draft-ietf-dmm-requirements-15.txt   draft-ietf-dmm-requirements-16.txt 
Network Working Group H. Chan (Ed.) Network Working Group H. Chan (Ed.)
Internet-Draft Huawei Technologies Internet-Draft Huawei Technologies
Intended status: Informational D. Liu Intended status: Informational D. Liu
Expires: September 4, 2014 China Mobile Expires: October 20, 2014 China Mobile
P. Seite P. Seite
Orange Orange
H. Yokota H. Yokota
KDDI Lab KDDI Lab
J. Korhonen J. Korhonen
Broadcom Communications Broadcom Communications
March 3, 2014 April 18, 2014
Requirements for Distributed Mobility Management Requirements for Distributed Mobility Management
draft-ietf-dmm-requirements-15 draft-ietf-dmm-requirements-16
Abstract Abstract
This document defines the requirements for Distributed Mobility This document defines the requirements for Distributed Mobility
Management (DMM) at the network layer. The hierarchical structure in Management (DMM) at the network layer. The hierarchical structure in
traditional wireless networks has led primarily to centrally deployed traditional wireless networks has led primarily to centrally deployed
mobility anchors. As some wireless networks are evolving away from mobility anchors. As some wireless networks are evolving away from
the hierarchical structure, it can be useful have a distributed model the hierarchical structure, it can be useful to have a distributed
for mobility management in which traffic does not need to traverse model for mobility management in which traffic does not need to
centrally deployed mobility anchors far from the optimal route. The traverse centrally deployed mobility anchors far from the optimal
motivation and the problems addressed by each requirement are also route. The motivation and the problems addressed by each requirement
described. are also described.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 RFC 2119 document are to be interpreted as described in RFC 2119 [RFC2119].
[RFC2119].
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on October 20, 2014.
This Internet-Draft will expire on September 4, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions used in this document . . . . . . . . . . . . . . 5 2. Conventions used in this document . . . . . . . . . . . . . . 5
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
3. Centralized versus distributed mobility management . . . . . . 6 3. Centralized versus distributed mobility management . . . . . . 7
3.1. Centralized mobility management . . . . . . . . . . . . . 7 3.1. Centralized mobility management . . . . . . . . . . . . . 7
3.2. Distributed mobility management . . . . . . . . . . . . . 8 3.2. Distributed mobility management . . . . . . . . . . . . . 8
4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 9 4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 9
5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 11 5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14 6. Security Considerations . . . . . . . . . . . . . . . . . . . 15
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 15
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
9.1. Normative References . . . . . . . . . . . . . . . . . . . 17 9.1. Normative References . . . . . . . . . . . . . . . . . . . 17
9.2. Informative References . . . . . . . . . . . . . . . . . . 17 9.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
In the past decade a fair number of network-layer mobility protocols In the past decade a fair number of network-layer mobility protocols
have been standardized [RFC6275] [RFC5944] [RFC5380] [RFC6301] have been standardized [RFC6275] [RFC5944] [RFC5380] [RFC6301]
[RFC5213]. Although the protocols differ in terms of functions and [RFC5213]. Although these protocols differ in terms of functions and
associated message formats, they all employ a mobility anchor to associated message formats, they all employ a mobility anchor to
allow a mobile node to remain reachable after it has moved to a allow a mobile node to remain reachable after it has moved to a
different network. The anchor point, among other tasks, ensures different network. The anchor point, among other tasks, ensures
connectivity by forwarding packets destined to, or sent from, the connectivity by forwarding packets destined to, or sent from, the
mobile node. It is a centrally deployed mobility anchor in the sense mobile node. It is a centrally deployed mobility anchor in the sense
that the deployed architectures today have a small number of these that the deployed architectures today have a small number of these
anchors and the traffic of millions of mobile nodes in an operator anchors and the traffic of millions of mobile nodes in an operator
network are typically managed by the same anchor. network are typically managed by the same anchor. Such a mobility
anchor may still have to reside in the subscriber's provider network
even when the subscriber is roaming to a visited network, in order
that certain functions such as charging and billing can be performed
more readily by the provider's network. An example provider network
is a Third Generation Partnership Project (3GPP) network.
Distributed mobility management (DMM) is an alternative to the above Distributed mobility management (DMM) is an alternative to the above
centralized deployment. The background behind the interests to study centralized deployment. The background behind the interests to study
DMM are primarily in the following. DMM are primarily in the following.
(1) Mobile users are, more than ever, consuming Internet content (1) Mobile users are, more than ever, consuming Internet content
including that of local Content Delivery Networks (CDNs) which including that of local Content Delivery Networks (CDNs). Such
had not taken mobility service into account before. Such
traffic imposes new requirements on mobile core networks for traffic imposes new requirements on mobile core networks for
data traffic delivery. To prevent exceeding the available core data traffic delivery. To prevent exceeding the available core
network capacity, service providers need to implement new network capacity, service providers need to implement new
strategies such as selective IPv4 traffic offload (e.g., strategies such as selective IPv4 traffic offload (e.g.,
[RFC6909], Third Generation Partnership Project (3GPP) work [RFC6909], 3GPP work items Local IP Access (LIPA) and Selected
items Local IP Access (LIPA) and Selected IP Traffic Offload IP Traffic Offload (SIPTO) [TS.23.401]) through alternative
(SIPTO) [TS.23.401]) through alternative access networks such as access networks such as Wireless Local Area Network (WLAN)
Wireless Local Area Network (WLAN) [Paper- [Paper-Mobile.Data.Offloading]. In addition, a gateway
Mobile.Data.Offloading]. In addition, a gateway selection selection mechanism takes the user proximity into account within
mechanism takes the user proximity into account within the EPC the Evolved Packet Core (EPC) [TS.29303]. Yet these mechanisms
Evolved Packet Core (EPC) [TS.29303]. Yet these mechanisms were were not pursued in the past owing to charging and billing
not pursued in the past owing to charging and billing which considerations which require solutions beyond the mobility
require solutions beyond the mobility protocol. Consequently, protocol. Consequently, assigning a gateway anchor node from a
assigning a gateway anchor node from a visited network in visited network when roaming to the visited network has only
roaming scenario has until recently been done and are limited to recently been done and is limited to voice services.
voice services only.
Both traffic offloading and CDN mechanisms could benefit from Both traffic offloading and CDN mechanisms could benefit from
the development of mobile architectures with fewer levels of the development of mobile architectures with fewer hierarchical
routing hierarchy introduced into the data path by the mobility levels introduced into the data path by the mobility management
management system. This trend towards so-called "flat networks" system. This trend of "flattening" the mobile networks works
works best for direct communications among peers in the same best for direct communications among peers in the same
geographical area. Distributed mobility management in a truly geographical area. Distributed mobility management in the
flat mobile architecture would anchor the traffic closer to the flattening mobile networks would anchor the traffic closer to
point of attachment of the user. the point of attachment of the user.
(2) Today's mobile networks present service providers with new (2) Today's mobile networks present service providers with new
challenges. Mobility patterns indicate that mobile nodes often challenges. Mobility patterns indicate that mobile nodes often
remain attached to the same point of attachment for considerable remain attached to the same point of attachment for considerable
periods of time [Paper-Locating.User]. Specific IP mobility periods of time [Paper-Locating.User]. Specific IP mobility
management support is not required for applications that launch management support is not required for applications that launch
and complete their sessions while the mobile node is connected and complete their sessions while the mobile node is connected
to the same point of attachment. However, currently, IP to the same point of attachment. However, currently, IP
mobility support is designed for always-on operation, mobility support is designed for always-on operation,
maintaining all parameters of the context for each mobile maintaining all parameters of the context for each mobile
subscriber for as long as they are connected to the network. subscriber for as long as they are connected to the network.
This can result in a waste of resources and unnecessary costs This can result in a waste of resources and unnecessary costs
for the service provider. Infrequent node mobility coupled with for the service provider. Infrequent node mobility coupled with
application intelligence suggest that mobility support could be application intelligence suggest that mobility support could be
provided selectively such as in [I-D.bhandari-dhc-class-based- provided selectively such as in [I-D.bhandari-dhc-class-based-
prefix] and [I-D.korhonen-6man-prefix-properties], thus reducing prefix] and [I-D.korhonen-6man-prefix-properties], thus reducing
the amount of context maintained in the network. the amount of context maintained in the network.
DMM may distribute the mobility anchors in the data-plane towards a DMM may distribute the mobility anchors in the data-plane in
more flat network such that the mobility anchors are positioned flattening the mobility network such that the mobility anchors are
closer to the user; ideally, mobility agents could be collocated with positioned closer to the user; ideally, mobility agents could be
the first-hop router. Facilitated by the distribution of mobility collocated with the first-hop router. Facilitated by the
anchors, it may be possible to selectively use or not use mobility distribution of mobility anchors, it may be possible to selectively
protocol support depending on whether such support is needed or not. use or not use mobility protocol support depending on whether such
It can thus reduce the amount of state information that must be support is needed or not. It can thus reduce the amount of state
maintained in various mobility agents of the mobile network. It can information that must be maintained in various mobility agents of the
then avoid the unnecessary establishment of mechanisms to forward mobile network. It can then avoid the unnecessary establishment of
traffic from an old to a new mobility anchor. mechanisms to forward traffic from an old to a new mobility anchor.
This document compares distributed mobility management with This document compares distributed mobility management with
centralized mobility management in Section 3. The problems that can centralized mobility management in Section 3. The problems that can
be addressed with DMM are summarized in Section 4. The mandatory be addressed with DMM are summarized in Section 4. The mandatory
requirements as well as the optional requirements for network-layer requirements as well as the optional requirements for network-layer
distributed mobility management are given in Section 5. Finally, distributed mobility management are given in Section 5. Finally,
security considerations are discussed in Section 6. security considerations are discussed in Section 6.
The problem statement and the use cases [I-D.yokota-dmm-scenario] can The problem statement and the use cases [I-D.yokota-dmm-scenario] can
be found in [Paper-Distributed.Mobility.Review]. be found in [Paper-Distributed.Mobility.Review].
skipping to change at page 6, line 25 skipping to change at page 6, line 28
Centralized mobility management Centralized mobility management
makes use of centrally deployed mobility anchors. makes use of centrally deployed mobility anchors.
Distributed mobility management Distributed mobility management
is not centralized so that traffic does not need to traverse is not centralized so that traffic does not need to traverse
centrally deployed mobility anchors far from the optimal route. centrally deployed mobility anchors far from the optimal route.
Flat mobile network Hierarchical mobile network
has few levels of routing hierarchy introduced into the data path has a hierarchy of network elements arranged into multiple
by the mobility management system. hierarchical levels which are introduced into the data path by the
mobility management system.
Flattening mobile network
refers to the hierarchical mobile network which is going through
the trend of reducing its number of hierarchical levels.
Flatter mobile network
has fewer hierarchical levels compared to a hierarchical mobile
network.
Mobility context Mobility context
is the collection of information required to provide mobility is the collection of information required to provide mobility
management support for a given mobile node. management support for a given mobile node.
3. Centralized versus distributed mobility management 3. Centralized versus distributed mobility management
Mobility management is needed because the IP address of a mobile node Mobility management is needed because the IP address of a mobile node
may change as the node moves. Mobility management functions may be may change as the node moves. Mobility management functions may be
implemented at different layers of the protocol stack. At the IP implemented at different layers of the protocol stack. At the IP
(network) layer, mobility management can be client-based or network- (network) layer, mobility management can be client-based or network-
based. based.
An IP-layer mobility management protocol is typically based on the An IP-layer mobility management protocol is typically based on the
principle of distinguishing between a session identifier and a principle of distinguishing between a session identifier and a
routing address and maintaining a mapping between the two. In Mobile forwarding address and maintaining a mapping between the two. In
IP, the new IP address of the mobile node after the node has moved is Mobile IP, the new IP address of the mobile node after the node has
the routing address, whereas the original IP address before the moved is the forwarding address, whereas the original IP address
mobile node moves serves as the session identifier. The location before the mobile node moves serves as the session identifier. The
management (LM) information is kept by associating the routing location management (LM) information is kept by associating the
address with the session identifier. Packets addressed to the forwarding address with the session identifier. Packets addressed to
session identifier will first route to the original network which re- the session identifier will first route to the original network which
directs them using the routing address to deliver to the session. re-directs them using the forwarding address to deliver to the
Re-directing packets this way can result in long routes. An existing session. Re-directing packets this way can result in long routes.
optimization routes directly using the routing address of the host, An existing optimization routes directly using the forwarding address
and such is a host-based solution. of the host, and such is a host-based solution.
The next two subsections explain centralized and distributed mobility The next two subsections explain centralized and distributed mobility
management functions in the network. management functions in the network.
3.1. Centralized mobility management 3.1. Centralized mobility management
In centralized mobility management, the location information in terms In centralized mobility management, the location information in terms
of a mapping between the session identifier and the routing address of a mapping between the session identifier and the forwarding
is kept at a single mobility anchor, and packets destined to the address is kept at a single mobility anchor, and packets destined to
session identifier are routed via this anchor. In other words, such the session identifier are forwarded via this anchor. In other
mobility management systems are centralized in both the control plane words, such mobility management systems are centralized in both the
and the data plane (mobile node IP traffic). control plane and the data plane (mobile node IP traffic).
Many existing mobility management deployments make use of centralized Many existing mobility management deployments make use of centralized
mobility anchoring in a hierarchical network architecture, as shown mobility anchoring in a hierarchical network architecture, as shown
in Figure 1. Examples are the home agent (HA) and local mobility in Figure 1. Examples are the home agent (HA) and local mobility
anchor (LMA) serving as the anchors for the mobile node (MN) and anchor (LMA) serving as the anchors for the mobile node (MN) and
Mobile Access Gateway (MAG) in Mobile IPv6 [RFC6275] and in Proxy Mobile Access Gateway (MAG) in Mobile IPv6 [RFC6275] and in Proxy
Mobile IPv6 [RFC5213] respectively. Cellular networks such as the Mobile IPv6 [RFC5213] respectively. Cellular networks such as the
3GPP General Packet Radio System (GPRS) networks and 3GPP Evolved 3GPP General Packet Radio System (GPRS) networks and 3GPP Evolved
Packet System (EPS) networks employ centralized mobility management Packet System (EPS) networks employ centralized mobility management
too. In the 3GPP GPRS network, the Gateway GPRS Support Node (GGSN), too. In the 3GPP GPRS network, the Gateway GPRS Support Node (GGSN),
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/ \ / \ / \ / \
/ \ / \ / \ / \
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
|RNC| |RNC| |RNC| |RNC| |RNC| |RNC| |RNC| |RNC|
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
Figure 1. Centralized mobility management. Figure 1. Centralized mobility management.
3.2. Distributed mobility management 3.2. Distributed mobility management
Mobility management functions may also be distributed to multiple Mobility management functions may also be distributed in the data
networks as shown in Figure 2, so that a mobile node in any of these plane to multiple networks as shown in Figure 2, so that a mobile
networks may be served by a nearby function with appropriate node in any of these networks may be served by a nearby function with
mobility/routing management (RM) capability. appropriate forwarding management (FM) capability.
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| RM | | RM | | RM | | RM | | FM | | FM | | FM | | FM |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| |
+----+ +----+
| MN | | MN |
+----+ +----+
Figure 2. Distributed mobility management. Figure 2. Distributed mobility management.
Mobility management may be partially or fully distributed DMM is distributed in the data plane, whereas the control plane may
[I-D.yokota-dmm-scenario]. In the former case only the data plane is either be centralized or distributed [I-D.yokota-dmm-scenario]. The
distributed, implicitly assuming separation of data and control former case implicitly assumes separation of data and control planes
planes as described in [I-D.wakikawa-netext-pmip-cp-up-separation]. as described in [I-D.wakikawa-netext-pmip-cp-up-separation]. While
Fully distributed mobility management implies that both the data mobility management can be distributed, it is not necessary for other
plane and the control plane are distributed. While mobility
management can be distributed, it is not necessary for other
functions such as subscription management, subscription database, and functions such as subscription management, subscription database, and
network access authentication to be similarly distributed. network access authentication to be similarly distributed.
A distributed mobility management scheme for a flat mobile network of A distributed mobility management scheme for a flattening mobile
access nodes is proposed in [Paper-Distributed.Dynamic.Mobility]. network consisting of access nodes is proposed in [Paper-
Its benefits over centralized mobility management have been shown Distributed.Dynamic.Mobility]. Its benefits over centralized
through simulations [Paper-Distributed.Centralized.Mobility]. mobility management have been shown through simulations [Paper-
Moreover, the (re)use and extension of existing protocols in the Distributed.Centralized.Mobility]. Moreover, the (re)use and
design of both fully distributed mobility management [Paper- extension of existing protocols in the design of both fully
Migrating.Home.Agents] [Paper-Distributed.Mobility.SAE] and partially distributed mobility management [Paper-Migrating.Home.Agents] [Paper-
distributed mobility management [Paper-Distributed.Mobility.PMIP] Distributed.Mobility.SAE] and partially distributed mobility
[Paper-Distributed.Mobility.MIP] have been reported in the management [Paper-Distributed.Mobility.PMIP] [Paper-
literature. Therefore, before designing new mobility management Distributed.Mobility.MIP] have been reported in the literature.
protocols for a future distributed architecture, it is recommended to Therefore, before designing new mobility management protocols for a
first consider whether existing mobility management protocols can be future distributed architecture, it is recommended to first consider
extended. whether existing mobility management protocols can be extended.
4. Problem Statement 4. Problem Statement
The problems that can be addressed with DMM are summarized in the The problems that can be addressed with DMM are summarized in the
following: following:
PS1: Non-optimal routes PS1: Non-optimal routes
Routing via a centralized anchor often results in non-optimal Forwarding via a centralized anchor often results in non-
routes, thereby increasing the end-to-end delay. The problem optimal routes, thereby increasing the end-to-end delay. The
is manifested, for example, when accessing a nearby server or problem is manifested, for example, when accessing a nearby
servers of a Content Delivery Network (CDN), or when receiving server or servers of a Content Delivery Network (CDN), or when
locally available IP multicast or sending IP multicast packets. receiving locally available IP multicast or sending IP
(Existing route optimization is only a host-based solution. On multicast packets. (Existing route optimization is only a
the other hand, localized routing with PMIPv6 [RFC6705] host-based solution. On the other hand, localized routing with
addresses only a part of the problem where both the MN and the PMIPv6 [RFC6705] addresses only a part of the problem where
correspondent node (CN) are attached to the same MAG, and it is both the MN and the correspondent node (CN) are attached to the
not applicable when the CN does not behave like an MN.) same MAG, and it is not applicable when the CN does not behave
like an MN.)
PS2: Divergence from other evolutionary trends in network PS2: Divergence from other evolutionary trends in network
architectures such as distribution of content delivery. architectures such as distribution of content delivery.
Mobile networks have generally been evolving towards a flat Mobile networks have generally been evolving towards a flatter
network. Centralized mobility management, which is non-optimal and flatter network. Centralized mobility management, which is
with a flat network architecture, does not support this non-optimal with a flatter network architecture, does not
evolution. support this evolution.
PS3: Lack of scalability of centralized tunnel management and PS3: Lack of scalability of centralized tunnel management and
mobility context maintenance mobility context maintenance
Setting up tunnels through a central anchor and maintaining Setting up tunnels through a central anchor and maintaining
mobility context for each MN usually requires more concentrated mobility context for each MN usually requires more concentrated
resources in a centralized design, thus reducing scalability. resources in a centralized design, thus reducing scalability.
Distributing the tunnel maintenance function and the mobility Distributing the tunnel maintenance function and the mobility
context maintenance function among different network entities context maintenance function among different network entities
with proper signaling protocol design can avoid increasing the with proper signaling protocol design can avoid increasing the
concentrated resources with an increasing number of MNs. concentrated resources with an increasing number of MNs.
PS4: Single point of failure and attack PS4: Single point of failure and attack
Centralized anchoring designs may be more vulnerable to single Centralized anchoring designs may be more vulnerable to single
points of failures and attacks than a distributed system. The points of failures and attacks than a distributed system. The
impact of a successful attack on a system with centralized impact of a successful attack on a system with centralized
skipping to change at page 11, line 17 skipping to change at page 11, line 15
more severe in a distributed mobility environment. more severe in a distributed mobility environment.
5. Requirements 5. Requirements
After comparing distributed mobility management against centralized After comparing distributed mobility management against centralized
deployment in Section 3 and describing the problems in Section 4, deployment in Section 3 and describing the problems in Section 4,
this section identifies the following requirements: this section identifies the following requirements:
REQ1: Distributed mobility management REQ1: Distributed mobility management
IP mobility, network access and routing solutions provided by IP mobility, network access and forwarding solutions provided
DMM MUST enable traffic to avoid traversing single mobility by DMM MUST enable traffic to avoid traversing single mobility
anchor far from the optimal route. anchor far from the optimal route.
This requirement on distribution is in the data plane only.
It does not impose constraints on whether the control plane
should be distributed or centralized. However, if the control
plane is centralized while the data plane is distributed, it
is implicit that the control plane and data plane need to
separate (Section 3.2).
Motivation: This requirement is motivated by current trends in Motivation: This requirement is motivated by current trends in
network evolution: (a) it is cost- and resource-effective to network evolution: (a) it is cost- and resource-effective to
cache contents, and the caching (e.g., CDN) servers are cache contents, and the caching (e.g., CDN) servers are
distributed so that each user in any location can be close to distributed so that each user in any location can be close to
one of the servers; (b) the significantly larger number of one of the servers; (b) the significantly larger number of
mobile nodes and flows call for improved scalability; (c) mobile nodes and flows call for improved scalability; (c)
single points of failure are avoided in a distributed system; single points of failure are avoided in a distributed system;
(d) threats against centrally deployed anchors, e.g., home (d) threats against centrally deployed anchors, e.g., home
agent and local mobility anchor, are mitigated in a agent and local mobility anchor, are mitigated in a
distributed system. distributed system.
This requirement addresses the problems PS1, PS2, PS3, and PS4 This requirement addresses the problems PS1, PS2, PS3, and PS4
described in Section 4. described in Section 4.
REQ2: Bypassable network-layer mobility support REQ2: Bypassable network-layer mobility support for each application
session
DMM solutions MUST enable network-layer mobility but it MUST DMM solutions MUST enable network-layer mobility but it MUST
be possible to not use it. Mobility support is needed, for be possible for any individual active application session
(flow) to not use it. Mobility support is needed, for
example, when a mobile host moves and an application cannot example, when a mobile host moves and an application cannot
cope with a change in the IP address. Mobility support is cope with a change in the IP address. Mobility support is
also needed when a mobile router changes its IP address as it also needed when a mobile router changes its IP address as it
moves together with a host and, in the presence of ingress moves together with a host and, in the presence of ingress
filtering, an application in the host is interrupted. However filtering, an application in the host is interrupted. However
mobility support at the network-layer is not always needed; a mobility support at the network-layer is not always needed; a
mobile node can often be stationary, and mobility support can mobile node can often be stationary, and mobility support can
also be provided at other layers. It is then not always also be provided at other layers. It is then not always
necessary to maintain a stable IP address or prefix. necessary to maintain a stable IP address or prefix for an
active application session.
Different active sessions can also differ in whether network-
layer mobility support is needed. IP mobility, network access
and forwarding solutions provided by DMM MUST then enable the
possibility of independent handling for each application
session of a user or mobile device.
The handling of mobility management to the granularity of an
individual session of a user/device SHOULD need proper session
identification in addition to user/device identification.
Motivation: The motivation of this requirement is to enable Motivation: The motivation of this requirement is to enable
more efficient routing and more efficient use of network more efficient forwarding and more efficient use of network
resources by selecting an IP address or prefix according to resources by selecting an IP address or prefix according to
whether mobility support is needed and by not maintaining whether mobility support is needed and by not maintaining
context at the mobility anchor when there is no such need. context at the mobility anchor when there is no such need.
This requirement addresses the problems PS5 and PS6 described in This requirement addresses the problems PS5 and PS6 described
Section 4. in Section 4.
REQ3: IPv6 deployment REQ3: IPv6 deployment
DMM solutions SHOULD target IPv6 as the primary deployment DMM solutions SHOULD target IPv6 as the primary deployment
environment and SHOULD NOT be tailored specifically to support environment and SHOULD NOT be tailored specifically to support
IPv4, in particular in situations where private IPv4 addresses IPv4, in particular in situations where private IPv4 addresses
and/or NATs are used. and/or NATs are used.
Motivation: This requirement conforms to the general Motivation: This requirement conforms to the general
orientation of IETF work. DMM deployment is foreseen in mid- orientation of IETF work. DMM deployment is foreseen in mid-
to long-term horizon, when IPv6 is expected to be far more to long-term horizon, when IPv6 is expected to be far more
common than today. common than today.
This requirement avoids the unnecessarily complexity in solving the This requirement avoids the unnecessarily complexity in
problems in Section 4 for IPv4, which will not be able to use some of solving the problems in Section 4 for IPv4, which will not be
the IPv6-specific features. able to use some of the IPv6-specific features.
REQ4: Existing mobility protocols REQ4: Existing mobility protocols
A DMM solution MUST first consider reusing and extending IETF- A DMM solution MUST first consider reusing and extending IETF-
standardized protocols before specifying new protocols. standardized protocols before specifying new protocols.
Motivation: Reuse of existing IETF work is more efficient and Motivation: Reuse of existing IETF work is more efficient and
less error-prone. less error-prone.
This requirement attempts to avoid the need of new protocols This requirement attempts to avoid the need of new protocols
development and therefore their potential problems of being time- development and therefore their potential problems of being
consuming and error-prone. time-consuming and error-prone.
REQ5: Coexistence with deployed networks and hosts REQ5: Coexistence with deployed networks/hosts and operability
across different networks
The DMM solution may require loose, tight or no integration A DMM solution may require loose, tight or no integration into
into existing mobility protocols and host IP stack. existing mobility protocols and host IP stack. Regardless of
Regardless of the integration level, the DMM solution MUST be the integration level, such a DMM solution MUST be able to
able to coexist with existing network deployments, end hosts coexist with existing network deployments, end hosts and
and routers that may or may not implement existing mobility routers that may or may not implement existing mobility
protocols. Furthermore, a DMM solution SHOULD work across protocols. Furthermore, a DMM solution SHOULD work across
different networks, possibly operated as separate different networks, possibly operated as separate
administrative domains, when allowed by the trust relationship administrative domains, when the needed mobility management
between them. signaling, forwarding, and network access are allowed by the
trust relationship between them.
Motivation: (a) to preserve backwards compatibility so that Motivation: (a) to preserve backwards compatibility so that
existing networks and hosts are not affected and continue to existing networks and hosts are not affected and continue to
function as usual, and (b) enable inter-domain operation if function as usual, and (b) enable inter-domain operation if
desired. desired.
This requirement addresses the problem PS7 described in Section 4. This requirement addresses the problem PS7 described in
Section 4.
REQ6: Security considerations REQ6: Security considerations
A DMM solution MUST NOT introduce new security risks, or A DMM solution MUST support any security protocols and
amplify existing security risks, that cannot be mitigated by mechanisms needed to secure the network and to make continuous
existing security mechanisms or protocols. security improvements. In addition, with security taken into
consideration early in the design, a DMM solution MUST NOT
introduce new security risks, or amplify existing security
risks, that cannot be mitigated by existing security protocols
and mechanisms.
Motivation: Various attacks such as impersonation, denial of Motivation: Various attacks such as impersonation, denial of
service, man-in-the-middle attacks, and so on, may be launched service, man-in-the-middle attacks, and so on, may be launched
in a DMM deployment. For instance, an illegitimate node may in a DMM deployment. For instance, an illegitimate node may
attempt to access a network providing DMM. Another example is attempt to access a network providing DMM. Another example is
that a malicious node can forge a number of signaling messages that a malicious node can forge a number of signaling messages
thus redirecting traffic from its legitimate path. thus redirecting traffic from its legitimate path.
Consequently, the specific node or nodes to which the traffic Consequently, the specific node or nodes to which the traffic
is redirected may be under a denial of service attack, whereas is redirected may be under a denial of service attack, whereas
other nodes do not receive their traffic. Accordingly, other nodes do not receive their traffic. Accordingly,
security mechanisms/protocols providing access control, security mechanisms/protocols providing access control,
integrity, authentication, authorization, confidentiality, integrity, authentication, authorization, confidentiality,
etc. should be used to protect the DMM entities as they are etc. should be used to protect the DMM entities as they are
already used to protect against existing networks and existing already used to protect against existing networks and existing
mobility protocols defined in IETF. Yet if a candidate DMM mobility protocols defined in IETF. Yet if a candidate DMM
solution is such that even the proper use of these existing solution is such that even the proper use of these existing
security mechanisms/protocols are unable to provide sufficient security mechanisms/protocols are unable to provide sufficient
security protection, that candidate DMM solution is causing security protection, that candidate DMM solution is causing
uncontrollable security problems. uncontrollable security problems.
This requirement prevents a DMM solution from introducing This requirement prevents a DMM solution from introducing
uncontrollable problems of potentially insecure mobility management uncontrollable problems of potentially insecure mobility
protocols which make deployment infeasible because platforms management protocols which make deployment infeasible because
conforming to the protocols are at risk for data loss and numerous platforms conforming to the protocols are at risk for data
other dangers, including financial harm to the users. loss and numerous other dangers, including financial harm to
the users.
REQ7: Multicast considerations REQ7: Multicast considerations
DMM SHOULD enable multicast solutions to be developed to avoid DMM SHOULD enable multicast solutions to be developed to avoid
network inefficiency in multicast traffic delivery. network inefficiency in multicast traffic delivery.
Motivation: Existing multicast deployment have been introduced Motivation: Existing multicast deployment have been introduced
after completing the design of the reference mobility after completing the design of the reference mobility
protocol, often leading to network inefficiency and non- protocol, often leading to network inefficiency and non-
optimal routing for the multicast traffic. Instead DMM should optimal forwarding for the multicast traffic. Instead DMM
consider multicast early so that the multicast solutions can should consider multicast early so that the multicast
better consider efficiency nature in the multicast traffic solutions can better consider efficiency nature in the
delivery (such as duplicate multicast subscriptions towards multicast traffic delivery (such as duplicate multicast
the downstream tunnel entities). The multicast solutions subscriptions towards the downstream tunnel entities). The
should then avoid restricting the management of all IP multicast solutions should then avoid restricting the
multicast traffic to a single host through a dedicated management of all IP multicast traffic to a single host
(tunnel) interface on multicast-capable access routers. through a dedicated (tunnel) interface on multicast-capable
access routers.
This requirement addresses the problems PS1 and PS8 described in This requirement addresses the problems PS1 and PS8 described
Section 4. in Section 4.
REQ8: OAM considerations
DMM SHOULD support operations, administration and management
(OAM) solutions to reduce OAM complexity and operational
expenditure.
Motivation: A DMM solution that takes OAM into considerations
from the beginning of its design can avoid difficulty or
incompatibility to implement efficient OAM solutions.
This requirement avoids DMM designs that make OAM difficult or
costly.
6. Security Considerations 6. Security Considerations
Please refer to the discussion under Security requirement in Section Please refer to the discussion under Security requirement in Section
5. 5.
7. IANA Considerations 7. IANA Considerations
None None
8. Contributors 8. Contributors
This requirements document is a joint effort among numerous This requirements document is a joint effort among numerous
participants working in a team. In addition to the authors, each of participants working in a team. Valuable comments and suggestions in
the following has made very significant and important contributions various reviews from the following area directors and IESG members
to this work: have also contributed to much improvements: Russ Housley, Catherine
Meadows, Adrian Farrel, Barry Leiba, Alissa Cooper, Ted Lemon, Brian
Haberman, Stephen Farrell, Joel Jaeggli, Alia Atlas, and Benoit
Claise. In addition to the authors, each of the following has made
very significant and important contributions to the working group
draft in this work:
Charles E. Perkins Charles E. Perkins
Huawei Technologies Huawei Technologies
Email: charliep@computer.org Email: charliep@computer.org
Melia Telemaco Melia Telemaco
Alcatel-Lucent Bell Labs Alcatel-Lucent Bell Labs
Email: telemaco.melia@googlemail.com Email: telemaco.melia@googlemail.com
Elena Demaria Elena Demaria
skipping to change at page 17, line 4 skipping to change at page 17, line 44
Hassan Ali-Ahmad Hassan Ali-Ahmad
Orange Orange
Email: hassan.aliahmad@orange.com Email: hassan.aliahmad@orange.com
Alper Yegin Alper Yegin
Samsung Samsung
Email: alper.yegin@partner.samsung.com Email: alper.yegin@partner.samsung.com
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
9.2. Informative References 9.2. Informative References
[I-D.bhandari-dhc-class-based-prefix] [I-D.bhandari-dhc-class-based-prefix]
Bhandari, S., Halwasia, G., Gundavelli, S., Deng, H., Bhandari, S., Halwasia, G., Gundavelli, S., Deng, H.,
Thiebaut, L., Korhonen, J., and I. Farrer, "DHCPv6 class Thiebaut, L., Korhonen, J., and I. Farrer, "DHCPv6 class
based prefix", draft-bhandari-dhc-class-based-prefix-05 based prefix", draft-bhandari-dhc-class-based-prefix-05
(work in progress), July 2013. (work in progress), July 2013.
[I-D.korhonen-6man-prefix-properties] [I-D.korhonen-6man-prefix-properties]
Korhonen, J., Patil, B., Gundavelli, S., Seite, P., and D. Korhonen, J., Patil, B., Gundavelli, S., Seite, P., and D.
Liu, "IPv6 Prefix Properties", Liu, "IPv6 Prefix Properties",
draft-korhonen-6man-prefix-properties-02 (work in draft-korhonen-6man-prefix-properties-02 (work in
progress), July 2013. progress), July 2013.
[I-D.wakikawa-netext-pmip-cp-up-separation] [I-D.wakikawa-netext-pmip-cp-up-separation]
Wakikawa, R., Pazhyannur, R., and S. Gundavelli, Wakikawa, R., Pazhyannur, R., and S. Gundavelli,
"Separation of Control and User Plane for Proxy Mobile "Separation of Control and User Plane for Proxy Mobile
IPv6", draft-wakikawa-netext-pmip-cp-up-separation-00 IPv6", draft-wakikawa-netext-pmip-cp-up-separation-00
(work in progress), July 2013. (work in progress), February 2014.
[I-D.yokota-dmm-scenario] [I-D.yokota-dmm-scenario]
Yokota, H., Seite, P., Demaria, E., and Z. Cao, "Use case Yokota, H., Seite, P., Demaria, E., and Z. Cao, "Use case
scenarios for Distributed Mobility Management", scenarios for Distributed Mobility Management",
draft-yokota-dmm-scenario-00 (work in progress), draft-yokota-dmm-scenario-00 (work in progress),
October 2010. October 2010.
[Paper-Distributed.Centralized.Mobility] [Paper-Distributed.Centralized.Mobility]
Bertin, P., Bonjour, S., and J-M. Bonnin, "A Distributed Bertin, P., Bonjour, S., and J-M. Bonnin, "A Distributed
or Centralized Mobility", Proceedings of Global or Centralized Mobility", Proceedings of Global
skipping to change at page 18, line 38 skipping to change at page 19, line 41
Wakikawa, R., Valadon, G., and J. Murai, "Migrating Home Wakikawa, R., Valadon, G., and J. Murai, "Migrating Home
Agents Towards Internet-scale Mobility Deployments", Agents Towards Internet-scale Mobility Deployments",
Proceedings of the ACM 2nd CoNEXT Conference on Future Proceedings of the ACM 2nd CoNEXT Conference on Future
Networking Technologies, December 2006. Networking Technologies, December 2006.
[Paper-Mobile.Data.Offloading] [Paper-Mobile.Data.Offloading]
Lee, K., Lee, J., Yi, Y., Rhee, I., and S. Chong, "Mobile Lee, K., Lee, J., Yi, Y., Rhee, I., and S. Chong, "Mobile
Data Offloading: How Much Can WiFi Deliver?", SIGCOMM Data Offloading: How Much Can WiFi Deliver?", SIGCOMM
2010, 2010. 2010, 2010.
[RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5380] Soliman, H., Castelluccia, C., ElMalki, K., and L. [RFC5380] Soliman, H., Castelluccia, C., ElMalki, K., and L.
Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility
Management", RFC 5380, October 2008. Management", RFC 5380, October 2008.
[RFC5944] Perkins, C., "IP Mobility Support for IPv4, Revised", [RFC5944] Perkins, C., "IP Mobility Support for IPv4, Revised",
RFC 5944, November 2010. RFC 5944, November 2010.
[RFC6224] Schmidt, T., Waehlisch, M., and S. Krishnan, "Base [RFC6224] Schmidt, T., Waehlisch, M., and S. Krishnan, "Base
Deployment for Multicast Listener Support in Proxy Mobile Deployment for Multicast Listener Support in Proxy Mobile
IPv6 (PMIPv6) Domains", RFC 6224, April 2011. IPv6 (PMIPv6) Domains", RFC 6224, April 2011.
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
[RFC6301] Zhu, Z., Wakikawa, R., and L. Zhang, "A Survey of Mobility [RFC6301] Zhu, Z., Wakikawa, R., and L. Zhang, "A Survey of Mobility
Support in the Internet", RFC 6301, July 2011. Support in the Internet", RFC 6301, July 2011.
[RFC6705] Krishnan, S., Koodli, R., Loureiro, P., Wu, Q., and A. [RFC6705] Krishnan, S., Koodli, R., Loureiro, P., Wu, Q., and A.
Dutta, "Localized Routing for Proxy Mobile IPv6", Dutta, "Localized Routing for Proxy Mobile IPv6",
RFC 6705, September 2012. RFC 6705, September 2012.
[RFC6909] Gundavelli, S., Zhou, X., Korhonen, J., Feige, G., and R. [RFC6909] Gundavelli, S., Zhou, X., Korhonen, J., Feige, G., and R.
Koodli, "IPv4 Traffic Offload Selector Option for Proxy Koodli, "IPv4 Traffic Offload Selector Option for Proxy
Mobile IPv6", RFC 6909, April 2013. Mobile IPv6", RFC 6909, April 2013.
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