draft-ietf-dmm-distributed-mobility-anchoring-07.txt   draft-ietf-dmm-distributed-mobility-anchoring-08.txt 
DMM H. Chan, Ed. DMM H. Chan, Ed.
Internet-Draft X. Wei Internet-Draft X. Wei
Intended status: Informational Huawei Technologies Intended status: Informational Huawei Technologies
Expires: May 16, 2018 J. Lee Expires: September 3, 2018 J. Lee
Sangmyung University Sangmyung University
S. Jeon S. Jeon
Sungkyunkwan University Sungkyunkwan University
A. Petrescu CJ. Bernardos, Ed.
CEA, LIST UC3M
F. Templin March 2, 2018
Boeing Research and Technology
November 12, 2017
Distributed Mobility Anchoring Distributed Mobility Anchoring
draft-ietf-dmm-distributed-mobility-anchoring-07 draft-ietf-dmm-distributed-mobility-anchoring-08
Abstract Abstract
This document defines distributed mobility anchoring in terms of the This document defines distributed mobility anchoring in terms of the
different configurations, operations and parameters of mobility different configurations and functions to provide IP mobility
functions to provide different IP mobility support for the diverse support. A network may be configured with distributed mobility
mobility needs in 5G Wireless and beyond. A network may be anchoring functions for both network-based or host-based mobility
configured with distributed mobility anchoring functions according to support according to the needs of mobility support. In the
the needs of mobility support. In the distributed mobility anchoring distributed mobility anchoring environment, multiple anchors are
environment, multiple anchors are available for mid-session switching available for mid-session switching of an IP prefix anchor. To start
of an IP prefix anchor. To start a new flow or to handle a flow not a new flow or to handle a flow not requiring IP session continuity as
requiring IP session continuity as a mobile node moves to a new a mobile node moves to a new network, the flow can be started or re-
network, the flow can be started or re-started using a new IP address started using a new IP address configured from the new IP prefix
configured from the new IP prefix which is anchored to the new which is anchored to the new network. The mobility functions and
network. For a flow requiring IP session continuity, the anchoring their operations and parameters are general for different
of the prior IP prefix may be moved to the new network. The mobility configurations.
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 Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 5 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 3
3. Distributed Mobility Anchoring . . . . . . . . . . . . . . . 6 3. Distributed Mobility Anchoring . . . . . . . . . . . . . . . 5
3.1. Configurations for Different Networks . . . . . . . . . . 6 3.1. Configurations for Different Networks . . . . . . . . . . 5
3.1.1. Network-based Mobility Support for a Flat Network . . 7 3.1.1. Network-based DMM . . . . . . . . . . . . . . . . . . 5
3.1.2. Network-based Mobility Support for a Hierarchical 3.1.2. Client-based DMM . . . . . . . . . . . . . . . . . . 6
Network . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.3. Host-based Mobility Support . . . . . . . . . . . . . 10
3.1.4. NEtwork MObility (NEMO) Basic Support . . . . . . . . 11
3.2. Operations and Parameters . . . . . . . . . . . . . . . . 12
3.2.1. Location Management . . . . . . . . . . . . . . . . . 12
3.2.2. Forwarding Management . . . . . . . . . . . . . . . . 15
4. IP Mobility Handling in Distributed Anchoring Environments - 4. IP Mobility Handling in Distributed Anchoring Environments -
Mobility Support Only When Needed . . . . . . . . . . . . . . 21 Mobility Support Only When Needed . . . . . . . . . . . . . . 7
4.1. No Need of IP Mobility: Changing to New IP Prefix/Address 22 4.1. No Need of IP Mobility: Changing to New IP Prefix/Address 8
4.1.1. Guidelines for IPv6 Nodes: Changing to New IP 4.2. Need of IP Mobility . . . . . . . . . . . . . . . . . . . 9
Prefix/Address . . . . . . . . . . . . . . . . . . . 23
4.2. Need of IP Mobility . . . . . . . . . . . . . . . . . . . 25
4.2.1. Guidelines for IPv6 Nodes: Need of IP Mobility . . . 26
5. IP Mobility Handling in Distributed Mobility Anchoring 5. IP Mobility Handling in Distributed Mobility Anchoring
Environments - Anchor Switching to the New Network . . . . . 28 Environments - Anchor Switching to the New Network . . . . . 11
5.1. IP Prefix/Address Anchor Switching for Flat Network . . . 28 5.1. IP Prefix/Address Anchor Switching for Flat Network . . . 11
5.1.1. Guidelines for IPv6 Nodes: Switching Anchor for Flat 6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
Network . . . . . . . . . . . . . . . . . . . . . . . 29 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2. IP Prefix/Address Anchor Switching for Flat Network with 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
Centralized Control Plane . . . . . . . . . . . . . . . . 30 9.1. Normative References . . . . . . . . . . . . . . . . . . 12
5.2.1. Additional Guidelines for IPv6 Nodes: Switching 9.2. Informative References . . . . . . . . . . . . . . . . . 14
Anchor with Centralized CP . . . . . . . . . . . . . 33 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
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
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 42
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.1. Normative References . . . . . . . . . . . . . . . . . . 42
9.2. Informative References . . . . . . . . . . . . . . . . . 45
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45
1. Introduction 1. Introduction
A key requirement in distributed mobility management [RFC7333] is to A key requirement in distributed mobility management [RFC7333] is to
enable traffic to avoid traversing a single mobility anchor far from enable traffic to avoid traversing a single mobility anchor far from
an optimal route. This draft defines different configurations, an optimal route. This document defines different configurations,
functional operations and parameters for distributed mobility functional operations and parameters for distributed mobility
anchoring and explains how to use them to make the route changes to anchoring and explains how to use them to make the route changes to
avoid unnecessarily long routes. avoid unnecessarily long routes.
Companion distributed mobility management documents are already Companion distributed mobility management documents are already
addressing the architecture and deployment addressing the architecture and deployment
[I-D.ietf-dmm-deployment-models], source address selection [I-D.ietf-dmm-deployment-models], source address selection
[I-D.ietf-dmm-ondemand-mobility], and control-plane data-plane [I-D.ietf-dmm-ondemand-mobility], and control-plane data-plane
signaling [I-D.ietf-dmm-fpc-cpdp]. A number of distributed mobility signaling [I-D.ietf-dmm-fpc-cpdp]. A number of distributed mobility
solutions have also been proposed, for example, in solutions have also been proposed, for example, in
[I-D.seite-dmm-dma], [I-D.bernardos-dmm-cmip], [I-D.seite-dmm-dma], [I-D.bernardos-dmm-pmipv6-dlif],
[I-D.bernardos-dmm-pmip], [I-D.sarikaya-dmm-for-wifi], [I-D.sarikaya-dmm-for-wifi], [I-D.yhkim-dmm-enhanced-anchoring], and
[I-D.yhkim-dmm-enhanced-anchoring], and [I-D.matsushima-stateless-uplane-vepc].
[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 mobility support are possible
depending on the needs. In designing mobility solutions, it 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 Distributed mobility anchoring employs multiple anchors in the data
plane. In general, control plane functions may be separate from data plane. In general, control plane functions may be separated from
plane functions and be centralized but may also be co-located with data plane functions and be centralized but may also be co-located
the data plane functions at the distributed anchors. Different with the data plane functions at the distributed anchors. Different
configurations of distributed mobility anchoring are described in configurations of distributed mobility anchoring are described in
Section 3.1. For instance, the configurations for network-based Section 3.1.
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 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 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 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 configure a global IPv6 address from this prefix and use it as the
source IP address in a flow to communicate with its correspondent source IP address in a flow to communicate with its correspondent
node (CN). When there are multiple mobility anchors, an address node (CN). When there are multiple mobility anchors, an address
selection for a given flow is first required before the flow is 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 initiated. Using an anchor in an MN's network of attachment has the
advantage that the packets can simply be forwarded according to the advantage that the packets can simply be forwarded according to the
forwarding table. However, after the flow has been initiated, the MN forwarding table. However, after the flow has been initiated, the MN
may later move to another network, so that the IP address no longer may later move to another network, so that the IP address no longer
belongs to the current network of attachment of the MN. belongs to the current network of attachment of the MN.
Whether the flow needs IP session continuity will determine how to The IP session continuity needs of a flow (application) determines
ensure that the IP address of the flow will be anchored to the new the how the IP address used by the traffic of this flow has to be
network of attachment. If the ongoing IP flow can cope with an IP anchored. If the ongoing IP flow can cope with an IP prefix/address
prefix/address change, the flow can be reinitiated with a new IP change, the flow can be reinitiated with a new IP address anchored in
address anchored in the new network as shown in Section 4.1. On the the new network. On the other hand, if the ongoing IP flow cannot
other hand, if the ongoing IP flow cannot cope with such change, cope with such change, mobility support is needed. A network
mobility support is needed as shown in Section 4.2. A network
supporting a mix of flows both requiring and not requiring IP supporting a mix of flows both requiring and not requiring IP
mobility support will need to distinguish these flows. The mobility support will need to distinguish these flows.
guidelines for the network to make such a distinction are described
in Section 4.1.1. The general guidelines for such network to provide
IP mobility support are described in Section 4.2.1.
Specifically, IP mobility support can be provided by relocating the
anchoring of the IP prefix/address of the flow from the home network
of the flow to 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 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 All general mobility-related terms and their acronyms used in this
document are to be interpreted as defined in the Mobile IPv6 (MIPv6) document are to be interpreted as defined in the Mobile IPv6 (MIPv6)
base specification [RFC6275], the Proxy Mobile IPv6 (PMIPv6) base specification [RFC6275], the Proxy Mobile IPv6 (PMIPv6)
specification [RFC5213], the "Mobility Related Terminologies" specification [RFC5213], the "Mobility Related Terminologies"
[RFC3753], and the DMM current practices and gap analysis [RFC7429]. [RFC3753], and the DMM current practices and gap analysis [RFC7429].
These include terms such as mobile node (MN), correspondent node These include terms such as mobile node (MN), correspondent node
(CN), home agent (HA), home address (HoA), care-of-address (CoA), (CN), home agent (HA), home address (HoA), care-of-address (CoA),
local mobility anchor (LMA), and mobile access gateway (MAG). local mobility anchor (LMA), and mobile access gateway (MAG).
In addition, this document uses the following terms: In addition, this document uses the following terms:
skipping to change at page 6, line 41 skipping to change at page 5, line 22
FM-DP may be distributed with distributed mobility management. It FM-DP may be distributed with distributed mobility management. It
may be a function in a data plane anchor or data plane node. 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 FM-CP may be distributed or centralized. It may be a function in
a control plane node, control plane anchor or mobility controller. a control plane node, control plane anchor or mobility controller.
3. Distributed Mobility Anchoring 3. Distributed Mobility Anchoring
3.1. Configurations for Different Networks 3.1. Configurations for Different Networks
The mobility functions may be implemented in different configurations We next describe some configurations with multiple distributed
of distributed mobility anchoring in architectures separating the anchors. To cover the widest possible spectrum of scenarios, we
control and data planes. The separation described in consider architectures in which the control and data planes are
[I-D.ietf-dmm-deployment-models] has defined the home control plane separated, as described in [I-D.ietf-dmm-deployment-models].
anchor (Home-CPA), home data plane anchor (Home-DPA), access control
plane node (Access-CPN), and access data plane node (Access-DPN),
which are respectively abbreviated as CPA, DPA, CPN, and DPN here.
Different networks may have different configurations in distributed
mobility anchoring.
The configurations also differ depending on the desired mobility
supports: network-based mobility support for 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 are: 3.1.1. Network-based DMM
dmm:1 There are multiple instances of DPA, each with an FM-DP Figure 1 shows a general scenario for network-based distributed
function. mobility management.
dmm:2 The control plane may either be distributed (not shown) or The main characteristics of a network-based DMM solution are:
centralized. The CPA and DPA may co-locate or may be
separate. When the CPA, each with an FM-CP function, is co-
located with the distributed DPA there will be multiple
instances of the co-located CPA and DPA (not shown).
dmm:3 An IP prefix/address IP1, which is anchored to the DPA with There are multiple data plane anchors (i.e., DPA instances), each
the IP prefix/address IPa1, is assigned for use by an MN. The with an FM-DP function.
MN uses IP1 to communicate with a CN not shown in the figure. The control plane may either be distributed (not shown in the
The flow of this communication session is shown as flow(IP1, figure) or centralized (as shown in the figure).
...), meaning it uses IP1 and other parameters. The control plane and the data plane (Control Plane Anchor -- CPA
-- and Data Plane Anchor -- DPA) may be co-located or not. If the
CPA is co-located with the distributed DPAs, then there are
multiple co-located CPA-DPA instances (not shown in the figure).
An IP prefix/address IP1 (anchored to the DPA with IP address
IPa1) is assigned for use by an MN. The MN uses this IP1 address
to communicate with CNs (not shown in the figure).
The location management (LM) function may be co-located or split
(as shown in the figure) into a separate server (LMs) and 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.
____________ Network ____________ Network
___/ \___________ ___/ \___________
/ +-----+ \___ / +-----+ \___
( |LMs | Control \ ( |LMs | Control \
/ +-.---+ plane \ / +-.---+ plane \
/ +--------.---+ functions \ / +--------.---+ functions \
( |CPA: . | in the ) ( |CPA: . | in the )
( |FM-CP, LMc | network ) ( |FM-CP, LMc | network )
( +------------+ \ ( +------------+ \
/ . . \ / . . \
( . . ) ( . . )
( . . ) ( . . )
( . . \ ( . . \
\ +------------+ +------------+Distributed ) \ +------------+ +------------+Distributed )
( |DPA(IPa1): | |DPA(IPa2): |DPA's ) ( |DPA(IPa1): | |DPA(IPa2): |DPAs )
( |anchors IP1 | |anchors IP2 | _/ ( |anchors IP1 | |anchors IP2 | _/
\ |FM-DP | |FM-DP | etc. / \ |FM-DP | |FM-DP | etc. /
\ +------------+ +------------+ / \ +------------+ +------------+ /
\___ Data plane _____/ \___ Data plane _____/
\______ functions / \______ functions /
\__________________/ \__________________/
+------------+ +------------+
|MN(IP1) | Mobile node attached |MN(IP1) | Mobile node attached
|flow(IP1,..)| to the network |flow(IP1,..)| to the network
+------------+ +------------+
Figure 1. Configurations of network-based mobility management for a Figure 1: Network-based DMM configuration
flat network to which MN is attached. The mobility management
functions in the network are LMs in the control plane, LMc at CPA,
and FM-DP at DPA.
In Figure 1, the LM function is split into a separate server LMs and
a client LMc at the CPA. Then, the LMs may be centralized whereas
the LMc may be distributed or centralized according to whether the
CPA is distributed (not shown) or centralized.
In a special case (not shown), LMs 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
management for a hierarchical network.
+-----+
|LMs |
+-.---+
+--------.---+
|CPA: . |
|FM-CP, LMp |
+------------+
. .
. .
. .
. .
+------------+ +------------+ Distributed
|DPA(IPa1): | |DPA(IPa2): | DPA's
|anchors IP1 | |anchors IP2 | etc.
|FM-DP | |FM-DP |
+------------+ +------------+
+------------+
|CPN: |
|FM-CP, LMc |
+------------+
. .
. .
. .
. .Distributed DPN's
+------------+ +------------+ +------------+ +------------+
|DPN(IPn11): | |DPN(IPn12): | |DPN(IPn21): | |DPN(IPn22): |
|FM-DP | |FM-DP | etc. |FM-DP | |FM-DP | etc.
+------------+ +------------+ +------------+ +------------+
+------------+Mobile node +------------+Mobile node
|MN(IP1) |using IP1 |MN(IP2) |using IP1
|flow(IP1,..)|anchored to |flow(IP2,..)|anchored to
+------------+DPA(IPa1) +------------+DPA(IPa2)
Figure 2. Configurations of network-based mobility management for a
hierarchical network to which MN is attached. The mobility
management functions in 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 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 when the CPN,
each with an FM-CP function, is co-located with the distributed DPN
there will be multiple instances 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 may be
centralized whereas the LMp may be distributed or centralized
according to whether the CPA is distributed or centralized.
In a particular case (not shown), LMs and LMp may co-locate.
3.1.3. Host-based Mobility Support 3.1.2. Client-based DMM
Host-based mobility function configurations as variants from Figure 2 Figure 2 shows a general scenario for client-based distributed
is shown in Figure 3 where the role to perform mobility functions by mobility management. In this configuration, the mobile node performs
CPN and DPN are now taken by the MN. The MN then needs to possess Control Plane Node (CPN) and Data Plane Node (DPN) mobility
the mobility functions FM and LMc. functions, namely the forwarding management and location management
(client role) ones.
+-----+ +-----+
|LMs | |LMs |
+-.---+ +-.---+
+--------.---+ +--------.---+
|CPA: . | |CPA: . |
|FM-CP, LMp | |FM-CP, LMp |
+------------+ +------------+
. . . .
. . . .
. . . .
. . . .
+------------+ +------------+ Distributed +------------+ +------------+ Distributed
|DPA(IPa1): | |DPA(IPa2): | DPA's |DPA(IPa1): | |DPA(IPa2): | DPAs
|anchors IP1 | |anchors IP2 | |anchors IP1 | |anchors IP2 |
|FM-DP | |FM-DP | etc. |FM-DP | |FM-DP | etc.
+------------+ +------------+ +------------+ +------------+
+------------+ +------------+
|MN(IP1) |Mobile node |MN(IP1) |Mobile node
|flow(IP1,..)|using IP1 |flow(IP1,..)|using IP1
|FM, LMc |anchored to |FM, LMc |anchored to
+------------+DPA(IPa1) +------------+DPA(IPa1)
Figure 3. Configuration of host-based mobility management. The Figure 2: Client-based DMM configuration
mobility management functions in the 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 the host (MN).
Figure 3 shows configurations of host-based mobility management with
multiple instances of DPA for a distributed mobility anchoring
environment. Figure 3 can be obtained by simply collapsing CPN, DPN
and MN from the Figure 2 into the MN in Figure 3 which now possesses
the mobility functions FM and LMc that were performed previously by
the CPN and the DPN.
3.1.4. NEtwork MObility (NEMO) Basic Support
Figure 4 shows the configurations of NEMO basic support for a mobile
router.
+-----+
|LMs |
+-.---+
+--------.---+
|CPA: . |
|FM-CP, LMp |
+------------+
. .
. .
. .
. .
+--------------+ +--------------+ Distributed
|DPA(IPa1): | |DPA(IPa2): | DPA's
|anchors IP1 | |anchors IP2 |
|DHCPv6-PD IPn1| |DHCPv6-PD IPn2| etc.
|FM-DP | |FM-DP |
+--------------+ +--------------+
+--------------+Mobile router
|MR(IP1) |using IP1
|delegated IPn1|anchored to
|FM, LMc |DPA(IPa1)
+--------------+
+------------+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 to a network. The mobility management functions 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
the MN from the Figure 3 into the MR carrying a mobile network
consisting of mobile 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 to communicate with
a correspondent node (CN) not shown in the figure. The flow of this
communication session is shown as flow(IPn1, ...), meaning it uses
IPn1 and other parameters.
To enable the MR to assign the IP prefix IPn1, the DPA delegates the
prefix using DHCPv6-PD to the MR.
3.2. Operations and Parameters
The operations of distributed mobility anchoring are defined in order
that they might work together to produce a distributed mobility
solution. The needed information is passed as mobility message
parameters, which must be protected in terms of integrity. Some
parameters may require a means to support privacy of an MN or MR.
The 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
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 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 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 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 - 4. IP Mobility Handling in Distributed Anchoring Environments -
Mobility Support Only When Needed Mobility Support Only When Needed
IP mobility support may be provided only when needed instead of being IP mobility support may be provided only when needed instead of being
provided by default. The LM and FM functions in the different provided by default.
configurations shown in Section 3.1 are then utilized only when
needed.
A straightforward choice of mobility anchoring is for a flow to use 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 the IP prefix of the network to which the MN is attached when the
flow is initiated [I-D.seite-dmm-dma]. flow is initiated [I-D.seite-dmm-dma]
[I-D.bernardos-dmm-pmipv6-dlif].
The IP prefix/address at the MN's side of a flow may be anchored at 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 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 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 IP prefix from the attached network is assigned to the MN's
interface. In addition to configuring new link-local addresses, the interface. In addition to configuring new link-local addresses, the
MN configures from this prefix an IP address which is typically a 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 dynamic IP address. It then uses this IP address when a flow is
initiated. Packets to the MN in this flow are simply forwarded initiated. Packets to the MN in this flow are simply forwarded
according to the forwarding table. according to the forwarding table.
skipping to change at page 22, line 12 skipping to change at page 8, line 16
may choose the one with the least cost. In addition, these IP may choose the one with the least cost. In addition, these IP
prefixes/addresses may be of different types regarding whether prefixes/addresses may be of different types regarding whether
mobility support is needed [I-D.ietf-dmm-ondemand-mobility]. A flow mobility support is needed [I-D.ietf-dmm-ondemand-mobility]. A flow
will need to choose the appropriate one according to whether it needs will need to choose the appropriate one according to whether it needs
IP mobility support. IP mobility support.
4.1. No Need of IP Mobility: Changing to New IP Prefix/Address 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 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 functions are not utilized so that the configurations in Section 3.1
are simplified as shown in Figure 5. are simplified as shown in Figure 3.
Net1 Net2 Net1 Net2
+---------------+ +---------------+ +---------------+ +---------------+
|AR1 | AR is changed |AR2 | |AR1 | AR is changed |AR2 |
+---------------+ -------> +---------------+ +---------------+ -------> +---------------+
|CPA: | |CPA: | |CPA: | |CPA: |
|---------------| |---------------| |---------------| |---------------|
|DPA(IPa1): | |DPA(IPa2): | |DPA(IPa1): | |DPA(IPa2): |
|anchors IP1 | |anchors IP2 | |anchors IP1 | |anchors IP2 |
+---------------+ +---------------+ +---------------+ +---------------+
+...............+ +---------------+ +...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2) | .MN(IP1) . MN moves |MN(IP2) |
.flow(IP1,...) . =======> |flow(IP2,...) | .flow(IP1,...) . =======> |flow(IP2,...) |
+...............+ +---------------+ +...............+ +---------------+
Figure 5. Changing to the new IP prefix/address. MN running a flow Figure 3: Changing to a new IP address/prefix
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 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 use a new IP address acquired from a new network as the MN moves to
the new network. the new network.
Regardless of whether IP mobility is needed, if the flow has Regardless of whether IP mobility is needed, if the flow has
terminated before the MN moves to a new network, the flow may terminated before the MN moves to a new network, the flow may
subsequently restart using the new IP address assigned from the new subsequently restart using the new IP address assigned from the new
network. network.
When IP session continuity is needed, even if a flow is ongoing as 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 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 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 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 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 enabled using a higher layer mobility support which is not in the
scope of this document. scope of this document.
In Figure 5, a flow initiated while the MN was using the IP prefix In Figure 3, a flow initiated while the MN was using the IP prefix
IP1 anchored to a previous access router AR1 in network Net1 has IP1 anchored to a previous access router AR1 in network Net1 has
terminated before the MN moves to a new network Net2. After moving 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 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 router AR2 in network Net2 to start a new flow. The packets may then
be forwarded without requiring IP layer mobility support. be forwarded without requiring IP layer mobility support.
An example call flow is outlined in Figure 6. An example call flow is outlined in Figure 4
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 MN AR1 AR2 CN
is conveyed to the network such as by choosing an IP |MN attaches to AR1: | | |
address to be provided with mobility support as described |acquire MN-ID and profile | |
in [I-D.ietf-dmm-ondemand-mobility]. Then as the MN |--RS---------------->| | |
attaches to a new network, if the MN was using an IP | | | |
address that is not supposed to be provided with mobility |<----------RA(IP1)---| | |
support, the access router will not invoke the mobility | | | |
functions described in Section 3.2 for this IP address. Assigned prefix IP1 | | |
That is, the IP address from the prior network is simply IP1 address configuration | |
not used in the new network. | | | |
|<-Flow(IP1,IPcn,...)-+------------------------------------------>|
| | | |
|MN detaches from AR1 | | |
|MN attaches to AR2 | | |
| | | |
|--RS------------------------------>| |
| | | |
|<--------------RA(IP2)-------------| |
| | | |
Assigned prefix IP2 | | |
IP2 address configuration | |
| | | |
|<-new Flow(IP2,IPcn,...)-----------+---------------------------->|
| | | |
The above guidelines are only to enable distinguishing whether there Figure 4: Re-starting a flow with new IP prefix/address
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 4.2. Need of IP Mobility
When IP mobility is needed for a flow, the LM and FM functions in 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 Section 3.1 are utilized. The mobility support may be provided by IP
prefix anchor switching to the new network to be described in prefix anchor switching to the new network to be described in
Section 5 or by using other mobility management methods Section 5 or by using other mobility management methods
([Paper-Distributed.Mobility], [Paper-Distributed.Mobility.PMIP] and ([Paper-Distributed.Mobility], [Paper-Distributed.Mobility.PMIP] and
[Paper-Distributed.Mobility.Review]). Then the flow may continue to [Paper-Distributed.Mobility.Review]). Then the flow may continue to
use the IP prefix from the prior network of attachment. Yet some 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 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 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 prior network's IP address to avoid having to invoke IP mobility
support. This may be the case where a dynamic IP prefix/address 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 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 IP prefix in the network where the flow is being initiated. Routing
is again kept simpler without employing IP mobility and will remain 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 so as long as the MN which is now in the new network has not moved
again and left to another new network. again and left to another new network.
An example call flow in this case is outlined in Figure 7. 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 | | |
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 MN AR1 AR2 CN
at AR2 and the far end DPA as well as other affected |MN attaches to AR1: | | |
switches/routers between them so that these packets will |acquire MN-ID and profile | |
traverse towards AR2. Meanwhile, changes to the forwarding |--RS---------------->| | |
table entries will also occur at AR1 and the far end DPA as | | | |
well as other affected switches/routers between them so |<----------RA(IP1)---| | |
that if these packets ever reach any of them, they will not | | | |
traverse towards AR1 but will traverse towards AR2 (see Assigned prefix IP1 | | |
Section 3.2.2). 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,...)-----------+---------------------------->|
| | | |
GL-mix:9 Alternatively when using a mechanism of indirection, the FM Figure 5: A flow continues to use the IP prefix from its home network
operations and mobility message parameters are described in after MN has moved to a new network
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 Multiple instances of DPAs (at access routers), which are providing
the MN is moving to the new anchor, it may be necessary to IP prefix to the MNs, are needed to provide distributed mobility
buffer these packets and then forward to the new anchor anchoring in an appropriate configuration such as those described in
after the old anchor knows that the new anchor is ready. Figure 1 (Section 3.1.1) for network-based distributed mobility or in
Such procedures are described in the FM operations and Figure 2 (Section 3.1.2) for client-based distributed mobility.
mobility message parameters (FM-buffer) in Section 3.2.2.
5. IP Mobility Handling in Distributed Mobility Anchoring Environments 5. IP Mobility Handling in Distributed Mobility Anchoring Environments
- Anchor Switching to the New Network - Anchor Switching to the New Network
IP mobility is invoked to enable IP session continuity for an ongoing 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 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 address of the flow is in the home network of the flow, which is not
in the current network of attachment. A centralized mobility in the current network of attachment. A centralized mobility
management mechanism may employ indirection from the anchor in the management mechanism may employ indirection from the anchor in the
home network to the current network of attachment. Yet it may be home network to the current network of attachment. Yet it may be
difficult to avoid unnecessarily long route when the route between difficult to avoid unnecessarily long route when the route between
the MN and the CN via the anchor in the home network is significantly 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 longer than the direct route between them. An alternative is to
switch the IP prefix/address anchoring to the new network. switch the IP prefix/address anchoring to the new network.
5.1. IP Prefix/Address Anchor Switching for Flat Network 5.1. IP Prefix/Address Anchor Switching for Flat Network
The IP prefix/address anchoring may move without changing the IP 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 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. in Section 3.1 are implemented as shown in Figure 6.
Net1 Net2 Net1 Net2
+---------------+ +---------------+ +---------------+ +---------------+
|AR1 | |AR2 | |AR1 | |AR2 |
+---------------+ +---------------+ +---------------+ +---------------+
|CPA: | |CPA: | |CPA: | |CPA: |
|LM:IP1 at IPa1 | |LM:IP1 at IPa2 | |LM:IP1 at IPa1 | |LM:IP1 at IPa2 |
| changes to | | | | changes to | | |
| IP1 at IPa2 | | | | IP1 at IPa2 | | |
|---------------| |---------------| |---------------| |---------------|
|DPA(IPa1): | anchoring of IP1 is effectively moved|DPA(IPa2): | |DPA(IPa1): | IP1 anchoring is effectively moved|DPA(IPa2): |
|anchored IP1 | =======> |anchors IP2,IP1| |anchored IP1 | =======> |anchors IP2,IP1|
+---------------+ +---------------+ +---------------+ +---------------+
+...............+ +---------------+ +...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2,IP1) | .MN(IP1) . MN moves |MN(IP2,IP1) |
.flow(IP1,...) . =======> |flow(IP1,...) | .flow(IP1,...) . =======> |flow(IP1,...) |
+...............+ +---------------+ +...............+ +---------------+
Figure 8. IP prefix/address anchor switching to the new network. MN Figure 6: Anchor mobility
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 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 preserve IP session continuity by moving the anchoring of the
original IP prefix/address of the flow to the new network. One way original IP prefix/address of the flow to the new network.
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.
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. In addition, the
following are required.
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.
Net1 Net2
+----------------------------------------------------------------------+
| CPA: |
| LM:IP1 at IPa2 |
| FM-CP |
+----------------------------------------------------------------------+
+---------------+ +---------------+
|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 and mobility message parameters
described in Section 3.2.1 provide information of which
IP 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 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 | |AR2 |
+---------------+ +---------------+
|DPA(IPa1): | anchoring of IP1 is effectively moved|DPA(IPa2): |
|anchored IP1 | =======> |anchors IP2,IP1|
+---------------+ +---------------+
+---------------+ +---------------+
|FW1 | |FW2 |
+---------------+ FW is changed +---------------+
|DPN(IPn1): | -------> |DPN(IPn2): |
|FM-DP | |FM-DP |
+---------------+ +---------------+
+...............+ +---------------+
.MN(IP1) . MN moves |MN(IP2,IP1) |
.flow(IP1,...) . =======> |flow(IP1,...) |
+...............+ +---------------+
Figure 12. Mobility involving change of IP anchoring in a network
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 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 of flows both requiring and
not requiring IP mobility support apply here.
The guidelines (GL-switch) in Section 5.1.1 for anchoring relocation
and in Section 5.2.1 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 the
associated LM and FM-CP are all co-located. There are multiple DPAs
(each with FM-DP) in the data plane in distributed mobility
anchoring. The MR possesses the mobility functions FM and LMc. The
IP prefix IPn1 is delegated to the MR, to which an MNN is attached
and has an IP address from IPn1 assigned to its interface.
Figure 13 shows a distributed mobility event in a hierarchical
network with a centralized control plane involving a change of
attachment of the MR from a previous DPA to a new DPA while the MNN
is attached to the MR and therefore moves with the MR.
Net1 Net2
+----------------------------------------------------------------------+
| CPA,Aggregate Router: LM:IP1 at IPa2; IPn1 at IP1 |
| FM-CP, LM |
+----------------------------------------------------------------------+
+-----------------+
|Aggregate Router |
+-----------------+
|FM-DP |
+-----------------+
+---------------+ +---------------+
|AR1 | |AR2 |
+---------------+ +---------------+
|DPA(IPa1): | anchoring of IP1 is effectively moved|DPA(IPa2): |
|anchored IP1 | =======> |anchors IP2,IP1|
|DHCPv6-PD IPn1 | | |
|FM-DP | |FM-DP |
+---------------+ +---------------+
+...............+ +---------------+
.MR(IP1) . MR moves |MR(IP2,IP1) |
+...............+ =======> +---------------+
.FM, LMc . |FM, LMc |
.delegated IPn1 . |delegated IPn1 |
+...............+ +---------------+
+...............+ +---------------+
.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 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 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 prefix delegated to the MR. Therefore the
anchor of the MR may change to a new AR. The new AR may
delegate new IP prefix to the MR, so that the MR may
support potential MNNs to attach to it. On the other hand
the delegation of IP prefix to the MR from the old AR may
be deleted.
The guidelines (GL-switch) in Section 5.1.1 for 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 as 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 in the new
network, the security policy must allow the anchor node
to advertise the prefix of the original IP address and
also allow the MNN to send and receive data packets with
the original IP address.
GL-switch:12 The security policy must allow the mobile router to One way to accomplish such move is to use a centralized routing
configure the original IP prefix/address delegated to protocol, but note that this solution presents some scalability
the MR from the previous (original) network when the concerns and its applicability is typically limited to small
original IP prefix/address is being delegated to the MR networks.
in the new network. The security policy must also
allows to use the original IP address by the MNN for the
previous flow in the new network.
6. Security Considerations 6. Security Considerations
Security protocols and mechanisms are employed to secure the network Security protocols and mechanisms are employed to secure the network
and to make continuous security improvements, and a DMM solution is and to make continuous security improvements, and a DMM solution is
required to support them [RFC7333]. In a DMM deployment required to support them [RFC7333].
[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 in
Section 3.2. Here the 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 the
guidelines for IPv6 nodes in various subsections in Section 4, and
Section 5.
The IP address anchoring of an IP prefix is effectively moved from
one network to another network to support IP mobility Section 5.1.
As is considered in the guidelines for IPv6 nodes in Section 5.1.1,
the security policy needs to enable the use in the new network of
attachment the IP prefix assigned from another network. Yet it must
do so without compromising on the needed security to prevent 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 to within specific regions with the proper trust relationship.
In network mobility, the MNN using an IP prefix assigned to it from In a DMM deployment [I-D.ietf-dmm-deployment-models] various attacks
the MR when the MR was in a prior network moves with the MR to a new such as impersonation, denial of service, man-in-the-middle attacks
network Section 5.5. As is considered in the guidelines for IPv6 need to be prevented.
nodes in Section 5.5.1 to support IP mobility for an ongoing flow,
the security management function needs to enable the continued use of
this IP prefix by 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 of an IP prefix belonging to another
network. Again, a viable solution is likely not be a global
solution, but is limited in scope to within specific regions with the
proper trust relationship.
7. IANA Considerations 7. IANA Considerations
This document presents no IANA considerations. This document presents no IANA considerations.
8. Contributors 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 This document has benefited from other work on mobility support in
SDN network, on providing mobility support only when needed, and on SDN network, on providing mobility support only when needed, and on
mobility support in enterprise network. These works have been mobility support in enterprise network. These works have been
referenced. While some of these authors have taken the work to referenced. While some of these authors have taken the work to
jointly write this document, others have contributed at least jointly write this document, others have contributed at least
indirectly by writing these drafts. The latter include Philippe indirectly by writing these drafts. The latter include Philippe
Bertin, Dapeng Liu, Satoru Matushima, Pierrick Seite, Jouni Korhonen, Bertin, Dapeng Liu, Satoru Matushima, Pierrick Seite, Jouni Korhonen,
and Sri Gundavelli. and Sri Gundavelli.
Valuable comments have been received from John Kaippallimalil, Valuable comments have been received from John Kaippallimalil,
ChunShan Xiong, and Dapeng Liu. Dirk von Hugo, Byju Pularikkal, ChunShan Xiong, and Dapeng Liu. Dirk von Hugo, Byju Pularikkal,
Pierrick Seite, Carlos Bernardos have generously provided careful Pierrick Seite have generously provided careful review with helpful
review with helpful corrections and suggestions. corrections and suggestions.
9. References 9. References
9.1. Normative 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 Bernardos, C., Oliva, A., Giust, F., and J. Zuniga, "Proxy
Distributed Client Mobility Management approach using Mobile IPv6 extensions for Distributed Mobility
existing mechanisms", draft-bernardos-dmm-cmip-08 (work in Management", draft-bernardos-dmm-pmipv6-dlif-00 (work in
progress), September 2017. progress), October 2017.
[I-D.bernardos-dmm-pmip]
Bernardos, C., Oliva, A., and F. Giust, "A PMIPv6-based
solution for Distributed Mobility Management", draft-
bernardos-dmm-pmip-09 (work in progress), September 2017.
[I-D.ietf-dmm-deployment-models] [I-D.ietf-dmm-deployment-models]
Gundavelli, S. and S. Jeon, "DMM Deployment Models and Gundavelli, S. and S. Jeon, "DMM Deployment Models and
Architectural Considerations", draft-ietf-dmm-deployment- Architectural Considerations", draft-ietf-dmm-deployment-
models-03 (work in progress), November 2017. models-03 (work in progress), November 2017.
[I-D.ietf-dmm-fpc-cpdp] [I-D.ietf-dmm-fpc-cpdp]
Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S., Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S.,
Moses, D., and C. Perkins, "Protocol for Forwarding Policy Moses, D., and C. Perkins, "Protocol for Forwarding Policy
Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-09 Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-09
(work in progress), October 2017. (work in progress), October 2017.
[I-D.ietf-dmm-ondemand-mobility] [I-D.ietf-dmm-ondemand-mobility]
Yegin, A., Moses, D., Kweon, K., Lee, J., Park, J., and S. Yegin, A., Moses, D., Kweon, K., Lee, J., Park, J., and S.
Jeon, "On Demand Mobility Management", draft-ietf-dmm- Jeon, "On Demand Mobility Management", draft-ietf-dmm-
ondemand-mobility-12 (work in progress), July 2017. ondemand-mobility-13 (work in progress), January 2018.
[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 (work in progress), November 2017.
[I-D.matsushima-stateless-uplane-vepc] [I-D.matsushima-stateless-uplane-vepc]
Matsushima, S. and R. Wakikawa, "Stateless user-plane Matsushima, S. and R. Wakikawa, "Stateless user-plane
architecture for virtualized EPC (vEPC)", draft- architecture for virtualized EPC (vEPC)", draft-
matsushima-stateless-uplane-vepc-06 (work in progress), matsushima-stateless-uplane-vepc-06 (work in progress),
March 2016. March 2016.
[I-D.mccann-dmm-prefixcost] [I-D.mccann-dmm-prefixcost]
McCann, P. and J. Kaippallimalil, "Communicating Prefix McCann, P. and J. Kaippallimalil, "Communicating Prefix
Cost to Mobile Nodes", draft-mccann-dmm-prefixcost-03 Cost to Mobile Nodes", draft-mccann-dmm-prefixcost-03
skipping to change at page 44, line 20 skipping to change at page 13, line 42
[I-D.sarikaya-dmm-for-wifi] [I-D.sarikaya-dmm-for-wifi]
Sarikaya, B. and L. Li, "Distributed Mobility Management Sarikaya, B. and L. Li, "Distributed Mobility Management
Protocol for WiFi Users in Fixed Network", draft-sarikaya- Protocol for WiFi Users in Fixed Network", draft-sarikaya-
dmm-for-wifi-05 (work in progress), October 2017. dmm-for-wifi-05 (work in progress), October 2017.
[I-D.seite-dmm-dma] [I-D.seite-dmm-dma]
Seite, P., Bertin, P., and J. Lee, "Distributed Mobility Seite, P., Bertin, P., and J. Lee, "Distributed Mobility
Anchoring", draft-seite-dmm-dma-07 (work in progress), Anchoring", draft-seite-dmm-dma-07 (work in progress),
February 2014. 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] [I-D.yhkim-dmm-enhanced-anchoring]
Kim, Y. and S. Jeon, "Enhanced Mobility Anchoring in Kim, Y. and S. Jeon, "Enhanced Mobility Anchoring in
Distributed Mobility Management", draft-yhkim-dmm- Distributed Mobility Management", draft-yhkim-dmm-
enhanced-anchoring-05 (work in progress), July 2016. 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 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related
Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004,
<https://www.rfc-editor.org/info/rfc3753>. <https://www.rfc-editor.org/info/rfc3753>.
[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, DOI 10.17487/RFC5213, August 2008, RFC 5213, DOI 10.17487/RFC5213, August 2008,
<https://www.rfc-editor.org/info/rfc5213>. <https://www.rfc-editor.org/info/rfc5213>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://www.rfc-editor.org/info/rfc6275>. 2011, <https://www.rfc-editor.org/info/rfc6275>.
[RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen, [RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen,
T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)", Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, DOI 10.17487/RFC6459, January 2012, RFC 6459, DOI 10.17487/RFC6459, January 2012,
<https://www.rfc-editor.org/info/rfc6459>. <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. [RFC7333] Chan, H., Ed., Liu, D., Seite, P., Yokota, H., and J.
Korhonen, "Requirements for Distributed Mobility Korhonen, "Requirements for Distributed Mobility
Management", RFC 7333, DOI 10.17487/RFC7333, August 2014, Management", RFC 7333, DOI 10.17487/RFC7333, August 2014,
<https://www.rfc-editor.org/info/rfc7333>. <https://www.rfc-editor.org/info/rfc7333>.
[RFC7429] Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and [RFC7429] Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and
CJ. Bernardos, "Distributed Mobility Management: Current CJ. Bernardos, "Distributed Mobility Management: Current
Practices and Gap Analysis", RFC 7429, Practices and Gap Analysis", RFC 7429,
DOI 10.17487/RFC7429, January 2015, DOI 10.17487/RFC7429, January 2015,
<https://www.rfc-editor.org/info/rfc7429>. <https://www.rfc-editor.org/info/rfc7429>.
skipping to change at page 46, line 28 skipping to change at page 15, line 39
Email: jonghyouk@smu.ac.kr Email: jonghyouk@smu.ac.kr
Seil Jeon Seil Jeon
Sungkyunkwan University Sungkyunkwan University
2066 Seobu-ro, Jangan-gu 2066 Seobu-ro, Jangan-gu
Suwon, Gyeonggi-do Suwon, Gyeonggi-do
Republic of Korea Republic of Korea
Email: seiljeon@skku.edu Email: seiljeon@skku.edu
Alexandre Petrescu Carlos J. Bernardos (editor)
CEA, LIST Universidad Carlos III de Madrid
CEA Saclay Av. Universidad, 30
Gif-sur-Yvette, Ile-de-France 91190 Leganes, Madrid 28911
France Spain
Phone: +33169089223
Email: Alexandre.Petrescu@cea.fr
Fred L. Templin
Boeing Research and Technology
P.O. Box 3707
Seattle, WA 98124
USA
Email: fltemplin@acm.org Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/
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