturally almost identical to MIPv6, as the mobility
signaling and routing between LMA and MAG in PMIPv6 is similar to
those between HA and MN in MIPv6. The required mobility
functionality at the MN is provided by the MAG so that the
involvement in mobility support by the MN is not required.
We next describe some practices that show how network-based mobility
protocols and several other protocol extensions can be deployed in a
distributed mobility management environment.
One way to decentralize Proxy Mobile IPv6 operation can be to deploy
several Local Mobility Anchors and use some selection criteria to
assign LMAs to attaching mobile nodes. An example of this type of
assignment is shown in Figure 4. As with the client based approach,
a mobile node may use several anchors at the same time, each of them
anchoring IP flows initiated at a different point of attachment.
This assignment can be static or dynamic. The main advantage of this
simple approach is that the IP address anchor, i.e., the LMA, could
be placed closer to the mobile node. Therefore the resulting paths
are close-to-optimal. On the other hand, as soon as the mobile node
moves, the resulting path will start deviating from the optimal one.
<INTERNET> <--- HOME NETWORK ---> <------ ACCESS NETWORK ------->
+--------+ +---+
=======| MAG1 |------|MN1|
+-----+ +-----------+ // |(FM,LMc)| +---+
| CN1 |-------| LMA1 |======= +--------+
+-----+ |(AF,FM,LMs)|
+-----------+ +--------+
+-----+ | MAG2 |
| CN2 |--- |(FM,LMc)|
+-----+ \ +-----------+ +--------+
---| LMA2 |=======
+-----+ |(AF,FM,LMs)| \\ +--------+ +---+
| CN3 | +-----------+ =======| MAG3 |------|MN2|
+-----+ |(FM,LMs)| +---+
+--------+
CN1 CN2 LMA1 LMA2 MAG1 MAG3 MN1 MN2
| | | | | | | |
|<-------------->|<===========tunnel========>|<----------->| |
| | | | | | | |
| |<-------------->|<=====tunnel=============>|<----------->|
| | | | | | | |
Figure 4: Distributed operation of Proxy Mobile IPv6
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In a similar way to the host-based IP mobility case, network-based IP
mobility has some extensions defined to mitigate the suboptimal
routing issues that may arise due to the use of a centralized anchor.
The Local Routing extensions [RFC6705] enable optimal routing in
Proxy Mobile IPv6 in three cases: i) when two communicating MNs are
attached to the same MAG and LMA, ii) when two communicating MNs are
attached to different MAGs but to the same LMA, and iii) when two
communicating MNs are attached to the same MAG but have different
LMAs. In these three cases, data traffic between the two mobile
nodes does not traverse the LMA(s), thus providing some form of path
optimization since the traffic is locally routed at the edge. The
main disadvantage of this approach is that it only tackles the MN-to-
MN communication scenario, and only under certain circumstances.
An interesting extension that can also be used to facilitate the
deployment of network-based mobility protocols in a distributed
mobility management environment is the support of LMA runtime
assignment described in [RFC6463]. This extension specifies a
runtime Local Mobility Anchor assignment functionality and
corresponding mobility options for Proxy Mobile IPv6. This runtime
Local Mobility Anchor assignment takes place during the Proxy Binding
Update / Proxy Binding Acknowledgment message exchange between a
mobile access gateway and a local mobility anchor. While this
mechanism is mainly aimed for load-balancing purposes, it can also be
used to select an optimal LMA from the routing point of view. A
runtime LMA assignment can be used to change the assigned LMA of an
MN, for example, in cases when the mobile node does not have any
active session, or when the running sessions can survive an IP
address change. Note that several possible dynamic Local Mobility
Anchor discovery solutions can be used, as described in [RFC6097].
4.3. Flattening 3GPP mobile network approaches
The 3rd Generation Partnership Project (3GPP) is the standards
development organization that specifies the 3rd generation mobile
network and the Evolved Packet System (EPS) [SDO-3GPP.23.402], which
mainly comprises the Evolved Packet Core (EPC) and a new radio access
network, usually referred to as LTE (Long Term Evolution).
Architecturally, the 3GPP Evolved Packet Core (EPC) network is
similar to an IP wireless network running PMIPv6 or MIPv6, as it
relies on the Packet Data Network Gateway (PGW) anchoring services to
provide mobile nodes with mobility support (see Figure 5). There are
client-based and network-based mobility solutions in 3GPP, which for
simplicity will be analyzed together. We next describe how 3GPP
mobility protocols and several other completed or ongoing extensions
can be deployed to meet some of the DMM requirements [RFC7333].
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+---------------------------------------------------------+
| PCRF |
+-----------+--------------------------+----------------+-+
| | |
+----+ +-----------+------------+ +--------+-----------+ +-+-+
| | | +-+ | | Core Network | | |
| | | +------+ |S|__ | | +--------+ +---+ | | |
| | | |GERAN/|_|G| \ | | | HSS | | | | | |
| +-----+ UTRAN| |S| \ | | +---+----+ | | | | E |
| | | +------+ |N| +-+-+ | | | | | | | x |
| | | +-+ /|MME| | | +---+----+ | | | | t |
| | | +---------+ / +---+ | | | 3GPP | | | | | e |
| +-----+ E-UTRAN |/ | | | AAA | | | | | r |
| | | +---------+\ | | | SERVER | | | | | n |
| | | \ +---+ | | +--------+ | | | | a |
| | | 3GPP AN \|SGW+----- S5---------------+ P | | | l |
| | | +---+ | | | G | | | |
| | +------------------------+ | | W | | | I |
| UE | | | | | | P |
| | +------------------------+ | | +-----+ |
| | |+-------------+ +------+| | | | | | n |
| | || Untrusted +-+ ePDG +-S2b---------------+ | | | e |
| +---+| non-3GPP AN | +------+| | | | | | t |
| | |+-------------+ | | | | | | w |
| | +------------------------+ | | | | | o |
| | | | | | | r |
| | +------------------------+ | | | | | k |
| +---+ Trusted non-3GPP AN +-S2a--------------+ | | | s |
| | +------------------------+ | | | | | |
| | | +-+-+ | | |
| +--------------------------S2c--------------------| | | |
| | | | | |
+----+ +--------------------+ +---+
Figure 5: EPS (non-roaming) architecture overview
The GPRS Tunneling Protocol (GTP) [SDO-3GPP.29.060] [SDO-3GPP.29.281]
[SDO-3GPP.29.274] is a network-based mobility protocol specified for
3GPP networks (S2a, S2b, S5 and S8 interfaces). In a similar way to
PMIPv6, it can handle mobility without requiring the involvement of
the mobile nodes. In this case, the mobile node functionality is
provided in a proxy manner by the Serving Data Gateway (SGW), Evolved
Packet Data Gateway (ePDG), or Trusted Wireless Access Gateway (TWAG
[SDO-3GPP.23.402]) .
3GPP specifications also include client-based mobility support, based
on adopting the use of Dual-Stack Mobile IPv6 (DSMIPv6) [RFC5555] for
the S2c interface [SDO-3GPP.24.303]. In this case, the User
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Equipment (UE) implements the binding update functionality, while the
home agent role is played by the PGW.
A Local IP Access (LIPA) and Selected IP Traffic Offload (SIPTO)
enabled network [SDO-3GPP.23.401] allows offloading some IP services
at the local access network above the Radio Access Network (RAN)
without the need to travel back to the PGW (see Figure 6).
+---------+ IP traffic to mobile operator's CN
| User |....................................(Operator's CN)
| Equipm. |..................
+---------+ . Local IP traffic
.
+-----------+
|Residential|
|enterprise |
|IP network |
+-----------+
Figure 6: LIPA scenario
SIPTO enables an operator to offload certain types of traffic at a
network node close to the UE's point of attachment to the access
network, by selecting a set of GWs (SGW and PGW) that are
geographically/topologically close to the UE's point of attachment.
SIPTO Traffic
|
.
.
+-------+ +------+
| L-PGW | ---- | MME |
+-------+ / +------+
| /
+------+ +-----+ +-----+/ +-----+
| UE |.....| eNB |....| SGW |........| PGW |.... CN Traffic
+------+ +-----+ +-----+ +-----+
Figure 7: SIPTO architecture
LIPA, on the other hand, enables an IP addressable UE connected via a
Home eNB (HeNB) to access other IP addressable entities in the same
residential/enterprise IP network without traversing the mobile
operator's network core in the user plane. In order to achieve this,
a Local GW (LGW) collocated with the HeNB is used. LIPA is
established by the UE requesting a new Public Data Network (PDN)
connection to an access point name for which LIPA is permitted, and
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the network selecting the Local GW associated with the HeNB and
enabling a direct user plane path between the Local GW and the HeNB.
+---------------+------+ +----------+ +-------------+ =====
|Residential | | HeNB | | Backhaul | |Mobile | ( IP )
|Enterprise |..|------|..| |..|Operator |..(Network)
|Network | | LGW | | | |Core network | =======
+---------------+------+ +----------+ +-------------+
/
|
/
+-----+
| UE |
+-----+
Figure 8: LIPA architecture
The 3GPP architecture specifications also provide mechanisms to allow
discovery and selection of gateways [SDO-3GPP.29.303]. These
mechanisms enable decisions taking into consideration topological
location and gateway collocation aspects, relying upon the DNS as a
"location database."
Both SIPTO and LIPA have a very limited mobility support, especially
in 3GPP specifications up to Rel-12. Briefly, LIPA mobility support
is limited to handovers between HeNBs that are managed by the same
LGW (i.e., mobility within the local domain). There is no guarantee
of IP session continuity for SIPTO.
5. Gap analysis
This section identifies the limitations in the current practices,
described in Section 4, with respect to the DMM requirements listed
in [RFC7333].
5.1. Distributed mobility management - REQ1
According to requirement REQ1 stated in [RFC7333], IP mobility,
network access and forwarding solutions provided by DMM must make it
possible for traffic to avoid traversing a single mobility anchor far
from the optimal route.
From the analysis performed in Section 4, a DMM deployment can meet
the requirement "REQ1 Distributed mobility management" usually
relying on the following functions:
o Multiple (distributed) anchoring: ability to anchor different
sessions of a single mobile node at different anchors. In order
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to provide improved routing, some anchors might need to be placed
closer to the mobile node or the corresponding node.
o Dynamic anchor assignment/re-location: ability to i) assign the
initial anchor, and ii) dynamically change the initially assigned
anchor and/or assign a new one (this may also require the transfer
of mobility context between anchors). This can be achieved either
by changing anchor for all ongoing sessions or by assigning new
anchors just for new sessions.
GAP1-1: Both the main client- and network-based IP mobility
protocols, namely (DS)MIPv6 and PMIPv6 allow deploying
multiple anchors (i.e., home agents and localized mobility
anchors), thereby providing the multiple anchoring function.
However, existing solutions only provide an initial anchor
assignment, thus the lack of dynamic anchor change/new
anchor assignment is a gap. Neither the HA switch nor the
LMA runtime assignment allows changing the anchor during an
ongoing session. This actually comprises several gaps:
ability to perform anchor assignment at any time (not only
at the initial MN's attachment), ability of the current
anchor to initiate/trigger the relocation, and ability to
transfer registration context between anchors.
GAP1-2: Dynamic anchor assignment may lead the MN to manage
different mobility sessions served by different mobility
anchors. This is not an issue with client based mobility
management where the mobility client natively knows the
anchor associated with each of its mobility sessions.
However, there is one gap, as the MN should be capable of
handling IP addresses in a DMM-friendly way, meaning that
the MN can perform smart source address selection (i.e.,
deprecating IP addresses from previous mobility anchors, so
they are not used for new sessions). Besides, managing
different mobility sessions served by different mobility
anchors may raise issues with network based mobility
management. In this case, the mobile client located in the
network, e.g., MAG, usually retrieves the MN's anchor from
the MN's policy profile as described in Section 6.2 of
[RFC5213]. Currently, the MN's policy profile implicitly
assumes a single serving anchor and thus does not maintain
the association between home network prefix and anchor.
GAP1-3: The consequence of the distribution of the mobility anchors
is that there might be more than one available anchor for a
mobile node to use, which leads to an anchor discovery and
selection issue. Currently, there is no efficient mechanism
specified to allow the dynamic discovery of the presence of
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nodes that can play the anchor role, discovering their
capabilities and selecting the most suitable one. There is
also no mechanism to allow selecting a node that is
currently anchoring a given home address/prefix (capability
sometimes required to meet REQ#2). However, there are some
mechanisms that could help to discover anchors, such as the
Dynamic Home Agent Address Discovery (DHAAD) [RFC6275], the
use of the home agent flag (H) in Router Advertisements
(which indicates that the router sending the Router
Advertisement is also functioning as a Mobile IPv6 home
agent on the link) or the MAP option in Router
Advertisements defined by HMIPv6. Note that there are 3GPP
mechanisms providing that functionality defined in
[SDO-3GPP.29.303].
Regarding the ability to transfer registration context between
anchors, there are already some solutions that could be reused or
adapted to fill that gap, such as Fast Handovers for Mobile IPv6
[RFC5568] -- to enable traffic redirection from the old to the new
anchor --, the Context Transfer protocol [RFC4067] -- to enable the
required transfer of registration information between anchors --, or
the Handover Keying architecture solutions [RFC6697], to speed up the
re-authentication process after a change of anchor. Note that some
extensions might be needed in the context of DMM, as these protocols
were designed in the context of centralized client IP mobility,
focusing on the access re-attachment and authentication.
GAP1-4: Also note that REQ1 is intended to prevent the data plane
traffic from taking a suboptimal route. Distributed
processing of the traffic may then be needed only in the
data plane. Provision of this capability for distributed
processing should not conflict with the use of a centralized
control plane. Other control plane solutions such as
charging, lawful interception, etc. should not be
constrained by the DMM solution. On the other hand
combining the control plane and data plane forwarding
management (FM) function may limit the choice of solutions
to those that distribute both data plane and control plane
together. In order to enable distribution of only the data
plane without distributing the control plane, it would be
necessary to split the forwarding management function into
the control plane (FM-CP) and data plane (FM-DP) components;
there is currently a gap here.
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5.2. Bypassable network-layer mobility support for each application
session - REQ2
The requirement REQ2 for "bypassable network-layer mobility support
for each application session" introduced in [RFC7333] requires
flexibility in determining whether network-layer mobility support is
needed. This requirement enables one to choose whether or not to use
network-layer mobility support. The following two functions are also
needed:
o Dynamically assign/relocate anchor: a mobility anchor is assigned
only to sessions which use the network-layer mobility support.
The MN may thus manage more than one session; some of them may be
associated with anchored IP address(es), while the others may be
associated with local IP address(es).
o Multiple IP address management: this function is related to the
preceding and is about the ability of the mobile node to
simultaneously use multiple IP addresses and select the best one
(from an anchoring point of view) to use on a per-
session/application/service basis. This requires MN to acquire
information regarding the properties of the available IP
addresses.
GAP2-1: The dynamic anchor assignment/relocation needs to ensure
that IP address continuity is guaranteed for sessions that
uses such mobility support (e.g., in some scenarios, the
provision of mobility locally within a limited area might be
enough from the mobile node or the application point of
view) at the relocated anchor. Implicitly, when no
applications are using the network-layer mobility support,
DMM may release the needed resources. This may imply having
the knowledge of which sessions at the mobile node are
active and are using the mobility support. This is
something typically known only by the MN, e.g., by its
connection manager, and would also typically require some
signaling support such as socket API extensions from
applications to indicate to the IP stack whether mobility
support is required or not. Therefore, (part of) this
knowledge might need to be transferred to/shared with the
network.
GAP2-2: Multiple IP address management provides the MN with the
choice to pick the correct address, e.g., from those
provided or not provided with mobility support, depending on
the application requirements. When using client based
mobility management, the mobile node is itself aware of the
anchoring capabilities of its assigned IP addresses. This
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is not necessarily the case with network based IP mobility
management; current mechanisms do not allow the MN to be
aware of the properties of its IP addresses. For example,
the MN does not know whether the allocated IP addresses are
anchored. However, there are proposals, such as
[I-D.bhandari-dhc-class-based-prefix],
[I-D.korhonen-6man-prefix-properties] and
[I-D.anipko-mif-mpvd-arch] that the network could indicate
such IP address properties during assignment procedures.
Although these individual efforts exist and they could be
considered as attempts to fix the gap, there is no solution
adopted as a work item within any IETF working group.
GAP2-3: The handling of mobility management to the granularity of an
individual session of a user/device needs proper session
identification in addition to user/device identification.
5.3. IPv6 deployment - REQ3
This requirement states that DMM solutions should primarily target
IPv6 as the primary deployment environment. IPv4 support is not
considered mandatory and solutions should not be tailored
specifically to support IPv4.
All analyzed DMM practices support IPv6. Some of them, such as
MIPv6/NEMO including the support of dynamic HA selection, MOBIKE,
SIPTO also have IPv4 support. Some solutions, e.g., PMIPv6, also
have some limited IPv4 support. In conclusion, this requirement is
met by existing DMM practices.
5.4. Considering existing mobility protocols - REQ4
A DMM solution must first consider reusing and extending IETF-
standardized protocols before specifying new protocols.
As stated in [RFC7333], a DMM solution could reuse existing IETF and
standardized protocols before specifying new protocols. Besides,
Section 4 of this document discusses various ways to flatten and
distribute current mobility solutions. Actually, nothing prevents
the distribution of mobility functions within IP mobility protocols.
However, as discussed in Section 5.1 and Section 5.2, limitations
exist.
The 3GPP data plane anchoring function, i.e., the PGW, can also be
distributed, but with limitations; e.g., no anchoring relocation, no
context transfer between anchors and centralized control plane. The
3GPP architecture is also going in the direction of flattening with
SIPTO and LIPA, though they do not provide full mobility support.
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For example, mobility support for SIPTO traffic can be rather
limited, and offloaded traffic cannot access operator services.
Thus, the operator must be very careful in selecting which traffic to
offload.
5.5. Coexistence with deployed networks/hosts and operability across
different networks - REQ5
According to [RFC7333], DMM implementations are required to co-exist
with existing network deployments, end hosts and routers.
Additionally, DMM solutions are expected to work across different
networks, possibly operated as separate administrative domains, when
the necessary mobility management signaling, forwarding, and network
access are allowed by the trust relationship between them. All
current mobility protocols can co-exist with existing network
deployments and end hosts. There is no gap between existing mobility
protocols and this requirement.
5.6. Operation and management considerations - REQ6
This requirement actually comprises several aspects, as summarized
below.
o A DMM solution needs to consider configuring a device, monitoring
the current operational state of a device, responding to events
that impact the device, possibly by modifying the configuration
and storing the data in a format that can be analyzed later.
o A DMM solution has to describe in what environment and how it can
be scalably deployed and managed.
o A DMM solution has to support mechanisms to test if the DMM
solution is working properly.
o A DMM solution is expected to expose the operational state of DMM
to the administrators of the DMM entities.
o A DMM solution, which supports flow mobility, is also expected to
support means to correlate the flow routing policies and the
observed forwarding actions.
o A DMM solution is expected to support mechanisms to check the
liveness of the forwarding path.
o A DMM solution has to provide fault management and monitoring
mechanisms to manage situations where update of the mobility
session or the data path fails.
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o A DMM solution is expected to be able to monitor the usage of the
DMM protocol.
o DMM solutions have to support standardized configuration with
NETCONF [RFC6241], using YANG [RFC6020] modules, which are
expected to be created for DMM when needed for such configuration.
GAP6-1: Existing mobility management protocols have not thoroughly
documented how, or whether, they support the above list of
operation and management considerations. Each of the above
needs to be considered from the beginning in a DMM solution.
GAP6-2: Management information base (MIB) objects are currently
defined in [RFC4295] for MIPv6 and in [RFC6475] for PMIPv6.
Standardized configuration with NETCONF [RFC6241], using
YANG [RFC6020] modules is lacking.
5.7. Security considerations - REQ7
As stated in [RFC7333], a DMM solution has to support any security
protocols and mechanisms needed to secure the network and to make
continuous security improvements. In addition, with security taken
into consideration early in the design, a DMM solution cannot
introduce new security risks, or privacy concerns, or amplify
existing security risks, that cannot be mitigated by existing
security protocols and mechanisms.
Any solutions that are intended to fill in gaps identified in this
document need to meet this requirement. At present, it does not
appear that using existing solutions to support DMM has introduced
any new security issues. For example, Mobile IPv6 defines security
features to protect binding updates both to home agents and
correspondent nodes. It also defines mechanisms to protect the data
packets transmission for Mobile IPv6 users. Proxy Mobile IPv6 and
other variations of mobile IP also have similar security
considerations.
5.8. Multicast - REQ8
It is stated in [RFC7333] that DMM solutions are expected to allow
the development of multicast solutions to avoid network inefficiency
in multicast traffic delivery.
Current IP mobility solutions address mainly the mobility problem for
unicast traffic. Solutions relying on the use of an anchor point for
tunneling multicast traffic down to the access router, or to the
mobile node, introduce the so-called "tunnel convergence problem."
This means that multiple instances of the same multicast traffic can
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converge to the same node, diminishing the advantage of using
multicast protocols.
[RFC6224] documents a baseline solution for the previous issue, and
[RFC7028] a routing optimization solution. The baseline solution
suggests deploying a Multicast Listener Discovery (MLD) proxy
function at the MAG, and either a multicast router or another MLD
proxy function at the LMA. The routing optimization solution
describes an architecture where a dedicated multicast tree mobility
anchor or a direct routing option can be used to avoid the tunnel
convergence problem.
Besides the solutions highlighted before, there are no other
mechanisms for mobility protocols to address the multicast tunnel
convergence problem.
5.9. Summary
We next list the main gaps identified from the analysis performed
above:
GAP1-1: Existing solutions only provide an optimal initial anchor
assignment, a gap being the lack of dynamic anchor change/
new anchor assignment. Neither the HA switch nor the LMA
runtime assignment allows changing the anchor during an
ongoing session. MOBIKE allows change of GW but its
applicability has been scoped to a very narrow use case.
GAP1-2: The MN needs to be able to perform source address selection.
Proper mechanism to inform the MN is lacking to provide the
basis for the proper selection.
GAP1-3: Currently, there is no efficient mechanism specified by the
IETF that allows the dynamic discovery of the presence of
nodes that can play the role of anchor, discover their
capabilities and allow the selection of the most suitable
one. However, the following mechanisms could help
discovering anchors:
Dynamic Home Agent Address Discovery (DHAAD): the use of the
home agent (H) flag in Router Advertisements (which
indicates that the router sending the Router Advertisement
is also functioning as a Mobile IPv6 home agent on the link)
and the MAP option in Router Advertisements defined by
HMIPv6.
GAP1-4: While existing network-based DMM practices may allow the
deployment of multiple LMAs and dynamically select the best
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one, this requires to still keep some centralization in the
control plane, to access the policy database (as defined in
RFC5213). Although [I-D.ietf-netext-pmip-cp-up-separation]
allows a MAG to perform splitting of its control and user
planes, there is a lack of solutions/extensions that support
a clear control and data plane separation for IETF IP
mobility protocols in a DMM context.
GAP2-1: The information of which sessions at the mobile node are
active and are using the mobility support need to be
transferred to or shared with the network. Such mechanism
has not been defined.
GAP2-2: The mobile node needs to simultaneously use multiple IP
addresses with different properties. There is a lack of
mechanism to expose this information to the mobile node
which can then update accordingly its source address
selection mechanism.
GAP2-3: The handling of mobility management has not been to the
granularity of an individual session of a user/device
before. The combination of session identification and user/
device identification may be lacking.
GAP6-1: Mobility management protocols have not thoroughly documented
how, or whether, they support the following list of
operation and management considerations:
* A DMM solution needs to consider configuring a device,
monitoring the current operational state of a device,
responding to events that impact the device, possibly by
modifying the configuration and storing the data in a
format that can be analyzed later.
* A DMM solution has to describe in what environment and
how it can be scalably deployed and managed.
* A DMM solution has to support mechanisms to test if the
DMM solution is working properly.
* A DMM solution is expected to expose the operational
state of DMM to the administrators of the DMM entities.
* A DMM solution, which supports flow mobility, is also
expected to support means to correlate the flow routing
policies and the observed forwarding actions.
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* A DMM solution is expected to support mechanisms to check
the liveness of the forwarding path.
* A DMM solution has to provide fault management and
monitoring mechanisms to manage situations where update
of the mobility session or the data path fails.
* A DMM solution is expected to be able to monitor the
usage of the DMM protocol.
* DMM solutions have to support standardized configuration
with NETCONF [RFC6241], using YANG [RFC6020] modules,
which are expected to be created for DMM when needed for
such configuration.
GAP6-2: Management information base (MIB) objects are currently
defined in [RFC4295] for MIPv6 and in [RFC6475] for PMIPv6.
Standardized configuration with NETCONF [RFC6241], using
YANG [RFC6020] modules is lacking.
6. Security Considerations
The deployment of DMM using existing IP mobility protocols raises
similar security threats as those encountered in centralized mobility
management systems. Without authentication, a malicious node could
forge signaling messages and redirect traffic from its legitimate
path. This would amount to a denial of service attack against the
specific node or nodes for which the traffic is intended.
Distributed mobility anchoring, while keeping current security
mechanisms, might require more security associations to be managed by
the mobility management entities, potentially leading to scalability
and performance issues. Moreover, distributed mobility anchoring
makes mobility security problems more complex, since traffic
redirection requests might come from previously unconsidered origins,
thus leading to distributed points of attack. Consequently, the DMM
security design needs to account for the distribution of security
associations between additional mobility entities and fulfill the
security requirement of [RFC7333].
7. Contributors
This document has benefited to valuable contributions from
Charles E. Perkins
Huawei Technologies
EMail: charliep@computer.org
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who had produced a matrix to compare the different mobility protocols
and extensions against a list of desired DMM properties. They were
useful inputs in the early work of gap analysis. He had continued to
give suggestions as well as extensive review comments to this
documents.
8. References
8.1. Normative References
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
[RFC7333] Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen,
"Requirements for Distributed Mobility Management", RFC
7333, August 2014.
8.2. Informative References
[I-D.anipko-mif-mpvd-arch]
Anipko, D., "Multiple Provisioning Domain Architecture",
draft-anipko-mif-mpvd-arch-05 (work in progress), November
2013.
[I-D.bhandari-dhc-class-based-prefix]
Systems, C., Halwasia, G., Gundavelli, S., Deng, H.,
Thiebaut, L., Korhonen, J., and I. Farrer, "DHCPv6 class
based prefix", draft-bhandari-dhc-class-based-prefix-05
(work in progress), July 2013.
[I-D.gundavelli-v6ops-community-wifi-svcs]
Gundavelli, S., Grayson, M., Seite, P., and Y. Lee,
"Service Provider Wi-Fi Services Over Residential
Architectures", draft-gundavelli-v6ops-community-wifi-
svcs-06 (work in progress), April 2013.
[I-D.ietf-netext-pmip-cp-up-separation]
Wakikawa, R., Pazhyannur, R., Gundavelli, S., and C.
Perkins, "Separation of Control and User Plane for Proxy
Mobile IPv6", draft-ietf-netext-pmip-cp-up-separation-07
(work in progress), August 2014.
[I-D.korhonen-6man-prefix-properties]
Korhonen, J., Patil, B., Gundavelli, S., Seite, P., and D.
Liu, "IPv6 Prefix Properties", draft-korhonen-6man-prefix-
properties-02 (work in progress), July 2013.
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[IEEE.802-16.2009]
"IEEE Standard for Local and metropolitan area networks
Part 16: Air Interface for Broadband Wireless Access
Systems", IEEE Standard 802.16, 2009,
<http://standards.ieee.org/getieee802/
download/802.16-2009.pdf>.
[RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
Thubert, "Network Mobility (NEMO) Basic Support Protocol",
RFC 3963, January 2005.
[RFC4066] Liebsch, M., Singh, A., Chaskar, H., Funato, D., and E.
Shim, "Candidate Access Router Discovery (CARD)", RFC
4066, July 2005.
[RFC4067] Loughney, J., Nakhjiri, M., Perkins, C., and R. Koodli,
"Context Transfer Protocol (CXTP)", RFC 4067, July 2005.
[RFC4225] Nikander, P., Arkko, J., Aura, T., Montenegro, G., and E.
Nordmark, "Mobile IP Version 6 Route Optimization Security
Design Background", RFC 4225, December 2005.
[RFC4295] Keeni, G., Koide, K., Nagami, K., and S. Gundavelli,
"Mobile IPv6 Management Information Base", RFC 4295, April
2006.
[RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, June 2006.
[RFC4640] Patel, A. and G. Giaretta, "Problem Statement for
bootstrapping Mobile IPv6 (MIPv6)", RFC 4640, September
2006.
[RFC4889] Ng, C., Zhao, F., Watari, M., and P. Thubert, "Network
Mobility Route Optimization Solution Space Analysis", RFC
4889, July 2007.
[RFC4960] Stewart, R., "Stream Control Transmission Protocol", RFC
4960, September 2007.
[RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6
Socket API for Source Address Selection", RFC 5014,
September 2007.
[RFC5026] Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile IPv6
Bootstrapping in Split Scenario", RFC 5026, October 2007.
Liu, et al. Expires May 8, 2015 [Page 27]
Internet-Draft DMM-best-practices-gap-analysis November 2014
[RFC5142] Haley, B., Devarapalli, V., Deng, H., and J. Kempf,
"Mobility Header Home Agent Switch Message", RFC 5142,
January 2008.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5380] Soliman, H., Castelluccia, C., ElMalki, K., and L.
Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility
Management", RFC 5380, October 2008.
[RFC5555] Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
Routers", RFC 5555, June 2009.
[RFC5568] Koodli, R., "Mobile IPv6 Fast Handovers", RFC 5568, July
2009.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
[RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
"Internet Key Exchange Protocol Version 2 (IKEv2)", RFC
5996, September 2010.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC6097] Korhonen, J. and V. Devarapalli, "Local Mobility Anchor
(LMA) Discovery for Proxy Mobile IPv6", RFC 6097, February
2011.
[RFC6224] Schmidt, T., Waehlisch, M., and S. Krishnan, "Base
Deployment for Multicast Listener Support in Proxy Mobile
IPv6 (PMIPv6) Domains", RFC 6224, April 2011.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)", RFC
6241, June 2011.
[RFC6463] Korhonen, J., Gundavelli, S., Yokota, H., and X. Cui,
"Runtime Local Mobility Anchor (LMA) Assignment Support
for Proxy Mobile IPv6", RFC 6463, February 2012.
[RFC6475] Keeni, G., Koide, K., Gundavelli, S., and R. Wakikawa,
"Proxy Mobile IPv6 Management Information Base", RFC 6475,
May 2012.
Liu, et al. Expires May 8, 2015 [Page 28]
Internet-Draft DMM-best-practices-gap-analysis November 2014
[RFC6611] Chowdhury, K. and A. Yegin, "Mobile IPv6 (MIPv6)
Bootstrapping for the Integrated Scenario", RFC 6611, May
2012.
[RFC6697] Zorn, G., Wu, Q., Taylor, T., Nir, Y., Hoeper, K., and S.
Decugis, "Handover Keying (HOKEY) Architecture Design",
RFC 6697, July 2012.
[RFC6705] Krishnan, S., Koodli, R., Loureiro, P., Wu, Q., and A.
Dutta, "Localized Routing for Proxy Mobile IPv6", RFC
6705, September 2012.
[RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, September 2012.
[RFC7028] Zuniga, JC., Contreras, LM., Bernardos, CJ., Jeon, S., and
Y. Kim, "Multicast Mobility Routing Optimizations for
Proxy Mobile IPv6", RFC 7028, September 2013.
[SDO-3GPP.23.401]
3GPP, "General Packet Radio Service (GPRS) enhancements
for Evolved Universal Terrestrial Radio Access Network
(E-UTRAN) access", 3GPP TS 23.401 10.10.0, March 2013.
[SDO-3GPP.23.402]
3GPP, "Architecture enhancements for non-3GPP accesses",
3GPP TS 23.402 10.8.0, September 2012.
[SDO-3GPP.24.303]
3GPP, "Mobility management based on Dual-Stack Mobile
IPv6; Stage 3", 3GPP TS 24.303 10.0.0, June 2013.
[SDO-3GPP.29.060]
3GPP, "General Packet Radio Service (GPRS); GPRS
Tunnelling Protocol (GTP) across the Gn and Gp interface",
3GPP TS 29.060 3.19.0, March 2004.
[SDO-3GPP.29.274]
3GPP, "3GPP Evolved Packet System (EPS); Evolved General
Packet Radio Service (GPRS) Tunnelling Protocol for
Control plane (GTPv2-C); Stage 3", 3GPP TS 29.274 10.11.0,
June 2013.
[SDO-3GPP.29.281]
3GPP, "General Packet Radio System (GPRS) Tunnelling
Protocol User Plane (GTPv1-U)", 3GPP TS 29.281 10.3.0,
September 2011.
Liu, et al. Expires May 8, 2015 [Page 29]
Internet-Draft DMM-best-practices-gap-analysis November 2014
[SDO-3GPP.29.303]
3GPP, "Domain Name System Procedures; Stage 3", 3GPP TS
29.303 10.4.0, September 2012.
Authors' Addresses
Dapeng Liu (editor)
China Mobile
Unit2, 28 Xuanwumenxi Ave, Xuanwu District
Beijing 100053
China
Email: liudapeng@chinamobile.com
Juan Carlos Zuniga (editor)
InterDigital Communications, LLC
1000 Sherbrooke Street West, 10th floor
Montreal, Quebec H3A 3G4
Canada
Email: JuanCarlos.Zuniga@InterDigital.com
URI: http://www.InterDigital.com/
Pierrick Seite
Orange
4, rue du Clos Courtel, BP 91226
Cesson-Sevigne 35512
France
Email: pierrick.seite@orange.com
H Anthony Chan
Huawei Technologies
5340 Legacy Dr. Building 3
Plano, TX 75024
USA
Email: h.a.chan@ieee.org
Liu, et al. Expires May 8, 2015 [Page 30]
Internet-Draft DMM-best-practices-gap-analysis November 2014
Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/
Liu, et al. Expires May 8, 2015 [Page 31]
