RFC7333

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Internet Engineering Task Force (IETF) H. Chan, Ed. Request for Comments: 7333 Huawei Technologies Category: Informational D. Liu ISSN: 2070-1721 China Mobile

                                                            P. Seite
                                                              Orange
                                                           H. Yokota
                                                          Landis+Gyr
                                                         J. Korhonen
                                             Broadcom Communications
                                                         August 2014
        Requirements for Distributed Mobility Management

Abstract

This document defines the requirements for Distributed Mobility Management (DMM) at the network layer. The hierarchical structure in traditional wireless networks has led primarily to centrally deployed mobility anchors. As some wireless networks are evolving away from the hierarchical structure, it can be useful to have a distributed model for mobility management in which traffic does not need to traverse centrally deployed mobility anchors far from the optimal route. The motivation and the problems addressed by each requirement are also described.

Status of This Memo

This document is not an Internet Standards Track specification; it is published for informational purposes.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7333.

Copyright Notice

Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

Introduction

In the past decade, a fair number of network-layer mobility protocols have been standardized RFC6275 RFC5944 RFC5380 RFC6301 RFC5213. Although these protocols differ in terms of functions and associated message formats, they all employ a mobility anchor to allow a mobile node to remain reachable after it has moved to a different network. Among other tasks that the anchor point performs, the anchor point ensures connectivity by forwarding packets destined to, or sent from, the mobile node. It is a centrally deployed mobility anchor in the sense that the deployed architectures today have a small number of these anchors and the traffic of millions of mobile nodes in an operator network is 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- mentioned centralized deployment. The background behind the interest in studying DMM is primarily as follows.

(1) More than ever, mobile users are consuming Internet content,

    including that of local Content Delivery Networks (CDNs).  Such
    traffic imposes new requirements on mobile core networks for
    data traffic delivery.  To prevent exceeding the available core
    network capacity, service providers need to implement new
    strategies such as selective IPv4 traffic offload (e.g.,
    RFC6909, 3GPP Local IP Access (LIPA) and Selected IP Traffic
    Offload (SIPTO) work items [TS.23.401]) through alternative
    access networks such as Wireless Local Area Networks (WLANs)
    [MOB-DATA-OFFLOAD].  In addition, a gateway selection mechanism
    takes user proximity into account within the Evolved Packet Core
    (EPC) [TS.29.303].  However, these mechanisms were not pursued
    in the past, owing to charging and billing considerations that
    require solutions beyond the mobility protocol.  Consequently,
    assigning a gateway anchor node from a visited network when
    roaming to the visited network has only recently been done and
    is limited to voice services.
    Both traffic offloading and CDN mechanisms could benefit from
    the development of mobile architectures with fewer hierarchical
    levels introduced into the data path by the mobility management
    system.  This trend of "flattening" the mobile networks works
    best for direct communications among peers in the same
    geographical area.  Distributed mobility management in the
    flattening mobile networks would anchor the traffic closer to
    the point of attachment of the user.

(2) Today's mobile networks present service providers with new

    challenges.  Mobility patterns indicate that mobile nodes often
    remain attached to the same point of attachment for considerable
    periods of time [LOCATING-USER].  Specific IP mobility
    management support is not required for applications that launch
    and complete their sessions while the mobile node is connected
    to the same point of attachment.  However, IP mobility support
    is currently designed for always-on operation, maintaining all
    parameters of the context for each mobile subscriber for as long
    as they are connected to the network.  This can result in a
    waste of resources and unnecessary costs for the service
    provider.  Infrequent node mobility coupled with application
    intelligence suggest that mobility support could be provided
    selectively, e.g., as described in [DHCPv6-CLASS-BASED-PREFIX]
    and [IPv6-PREFIX-PROPERTIES], thus reducing the amount of
    context maintained in the network.

DMM may distribute the mobility anchors in the data plane in flattening the mobility network such that the mobility anchors are positioned closer to the user; ideally, mobility agents could be collocated with the first-hop router. Facilitated by the distribution of mobility anchors, it may be possible to selectively use or not use mobility protocol support, depending on whether such support is needed or not. DMM can thus reduce the amount of state information that must be maintained in various mobility agents of the mobile network and can then avoid the unnecessary establishment of mechanisms to forward traffic from an old mobility anchor to a new mobility anchor.

This document compares distributed mobility management with centralized mobility management in Section 3. The problems that can be addressed with DMM are summarized in Section 4. The mandatory requirements as well as the optional requirements for network-layer distributed mobility management are given in Section 5. Security considerations are mentioned in Section 6.

The problem statement and use cases [DMM-SCENARIO] can be found in [DIST-MOB-REVIEW].

Conventions Used in This Document

Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 RFC2119.

Terminology

All of the general mobility-related terms, and their acronyms as used in this document, are to be interpreted as defined in the Mobile IPv6 base specification RFC6275, the Proxy Mobile IPv6 (PMIPv6) specification RFC5213, and "Mobility Related Terminology" RFC3753. These terms include the following: mobile node (MN), correspondent node (CN), and home agent (HA) as per RFC6275; local mobility anchor (LMA) and mobile access gateway (MAG) as per RFC5213; and context as per RFC3753.

In addition, this document introduces the following terms:

Centrally deployed mobility anchors

  refers to the mobility management deployments in which there are
  very few mobility anchors and the traffic of millions of mobile
  nodes in an operator network is managed by the same anchor.

Centralized mobility management

  makes use of centrally deployed mobility anchors.

Distributed mobility management

  is not centralized, so that traffic does not need to traverse
  centrally deployed mobility anchors far from the optimal route.

Hierarchical mobile network

  has a hierarchy of network elements arranged into multiple
  hierarchical levels that are introduced into the data path by the
  mobility management system.

Flattening mobile network

  refers to the hierarchical mobile network that 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

  is the collection of information required to provide mobility
  management support for a given mobile node.

Centralized versus Distributed Mobility Management

Mobility management is needed because the IP address of a mobile node may change as the node moves. Mobility management functions may be implemented at different layers of the protocol stack. At the IP (network) layer, mobility management can be client-based or network-based.

An IP-layer mobility management protocol is typically based on the principle of distinguishing between a session identifier and a forwarding address and maintaining a mapping between the two. In Mobile IP, the new IP address of the mobile node after the node has moved is the forwarding address, whereas the original IP address before the mobile node moves serves as the session identifier. The location management (LM) information is kept by associating the forwarding address with the session identifier. Packets addressed to the session identifier will first route to the original network, which redirects them using the forwarding address to deliver to the session. Redirecting packets this way can result in long routes. An existing optimization routes directly, using the forwarding address of the host, and as such is a host-based solution.

The next two subsections explain centralized and distributed mobility management functions in the network.

Centralized Mobility Management

In centralized mobility management, the location information in terms of a mapping between the session identifier and the forwarding address is kept at a single mobility anchor, and packets destined to the session identifier are forwarded via this anchor. In other words, such mobility management systems are centralized in both the control plane and the data plane (mobile node IP traffic).

Many existing mobility management deployments make use of centralized mobility anchoring in a hierarchical network architecture, as shown in Figure 1. Examples are the home agent (HA) and local mobility anchor (LMA) serving as the anchors for the mobile node (MN) and mobile access gateway (MAG) in Mobile IPv6 RFC6275 and in Proxy Mobile IPv6 RFC5213, respectively. Cellular networks, such as 3GPP General Packet Radio System (GPRS) networks and 3GPP Evolved Packet System (EPS) networks, also employ centralized mobility management. In the 3GPP GPRS network, the Gateway GPRS Support Node (GGSN), Serving GPRS Support Node (SGSN), and Radio Network Controller (RNC) constitute a hierarchy of anchors. In the 3GPP EPS network, the Packet Data Network Gateway (P-GW) and Serving Gateway (S-GW) constitute another hierarchy of anchors.

    3GPP GPRS                3GPP EPS                MIP/PMIP
     +------+                +------+                +------+
     | GGSN |                | P-GW |                |HA/LMA|
     +------+                +------+                +------+
        /\                      /\                      /\
       /  \                    /  \                    /  \
      /    \                  /    \                  /    \
     /      \                /      \                /      \
    /        \              /        \              /        \
   /          \            /          \            /          \
  /            \          /            \          /            \
 +------+      +------+  +------+      +------+  +------+      +------+
 | SGSN |      | SGSN |  | S-GW |      | S-GW |  |MN/MAG|      |MN/MAG|
 +------+      +------+  +------+      +------+  +------+      +------+
 /\            /\
/  \          /  \

/ \ / \ +---+ +---+ +---+ +---+ |RNC| |RNC| |RNC| |RNC| +---+ +---+ +---+ +---+

             Figure 1: Centralized Mobility Management

Distributed Mobility Management

Mobility management functions may also be distributed in the data plane to multiple networks as shown in Figure 2, so that a mobile node in any of these networks may be served by a nearby function with appropriate forwarding management (FM) capability.

               +------+  +------+  +------+  +------+
               |  FM  |  |  FM  |  |  FM  |  |  FM  |
               +------+  +------+  +------+  +------+
                                      |
                                    +----+
                                    | MN |
                                    +----+
             Figure 2: Distributed Mobility Management

DMM is distributed in the data plane, whereas the control plane may be either centralized or distributed [DMM-SCENARIO]. The former case implicitly assumes separation of data and control planes as described in [PMIP-CP-UP-SPLIT]. While mobility management can be distributed, it is not necessary for other functions such as subscription management, subscription databases, and network access authentication to be similarly distributed.

A distributed mobility management scheme for a flattening mobile network consisting of access nodes is proposed in [DIST-DYNAMIC-MOB]. Its benefits over centralized mobility management have been shown through simulations [DIST-CENTRAL-MOB]. Moreover, the (re)use and extension of existing protocols in the design of both fully distributed mobility management [MIGRATING-HAs] [DIST-MOB-SAE] and partially distributed mobility management [DIST-MOB-PMIP] [DIST-MOB-MIP] have been reported in the literature. Therefore, before designing new mobility management protocols for a future distributed architecture, it is recommended to first consider whether existing mobility management protocols can be extended.

Problem Statement

The problems that can be addressed with DMM are summarized as follows:

PS1: Non-optimal routes

     Forwarding via a centralized anchor often results in
     non-optimal routes, thereby increasing the end-to-end delay.
     The problem is manifested, for example, when accessing a nearby
     server or servers of a Content Delivery Network (CDN), or when
     receiving locally available IP multicast packets or sending IP
     multicast packets.  (Existing route optimization is only a
     host-based solution.  On the other hand, localized routing with
     PMIPv6 RFC6705 addresses only a part of the problem where
     both the MN and the correspondent node (CN) are attached to the
     same MAG, and it is not applicable when the CN does not behave
     like an MN.)

PS2: Divergence from other evolutionary trends in network

     architectures such as distribution of content delivery
     Mobile networks have generally been evolving towards a flatter
     and flatter network.  Centralized mobility management, which is
     non-optimal with a flatter network architecture, does not
     support this evolution.

PS3: Lack of scalability of centralized tunnel management and

     mobility context maintenance
     Setting up tunnels through a central anchor and maintaining
     mobility context for each MN usually requires more concentrated
     resources in a centralized design, thus reducing scalability.
     Distributing the tunnel maintenance function and the mobility
     context maintenance function among different network entities
     with proper signaling protocol design can avoid increasing the
     concentrated resources with an increasing number of MNs.

PS4: Single point of failure and attack

     Centralized anchoring designs may be more vulnerable to a
     single point of failure and attacks than a distributed system.
     The impact of a successful attack on a system with centralized
     mobility management can be far greater as well.

PS5: Unnecessary mobility support to clients that do not need it

     IP mobility support is usually provided to all MNs.  However,
     it is not always required, and not every parameter of mobility
     context is always used.  For example, some applications or
     nodes do not need a stable IP address during a handover to
     maintain session continuity.  Sometimes, the entire application
     session runs while the MN does not change the point of
     attachment.  Besides, some sessions, e.g., SIP-based sessions,
     can handle mobility at the application layer and hence do not
     need IP mobility support; it is then unnecessary to provide IP
     mobility support for such sessions.

PS6: Mobility signaling overhead with peer-to-peer communication

     Resources may be wasted when mobility signaling (e.g.,
     maintenance of the tunnel, keep-alive signaling, etc.) is not
     turned off for peer-to-peer communication.

PS7: Deployment with multiple mobility solutions

     There are already many variants and extensions of MIP as well
     as mobility solutions at other layers.  Deployment of new
     mobility management solutions can be challenging, and debugging
     difficult, when they coexist with solutions already deployed in
     the field.

PS8: Duplicate multicast traffic

     IP multicast distribution over architectures using IP mobility
     solutions (e.g., RFC6224) may lead to convergence of
     duplicated multicast subscriptions towards the downstream
     tunnel entity (e.g., MAG in PMIPv6).  Concretely, when
     multicast subscription for individual mobile nodes is coupled
     with mobility tunnels (e.g., a PMIPv6 tunnel), duplicate
     multicast subscription(s) is prone to be received through
     different upstream paths.  This problem may also exist or be
     more severe in a distributed mobility environment.

Requirements

Now that distributed mobility management has been compared with centralized deployment (Section 3) and the problems have been described (Section 4), this section identifies the following requirements:

REQ1: Distributed mobility management

      IP mobility, network access solutions, and forwarding
      solutions provided by DMM MUST enable traffic to avoid
      traversing a single mobility anchor far from the optimal
      route.
      This requirement on distribution applies to 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 implied that the control plane and data
      plane need to separate (Section 3.2).
      Motivation: This requirement is motivated by current trends in
      network evolution: (a) it is cost- and resource-effective to
      cache contents, and the caching (e.g., CDN) servers are
      distributed so that each user in any location can be close to
      one of the servers; (b) the significantly larger number of
      mobile nodes and flows call for improved scalability; (c)
      single points of failure are avoided in a distributed system;
      and (d) threats against centrally deployed anchors, e.g., a
      home agent and a local mobility anchor, are mitigated in a
      distributed system.
      This requirement addresses the problems PS1, PS2, PS3, and PS4
      described in Section 4.

REQ2: Bypassable network-layer mobility support for each application

      session
      DMM solutions MUST enable network-layer mobility, but it MUST
      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
      cope with a change in the IP address.  Mobility support is
      also needed when a mobile router changes its IP address as it
      moves together with a host and, in the presence of ingress
      filtering, an application in the host is interrupted.
      However, mobility support at the network layer is not always
      needed; a mobile node can often be stationary, and mobility
      support can also be provided at other layers.  It is then not
      always 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
      solutions, and forwarding solutions provided by DMM MUST then
      provide 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
      more efficient forwarding and more efficient use of network
      resources by selecting an IP address or prefix according to
      whether mobility support is needed and by not maintaining
      context at the mobility anchor when there is no such need.
      This requirement addresses the problems PS5 and PS6 described
      in Section 4.

REQ3: IPv6 deployment

      DMM solutions SHOULD target IPv6 as the primary deployment
      environment and SHOULD NOT be tailored specifically to support
      IPv4, particularly in situations where private IPv4 addresses
      and/or NATs are used.
      Motivation: This requirement conforms to the general
      orientation of IETF work.  DMM deployment is foreseen as "on
      the mid- to long-term horizon", when IPv6 is expected to be
      far more common than today.
      This requirement avoids the unnecessarily complex solution of
      trying to provide the same level of functionality to both IPv4
      and IPv6.  Some of the IPv6-specific features are not
      available for IPv4.

REQ4: Existing mobility protocols

      A DMM solution MUST first consider reusing and extending IETF
      standard protocols before specifying new protocols.
      Motivation: Reuse of existing IETF work is more efficient and
      less error-prone.
      This requirement attempts to avoid the need for development of
      new protocols and therefore their potential for being time-
      consuming and error-prone.

REQ5: Coexistence with deployed networks/hosts and operability

      across different networks
      A DMM solution may require loose, tight, or no integration
      into existing mobility protocols and host IP stacks.
      Regardless of the integration level, DMM implementations MUST
      be able to coexist with existing network deployments, end
      hosts, and routers that may or may not implement existing
      mobility protocols.  Furthermore, a DMM solution SHOULD work
      across different networks, possibly operated as separate
      administrative domains, when the needed mobility management
      signaling, forwarding, and network access are allowed by the
      trust relationship between them.
      Motivation: to (a) preserve backwards compatibility so that
      existing networks and hosts are not affected and continue to
      function as usual, and (b) enable inter-domain operation if
      desired.
      This requirement addresses the problem PS7 described in
      Section 4.

REQ6: Operation and management considerations

      A DMM solution needs to consider configuring a device,
      monitoring the current operational state of a device, and
      responding to events that impact the device, possibly by
      modifying the configuration and storing the data in a format
      that can be analyzed later.  Different management protocols
      are available.  For example:
      (a)  the Simple Network Management Protocol (SNMP) RFC1157,
           with definitions of standardized management information
           base (MIB) objects for DMM that allow the monitoring of
           traffic steering in a consistent manner across different
           devices
      (b)  the Network Configuration Protocol (NETCONF) RFC6241,
           with definitions of standardized YANG RFC6020 modules
           for DMM to achieve a standardized configuration
      (c)  syslog RFC5424, which is a one-way protocol allowing a
           device to report significant events to a log analyzer in
           a network management system
      (d)  the IP Flow Information Export (IPFIX) Protocol, which
           serves as a means for transmitting traffic flow
           information over the network RFC7011, with a formal
           description of IPFIX Information Elements RFC7012
      It is not the goal of this requirements document to impose
      which management protocol(s) should be used.  An inventory of
      the management protocols and data models is covered in
      RFC6632.
      The following paragraphs list the operation and management
      considerations required for a DMM solution; this list of
      considerations may not be exhaustive and may be expanded
      according to the needs of the solutions:
      A DMM solution MUST describe how, and in what types of
      environments, it can be scalably deployed and managed.
      A DMM solution MUST support mechanisms to test whether the DMM
      solution is working properly.  For example, when a DMM
      solution employs traffic indirection to support a mobility
      session, implementations MUST support mechanisms to test that
      the appropriate traffic indirection operations are in place,
      including the setup of traffic indirection and the subsequent
      teardown of the indirection to release the associated network
      resources when the mobility session has closed.
      A DMM solution SHOULD expose the operational state of DMM to
      the administrators of the DMM entities.  For example, when a
      DMM solution employs separation between a session identifier
      and forwarding address, it should expose the association
      between them.
      When flow mobility is supported by a DMM solution, the
      solution SHOULD support means to correlate the flow routing
      policies and the observed forwarding actions.
      A DMM solution SHOULD support mechanisms to check the liveness
      of a forwarding path.  If the DMM solution sends periodic
      update refresh messages to configure the forwarding path, the
      refresh period SHOULD be configurable and a reasonable default
      configuration value proposed.  Information collected can be
      logged or made available with protocols such as SNMP
      RFC1157, NETCONF RFC6241, IPFIX RFC7011, or syslog
      RFC5424.
      A DMM solution MUST provide fault management and monitoring
      mechanisms to manage situations where an update of the
      mobility session or the data path fails.  The system must also
      be able to handle situations where a mobility anchor with
      ongoing mobility sessions fails.
      A DMM solution SHOULD be able to monitor usage of the DMM
      protocol.  When a DMM solution uses an existing protocol, the
      techniques already defined for that protocol SHOULD be used to
      monitor the DMM operation.  When these techniques are
      inadequate, new techniques MUST be developed.
      In particular, the DMM solution SHOULD
      (a)  be able to monitor the number of mobility sessions per
           user, as well as their average duration
      (b)  provide an indication of DMM performance, such as
           (1)  handover delay, which includes the time necessary to
                reestablish the forwarding path when the point of
                attachment changes
           (2)  protocol reactivity, which is the time between
                handover events such as the attachment to a new
                access point and the completion of the mobility
                session update
      (c)  provide means to measure the signaling cost of the DMM
           protocol
      (d)  if tunneling is used for traffic redirection, monitor
           (1)  the number of tunnels
           (2)  their transmission and reception information
           (3)  the encapsulation method used, and its overhead
           (4)  the security used at the node level
      DMM solutions SHOULD support standardized configuration with
      NETCONF RFC6241, using YANG RFC6020 modules, which SHOULD
      be created for DMM when needed for such configuration.
      However, if a DMM solution creates extensions to MIPv6 or
      PMIPv6, the allowed addition of definitions of management
      information base (MIB) objects to the MIPv6 MIB RFC4295 or
      the PMIPv6 MIB RFC6475 that are needed for the control and
      monitoring of the protocol extensions SHOULD be limited to
      read-only objects.
      Motivation: A DMM solution that is designed from the beginning
      for operability and manageability can implement efficient
      operations and management solutions.
      These requirements avoid DMM designs that make operations and
      management difficult or costly.

REQ7: Security considerations

      A DMM solution MUST support any security protocols and
      mechanisms needed to secure the network and to make continuous
      security improvements.  In addition, with security taken into
      consideration early in the design, a DMM solution 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
      service, man-in-the-middle attacks, and so on may be launched
      in a DMM deployment.  For instance, an illegitimate node may
      attempt to access a network providing DMM.  Another example is
      that a malicious node can forge a number of signaling
      messages, thus redirecting traffic from its legitimate path.
      Consequently, the specific node or nodes to which the traffic
      is redirected may be under a denial-of-service attack and
      other nodes do not receive their traffic.  Accordingly,
      security mechanisms/protocols providing access control,
      integrity, authentication, authorization, confidentiality,
      etc. should be used to protect the DMM entities as they are
      already used to protect existing networks and existing
      mobility protocols defined in the IETF.  However, if a
      candidate DMM solution is such that these existing security
      mechanisms/protocols are unable to provide sufficient security
      protection even when properly used, then that candidate DMM
      solution is causing uncontrollable security problems.
      This requirement prevents a DMM solution from introducing
      uncontrollable problems of potentially insecure mobility
      management protocols that make deployment infeasible, because
      platforms conforming to such protocols are at risk for data
      loss and numerous other dangers, including financial harm to
      the users.

REQ8: Multicast considerations

      DMM SHOULD enable multicast solutions to be developed to avoid
      network inefficiency in multicast traffic delivery.
      Motivation: Existing multicast deployments have been
      introduced after completing the design of the reference
      mobility protocol, often leading to network inefficiency and
      non-optimal forwarding for the multicast traffic.  DMM should
      instead consider multicast early in the process, so that the
      multicast solutions can better consider the efficient nature
      of multicast traffic delivery (such as duplicate multicast
      subscriptions towards the downstream tunnel entities).  The
      multicast solutions should then avoid restricting the
      management of all IP multicast traffic to a single host
      through a dedicated (tunnel) interface on multicast-capable
      access routers.
      This requirement addresses the problems PS1 and PS8 described
      in Section 4.

Security Considerations

Please refer to REQ7 in Section 5.

Contributors

This requirements document is a joint effort among numerous participants working as a team. Valuable comments and suggestions in various reviews from the following area directors and IESG members have also contributed to many 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 this work:

 Charles E. Perkins
 Huawei Technologies
 EMail: [email protected]
 Melia Telemaco
 Alcatel-Lucent Bell Labs
 EMail: [email protected]
 Elena Demaria
 Telecom Italia
 via G. Reiss Romoli, 274, Torino, 10148, Italy
 EMail: [email protected]
 Jong-Hyouk Lee
 Sangmyung University, Korea
 EMail: [email protected]
 Kostas Pentikousis
 EICT GmbH
 EMail: [email protected]
 Tricci So
 ZTE
 EMail: [email protected]
 Carlos J. Bernardos
 Universidad Carlos III de Madrid
 Av. Universidad, 30, Leganes, Madrid 28911, Spain
 EMail: [email protected]
 Peter McCann
 Huawei Technologies
 EMail: [email protected]
 Seok Joo Koh
 Kyungpook National University, Korea
 EMail: [email protected]
 Wen Luo
 ZTE
 No. 68, Zijinhua Rd, Yuhuatai District, Nanjing, Jiangsu 210012, China
 EMail: [email protected]
 Sri Gundavelli
 Cisco
 [email protected]
 Hui Deng
 China Mobile
 EMail: [email protected]
 Marco Liebsch
 NEC Laboratories Europe
 EMail: [email protected]
 Carl Williams
 MCSR Labs
 EMail: [email protected]
 Seil Jeon
 Instituto de Telecomunicacoes, Aveiro
 EMail: [email protected]
 Sergio Figueiredo
 Universidade de Aveiro
 EMail: [email protected]
 Stig Venaas
 EMail: [email protected]
 Luis Miguel Contreras Murillo
 Telefonica I+D
 EMail: [email protected]
 Juan Carlos Zuniga
 InterDigital
 EMail: [email protected]
 Alexandru Petrescu
 EMail: [email protected]
 Georgios Karagiannis
 University of Twente
 EMail: [email protected]
 Julien Laganier
 Juniper
 EMail: [email protected]
 Wassim Michel Haddad
 Ericsson
 EMail: [email protected]
 Dirk von Hugo
 Deutsche Telekom Laboratories
 EMail: [email protected]
 Ahmad Muhanna
 Award Solutions
 EMail: [email protected]
 Byoung-Jo Kim
 ATT Labs
 EMail: [email protected]
 Hassan Ali-Ahmad
 Orange
 EMail: [email protected]
 Alper Yegin
 Samsung
 EMail: [email protected]
 David Harrington
 Effective Software
 EMail: [email protected]

References

Normative References

RFC1157 Case, J., Fedor, M., Schoffstall, M., and J. Davin,

          "Simple Network Management Protocol (SNMP)", STD 15,
          RFC 1157, May 1990.

RFC2119 Bradner, S., "Key words for use in RFCs to Indicate

          Requirement Levels", BCP 14, RFC 2119, March 1997.

RFC3753 Manner, J. and M. Kojo, "Mobility Related Terminology",

          RFC 3753, June 2004.

RFC4295 Keeni, G., Koide, K., Nagami, K., and S. Gundavelli,

          "Mobile IPv6 Management Information Base", RFC 4295,
          April 2006.

RFC5213 Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,

          and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.

RFC5424 Gerhards, R., "The Syslog Protocol", RFC 5424, March 2009.

RFC6020 Bjorklund, M., "YANG - A Data Modeling Language for the

          Network Configuration Protocol (NETCONF)", RFC 6020,
          October 2010.

RFC6241 Enns, R., Bjorklund, M., Schoenwaelder, J., and A.

          Bierman, "Network Configuration Protocol (NETCONF)",
          RFC 6241, June 2011.

RFC6275 Perkins, C., Johnson, D., and J. Arkko, "Mobility Support

          in IPv6", RFC 6275, July 2011.

RFC6475 Keeni, G., Koide, K., Gundavelli, S., and R. Wakikawa,

          "Proxy Mobile IPv6 Management Information Base", RFC 6475,
          May 2012.

RFC6632 Ersue, M. and B. Claise, "An Overview of the IETF Network

          Management Standards", RFC 6632, June 2012.

RFC7011 Claise, B., Trammell, B., and P. Aitken, "Specification of

          the IP Flow Information Export (IPFIX) Protocol for the
          Exchange of Flow Information", STD 77, RFC 7011,
          September 2013.

RFC7012 Claise, B. and B. Trammell, "Information Model for IP Flow

          Information Export (IPFIX)", RFC 7012, September 2013.

Informative References

[DHCPv6-CLASS-BASED-PREFIX]

          Bhandari, S., Halwasia, G., Gundavelli, S., Deng, H.,
          Thiebaut, L., Korhonen, J., and I. Farrer, "DHCPv6 class
          based prefix", Work in Progress, July 2013.

[DIST-CENTRAL-MOB]

          Bertin, P., Bonjour, S., and J-M. Bonnin, "Distributed or
          Centralized Mobility?", Proceedings of the 28th IEEE
          Conference on Global Telecommunications (GlobeCom),
          December 2009.

[DIST-DYNAMIC-MOB]

          Bertin, P., Bonjour, S., and J-M. Bonnin, "A Distributed
          Dynamic Mobility Management Scheme Designed for Flat IP
          Architectures", Proceedings of 3rd International
          Conference on New Technologies, Mobility and Security
          (NTMS), 2008.

[DIST-MOB-MIP]

          Chan, H., "Distributed Mobility Management with Mobile
          IP", Proceedings of IEEE International Communication
          Conference (ICC) Workshop on Telecommunications: from
          Research to Standards, June 2012.

[DIST-MOB-PMIP]

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

[DIST-MOB-REVIEW]

          Chan, H., Yokota, H., Xie, J., Seite, P., and D. Liu,
          "Distributed and Dynamic Mobility Management in Mobile
          Internet: Current Approaches and Issues", Journal of
          Communications, vol. 6, no. 1, pp. 4-15, February 2011.

[DIST-MOB-SAE]

          Fischer, M., Andersen, F., Kopsel, A., Schafer, G., and M.
          Schlager, "A Distributed IP Mobility Approach for 3G SAE",
          Proceedings of the 19th International Symposium on
          Personal, Indoor and Mobile Radio Communications (PIMRC),
          2008.

[DMM-SCENARIO]

          Yokota, H., Seite, P., Demaria, E., and Z. Cao, "Use case
          scenarios for Distributed Mobility Management", Work in
          Progress, October 2010.

[IPv6-PREFIX-PROPERTIES]

          Korhonen, J., Patil, B., Gundavelli, S., Seite, P., and
          D. Liu, "IPv6 Prefix Properties", Work in Progress,
          July 2013.

[LOCATING-USER]

          Kirby, G., "Locating the User", Communications
          International, 1995.

[MIGRATING-HAs]

          Wakikawa, R., Valadon, G., and J. Murai, "Migrating Home
          Agents Towards Internet-scale Mobility Deployments",
          Proceedings of the ACM 2nd CoNEXT Conference on Future
          Networking Technologies, December 2006.

[MOB-DATA-OFFLOAD]

          Lee, K., Lee, J., Yi, Y., Rhee, I., and S. Chong, "Mobile
          Data Offloading: How Much Can WiFi Deliver?", Proceedings
          of the ACM SIGCOMM 2010 Conference, 2010.

[PMIP-CP-UP-SPLIT]

          Wakikawa, R., Pazhyannur, R., and S. Gundavelli,
          "Separation of Control and User Plane for Proxy Mobile
          IPv6", Work in Progress, July 2013.

RFC5380 Soliman, H., Castelluccia, C., ElMalki, K., and L.

          Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility
          Management", RFC 5380, October 2008.

RFC5944 Perkins, C., "IP Mobility Support for IPv4, Revised",

          RFC 5944, November 2010.

RFC6224 Schmidt, T., Waehlisch, M., and S. Krishnan, "Base

          Deployment for Multicast Listener Support in Proxy Mobile
          IPv6 (PMIPv6) Domains", RFC 6224, April 2011.

RFC6301 Zhu, Z., Wakikawa, R., and L. Zhang, "A Survey of Mobility

          Support in the Internet", RFC 6301, July 2011.

RFC6705 Krishnan, S., Koodli, R., Loureiro, P., Wu, Q., and A.

          Dutta, "Localized Routing for Proxy Mobile IPv6",
          RFC 6705, September 2012.

RFC6909 Gundavelli, S., Zhou, X., Korhonen, J., Feige, G., and R.

          Koodli, "IPv4 Traffic Offload Selector Option for Proxy
          Mobile IPv6", RFC 6909, April 2013.

[TS.23.401]

          3GPP, "General Packet Radio Service (GPRS) enhancements
          for Evolved Universal Terrestrial Radio Access Network
          (E-UTRAN) access", 3GPP TS 23.401 12.5.0, June 2014,
          <http://www.3gpp.org/ftp/Specs/html-info/23401.htm>.

[TS.29.303]

          3GPP, "Domain Name System Procedures; Stage 3", 3GPP
          TS 29.303 12.3.0, June 2014, <http://www.3gpp.org/ftp/
          Specs/html-info/29303.htm>.

Authors' Addresses

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

EMail: [email protected]

Dapeng Liu China Mobile Unit 2, 28 Xuanwumenxi Ave, Xuanwu District Beijing 100053 China

EMail: [email protected]

Pierrick Seite Orange 4, rue du Clos Courtel, BP 91226 Cesson-Sevigne 35512 France

EMail: [email protected]

Hidetoshi Yokota Landis+Gyr

EMail: [email protected]

Jouni Korhonen Broadcom Communications Porkkalankatu 24 Helsinki FIN-00180 Finland

EMail: [email protected]