wdiff draft-ietf-dmm-distributed-mobility-anchoring-07.txt draft-ietf-dmm-distributed-mobility-anchoring-08.txt

DMM H. Chan, Ed.
Internet-Draft X. Wei
Intended status: Informational Huawei Technologies
Expires: May 16, September 3, 2018 J. Lee
Sangmyung University
S. Jeon
Sungkyunkwan University
A. Petrescu
CEA, LIST
F. Templin
Boeing Research and Technology
November 12, 2017
CJ. Bernardos, Ed.
UC3M
March 2, 2018

Distributed Mobility Anchoring
draft-ietf-dmm-distributed-mobility-anchoring-07
draft-ietf-dmm-distributed-mobility-anchoring-08

Abstract

This document defines distributed mobility anchoring in terms of the
different configurations, operations configurations and parameters of mobility functions to provide different IP mobility support for the diverse
mobility needs in 5G Wireless and beyond.
support. A network may be configured with distributed mobility
anchoring functions for both network-based or host-based mobility
support according to the needs of mobility support. In the
distributed mobility anchoring environment, multiple anchors are
available for mid-session switching of an IP prefix anchor. To start
a new flow or to handle a flow not requiring IP session continuity as
a mobile node moves to a new network, the flow can be started or re-started re-
started using a new IP address configured from the new IP prefix
which is anchored to the new network. For a flow requiring IP session continuity, the anchoring
of the prior IP prefix may be moved to the new network. The mobility functions and
their operations and parameters are general for different
configurations. The mobility signaling may be between
anchors and nodes in the network in a network-based mobility
solution. It may also be between the anchors and the mobile node in
a host-based solution. The mobile node may be a host, but may also
be a router carrying a network requiring network mobility support.

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 May 16, September 3, 2018.

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
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 . . . . . . . . . . . . . . . . . . . . . . . . 3 2
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 5 3
3. Distributed Mobility Anchoring . . . . . . . . . . . . . . . 6 5
3.1. Configurations for Different Networks . . . . . . . . . . 6 5
3.1.1. Network-based Mobility Support for a Flat Network . . 7
3.1.2. Network-based Mobility Support for a Hierarchical
Network . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.3. Host-based Mobility Support . . . . . . . . . . . . . 10
3.1.4. NEtwork MObility (NEMO) Basic Support . . . . . . . . 11
3.2. Operations and Parameters . . . . . . . . . . . . . DMM . . . 12
3.2.1. Location Management . . . . . . . . . . . . . . . 5
3.1.2. Client-based DMM . . 12
3.2.2. Forwarding Management . . . . . . . . . . . . . . . . 15 6
4. IP Mobility Handling in Distributed Anchoring Environments -
Mobility Support Only When Needed . . . . . . . . . . . . . . 21 7
4.1. No Need of IP Mobility: Changing to New IP Prefix/Address 22
4.1.1. Guidelines for IPv6 Nodes: Changing to New IP
Prefix/Address . . . . . . . . . . . . . . . . . . . 23 8
4.2. Need of IP Mobility . . . . . . . . . . . . . . . . . . . 25
4.2.1. Guidelines for IPv6 Nodes: Need of IP Mobility . . . 26 9
5. IP Mobility Handling in Distributed Mobility Anchoring
Environments - Anchor Switching to the New Network . . . . . 28 11
5.1. IP Prefix/Address Anchor Switching for Flat Network . . . 28
5.1.1. Guidelines for IPv6 Nodes: Switching Anchor for Flat
Network 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . . . . . 29

5.2. IP Prefix/Address Anchor Switching for Flat Network with
Centralized Control Plane . . . . . . . . . . . . . . . . 30
5.2.1. Additional Guidelines for IPv6 Nodes: Switching
Anchor with Centralized CP . . . . . . . . . . . . . 33
5.3. Hierarchical Network . . . . . . . . . . . . . . . . . . 34
5.3.1. Additional Guidelines for IPv6 Nodes: Hierarchical
Network with No Anchor Relocation . . . . . . . . . . 35
5.4. IP Prefix/Address Anchor Switching for a Hierarchical
Network . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.4.1. Additional Guidelines for IPv6 Nodes: Switching
Anchor with Hierarchical Network . . . . . . . . . . 37
5.5. Network Mobility . . . . . . . . . . . . . . . . . . . . 38
5.5.1. Additional Guidelines for IPv6 Nodes: Network
mobility . . . . . . . . . . . . . . . . . . . . . . 40
6. Security Considerations . . . . . . . . . . . . . . . . . . . 41 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42 12
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 42 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 42 12
9.1. Normative References . . . . . . . . . . . . . . . . . . 42 12
9.2. Informative References . . . . . . . . . . . . . . . . . 45 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45 15

1. Introduction

A key requirement in distributed mobility management [RFC7333] is to
enable traffic to avoid traversing a single mobility anchor far from
an optimal route. This draft document defines different configurations,
functional operations and parameters for distributed mobility
anchoring and explains how to use them to make the route changes to
avoid unnecessarily long routes.

Companion distributed mobility management documents are already
addressing the architecture and deployment
[I-D.ietf-dmm-deployment-models], source address selection
[I-D.ietf-dmm-ondemand-mobility], and control-plane data-plane
signaling [I-D.ietf-dmm-fpc-cpdp]. A number of distributed mobility
solutions have also been proposed, for example, in
[I-D.seite-dmm-dma], [I-D.bernardos-dmm-cmip],
[I-D.bernardos-dmm-pmip], [I-D.bernardos-dmm-pmipv6-dlif],
[I-D.sarikaya-dmm-for-wifi], [I-D.yhkim-dmm-enhanced-anchoring], and
[I-D.matsushima-stateless-uplane-vepc]. Yet in 5G Wireless and
beyond, the mobility requirements are diverse, and IP mobility
support is no longer by default with a one-size-fit-all solution. In
different networks, different kinds of

Distributed mobility support are possible
depending on anchoring employs multiple anchors in the needs. data
plane. In designing mobility solutions, it general, control plane functions may not
always be obvious on how to best configure and use only the needed
mobility functions to provide the specific mobility support. This
document aims at filling such background.

Distributed mobility anchoring employs multiple anchors in the data
plane. In general, control plane functions may be separate separated from
data plane functions and be centralized but may also be co-located
with the data plane functions at the distributed anchors. Different
configurations of distributed mobility anchoring are described in
Section 3.1. For instance, the configurations for network-based
mobility support in a flat network, for network-based mobility
support in a hierarchical network, for host-based mobility support,
and for network mobility basic support are described respectively in
Section 3.1.1, Section 3.1.2, Section 3.1.3 and Section 3.1.4.
Required operations and parameters for distributed mobility anchoring
are presented in Section 3.2. For instance, location management is
described in Section 3.2.1, forwarding management is described in
Section 3.2.2.

As an MN attaches to an access router and establishes a link between
them, a /64 IPv6 prefix anchored to the router may be assigned to the
link for exclusive use by the MN [RFC6459]. The MN may then
configure a global IPv6 address from this prefix and use it as the
source IP address in a flow to communicate with its correspondent
node (CN). When there are multiple mobility anchors, an address
selection for a given flow is first required before the flow is
initiated. Using an anchor in an MN's network of attachment has the
advantage that the packets can simply be forwarded according to the
forwarding table. However, after the flow has been initiated, the MN
may later move to another network, so that the IP address no longer
belongs to the current network of attachment of the MN.

Whether the flow needs

The IP session continuity will determine needs of a flow (application) determines
the how to
ensure that the IP address of used by the traffic of this flow will be anchored has to the new
network of attachment. be
anchored. If the ongoing IP flow can cope with an IP prefix/address
change, the flow can be reinitiated with a new IP address anchored in
the new network as shown in Section 4.1. network. On the other hand, if the ongoing IP flow cannot
cope with such change, mobility support is needed as shown in Section 4.2. needed. A network
supporting a mix of flows both requiring and not requiring IP
mobility support will need to distinguish these flows. The
guidelines for the network to make such a distinction are described
in Section 4.1.1. The

2. Conventions and Terminology

All general guidelines for such network to provide
IP mobility support are described mobility-related terms and their acronyms used in Section 4.2.1.

Specifically, IP mobility support can this
document are to be provided by relocating interpreted as defined in the
anchoring of Mobile IPv6 (MIPv6)
base specification [RFC6275], the IP prefix/address of Proxy Mobile IPv6 (PMIPv6)
specification [RFC5213], the flow from "Mobility Related Terminologies"
[RFC3753], and the DMM current practices and gap analysis [RFC7429].
These include terms such as mobile node (MN), correspondent node
(CN), home network
of the flow to agent (HA), home address (HoA), care-of-address (CoA),
local mobility anchor (LMA), and mobile access gateway (MAG).

In addition, this document uses the new network of attachment. The basic case may be
with network-based mobility for a flat network configuration
described in Section 5.1 with the guidelines described in
Section 5.1.1. This case is discussed further with a centralized
control plane in Section 5.2 with additional guidelines described in
Section 5.2.1. A level of hierarchy of nodes may then be added to
the network configuration as described in Section 5.3 with additional
guidelines described in Section 5.3.1. Local Mobility in such
hierarchical network is described in Section 5.4 with additional
guidelines described in Section 5.4.1. Network mobiltiy example is
described in Section 5.5 with additional guidelines described in
Section 5.5.1.

2. Conventions and Terminology

The key words "MUST", "MUST NOT", "GLUIRED", "SHALL","SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].

All general mobility-related terms and their acronyms used in this
document are to be interpreted as defined in the Mobile IPv6 (MIPv6)
base specification [RFC6275], the Proxy Mobile IPv6 (PMIPv6)
specification [RFC5213], the "Mobility Related Terminologies"
[RFC3753], and the DMM current practices and gap analysis [RFC7429].
These include terms such as mobile node (MN), correspondent node
(CN), home agent (HA), home address (HoA), care-of-address (CoA),
local mobility anchor (LMA), and mobile access gateway (MAG).

In addition, this document uses the following terms:

Home following terms:

Home network of an application session or a home address: the
network that has assigned the HoA used as the session identifier
by the application running in an MN. The MN may be running
multiple application sessions, and each of these sessions can have
a different home network.

Anchoring (an IP prefix/address): An IP prefix, i.e., Home Network
Prefix (HNP), or address, i.e., HoA, assigned for use by an MN is
topologically anchored to an anchor node when the anchor node is
able to advertise a connected route into the routing
infrastructure for the assigned IP prefix.

Location Management (LM) function: that keeps and manages the
network location information of an MN. The location information
may be a binding of the advertised IP 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.

When the MN is a mobile router (MR) carrying a mobile network of
mobile network nodes (MNN), the location information will also
include the mobile network prefix (MNP), which is the aggregate IP
prefix delegated to the MR to assign IP prefixes for use by the
MNNs in the mobile network.

In a client-server protocol model, location query and update
messages may be exchanged between a Location Management client
(LMc) and a Location Management server (LMs), where the location
information can be updated to or queried from the LMs.
Optionally, there may be a Location Management proxy (LMp) between
LMc and LMs.

With separation of control plane and data plane, the LM function
is in the control plane. It may be a logical function at the
control plane node, control plane anchor, or mobility controller.

It may be distributed or centralized.

Forwarding Management (FM) function: packet interception and
forwarding to/from the IP address/prefix assigned for use by 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.

This function may be used to achieve traffic indirection. With
separation of control plane and data plane, the FM function may
split into a FM function in the data plane (FM-DP) and a FM
function in the control plane (FM-CP).

FM-DP may be distributed with distributed mobility management. It
may be a function in a data plane anchor or data plane node.

FM-CP may be distributed or centralized. It may be a function in
a control plane node, control plane anchor or mobility controller.

3. Distributed Mobility Anchoring

3.1. Configurations for Different Networks

The mobility functions may be implemented in different

We next describe some configurations
of with multiple distributed mobility anchoring in architectures separating
anchors. To cover the
control and data planes. The separation described widest possible spectrum of scenarios, we
consider architectures in
[I-D.ietf-dmm-deployment-models] has defined which the home control plane
anchor (Home-CPA), home data plane anchor (Home-DPA), access control
plane node (Access-CPN), and access data plane node (Access-DPN),
which planes are respectively abbreviated
separated, as CPA, DPA, CPN, and DPN here.

Different networks may have different configurations described in [I-D.ietf-dmm-deployment-models].

3.1.1. Network-based DMM

Figure 1 shows a general scenario for network-based distributed
mobility anchoring. management.

The configurations also differ depending on the desired mobility
supports: network-based mobility support for main characteristics of a flat network in
Section 3.1.1, network-based mobility support for a hierarchical
network in Section 3.1.2, host-based mobility support in
Section 3.1.3, and NEtwork MObility (NEMO) based support in
Section 3.1.4.

3.1.1. Network-based Mobility Support for a Flat Network

Figure 1 show the configurations of network-based distributed
mobility management for a flat network.

The features in Figure 1 DMM solution are:

dmm:1

There are multiple instances of DPA, data plane anchors (i.e., DPA instances), each
with an FM-DP function.

dmm:2
The control plane may either be distributed (not shown) shown in the
figure) or
centralized. centralized (as shown in the figure).
The control plane and the data plane (Control Plane Anchor -- CPA
-- and DPA may co-locate or Data Plane Anchor -- DPA) may be
separate. When co-located or not. If the CPA, each with an FM-CP function,
CPA is co-
located co-located with the distributed DPA DPAs, then there will be are
multiple
instances of the co-located CPA and DPA CPA-DPA instances (not shown).

dmm:3 shown in the figure).
An IP prefix/address IP1, which is anchored IP1 (anchored to the DPA with
the IP prefix/address IPa1, address
IPa1) is assigned for use by an MN. The MN uses this IP1 address
to communicate with a CN not CNs (not shown in the figure. figure).
The flow of this communication session is location management (LM) function may be co-located or split
(as shown as flow(IP1,
...), meaning it uses IP1 in the figure) into a separate server (LMs) and other parameters. a client
(LMc). In this case, the LMs may be centralized whereas the LMc
may be distributed or centralized, according to whether the CPA is
distributed or centralized.

+------------+
|MN(IP1) | Mobile node attached
|flow(IP1,..)| to the network
+------------+

Figure 1. Configurations of network-based mobility management for 1: Network-based DMM configuration

3.1.2. Client-based DMM

Figure 2 shows a
flat network to which MN is attached. The general scenario for client-based distributed
mobility management
functions in the network are LMs in the control plane, LMc at CPA,
and FM-DP at DPA. management. In Figure 1, this configuration, the LM function is split into a separate server LMs mobile node performs
Control Plane Node (CPN) and
a client LMc at the CPA. Then, the LMs may be centralized whereas
the LMc may be distributed or centralized according to whether Data Plane Node (DPN) mobility
functions, namely the
CPA is distributed (not shown) or centralized.

In a special case (not shown), LMs forwarding management and LMc may co-locate.

3.1.2. Network-based Mobility Support for a Hierarchical Network

Figure 2 shows the configurations of network-based mobility location management for a hierarchical network.
(client role) ones.

+------------+

Figure 2. Configurations 2: Client-based DMM configuration

4. IP Mobility Handling in Distributed Anchoring Environments -
Mobility Support Only When Needed

IP mobility support may be provided only when needed instead of being
provided by default.

A straightforward choice of network-based mobility management anchoring is for a
hierarchical network flow to which MN is attached. The mobility
management functions in use
the IP prefix of the network include a separate LMs, FM-CP and
LMp at CPA, FM-DP at DPA; FM-CP and LMc at CPN, FM-DP at DPN.

In addition to which the dmm feature already described in Figure 1,
Figure 2 shows that there may be multiple instances of DPN, each with
an FM-DP function, for each DPA in the hierarchy. Also MN is attached when the CPN,
each with an FM-CP function,
flow is co-located with initiated [I-D.seite-dmm-dma]
[I-D.bernardos-dmm-pmipv6-dlif].

The IP prefix/address at the distributed DPN
there will be multiple instances MN's side of the co-located CPN and DPN (not
shown).

In Figure 2 the LMs is separated out, and a proxy LMp at the CPA is
added between the separate LMs and LMc at the CPN. Then, LMs flow may be
centralized whereas anchored at
the LMp may be distributed or centralized
according access router to whether which the CPA MN is distributed attached. For example, when an
MN attaches to a network (Net1) or centralized.

In moves to a particular case (not shown), LMs and LMp may co-locate.

3.1.3. Host-based Mobility Support

Host-based mobility function configurations as variants new network (Net2), an
IP prefix from Figure 2 the attached network is shown in Figure 3 where assigned to the role MN's
interface. In addition to perform mobility functions by
CPN and DPN are now taken by configuring new link-local addresses, the MN. The
MN configures from this prefix an IP address which is typically a
dynamic IP address. It then needs uses this IP address when a flow is
initiated. Packets to the MN in this flow are simply forwarded
according to the forwarding table.

There may be multiple IP prefixes/addresses that an MN can select
when initiating a flow. They may be from the same access network or
different access networks. The network may advertise these prefixes
with cost options [I-D.mccann-dmm-prefixcost] so that the mobile node
may choose the one with the least cost. In addition, these IP
prefixes/addresses may be of different types regarding whether
mobility support is needed [I-D.ietf-dmm-ondemand-mobility]. A flow
will need to possess choose the appropriate one according to whether it needs
IP mobility functions FM support.

4.1. No Need of IP Mobility: Changing to New IP Prefix/Address

When IP mobility support is not needed for a flow, the LM and LMc.

+-----+
|LMs FM
functions are not utilized so that the configurations in Section 3.1
are simplified as shown in Figure 3.

Net1 Net2

+---------------+ +---------------+
|AR1 |
+-.---+
+--------.---+ AR is changed |AR2 |
+---------------+ -------> +---------------+
|CPA: . |
|FM-CP, LMp |CPA: |
+------------+
. .
. .
. .
. .
+------------+ +------------+ Distributed
|---------------| |---------------|
|DPA(IPa1): | |DPA(IPa2): | DPA's
|anchors IP1 | |anchors IP2 |
|FM-DP | |FM-DP | etc.
+------------+ +------------+

+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2) |
.flow(IP1,...) . =======> |flow(IP2,...) |
+...............+ +---------------+

Figure 3. Configuration of host-based mobility management. The 3: Changing to a new IP address/prefix

When there is no need to provide IP mobility management functions in to a flow, the flow may
use a new IP address acquired from a new network include LMs in control
plane, FM-CP and LMp at CPA, FM-DP at DPA. The mobility management
functions FM and LMc are also at as the host (MN).

Figure 3 shows configurations of host-based mobility management with
multiple instances MN moves to
the new network.

Regardless of DPA for a distributed whether IP mobility anchoring
environment. Figure 3 can be obtained by simply collapsing CPN, DPN
and is needed, if the flow has
terminated before the MN moves to a new network, the flow may
subsequently restart using the new IP address assigned from the Figure 2 into new
network.

When IP session continuity is needed, even if a flow is ongoing as
the MN in Figure 3 which now possesses moves, it may still be desirable for the mobility functions FM and LMc that were performed previously by flow to change to
using the new IP prefix configured in the CPN new network. The flow may
then close and then restart using a new IP address configured in the DPN.

3.1.4. NEtwork MObility (NEMO) Basic Support

Figure 4 shows
new network. Such a change in the configurations IP address of NEMO basic the flow may be
enabled using a higher layer mobility support for which is not in the
scope of this document.

In Figure 3, a mobile
router.

+------------+Mobile network node
|MNN(IPn1) |using IPn1
|flow(IPn1,.)|attached to MR(IP1)
+------------+

Figure 4. Configurations of NEMO basic support for an MR which is
attached anchored to a network. The mobility management functions previous access router AR1 in the network are a separate LMs, FM-CP and LMp at CPA, FM-DP at DPA. The
mobility management functions FM and LMc are also at the MR to which
MNN is attached.

Figure 4 shows configurations of host-based mobility management for
an MR with multiple instances of DPA for a distributed mobility
anchoring environment. Figure 4 can be obtained by simply changing Net1 has
terminated before the MN from the Figure 3 into the MR carrying moves to a mobile network
consisting of mobile new network nodes (MNNs) in Figure 4.

An IP prefix/address IPn1 delegated to the MR is assigned for use by
the MNN in the mobile network. The MNN uses IPn1 Net2. After moving
to communicate with
a correspondent node (CN) not shown in Net2, the figure. The flow of this
communication session is shown as flow(IPn1, ...), meaning it MN uses
IPn1 and other parameters.

To enable the MR to assign the new IP prefix IPn1, the DPA delegates the
prefix using DHCPv6-PD IP2 anchored to the MR.

3.2. Operations and Parameters

The operations of distributed mobility anchoring are defined a new access
router AR2 in order
that they might work together network Net2 to produce start a distributed mobility
solution. new flow. The needed information is passed as mobility message
parameters, which must be protected in terms of integrity. Some
parameters packets may require a means to support privacy of an MN or MR.

The then
be forwarded without requiring IP layer mobility needs in 5G Wireless and beyond are diverse. Therefore
operations needed to enable different distributed mobility solutions
in different distributed mobility anchoring configurations are
extensive as illustrated below. It is however not necessary for
every distributed mobility solution to exhibit all the operations
listed in this section. A given distributed mobility solution may
exhibit only those operations needed.

3.2.1. Location Management support.

An example LM design consists of a distributed database with multiple
LMs servers. The location information about the prefix/address of an
MN is primarily at a given LMs. Peer LMs may exchange the location
information with each other. LMc may retrieve a given record or send
a given record update to LMs.

Location management configurations:

LM-cfg: As shown in Section 3.1:

LMs may be implemented at CPA, may be co-located with LMc at
CPA, or may be a separate server.

LMc may be at CPA, CPN, or MN.

LMp may proxy between LMs and LMc.

Specifically:

Location management operations and parameters:

LM-cfg:1 LMs and LMc may co-locate or may be separate, whereas LMc
is implemented in CPA in a flat network with network-based
mobility as shown in Figure 1 in Section 3.1.1.

LM-cfg:2 Either LMs may be a separate server with LMp implemented at
CPA, or LMs may be implemented at CPA. LMc call flow is implemented
at CPN in a hierarchical network with network-based
mobility as shown in Figure 2 in Section 3.1.2, at MN for
host-based mobility as shown in Figure 3 in Section 3.1.3,
or at MR for network mobility as shown outlined in Figure 4 in
Section 3.1.4.

LM-db: LM may manage the location information in a client-server
database system.

Example LM database functions are as follows:

LM-db:1 LMc may query LMs about location information for a prefix of

MN (pull).
Parameters:

- IP prefix of MN: integrity support required and privacy
support may be required.

LM-db:2 LMs may reply AR1 AR2 CN
|MN attaches to LMc query about location information for a
prefix of MN (pull).
Parameters:

- IP prefix of MN: integrity support required and privacy
support may be required,
- IP address of FM-DP/DPA/DPN to forward the packets of the
flow: integrity support required.

LM-db:3 LMs may inform LMc about location information for a prefix
of MN (push).
Parameters:

- IP prefix of MN: integrity support required and privacy
support may be required,
- IP address of FM-DP/DPA/DPN to forward the packets of the
flow: integrity support required.

This function in the PMIPv6 protocol is the Update
Notification (UPN) together with the Update Notification
Acknowledgment (UPA) as defined in [RFC7077].

LM-db:4 LMc may inform LMs about update location information for a
prefix of MN.
Parameters:

- IP prefix of MN: integrity support required and privacy
support may be required,
- IP address of FM-DP/DPA/DPN to forward the packets of the
flow: integrity support required.

This function in the MIPv6 / PMIPv6 protocol is the Binding
Update (BU) / Proxy Binding Update (PBU) together with the
Binding Acknowledgment (BA) / Proxy Binding Acknowledgment
(PBA) as defined in [RFC6275] / [RFC5213] respectively.

LM-db:5 The MN may be a host or a router. When the MN is an MR, the
prefix information may include the IP prefix delegated to
the MR.
Additional parameters:

- IP prefix delegated to MR: integrity support required and
privacy support may be required,
- IP prefix/address of the MR to forward the packets of the
prefix delegated to the MR: integrity support required.

LM-svr: The LM may be a distributed database with multiple LMs
servers.

For example:

LM-svr:1 A LMs may join a pool of LMs servers.
Parameters:

- IP address of the LMs: integrity support required,
- IP prefixes for which the LMs will host the primary
location information: integrity support required.

LM-svr:2 LMs may query a peer LMs about location information for a
prefix of MN.
Parameters:

- IP prefix: integrity support required and privacy support
may be required.

LM-svr:3 LMs may reply to a peer LMs about location information for
a prefix of MN.
Parameters:

- IP prefix of MN: integrity support required and privacy
support may be required,
- IP address of FM-DP/DPA/DPN to forward the packets of the
flow: integrity support required.

The list above only gives the minimal set of the required parameters.
In a specific mobility protocol, additional parameters should be
added as needed. Examples of these additional parameters are those
passed in the mobility options of the mobility header for MIPv6
[RFC6275] and for PMIPv6 [RFC5213].

3.2.2. Forwarding Management

Forwarding management configurations:

FM-cfg: As shown in Section 3.1:

FM-CP may be implemented at CPA, CPN, MN depending on the
configuration chosen.

FM-DP may also be implemented at CPA, CPN, MN depending on
the configuration chosen.

Specifically:

FM-cfg:1 FM-CP and FM-DP may be implemented at CPA and DPA
respectively in a flat network with network-based mobility
as shown in Figure 1 in Section 3.1.1.

FM-cfg:2 FM-CP may be implemented at both CPA and CPN and FM-DP is
implemented at both DPA and DPN in a hierarchical network
with network-based mobility as shown in Figure 2 in
Section 3.1.2.

FM-cfg:3 FM-CP and FM-DP may be implemented at CPA and DPA
respectively and also both implemented at MN for host-based
mobility as shown in Figure 3 in Section 3.1.3.

FM-cfg:4 FM-CP and FM-DP may be implemented at CPA and DPA
respectively and also both implemented at MR for network
mobility as shown in Figure 4 in Section 3.1.4.

Forwarding management operations and parameters:

FM-find:1 An anchor may discover and be discovered such as through
an anchor registration system as follows:

FM-find:2 FM registers and authenticates itself with a centralized
mobility controller.
Parameters:

- IP address of DPA and its CPA: integrity support
required,
- IP prefix anchored to the DPA: integrity support
required.

Registration reply: acknowledge of registration and echo
the input parameters.

FM-find:3 FM discovers the FM of another IP prefix by querying the
mobility controller based on the IP prefix.
Parameters:

- IP prefix of MN: integrity support required and privacy
support may be required.

FM-find:4 When making anchor discovery FM expects the answer
parameters:

- IP address of DPA to which IP prefix of MN is anchored:
integrity support required,
- IP prefix of the corresponding CPA: integrity support
required.

FM-flow:1 The FM may be carried out on the packets to/from an MN up
to the granularity of a flow.

FM-flow:2 Example matching parameters are in the 5-tuple of a flow.

FM-path:1 FM may change the forwarding path of a flow upon a change
of point of attachment of an MN. Prior to the changes,
packets coming from the CN to the MN would traverse from
the CN to the home network anchor of the flow for the MN
before reaching the MN. Changes are from this original
forwarding path or paths to a new forwarding path or paths
from the CN to the current AR of the MN and then the MN
itself.

FM-path:2 As an incoming packet is forwarded from the CN to the MN,
the far end where forwarding path change begins may in
general be any node in the original forwarding path from
the CN to the home network DPA. The packet is forwarded
to the MN for host-based mobility and to a node in the
network which will deliver the packets to the MN for
network-based mobility. The near-end is generally a DPN
with a hierarchical network but may also be another node
with DPA capability in a flattened network.

FM-path:3 The mechanisms to accomplish such changes may include
changes to the forwarding table and indirection such as
tunneling, rewriting packet header, segment routing
[I-D.matsushima-spring-dmm-srv6-mobile-uplane], or NAT.

Note: An emphasis in this document in distributed mobility
anchoring is to explain the use of multiple anchors to
avoid unnecessarily long route which may be encountered in
centralized mobility anchoring. It is therefore not the
emphasis of this document on which particular mechanism to
choose from.

FM-path-tbl:4 The objective of forwarding table updates is to change
the forwarding path so that the packets in the flow
will be forwarded from the CN to the new AR instead of
the home network anchor or previous AR. Each of the
affected forwarding switches will need appropriate
changes to its forwarding table.

Specifically, such forwarding table updates may
include: (1) addition of forwarding table entries
needed to forward the packets destined to the MN to
the new AR; (2) deletion of forwarding table entries
to forward the packets destined to the MN to the home
network anchor or to the previous AR.

FM-path-tbl:5 With a centralized control plane, forwarding table
updates may be achieved through messaging between the
centralized control plane and the distributed
forwarding switches as described above (FM-cpdp) in
this section.

FM-path-tbl:6 To reduce excessive signaling, the scope of such
updates for a given flow may be confined to only those
forwarding switches such that only the packets sent
from the "CN" to the MN will go to the new AR. Such
confinement may be made when using a centralized
control plane possessing a global view of all the
forwarding switches.

FM-path-tbl:7 FM reverts the changes previously made to the
forwarding path of a flow when such changes are no
longer needed, e.g., when all the ongoing flows using
an IP prefix/address requiring IP session continuity
have closed.

FM-path-ind:8 Indirection forwards the incoming packets of the flow
from the DPA at the far end to a DPA/DPN at the near
end of indirection. Both ends of the indirection need
to know the LM information of the MN for the flow and
also need to possess FM capability to perform
indirection.

FM-path-ind:9 The mechanism of changing the forwarding path in MIPv6
[RFC6275] and PMIPv6 [RFC5213] is tunneling. In the
control plane, the FM-CP sets up the tunnel by
instructing the FM-DP at both ends of the tunnel. In
the data plane, the FM-DP at the start of the tunnel
performs packet encapsulation, whereas the FM-DP at
the end of the tunnel decapsulates the packet.

Note that in principle the ends of the indirection
path can be any pair of network elements with the FM-
DP function.

FM-path-ind:10 FM reverts the changes previously made to the
forwarding path of a flow when such changes are no
longer needed, e.g., when all the ongoing flows using
an IP prefix/address requiring IP session continuity
have closed. When tunneling is used, the tunnels will
be torn down when they are no longer needed.

FM-cpdp: With separation of control plane function and data plane
function, FM-CP and FM-DP communicate with each other. Such
communication may be realized by the appropriate messages in
[I-D.ietf-dmm-fpc-cpdp].

For example:

FM-cpdp:1 CPA/FM-CP sends forwarding table updates to DPA/FM-DP.
Parameters:

- New forwarding table entries to add: integrity support
required,
- Expired forwarding table entries to delete: integrity
support required.

FM-cpdp:2 DPA/FM-DP sends to CPA/FM-CP about its status and load.

Parameters:

- State of forwarding function being active or not:
integrity support required,
- Loading percentage: integrity support required.

FM-CPA: The CPA possesses FM-CP function to make the changes to the
forwarding path as described in FM-path, and the changes may
be implemented through forwarding table changes or through
indirection as described respectively in FM-path-tbl and FM-
path-ind above.

The FM-CP communicates with the FM-DP using the appropriate
messages in [I-D.ietf-dmm-fpc-cpdp] as described in FM-cpdp
above so that it may instruct the FM-DP to perform the
changed forwarding tasks.

FM-DPA: The DPA possesses FM-DP function to forward packets according
to the changed forwarding path as described in FM-path, and
also FM-path-tbl or FM-path-ind depending on whether
forwarding table changes or indirection is used.

The FM-DP communicates with the FM-CP using the appropriate
messages in [I-D.ietf-dmm-fpc-cpdp] as described in FM-cpdp
above so that it may perform the changed forwarding tasks.

The operations and their parameters for the DPA to perform
distributed mobility management are described below:

FM-DPA:1 The DPAs perform the needed functions such that for the
incoming packets from the CN, forwarding path change by FM
is from the DPA at the far end which may be at any
forwarding switch (or even CN itself) in the original
forwarding path to the near end DPA/DPN.

FM-DPA:2 It is necessary that any incoming packet from the CN of the
flow must traverse the DPA (or at least one of the DPAs,
e.g., in the case of anycast) at the far end in order for
the packet to detour to a new forwarding path. Therefore a
convenient design is to locate the far end DPA at a unique
location which is always in the forwarding path. This is
the case in a centralized mobility design where the DPA at
the far end is the home network anchor of the flow.

Distributed mobility however may place the far end DPA at
other locations in order to avoid unnecessarily long route.

FM-DPA:3 With multiple nodes possessing DPA capabilities, the role
of FM to begin path change for the incoming packets of a
flow at the home network DPA at the far end may be passed
to or added to that of another DPA.

In particular, this DPA role may be moved upstream from the
home network DPA in the original forwarding path from CN to
MN.

FM-DPA:4 Optimization of the new forwarding path may be achieved
when the path change for the incoming packets begins at a
DPA where the original path and the direct IPv6 path
overlap. Then the new forwarding path will resemble the
direct IPv6 path from the CN to the MN.

FM-DPA-ind:5 Another mobility support employs indirection from the
far end DPA to the near end DPA. Both DPAs need to be
capable to performing indirection. For incoming
packets from the CN to the MN, the far end DPA needs to
start the indirection towards the near end DPA, which
will be the receiving end of indirection. In addition,
the near end DPA needs to continue the forwarding of
the packet towards the MN, such as through L2
forwarding or through another indirection towards the
MN.

FM-DPA-ind:6 With indirection, locating or moving the FM function to
begin indirection upstream along the forwarding path
from CN to MN again may help to reduce unnecessarily
long paths.

FM-DPA-ind:7 Changes made by FM to establish indirection at the DPA
and DPN, which are IPv6 nodes, at the ends of the path
change for a flow will be reverted when the mobility
support for the flow is no longer needed, e.g., when
the flows have terminated.

FM-buffer: An anchor can buffer packets of a flow in a mobility
event:

FM-buffer:1 CPA/FM-CP informs DPA/FM-DP to buffer packets of a flow.
Trigger:

- MN leaves DPA in a mobility event.

Parameters:

- IP prefix of the flow for which packets need to be
buffered: integrity support required

FM-buffer:2 CPA/FM-CP on behalf of a new DPA/FM-DP informs the CPA/
FM-CP of the prior DPA/FM-DP that it is ready to receive
any buffered packets of a flow.
Parameters:

- Destination IP prefix of the flow's packets: integrity
support required,
- IP address of the new DPA: integrity support required.

FM-mr:1 When the MN is a mobile router (MR) the access router
anchoring the IP prefix of the MR will also own the IP
prefix or prefixes to be delegated to the MR. The MNNs in
the network carried by the MR obtain IP prefixes from the
MR.

4. IP Mobility Handling in Distributed Anchoring Environments -
Mobility Support Only When Needed

IP mobility support may be provided only when needed instead of being
provided by default. The LM and FM functions in the different
configurations shown in Section 3.1 are then utilized only when
needed.

A straightforward choice of mobility anchoring is for a flow to use
the IP prefix of the network to which the MN is attached when the
flow is initiated [I-D.seite-dmm-dma].

The IP prefix/address at the MN's side of a flow may be anchored at
the access router to which the MN is attached. For example, when an
MN attaches to a network (Net1) or moves to a new network (Net2), an
IP prefix from the attached network is assigned to the MN's
interface. In addition to configuring new link-local addresses, the
MN configures from this prefix an IP address which is typically a
dynamic IP address. It then uses this IP address when a flow is
initiated. Packets to the MN in this flow are simply forwarded
according to the forwarding table.

There may be multiple IP prefixes/addresses that an MN can select
when initiating a flow. They may be from the same access network or
different access networks. The network may advertise these prefixes
with cost options [I-D.mccann-dmm-prefixcost] so that the mobile node
may choose the one with the least cost. In addition, these IP
prefixes/addresses may be of different types regarding whether
mobility support is needed [I-D.ietf-dmm-ondemand-mobility]. A flow
will need to choose the appropriate one according to whether it needs
IP mobility support.

4.1. No Need of IP Mobility: Changing to New IP Prefix/Address

When IP mobility support is not needed for a flow, the LM and FM
functions are not utilized so that the configurations in Section 3.1
are simplified as shown in Figure 5.

Net1 Net2

+---------------+ +---------------+
|AR1 | AR is changed |AR2 |
+---------------+ -------> +---------------+
|CPA: | |CPA: |
|---------------| |---------------|
|DPA(IPa1): | |DPA(IPa2): |
|anchors IP1 | |anchors IP2 |
+---------------+ +---------------+

+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2) |
.flow(IP1,...) . =======> |flow(IP2,...) |
+...............+ +---------------+

Figure 5. Changing to the new IP prefix/address. MN running a flow
using IP1 in a network Net1 changes to running a flow using IP2 in
Net2.

When there is no need to provide IP mobility to a flow, the flow may
use a new IP address acquired from a new network as the MN moves to
the new network.

Regardless of whether IP mobility is needed, if the flow has
terminated before the MN moves to a new network, the flow may
subsequently restart using the new IP address assigned from the new
network.

When IP session continuity is needed, even if a flow is ongoing as
the MN moves, it may still be desirable for the flow to change to
using the new IP prefix configured in the new network. The flow may
then close and then restart using a new IP address configured in the
new network. Such a change in the IP address of the flow may be
enabled using a higher layer mobility support which is not in the
scope of this document.

In Figure 5, a flow initiated while the MN was using the IP prefix
IP1 anchored to a previous access router AR1 in network Net1 has
terminated before the MN moves to a new network Net2. After moving
to Net2, the MN uses the new IP prefix IP2 anchored to a new access
router AR2 in network Net2 to start a new flow. The packets may then
be forwarded without requiring IP layer mobility support.

An example call flow is outlined in Figure 6.

MN AR1 AR2 CN
|MN attaches to AR1: | | |
|acquire MN-ID and profile | |
|--RS---------------->| | |
| | | |
|<----------RA(IP1)---| | |
| | | |
Assigned prefix IP1 | | |
IP1 address configuration | |
| | | |
|<-Flow(IP1,IPcn,...)-+--------------------------------------------->|
| | | |
|MN detaches from AR1 | | |
|MN attaches to AR2 | | |
| | | |
|--RS------------------------------>| |
| | | |
|<--------------RA(IP2)-------------| |
| | | |
Assigned prefix IP2 | | |
IP2 address configuration | |
| | | |
|<-new Flow(IP2,IPcn,...)-----------+------------------------------->|
| | | |

Figure 6. Re-starting a flow to use the IP prefix assigned from the
network at which the MN is attached.

4.1.1. Guidelines for IPv6 Nodes: Changing to New IP Prefix/Address

A network may not need IP mobility support. For example, a network
for stationary sensors only will never encounter mobility.

The standard functions in IPv6 already include dropping the old IPv6
prefix/address and acquiring new IPv6 prefix/address when the node
changes its point of attachment to a new network. Therefore, a
network not providing IP mobility support at all will not need any of
the functions with the mobility operations and messages described in
Section 3.2.

On the other hand, a network supporting a mix of flows both requiring
and not requiring IP mobility support will need the mobility
functions, which it will invoke or not invoke as needed.

The guidelines for the IPv6 nodes in a network supporting a mix of
flows both requiring and not requiring IP mobility support include
the following:

GL-cfg:1 A network supporting a mix of flows both requiring and not
requiring mobility support may take any of the
configurations described in Section 3.1 and need to
implement at the appropriate IPv6 nodes the mobility
functions LM and FM as described respectively in LM-cfg and
FM-cfg in Section 3.2 according to the configuration
chosen.

GL-mix:1 These mobility functions perform some of the operations
with the appropriate messages as described in Section 3.2
depending on which mobility mechanisms are being used. Yet
these mobility functions must not be invoked for a flow
that does not need IP mobility support so that it is
necessary to be able to distinguish the needs of a flow.
The guidelines for the MN and the AR are in the following.

GL-mix:2 Regardless of whether there are flows requiring IP mobility
support, when the MN changes its point of attachment to a
new network, it needs to configure a new global IP address
for use in the new network in addition to configuring the
new link-local addresses.

GL-mix:3 The MN needs to check whether a flow needs IP mobility
support. This can be performed when the application is
initiated. The specific method is not in the scope of this
document.

GL-mix:4 The information of whether a flow needs IP mobility support
is conveyed to the network such as by choosing an IP
address to be provided with mobility support as described
in [I-D.ietf-dmm-ondemand-mobility]. Then as the MN
attaches to a new network, if the MN was using an IP
address that is not supposed to be provided with mobility
support, the access router will not invoke the mobility
functions described in Section 3.2 for this IP address.
That is, the IP address from the prior network is simply
not used in the new network.

The above guidelines are only to enable distinguishing whether there
is need of IP mobility support for a flow that does not. When the
flow needs IP mobility support, the list of guidelines will continue
in Section 4.2.1.

4.2. Need of IP Mobility

When IP mobility is needed for a flow, the LM and FM functions in
Section 3.1 are utilized. The mobility support may be provided by IP
prefix anchor switching to the new network to be described in
Section 5 or by using other mobility management methods
([Paper-Distributed.Mobility], [Paper-Distributed.Mobility.PMIP] and
[Paper-Distributed.Mobility.Review]). Then the flow may continue to
use the IP prefix from the prior network of attachment. Yet some
time later, the user application for the flow may be closed. If the
application is started again, the new flow may not need to use the
prior network's IP address to avoid having to invoke IP mobility
support. This may be the case where a dynamic IP prefix/address
rather than a permanent one is used. The flow may then use the new
IP prefix in the network where the flow is being initiated. Routing
is again kept simpler without employing IP mobility and will remain
so as long as the MN which is now in the new network has not moved
again and left to another new network.

An example call flow in this case is outlined in Figure 7.

MN AR1 AR2 CN
|MN attaches to AR1: | | |
|acquire MN-ID and profile | |
|--RS---------------->| | |
| | | |
|<----------RA(IP1)---| | |
| | | |
Assigned prefix IP1 | | |
IP1 address configuration | |
| | | |
|<-Flow(IP1,IPcn,...)-+--------------------------------------------->|
| | | |
|MN detach from AR1 | | |
|MN attach to AR2 | | |
| | | |
|--RS------------------------------>| |
IP mobility support such as that described in next sub-section
|<--------------RA(IP2,IP1)---------| |
| | | |
|<-Flow(IP1,IPcn,...)---------------+------------------------------->|
| | | |
Assigned prefix IP2 | | |
IP2 address configuration | |
| | | |
Flow(IP1,IPcn) terminates | |
| | | |
|<-new Flow(IP2,IPcn,...)-----------+------------------------------->|
| | | |

Figure 7. A flow continues to use the IP prefix from its home
network after MN has moved to a new network.

4.2.1. Guidelines for IPv6 Nodes: Need of IP Mobility

The configuration guidelines of distributed mobility for the IPv6
nodes in a network supporting a mix of flows both requiring and not
requiring distributed mobility support are as follows:

GL-cfg:2 Multiple instances of DPAs (at access routers) which are
providing IP prefix to the MNs are needed to provide
distributed mobility anchoring in an appropriate
configuration such as those described in Figure 1
(Section 3.1.1) for network-based distributed mobility or
in Figure 3 (Section 3.1.3) for host-based distributed
mobility.

The appropriate IPv6 nodes (CPA, DPA, CPN, DPN) have to
implement the mobility functions LM and FM as described
respectively in LM-cfg and FM-cfg in Section 3.2 according
to the configuration chosen.

The guidelines of distributed mobility for the IPv6 nodes in a
network supporting a mix of flows both requiring and not requiring
distributed mobility support had begun with those given as GL-mix in
Section 4.1.1 and continue as follows:

GL-mix:5 The distributed anchors may need to message with each
other. When such messaging is needed, the anchors may need
to discover each other as described in the FM operations
and mobility message parameters (FM-find) in Section 3.2.2.

GL-mix:6 The anchors may need to provide mobility support on a per-
flow basis as described in the FM operations and mobility
message parameters (FM-flow) in Section 3.2.2.

GL-mix:7 Then the anchors need to properly forward the packets of
the flows in the appropriate FM operations and mobility
message parameters depending on the specific mobility
mechanism as described in Section 3.2.2.

GL-mix:8 When using a mechanism of changing forwarding table
entries, the FM operations and mobility message parameters
are described in FM-path, FM-path-tbl, and FM-DPA in
Section 3.2.2.

The forwarding table updates will take place at AR1, AR2,
the far end DPA, and other affected switches/routers such
that the packet from the CN to the MN will traverse from
the far end DPA towards AR2 instead of towards AR1.

Therefore new entries to the forwarding table will be added
at AR2 and the far end DPA as well as other affected
switches/routers between them so that these packets will
traverse towards AR2. Meanwhile, changes to the forwarding
table entries will also occur at AR1 and the far end DPA as
well as other affected switches/routers between them so
that if these packets ever reach any of them, they will not
traverse towards AR1 but will traverse towards AR2 (see
Section 3.2.2).

GL-mix:9 Alternatively when using a mechanism of indirection, the FM
operations and mobility message parameters are described in
FM-path, FM-path-ind, FM-DPA, and FM-DPA-ind in
Section 3.2.2.

GL-mix:10 If there are in-flight packets toward the old anchor while
the MN is moving to the new anchor, it may be necessary to
buffer these packets and then forward to the new anchor
after the old anchor knows that the new anchor is ready.
Such procedures are described in the FM operations and
mobility message parameters (FM-buffer) in Section 3.2.2.

5. IP Mobility Handling in Distributed Mobility Anchoring Environments
- Anchor Switching to the New Network

IP mobility is invoked to enable IP session continuity for an ongoing
flow as the MN moves to a new network. Here the anchoring of the IP
address of the flow is in the home network of the flow, which is not
in the current network of attachment. A centralized mobility
management mechanism may employ indirection from the anchor in the
home network to the current network of attachment. Yet it may be
difficult to avoid unnecessarily long route when the route between
the MN and the CN via the anchor in the home network is significantly
longer than the direct route between them. An alternative is to
switch the IP prefix/address anchoring to the new network.

5.1. IP Prefix/Address Anchor Switching for Flat Network

The IP prefix/address anchoring may move without changing the IP
prefix/address of the flow. Here the LM and FM functions in Figure 1
in Section 3.1 are implemented as shown in Figure 8.

Net1 Net2

+---------------+ +---------------+
|AR1 | |AR2 |
+---------------+ +---------------+
|CPA: | |CPA: |
|LM:IP1 at IPa1 | |LM:IP1 at IPa2 |
| changes to | | |
| IP1 at IPa2 | | |
|---------------| |---------------|
|DPA(IPa1): | anchoring of IP1 is effectively moved|DPA(IPa2): |
|anchored IP1 | =======> |anchors IP2,IP1|
+---------------+ +---------------+

+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2,IP1) |
.flow(IP1,...) . =======> |flow(IP1,...) |
+...............+ +---------------+

Figure 8. IP prefix/address anchor switching to the new network. MN
with flow using IP1 in Net1 continues to run the flow using IP1 as it
moves to Net2.

As an MN with an ongoing session moves to a new network, the flow may
preserve IP session continuity by moving the anchoring of the
original IP prefix/address of the flow to the new network. One way
to accomplish such move is to use a centralized routing protocol to
be described in Section 5.2 with a centralized control plane.

5.1.1. Guidelines for IPv6 Nodes: Switching Anchor for Flat Network

The configuration guideline for a flat network supporting a mix of
flows both requiring and not requiring IP mobility support is:

GL-cfg:3 Multiple instances of DPAs (at access routers) which are
providing IP prefix to the MNs are needed to provide
distributed mobility anchoring according to Figure 1 in
Section 3.1 for a flat network.

The appropriate IPv6 nodes (CPA, DPA) have to implement the
mobility functions LM and FM as described respectively in
LM-cfg:1 or LM-cfg:2 and FM-cfg:1 in Section 3.2.

GL-switch:1 The location management provides information about which
IP prefix from an AR in the original network is being
used by a flow in which AR in a new network. Such
information needs to be deleted or updated when such
flows have closed so that the IP prefix is no longer
used in a different network. The LM operations are
described in Section 3.2.1.

GL-switch:2 The anchor operations to properly forward the packets
for a flow are described in the FM operations and
mobility message parameters in FM-path, FM-path-tbl, FM-
cpdp, and FM-DPA in Section 3.2.2. If there are in-
flight packets toward the old anchor while the MN is
moving to the new anchor, it may be necessary to buffer
these packets and then forward to the new anchor after
the old anchor knows that the new anchor is ready as are
described in FM-buffer in Section 3.2.2. The anchors
may also need to discover each other as described also
in the FM operations and mobility message parameters
(FM-find).

GL-switch:3 The security policy must allow to assign to the anchor
node at the new network the original IP prefix/address
used by the mobile node at the previous (original)
network. As the assigned original IP prefix/address is
to be used in the new network, the security policy must
allow the anchor node in the new network to advertise
the prefix of the original IP address and also allow the
mobile node to send and receive data packets with the
original IP address.

GL-switch:4 The security policy must allow the mobile node to
configure the original IP prefix/address used at the
previous (original) network when the original IP prefix/
address is assigned by the anchor node in the new
network. It must also allow the mobile node to use the
original IP address for the previous flow in the new
network.

5.2. IP Prefix/Address Anchor Switching for Flat Network with
Centralized Control Plane

An example of IP prefix anchor switching is in the case where Net1
and Net2 both belong to the same operator network with separation of
control and data planes ([I-D.liu-dmm-deployment-scenario] and
[I-D.matsushima-stateless-uplane-vepc]), where the controller may
send to the switches/routers the updated information of the
forwarding tables with the IP address anchoring of the original IP
prefix/address at AR1 moved to AR2 in the new network. That is, the
IP address anchoring in the original network which was advertising
the prefix will need to move to the new network. As the anchoring in
the new network advertises the prefix of the original IP address in
the new network, the forwarding tables will be updated so that
packets of the flow will be forwarded according to the updated
forwarding tables.

The configurations in Figure 1 in Section 3.1 for which the FM-CP and
the LM are centralized and the FM-DPs are distributed apply here.
Figure 9 shows its implementation where the LM is a binding between
the original IP prefix/address of the flow and the IP address of the
new DPA, whereas the FM uses appropriate control plane to data plane
messages.

+---------------+ +---------------+
|AR1 | |AR2 |
+---------------+ +---------------+
|DPA(IPa1): | anchoring of IP1 is effectively moved|DPA(IPa2): |
|anchored IP1 | =======> |anchors IP2,IP1|
+---------------+ +---------------+

+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2,IP1) |
.flow(IP1,...) . =======> |flow(IP1,...) |
+...............+ +---------------+

Figure 9. IP prefix/address anchor switching to the new network with
the LM and the FM-CP in a centralized control plane whereas the FM-
DPs are distributed.

The example call flow in Figure 10 shows that IP1 is assigned to MN
when the MN attaches to the AR1 A flow running in MN and needing IP
mobility may continue to use the previous IP prefix by moving the
anchoring of the IP prefix to the new network. Yet a new flow to be
initiated in the new network may simply use a new IP prefix assigned
from the new network.

MN AR1 AR2 CPA CN
|MN attaches to AR1: | | | |
|acquire MN-ID and profile | | |
|--RS---------------->| | | |
|<----------RA(IP1)---| | | |
| | | Assign MN:IP1 |
IP addr config | | | |
| | | | |
|<-Flow(IP1,IPcn,...)-+--------------------------------------------->|
| | | | |
|MN detach from AR1 | | | |
|MN attach to AR2 | | | |
| | | | |
|--RS------------------------------>| | |
| | | | |
| |<---------------control messages-->| |
| | | | |
| | |<-control messages-->| |
| | | | |
| forwarding table updates <--------------| |
| | | | |
|<--------------RA(IP2,IP1)---------| | |
| | | Assign MN:IP2 |
IP addr config | | | |
| | | | |
|<-Flow(IP1,IPcn,...)---------------+------------------------------->|
| | | | |
| Flow(IP1,IPcn,...) terminates | | |
| | | | |
| forwarding table updates <--------------| |
| | | | |
|<-new Flow(IP2,IPcn,...)-----------+------------------------------->|
| | | | |

Figure 10. DMM solution. MN with flow using IP1 in Net1 continues
to run the flow using IP1 as it moves to Net2.

As the MN moves from AR1 to AR2, the AR1 may exchange messages with
CPA to release the IP1. It is now necessary for AR2 to learn the IP
prefix of the MN from the previous network so that it will be
possible for Net2 to assign both the previous network prefix and the
new network prefix. The network may learn the previous prefix in
different methods. For example, the MN may provide its previous
network prefix information by including it to the RS message
[I-D.jhlee-dmm-dnpp].

Then forwarding tables updates will take place here.

In addition, the MN also needs a new IP in the new network. The AR2
may now send RA to the MN with prefix information that includes IP1
and IP2. The MN may then continue to use IP1. In addition, the
prefix IP2 is assigned to the MN which may configure the IP addresses
of its interface. Now for flows using IP1, packets destined to IP1
will be forwarded to the MN via AR2.

As such flows have terminated, IP1 goes back to Net1. MN will then
be left with IP2 only, which it will use when it now starts a new
flow.

5.2.1. Additional Guidelines for IPv6 Nodes: Switching Anchor with
Centralized CP

The configuration guideline for a flat network with centralized
control plane and supporting a mix of flows both requiring and not
requiring IP mobility support is:

GL-cfg:4 Multiple instances of DPAs (at access routers) which are
providing IP prefix to the MNs are needed to provide
distributed mobility anchoring according to Figure 1 in
Section 3.1 with centralized control plane for a flat
network.

At the appropriate IPv6 nodes (CPA, DPA) have to implement
the mobility functions LM and FM as described respectively
in LM-cfg:1 or LM-cfg:2 and FM-cfg:1 in Section 3.2.

The guidelines (GL-mix) in Section 4.1.1 and in Section 4.2.1 for the
IPv6 nodes for a network supporting a mix of flows both requiring and
not requiring IP mobility support apply here. The guidelines (GL-
mix) in Section 5.1.1 for moving anchoring for a flat network also
apply here. In addition, the following are required.

GL-switch:5 It was already mentioned that the anchor operations to
properly forward the packets for a flow are described in
the FM operations and mobility message parameters in FM-
path, FM-path-tbl, FM-cpdp, and FM-DPA in Section 3.2.2
and such changes are reverted later when the application
has already closed. Here however, with separation of
control and data planes for the anchors and where the
LMs and the FM-CP are centralized in the same control
plane, messaging between anchors and the discovery of
anchors become internal to the control plane.

GL-switch:6 The centralized FM-CP needs to communicate with the
distributed FM-DP using the FM operations and mobility
message parameters as described in FM-cpdp in
Section 3.2.2. Such may be realized by the appropriate
messages in [I-D.ietf-dmm-fpc-cpdp].

GL-switch:7 It was also already mentioned before that, if there are
in-flight packets toward the previous anchor while the
MN is moving to the new anchor, it may be necessary to
buffer these packets and then forward to the new anchor
after the old anchor knows that the new anchor is ready.
Here however, the corresponding FM operations and
mobility message parameters as described in
Section 3.2.2 (FM-buffer) can be realized by the
internal operations in the control plane together with
signaling between the control plane and distributed data
plane. These signaling may be realized by the
appropriate messages in [I-D.ietf-dmm-fpc-cpdp].

5.3. Hierarchical Network

The configuration for a hierarchical network has been shown in
Figure 2 in Section 3.1.2. With centralized control plane, CPA and
CPN, with the associated LM and FM-CP are all co-located. There are
multiple DPAs (each with FM-DP) in distributed mobility anchoring.
In the data plane, there are multiple DPNs (each with FM-DP)
hierarchically below each DPA. The DPA at each AR supports
forwarding to the DPN at each of a number of forwarding switches
(FWs). A mobility event in this configuration belonging to
distributed mobility management will be deferred to Section 5.4.

In this distributed mobility configuration, a mobility event
involving change of FW only but not of AR as shown in Figure 11 may
still belong to centralized mobility management and may be supported
using PMIPv6. This configuration of network-based mobility is also
applicable to host-based mobility with the modification for the MN
directly taking the role of DPN and CPN, and the corresponding
centralized mobility event may be supported using MIPv6.

In Figure 11, the IP prefix assigned to the MN is anchored at the
access router (AR) supporting indirection to the old FW to which the
MN was originally attached as well as to the new FW to which the MN
has moved.

The realization of LM may be the binding between the IP prefix/
address of the flow used by the MN and the IP address of the DPN to
which MN has moved. The implementation of FM to enable change of FW
without changing AR may be accomplished using tunneling between the
AR and the FW as described in [I-D.korhonen-dmm-local-prefix] and in
[I-D.templin-aerolink] or using some other L2 mobility mechanism.

Net1 Net2
+----------------------------------------------------------------------+
| CPA,CPN: LM:IP1 at IPn2 |
| FM-CP |
+----------------------------------------------------------------------+

+---------------+
|AR1 |
+---------------+
|DPA(IPa1): |
|anchors IP1 |
|FM-DP |
+---------------+

+---------------+ +---------------+
|FW1 | |FW2 |
+---------------+ FW is changed +---------------+
|DPN(IPn1): | -------> |DPN(IPn2): |
|FM-DP | |FM-DP |
+---------------+ +---------------+

+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2) |
.flow(IP1,...) . =======> |flow(IP1,...) |
+...............+ +---------------+

Figure 11. Mobility without involving change of IP anchoring in a
network in which the IP prefix assigned to the MN is anchored at an
AR which is hierarchically above multiple FWs to which the MN may
connect.

5.3.1. Additional Guidelines for IPv6 Nodes: Hierarchical Network with
No Anchor Relocation

The configuration guideline for a hierarchical network with
centralized control plane and supporting a mix of flows both
requiring and not requiring IP mobility support is:

GL-cfg:5 Multiple instances of DPAs (at access routers) which are
providing IP prefix to the MNs are needed to provide
distributed mobility anchoring according to Figure 2 in
Section 3.1.2 with centralized control plane for a
hierarchical network.

The appropriate IPv6 nodes (CPA, DPA) have to implement the
mobility functions LM and FM as described respectively in
LM-cfg:3 or LM-cfg:4 and FM-cfg:2 in Section 3.2.

Even when the mobility event does not involve change of anchor, it is
still necessary to distinguish whether a flow needs IP mobility
support.

The GL-mix guidelines in Section 4.1.1 and in Section 4.2.1 for the
IPv6 nodes for a network supporting a mix of flows both requiring and
not requiring IP mobility support apply here. In addition, the
following are required.

GL-switch:8 Here, the LM operations AR1: | | |
|acquire MN-ID and mobility message parameters
described in Section 3.2.1 provide information of which
IP profile | |
|--RS---------------->| | |
| | | |
|<----------RA(IP1)---| | |
| | | |
Assigned prefix from its FW needs to be used by a flow using
which new FW. The anchor operations to properly forward
the packets of a flow described in the FM operations and
mobility message parameters (FM-path, FM-path-ind, FM-
cpdp in Section 3.2.2) may be realized with PMIPv6
protocol [I-D.korhonen-dmm-local-prefix] or with AERO
protocol [I-D.templin-aerolink] to tunnel between the AR
and the FW.

5.4. IP Prefix/Address Anchor Switching for a Hierarchical Network

The configuration for the hierarchical network has been shown in
Figure 2 in Section 3.1.2. Again, with centralized control plane,
CPA and CPN, with the associated LM and FM-CP are all co-located.
There are multiple DPAs (each with FM-DP) in distributed mobility
anchoring. In the data plane, there are multiple DPNs (each with FM-
DP) hierarchically below each DPA. The DPA at each AR supports
forwarding to the DPN at each of a number of forwarding switches
(FWs).

A distributed mobility event in this IP1 | | |
IP1 address configuration involves change
from a previous DPN which is hierarchically under the previous DPA to
a new DPN which is hierarchically under a new DPA. Such an event
involving change of both DPA and DPN is shown in Figure 12.

Net1 Net2
+----------------------------------------------------------------------+ | CPA,CPN,Aggregate Router: LM:IP1 at IPn2 at IPa2 |
| FM-CP |
+----------------------------------------------------------------------+

+-----------------+
|Aggregate Router |
+-----------------+
|FM-DP |
+-----------------+

+---------------+ +---------------+
|AR1
|<-Flow(IP1,IPcn,...)-+------------------------------------------>|
| | | |
|MN detaches from AR1 | | |
|MN attaches to AR2 | | |AR2 |
+---------------+ +---------------+
|DPA(IPa1):
| anchoring of IP1 is effectively moved|DPA(IPa2): |
|anchored IP1 | =======> |anchors IP2,IP1|
+---------------+ +---------------+

+---------------+ +---------------+
|FW1 | |FW2
|--RS------------------------------>| |
+---------------+ FW is changed +---------------+
|DPN(IPn1):
| -------> |DPN(IPn2): |
|FM-DP | |FM-DP |
+---------------+ +---------------+

+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2,IP1)
|<--------------RA(IP2)-------------| |
| | | |
Assigned prefix IP2 | | |
IP2 address configuration | |
| | | |
|<-new Flow(IP2,IPcn,...)-----------+---------------------------->|
| | |
.flow(IP1,...) . =======> |flow(IP1,...) |
+...............+ +---------------+

Figure 12. Mobility involving change of IP anchoring in 4: Re-starting a network flow with hierarchy in which the IP prefix assigned to the MN is anchored
at an Edge Router supporting multiple access routers to which the MN
may connect.

This deployment case involves both a change of anchor from AR1 to AR2
and a network hierarchy AR-FW. It can be realized by a combination
of relocating the new IP prefix/address anchoring from AR1 to AR2 with
the mechanism as described in Section 5.2 and then forwarding the
packets with network hierarchy AR-FW as described in Section 5.3.

5.4.1. Additional Guidelines for IPv6 Nodes: Switching Anchor with
Hierarchical Network

The configuration guideline (GL-cfg) for a hierarchical network with
centralized control plane described in Section 5.3.1 applies here.

The GL-mix guidelines in Section 4.1.1 and in Section 4.2.1 for the
IPv6 nodes for a network supporting a mix

4.2. Need of flows both requiring and
not requiring IP Mobility

When IP mobility support apply here.

The guidelines (GL-switch) in Section 5.1.1 for anchoring relocation
and in Section 5.2.1 is needed for a centralized control plane also apply here.

In addition, the guidelines for indirection between the new DPA and
the new DPN as described in Section 5.3.1 apply as well.

5.5. Network Mobility

The configuration for network mobility has been shown in Figure 4 in
Section 3.1.4. Again, with centralized control plane, CPA, with flow, the
associated LM and FM-CP are all co-located. There are multiple DPAs
(each with FM-DP) in the data plane FM functions in distributed mobility
anchoring.
Section 3.1 are utilized. The MR possesses mobility support may be provided by IP
prefix anchor switching to the new network to be described in
Section 5 or by using other mobility functions FM management methods
([Paper-Distributed.Mobility], [Paper-Distributed.Mobility.PMIP] and LMc. The
[Paper-Distributed.Mobility.Review]). Then the flow may continue to
use the IP prefix IPn1 from the prior network of attachment. Yet some
time later, the user application for the flow may be closed. If the
application is delegated to started again, the MR, new flow may not need to which an MNN is attached
and has an use the
prior network's IP address from IPn1 assigned to its interface.

Figure 13 shows a distributed avoid having to invoke IP mobility event in a hierarchical
network with a centralized control plane involving a change of
attachment of
support. This may be the MR from case where a previous DPA to dynamic IP prefix/address
rather than a permanent one is used. The flow may then use the new DPA while
IP prefix in the MNN
is attached to network where the MR flow is being initiated. Routing
is again kept simpler without employing IP mobility and therefore moves with will remain
so as long as the MR.

Net1 Net2
+----------------------------------------------------------------------+ MN which is now in the new network has not moved
again and left to another new network.

An example call flow in this case is outlined in Figure 5.

MN AR1 AR2 CN
|MN attaches to AR1: | | |
|acquire MN-ID and profile | |
|--RS---------------->| | |
| | | |
|<----------RA(IP1)---| | |
| | | |
Assigned prefix IP1 | | | CPA,Aggregate Router: LM:IP1 at IPa2; IPn1 at
IP1 address configuration | | FM-CP, LM
|
+----------------------------------------------------------------------+

+-----------------+
|Aggregate Router |
+-----------------+
|FM-DP |
+-----------------+

+...............+ +---------------+
.MNN(IPn1) . MNN moves with MR |MNN(IPn1) |
.flow(IPn1,...) . =======> |flow(IPn1,...) |
+...............+ +---------------+

Figure 13. Mobility involving change of IP anchoring for an MR to
which an MNN is attached.

As the MR with source
|--RS------------------------------>| |
IP prefix IP1 moves from AR1 to AR2, mobility support may be provided by moving the anchoring of IP1 from AR1 to
AR2 using the mechanism described in Section 5.2.

The forwarding table updates will take place at AR1, AR2, the
aggregate router, and other affected routers such that the packet
from the CN to the MNN will traverse from the aggregate router
towards AR2 instead of towards AR1.

5.5.1. Additional Guidelines for IPv6 Nodes: Network mobility

The configuration guideline for a network with centralized control
plane to provide network mobility is:

GL-cfg:6 Multiple instances of DPAs (at access routers) which are
providing IP prefix of the MRs are needed to provide
distributed mobility anchoring according to Figure 4 in
Section 3.1.

The appropriate IPv6 nodes (CPA, DPA) have to implement the
mobility functions LM and FM as that described respectively in
LM-cfg:3 or LM-cfg:4 and FM-cfg:4 in Section 3.2.

The GL-mix guidelines in Section 4.1.1 and in Section 4.2.1 for the
IPv6 nodes for a network supporting a mix of flows both requiring and
not requiring IP mobility support apply here.

Here, because the MN is an MR, the following guideline is added:

GL-mix:11 There are no flows requiring network mobility support when
there are no MNNs attaching to the MR. Here there are also
no MNNs using a next sub-section
|<--------------RA(IP2,IP1)---------| |
| | | |
|<-Flow(IP1,IPcn,...)---------------+---------------------------->|
| | | |
Assigned prefix delegated IP2 | | |
IP2 address configuration | |
| | | |
Flow(IP1,IPcn) terminates | |
| | | |
|<-new Flow(IP2,IPcn,...)-----------+---------------------------->|
| | | |

Figure 5: A flow continues to use the MR. Therefore the
anchor of the MR may change to a new AR. The new AR may
delegate new IP prefix from its home network
after MN has moved to the MR, so that the MR may
support potential MNNs to attach to it. On the other hand
the delegation a new network

Multiple instances of DPAs (at access routers), which are providing
IP prefix to the MR from the old AR may
be deleted.

The guidelines (GL-switch) in Section 5.1.1 for MNs, are needed to provide distributed mobility
anchoring relocation
and in Section 5.2.1 for a centralized control plane also apply here.

Again because the MN is an MR, the following guidelines are added:

GL-switch:9 Network mobility may be provided using the FM operations
and mobility message parameters appropriate configuration such as those described in FM-mr in
Section 3.2.2.

GL-switch:10 The following changes to forwarding table entries are
needed:

New entries to the forwarding tables are added at AR2
and the aggregate router as well as other affected
switches/routers between them so that packets from the
CN to the MNN destined to IPn1 will traverse towards
AR2. Meanwhile, changes to the forwarding table will
also occur at AR1 and the aggregate router as well as
other affected switches/routers between them so that in
case such packets ever reach any of these switches/
routers, the packets will not traverse towards AR1 but
will traverse towards AR2.

GL-switch:11 The security policy must allow the MNN to continue to
own the IP prefix/address originally delegated to the MR
and used by the MNN at the prior network. As this
original IP prefix/address is to be used
Figure 1 (Section 3.1.1) for network-based distributed mobility or in the new
network, the security policy must allow the anchor node
to advertise the prefix of the original
Figure 2 (Section 3.1.2) for client-based distributed mobility.

5. IP address and
also allow the MNN Mobility Handling in Distributed Mobility Anchoring Environments
- Anchor Switching to send and receive data packets with the original New Network

IP address.

GL-switch:12 The security policy must allow the mobile router mobility is invoked to
configure the original enable IP prefix/address delegated to
the MR from the previous (original) network when session continuity for an ongoing
flow as the
original IP prefix/address is being delegated MN moves to the MR
in the a new network. The security policy must also
allows to use Here the anchoring of the original IP
address by the MNN for of the
previous flow is in the new network.

6. Security Considerations

Security protocols and mechanisms are employed to secure the home network
and to make continuous security improvements, and a DMM solution is
required to support them [RFC7333]. In a DMM deployment
[I-D.ietf-dmm-deployment-models] various attacks such as
impersonation, denial of service, man-in-the-middle attacks need to
be prevented. An appropriate security management function as defined
in Section 2 controls these security protocols and mechanisms to
provide access control, integrity, authentication, authorization,
confidentiality, etc.

Security considerations are described in terms of integrity support,
privacy support etc. in describing the mobility functions flow, which is not
in
Section 3.2. Here the current network of attachment. A centralized mobility message parameters used in DMM must
be protected, and some parameters require means to support MN and MR
privacy. The security considerations are also described in
management mechanism may employ indirection from the
guidelines for IPv6 nodes in various subsections anchor in Section 4, and
Section 5.

The IP address anchoring of an IP prefix is effectively moved from
one the
home network to another the current network of attachment. Yet it may be
difficult to support IP mobility Section 5.1.
As is considered in avoid unnecessarily long route when the route between
the guidelines for IPv6 nodes in Section 5.1.1, MN and the security policy needs to enable CN via the use anchor in the new home network of
attachment the IP prefix assigned from another network. Yet it must
do so without compromising on is significantly
longer than the needed security direct route between them. An alternative is to prevent
switch the
possible misuse of an IP prefix belonging to another network. A
viable solution is likely not be a global solution, but is limited in
scope prefix/address anchoring to within specific regions with the proper trust relationship.

In network mobility, the MNN using an new network.

5.1. IP prefix assigned to it from Prefix/Address Anchor Switching for Flat Network

The IP prefix/address anchoring may move without changing the MR when IP
prefix/address of the MR was in a prior network moves with flow. Here the MR to a new
network Section 5.5. As is considered LM and FM functions in the guidelines for IPv6
nodes Figure 1
in Section 5.5.1 3.1 are implemented as shown in Figure 6.

Net1 Net2

+---------------+ +---------------+
|AR1 | |AR2 |
+---------------+ +---------------+
|CPA: | |CPA: |
|LM:IP1 at IPa1 | |LM:IP1 at IPa2 |
| changes to support IP | | |
| IP1 at IPa2 | | |
|---------------| |---------------|
|DPA(IPa1): | IP1 anchoring is effectively moved|DPA(IPa2): |
|anchored IP1 | =======> |anchors IP2,IP1|
+---------------+ +---------------+

+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2,IP1) |
.flow(IP1,...) . =======> |flow(IP1,...) |
+...............+ +---------------+

Figure 6: Anchor mobility for

As an MN with an ongoing flow,
the security management function needs session moves to enable a new network, the continued use of
this flow may
preserve IP prefix session continuity by moving the MNN with MR in the new network of attachment.
Yet it must do so without compromising on the needed security to
prevent the possible misuse anchoring of an the
original IP prefix belonging prefix/address of the flow to another the new network. Again, a viable solution

One way to accomplish such move is likely not be to use a global
solution, centralized routing
protocol, but note that this solution presents some scalability
concerns and its applicability is typically limited in scope to within specific regions with small
networks.

6. Security Considerations

Security protocols and mechanisms are employed to secure the
proper trust relationship. network
and to make continuous security improvements, and a DMM solution is
required to support them [RFC7333].

In a DMM deployment [I-D.ietf-dmm-deployment-models] various attacks
such as impersonation, denial of service, man-in-the-middle attacks
need to be prevented.

7. IANA Considerations

This document presents no IANA considerations.

8. Contributors

Alexandre Petrescu and Fred L. Templin had contributed to earlier
versions of this document regarding distributed anchoring for
hierarchical network and for network mobility, although these
extensions were removed to keep the document within reasonable
length.

This document has benefited from other work on mobility support in
SDN network, on providing mobility support only when needed, and on
mobility support in enterprise network. These works have been
referenced. While some of these authors have taken the work to
jointly write this document, others have contributed at least
indirectly by writing these drafts. The latter include Philippe
Bertin, Dapeng Liu, Satoru Matushima, Pierrick Seite, Jouni Korhonen,
and Sri Gundavelli.

Valuable comments have been received from John Kaippallimalil,
ChunShan Xiong, and Dapeng Liu. Dirk von Hugo, Byju Pularikkal,
Pierrick Seite, Carlos Bernardos Seite have generously provided careful review with helpful
corrections and suggestions.

9. References

9.1. Normative References

[I-D.bernardos-dmm-cmip]

[I-D.bernardos-dmm-pmipv6-dlif]
Bernardos, C., Oliva, A., and F. Giust, "An IPv6
Distributed Client Mobility Management approach using
existing mechanisms", draft-bernardos-dmm-cmip-08 (work in
progress), September 2017.

[I-D.bernardos-dmm-pmip]
Bernardos, C., Oliva, A., F., and F. Giust, "A PMIPv6-based
solution J. Zuniga, "Proxy
Mobile IPv6 extensions for Distributed Mobility
Management", draft-
bernardos-dmm-pmip-09 draft-bernardos-dmm-pmipv6-dlif-00 (work in
progress), September October 2017.

[I-D.ietf-dmm-deployment-models]
Gundavelli, S. and S. Jeon, "DMM Deployment Models and
Architectural Considerations", draft-ietf-dmm-deployment-
models-03 (work in progress), November 2017.

[I-D.ietf-dmm-fpc-cpdp]
Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S.,
Moses, D., and C. Perkins, "Protocol for Forwarding Policy
Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-09
(work in progress), October 2017.

[I-D.ietf-dmm-ondemand-mobility]
Yegin, A., Moses, D., Kweon, K., Lee, J., Park, J., and S.
Jeon, "On Demand Mobility Management", draft-ietf-dmm-
ondemand-mobility-12 (work in progress), July 2017.

[I-D.jhlee-dmm-dnpp]
Lee, J. and Z. Yan, "Deprecated Network Prefix Provision",
draft-jhlee-dmm-dnpp-01 (work in progress), April 2016.

[I-D.korhonen-dmm-local-prefix]
Korhonen, J., Savolainen, T., and S. Gundavelli, "Local
Prefix Lifetime Management for Proxy Mobile IPv6", draft-
korhonen-dmm-local-prefix-01 (work in progress), July
2013.

[I-D.liu-dmm-deployment-scenario]
Liu, V., Liu, D., Chan, A., Lingli, D., and X. Wei,
"Distributed mobility management deployment scenario and
architecture", draft-liu-dmm-deployment-scenario-05 (work
in progress), October 2015.

[I-D.matsushima-spring-dmm-srv6-mobile-uplane]
Matsushima, S., Filsfils, C., Kohno, M., and d.
daniel.voyer@bell.ca, "Segment Routing IPv6 for Mobile
User-Plane", draft-matsushima-spring-dmm-srv6-mobile-
uplane-03
ondemand-mobility-13 (work in progress), November 2017. January 2018.

[I-D.matsushima-stateless-uplane-vepc]
Matsushima, S. and R. Wakikawa, "Stateless user-plane
architecture for virtualized EPC (vEPC)", draft-
matsushima-stateless-uplane-vepc-06 (work in progress),
March 2016.

[I-D.mccann-dmm-prefixcost]
McCann, P. and J. Kaippallimalil, "Communicating Prefix
Cost to Mobile Nodes", draft-mccann-dmm-prefixcost-03
(work in progress), April 2016.

[I-D.sarikaya-dmm-for-wifi]
Sarikaya, B. and L. Li, "Distributed Mobility Management
Protocol for WiFi Users in Fixed Network", draft-sarikaya-
dmm-for-wifi-05 (work in progress), October 2017.

[I-D.seite-dmm-dma]
Seite, P., Bertin, P., and J. Lee, "Distributed Mobility
Anchoring", draft-seite-dmm-dma-07 (work in progress),
February 2014.

[I-D.templin-aerolink]
Templin, F., "Asymmetric Extended Route Optimization
(AERO)", draft-templin-aerolink-75 (work in progress), May
2017.

[I-D.yhkim-dmm-enhanced-anchoring]
Kim, Y. and S. Jeon, "Enhanced Mobility Anchoring in
Distributed Mobility Management", draft-yhkim-dmm-
enhanced-anchoring-05 (work in progress), July 2016.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.

[RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related
Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004,
<https://www.rfc-editor.org/info/rfc3753>.

[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>.

[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>.

[RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen,
T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, DOI 10.17487/RFC6459, January 2012,
<https://www.rfc-editor.org/info/rfc6459>.

[RFC7077] Krishnan, S., Gundavelli, S., Liebsch, M., Yokota, H., and
J. Korhonen, "Update Notifications for Proxy Mobile IPv6",
RFC 7077, DOI 10.17487/RFC7077, November 2013,
<https://www.rfc-editor.org/info/rfc7077>.

[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>.

[RFC7429] Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and
CJ. Bernardos, "Distributed Mobility Management: Current
Practices and Gap Analysis", RFC 7429,
DOI 10.17487/RFC7429, January 2015,
<https://www.rfc-editor.org/info/rfc7429>.

9.2. Informative References

[Paper-Distributed.Mobility]
Lee, J., Bonnin, J., Seite, P., and H. Chan, "Distributed
IP Mobility Management from the Perspective of the IETF:
Motivations, Requirements, Approaches, Comparison, and
Challenges", IEEE Wireless Communications, October 2013.

[Paper-Distributed.Mobility.PMIP]
Chan, H., "Proxy Mobile IP with Distributed Mobility
Anchors", Proceedings of GlobeCom Workshop on Seamless
Wireless Mobility, December 2010.

[Paper-Distributed.Mobility.Review]
Chan, H., Yokota, H., Xie, J., Seite, P., and D. Liu,
"Distributed and Dynamic Mobility Management in Mobile
Internet: Current Approaches and Issues", February 2011.

Authors' Addresses

H. Anthony Chan (editor)
Huawei Technologies
5340 Legacy Dr. Building 3
Plano, TX 75024
USA

Email: h.a.chan@ieee.org

Xinpeng Wei
Huawei Technologies
Xin-Xi Rd. No. 3, Haidian District
Beijing, 100095
P. R. China

Email: weixinpeng@huawei.com

Jong-Hyouk Lee
Sangmyung University
31, Sangmyeongdae-gil, Dongnam-gu
Cheonan 31066
Republic of Korea

Email: jonghyouk@smu.ac.kr

Seil Jeon
Sungkyunkwan University
2066 Seobu-ro, Jangan-gu
Suwon, Gyeonggi-do
Republic of Korea

Email: seiljeon@skku.edu

Alexandre Petrescu
CEA, LIST
CEA Saclay
Gif-sur-Yvette, Ile-de-France 91190
France

Carlos J. Bernardos (editor)
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain

Phone: +33169089223
Email: Alexandre.Petrescu@cea.fr

Fred L. Templin
Boeing Research and Technology
P.O. Box 3707
Seattle, WA 98124
USA +34 91624 6236
Email: fltemplin@acm.org cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/