Re: [DMM] I-D Action: draft-ietf-dmm-requirements-07.txt

[Jouni Korhonen <[e-mail]>]

Thanks Sri for detailed comments. We definitely need to hash these out
and address them.

- Jouni


On Aug 26, 2013, at 6:03 AM, Sri Gundavelli (sgundave) <[e-mail]> wrote:

> Please see inline for some comments.
> 
> 
> Regards
> Sri
> 
> 
> 
> 
> Abstract
> 
>    This document defines the requirements for Distributed Mobility
>    Management (DMM) in IPv6 deployments.  The hierarchical structure in
>    traditional wireless networks has led to deployment models which are
>    in practice centralized.  Mobility management with logically
>    centralized mobility anchoring in current mobile networks is prone to
>    suboptimal routing and raises scalability issues.  Such centralized
>    functions can lead to single points of failure and inevitably
>    introduce longer delays and higher signaling loads for network
>    operations related to mobility management.  The objective is to
>    enhance mobility management in order to meet the primary goals in
>    network evolution, i.e., improve scalability, avoid single points of
>    failure, enable transparent mobility support to upper layers only
>    when needed, and so on.  Distributed mobility management must be
>    secure and may co-exist with existing network deployments and end
>    hosts.
> 
> [Sri] We don’t need to argue against centralized model to justify distributed model. In the absence of proper data to compare on both the approaches, we cannot have such text.  The pros and cons extend to both the models. Please simply state distributed model can be useful in certain deployments and hence there is interest for this work.
> 
> 
> 1.  Introduction
> 
>    In the past decade a fair number of mobility protocols have been
>    standardized [RFC6275] [RFC5944] [RFC5380] [RFC6301] [RFC5213].
>    Although the protocols differ in terms of functions and associated
>    message formats, we can identify a few key common features:
> 
>    o  a centralized mobility anchor providing global reachability and an
>       always-on experience to the user;
> 
>    o  extensions to the base protocols to optimize handover performance
>       while users roam across wireless cells; and
> 
>    o  extensions to enable the use of heterogeneous wireless interfaces
>       for multi-mode terminals (e.g. smartphones).
> 
> 
> [Sri] Currently defined mobility protocols support handovers and multiple access technologies  ? Not sure, how these two "common features" make the case for DMM  If the point is about centralized anchor's, you don't need the other two points. 
> 
>    The presence of the centralized mobility anchor allows a mobile node
>    to remain reachable after it has moved to a different network.  The
>    anchor point, among other tasks, ensures connectivity by forwarding
>    packets destined to, or sent from, the mobile node.  In practice,
>    most of the deployed architectures today have a small number of
>    centralized anchors managing the traffic of millions of mobile nodes.
>    Compared with a distributed approach, a centralized approach is
>    likely to have several issues or limitations affecting performance
>    and scalability, which require costly network engineering to resolve.
> 
> 
> [Sri] All 3G/4G systems are based on this model and they are running fine. Again, we don’t need to argue against centralized model to justify distributed model. Please simply state distributed model can be useful in certain deployments and hence the motivation for this work.
> 
>    To optimize handovers from the perspective of mobile nodes, the base
>    protocols have been extended to efficiently handle packet forwarding
>    between the previous and new points of attachment.  These extensions
>    are necessary when applications have stringent requirements in terms
>    of delay.  Notions of localization and distribution of local agents
>    have been introduced to reduce signaling overhead at the centralized
>    routing anchor point [Paper-Distributed.Centralized.Mobility].
>    Unfortunately, today we witness difficulties in getting such
>    protocols deployed, resulting in sub-optimal choices for the network
>    Operators.
> 
> [Sri] I assume this is about hierarchical models / Chaining ? What are these "difficulties in getting such protocols deployed" ?   
>    Moreover, the availability of multiple-interface host and the
>    possibility of using several network interfaces simultaneously have
>    motivated the development of even more protocol extensions to add
>    more capabilities to the mobility management protocol.  In the end,
>    deployment is further complicated with the multitude of extensions.
> 
> [Sri] Not sure I follow. Mobile IP protocols are in general access agnostic. Not sure, what are the extensions that we have added on access-basis.
> 
> 
>    As an effective transport method for multimedia data delivery, IP
>    multicast support, including optimizations, have been introduced but
>    by "patching-up" procedure after completing the design of reference
>    mobility protocol, leading to network inefficiency and non-optimal
>    routing.
> 
> 
> [Sri] Multicast related extensions have nothing to do with multi-access support/host's capability to support multiple interfaces. Can you clarify ? This text is not clear.
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> 
>    Mobile users are, more than ever, consuming Internet content; such
>    traffic imposes new requirements on mobile core networks for data
>    traffic delivery.  The presence of content providers closer to
>    Internet Service Providers (ISP) network requires taking into account
>    local Content Delivery Networks (CDNs) while providing mobility
>    services.  Moreover, when the traffic demand exceeds available
>    capacity, service providers need to implement new strategies such as
>    selective traffic offload (e.g. 3GPP work items LIPA/SIPTO
>    [TS.23.401]) through alternative access networks (e.g.  WLAN) [Paper-
>    Mobile.Data.Offloading].  
> 
> [Sri] Please add reference to IETF SIPTO doc, RFC6909, before 23.401 :)
> 
> A gateway selection mechanism also takes
>    the user proximity into account within EPC [TS.29303].  These
>    mechanisms were not pursued in the past owing to charging and billing
>    reasons.   Assigning a gateway anchor node from a visited network in
> 
>    roaming scenario has until recently been done and are limited to
>    voice services only.  Charging and billing require solutions beyond
>    the mobility protocol.
> 
> 
>    Both traffic offloading and CDN mechanisms could benefit from the
>    development of mobile architectures with fewer levels of routing
>    hierarchy introduced into the data path by the mobility management
>    system.  This trend towards so-called "flat networks" works best for
>    direct communications among peers in the same geographical area.
>    Distributed mobility management in a truly flat mobile architecture
>    would anchor the traffic closer to the point of attachment of the
>    user.
> 
>    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 [Paper-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, currently, IP mobility support is
>    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. 
> 
> [Sri]  Is the intent of this is text is about routing based approaches ?
> If a mobile is attached to the network, it does have some state at the anchor. Also, if we consider the home link in mobility models, there is no state for the mobile node when it is at home. In case of DMM, or with the current models, if the gateway selection is based on the MN's location and when there is no node mobility, there should not be any state at the anchor. CDMA
> 
> 
>  Infrequent node mobility
>    coupled with application intelligence suggest that mobility support
>    could be provided selectively, thus reducing the amount of context
>    maintained in the network.
> 
>    The distributed mobility management (DMM) charter addresses two
>    complementary aspects of mobility management procedures: the
>    distribution of mobility anchors towards a more flat network and the
>    dynamic activation/deactivation of mobility protocol support as an
>    enabler to distributed mobility management.  
> 
> [Sri] Not sure, I follow this point on Dynamic activation/de-activation. Can you clarify.
> 
> The former aims at
>    positioning mobility anchors (e.g., HA, LMA) closer to the user;
>    ideally, mobility agents could be collocated with the first-hop
> 
> 
> 
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> 
>    router.  The latter, facilitated by the distribution of mobility
>    anchors, aims at identifying when mobility support must be activated
>    and identifying sessions that do not require mobility management
>    support -- thus reducing the amount of state information that must be
>    maintained in various mobility agents of the mobile network.  The key
>    idea is that dynamic mobility management relaxes some of the
>    constraints of previously-standardized mobility management solutions
>    and, by doing so, it can avoid the unnecessary establishment of
>    mechanisms to forward traffic from an old to a new mobility anchor.
> 
> 
> [Sri] The DMM model should not exclude the case of centralized anchor and distributed data plane. This is sub-case of DMM. 
> 
>    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 are given in
>    Section 5.  Finally, security considerations are discussed in Section
>    6.
> 
>    The problem statement and the use cases [I-D.yokota-dmm-scenario] can
>    be found in [Paper-Distributed.Mobility.Review].
> 
> 
> 2.  Conventions used in this document
> 
> 2.1.  Terminology
> 
>    All the general mobility-related terms and their acronyms used in
>    this document are to be interpreted as defined in the Mobile IPv6
>    base specification [RFC6275], in the Proxy mobile IPv6 specification
>    [RFC5213], and in 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 draft introduces the following term.
> 
>    Mobility context
> 
>       is the collection of information required to provide mobility
>       management support for a given mobile node.
> 
> 
> 
> [Sri] There needs to be some definition of "centrally deployed mobility anchor". This term is used through-out the document. What is central, what is local ? Even in the so called, "centralized anchor models", a gateway can be enabled locally. Ex: LMA/MAG, PGW/SGW functions can exist on the same node. 
> 
> 3.  Centralized versus distributed mobility management
> 
>    Mobility management functions may be implemented at different layers
>    of the protocol stack.  At the IP (network) layer, they may reside in
>    the network or in the mobile node.  In particular, a network-based
>    solution resides in the network only.  It therefore enables mobility
> 
> 
> 
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> 
>    for existing hosts and network applications which are already in
>    deployment but lack mobility support.
> 
> 
> [Sri] Above text is bit confusing to me, specially the last sentence. Mobility management can be based on client-based, or network-based. 
> 
> 
>    At the IP layer, a mobility management protocol supporting 
> session
>    continuity
>  is typically based on the principle of distinguishing
>    between identifier and routing address and maintaining a mapping
>    between the two.  
> 
> [Sri] Replace, "Session continuity" with "IP mobility" or "IP address continuity". 
> In Mobile IP, the home address serves as an
>    identifier of the device whereas the care-of-address (CoA) takes the
>    role of the routing address.  The binding between these two is
>    maintained at the home agent (mobility anchor).  If packets can be
>    continuously delivered to a mobile node at its home address, then all
>    sessions using that home address are unaffected even though the
>    routing address (CoA) changes.
> 
> 
> [Sri] We should leave it at, "IP address mobility".
>    The next two subsections explain centralized and distributed mobility
>    management functions in the network.
> 
> 3.1.  Centralized mobility management
> 
>    In centralized mobility management, the mapping information between
>    the persistent node identifier and the locator IP address of a mobile
>    node (MN) is kept at a single mobility anchor.  At the same time,
>    packets destined to the MN are routed via this anchor.
> 
> [Sri] Can we use the MIP terminology, home address/Care-of address terminology, as supposed to LISP terminology ? 
> 
>   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 of such centralized mobility anchors are the
>    home agent (HA) and local mobility anchor (LMA) in Mobile IPv6
>    [RFC6275] and Proxy Mobile IPv6 [RFC5213], respectively.  Current
>    cellular networks such as the Third Generation Partnership Project
>    (3GPP) GPRS networks, CDMA networks, and 3GPP Evolved Packet System
>    (EPS) networks employ centralized mobility management too.  In
>    particular, the Gateway GPRS Support Node (GGSN), Serving GPRS
>    Support Node (SGSN) and Radio Network Controller (RNC) in the 3GPP
>    GPRS hierarchical network, and the Packet Data Network Gateway (P-GW)
>    and Serving Gateway (S-GW) in the 3GPP EPS network all act as anchors
>    in a hierarchy.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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> 
>          3G 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.
> 
> 3.2.  Distributed mobility management
> 
>    Mobility management functions may also be distributed to multiple
>    networks as shown in Figure 2, so that a mobile node in any of these
>    networks may be served by a nearby mobility function (MF).
> 
> 
>                     +------+  +------+  +------+  +------+
>                     |  MF  |  |  MF  |  |  MF  |  |  MF  |
>                     +------+  +------+  +------+  +------+
>                                            |
>                                          +----+
>                                          | MN |
>                                          +----+
> 
>    Figure 2.  Distributed mobility management.
> 
> 
> 
>    Mobility management may be partially or fully distributed.  In the
>    former case only the data plane is distributed.  Fully distributed
>    mobility management implies that both the data plane and the control
>    plane are distributed.  Such concepts of data and control plane
>    separation are not yet described in the IETF developed mobility
>    protocols so far but are described in detail in [I-D.yokota-dmm-
>    scenario].  While mobility management can be distributed, it is not
>    necessary for other functions such as subscription management,
> 
> 
> 
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> 
>    subscription database, and network access authentication to be
>    similarly distributed.
> 
> 
> [Sri] The case of centralized CP and distributed DP is covered in IETF docs, 
> http://datatracker.ietf.org/doc/draft-wakikawa-netext-pmip-cp-up-separation/
> This is a variant of the DMM models. 
> 
>    A distributed mobility management scheme for flat IP-based mobile
>    network architecture consisting of access nodes is proposed in
>    [Paper-Distributed.Dynamic.Mobility].  Its benefits over centralized
>    mobility management are shown through simulations in [Paper-
>    Distributed.Centralized.Mobility].  Moreover, the (re)use and
>    extension of existing protocols in the design of both fully
>    distributed mobility management [Paper-Migrating.Home.Agents] [Paper-
>    Distributed.Mobility.SAE] and partially distributed mobility
>    management [Paper-Distributed.Mobility.PMIP] [Paper-
>    Distributed.Mobility.MIP] have been reported in the literature.
>    Therefore, before designing new mobility management protocols for a
>    future flat IP architecture, it is recommended to first consider
>    whether existing mobility management protocols can be extended to
>    serve a flat IP architecture.
> 
> 
> [Sri] Lot of unnecessary text in this document. Not sure, we need all of this text.
> 
> 
> 4.  Problem Statement
> 
>    The problems that can be addressed with DMM are summarized in the
>    following:
> 
>    PS1:  Non-optimal routes
> 
>          Routing via a centralized anchor often results in a longer
>          route.  
> 
> [Sri] "longer route" ?  I assume this is about routing/tx delay. Please re-word.
> 
> The problem is manifested, for example, when accessing
>          a local server or servers of a Content Delivery Network (CDN),
>          or when receiving locally available IP multicast or sending IP
>          multicast packets.
> 
> 
> [Sri] Does RFC 6705, or RFC 6909 does not address this issue ? May be the CDN example is incorrect. 
> 
> 
>    PS2:  Divergence from other evolutionary trends in network
>          architectures such as distribution of content delivery.
> 
>          Centralized mobility management can become non-optimal with a
>          flat network architecture.
> 
> 
> [Sri] How is this making the case of DMM ? We want the MN to access content locally in the access network and we want localized routing. We have that in the form of 6705 and 6909. The other approach is give localized IP addresses and have the content locally accessed. There are simply two many considerations and points may be valid, but when we bring all those assumptions. We are bringing these points in a less logical manner without stating the assumptions.
> 
>    PS3:  Low 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 increase scalability.
> 
> 
> 
> 
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> 
>    PS4:  Single point of failure and attack
> 
>          Centralized anchoring designs may be more vulnerable to single
>          points of failures 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:  Unnecessarily reserving resources to provide mobility support
>          to nodes that do not need such support
> 
>          IP mobility support is not always required, and not every
>          parameter of mobility context is always used.  For example,
>          some applications do not need a stable IP address during a
>          handover to maintain session continuity.  Sometimes, the entire
>          application session runs while the terminal 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 more
>          efficient to deactivate IP mobility support for such sessions.
> 
> 
> [Sri]  Mobility systems today do support the aspect of service for the subscriber, as "Simple IP", or "Mobile IP". A PDSN can assign a local IP address and it does not have to be the home address. Network does have this intelligence, but what is missing is the client's ability to pick the correct type of IP address, among different IP addresses. The network is also the missing the aspect of marking those addresses with proper properties. The currently active drafts in IETF are to address this issue. We should talk about these missing semantics.
> draft-bhandari-dhc-class-based-prefix-05  
> draft-korhonen-6man-prefix-properties-02
> 
> 
>    PS6:  (Related problem) Mobility signaling overhead with peer-to-peer
>          communication
> 
>          Wasting resources when mobility signaling (e.g., maintenance of
>          the tunnel, keep alive signaling, etc.) is not turned off for
>          peer-to-peer communication.  Peer-to-peer communications have
>          particular traffic patterns that often do not benefit from
>          mobility support from the network.  Thus, the associated
>          mobility support signaling (e.g., maintenance of the tunnel,
>          keep alive signaling, etc.) wastes network resources for no
>          application gain.  In such a case, it is better to enable
>          mobility support selectively.
> 
> 
> [Sri] How is PS6 different from PS5 ? We talk about application's ability to pick the address with or without mobility properties in PS5. So, the traffic patterns can be localized based on the application requirements. But, even if we take the argument that mobility is not required, operator needs visibility into these flows and so they can charge.  Again, we have 6705 and 6909 for adjusting to those traffic patterns. So, this P without those considerations is incomplete.
> 
> 
>    PS7:  (Related problem) Deployment with multiple mobility solutions
> 
>          There are already many variants and extensions of MIP.
>          Deployment of new mobility management solutions can be
>          challenging, and debugging difficult, when they must co-exist
>          with solutions already 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.  PMIPv6 tunnel), duplicate multicast subscription(s) is
> 
> 
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>          prone to be received through different upstream paths.  This
>          problem may also exist or be more severe in a distributed
>          mobility environment.
> 
> 
> [Sri] Is this for MN's from different LMA's attached to the same MAG ?
> 
> 5.  Requirements
> 
>    After comparing distributed mobility management against centralized
>    deployment in Section 3, this section identifies the following
>    requirements:
> 
> 5.1.  Distributed processing
> 
>    REQ1:  Distributed processing
> 
>           IP mobility, network access and routing solutions provided by
>           DMM MUST enable distributed processing for mobility management
>           so that traffic does not need to traverse centrally deployed
>           mobility anchors and thereby avoid non-optimal routes.
> 
>           Motivation: This requirement is motivated by current trends in
>           network evolution: (a) it is cost- and resource-effective to
>           cache and distribute content by combining distributed mobility
>           anchors with caching systems (e.g., CDN); (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; (d) threats against centrally
>           deployed anchors, e.g., home agent and local mobility anchor,
>           are mitigated in a distributed system.
> 
>    This requirement addresses the problems PS1, PS2, PS3, and PS4
>    described in Section 4.  (Existing route optimization is only a host-
>    based solution.  On the other hand, localized routing with PMIPv6
>    addresses only a part of the problem where both the MN and the CN are
>    located in the PMIP domain and attached to a MAG, and is not
>    applicable when the CN is outside the PMIP domain.)
> 
> 
> [Sri] I'm still stuck on the CDN example driving this requirement.
> 
> 
> 5.2.  Transparency to Upper Layers when needed
> 
>    REQ2:  Transparency to Upper Layers when needed
> 
>           DMM solutions MUST provide transparent mobility support above
>           the IP layer when needed.  Such transparency is needed, for
>           example, when, upon change of point of attachment to the
>           network, an application flow cannot cope with a change in the
>           IP address.  However, it is not always necessary to maintain a
>           stable home IP address or prefix for every application or at
>           all times for a mobile node.
> 
> 
> 
> [Sri] Please reflect the two key aspects of this requirement:
> 	• Network can assign IP addresses with different properties; It carries those properties
> 	• Applications have different requirements and will pick the address with the correct property.
> 
> 
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>           Motivation: The motivation of this requirement is to enable
>           more efficient use of network resources and more efficient
>           routing by not maintaining context at the mobility anchor when
>           there is no such need.
> 
>    This requirement addresses the problem PS5 as well as the related
>    problem PS6 stated in Section 4.
> 
> 5.3.  IPv6 deployment
> 
>    REQ3:  IPv6 deployment
> 
>           DMM solutions SHOULD target IPv6 as the primary deployment
>           environment and SHOULD NOT be tailored specifically to support
>           IPv4, in particular 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 in mid-
>           to long-term horizon, when IPv6 is expected to be far more
>           common than today.
> 
>    This requirement avoids the unnecessarily complexity in solving the
>    problems in Section 4 for IPv4, which will not be able to use some of
>    the IPv6-specific features.
> 
> 5.4.  Existing mobility protocols
> 
>    REQ4:  Existing mobility protocols
> 
>           A DMM solution SHOULD first consider reusing and extending
>           IETF-standardized 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 of new protocols
>    development and therefore their potential problems of being time-
>    consuming and error-prone.
> 
> 5.5.  Co-existence
> 
>    REQ5:  Co-existence with deployed networks and hosts
> 
>           The DMM solution MUST be able to co-exist with existing
>           network deployments and end hosts.  For example, depending on
>           the environment in which DMM is deployed, DMM solutions may
>           need to be compatible with other deployed mobility protocols
> 
> 
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>           or may need to co-exist with a network or mobile hosts/routers
>           that do not support DMM protocols.  The mobile node may also
>           move between different access networks, where some of them may
>           support neither DMM nor another mobility protocol.
>           Furthermore, a DMM solution SHOULD work across different
>           networks, possibly operated as separate administrative
>           domains, when allowed by the trust relationship between them.
> 
>           Motivation: (a) to 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 related problem PS7 described in
>    Section 4.
> 
> 5.6.  Security considerations
> 
>    REQ6:  Security considerations
> 
>           A DMM solution MUST not introduce new security risks or
>           amplify existing security risks against which the existing
>           security mechanisms/protocols cannot offer sufficient
>           protection.
> 
>           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 is under a denial of service
>           attack, whereas other nodes do not receive their traffic.
>           Accordingly, security mechanisms/protocols providing access
>           control, integrity, authentication, authorization,
>           confidentiality, etc. can be used to protect the DMM entities
>           as they are already used to protect against existing networks
>           and existing mobility protocols defined in IETF.  In addition,
>           end-to-end security measures between communicating nodes may
>           already be used when deploying existing mobility protocols
>           where the signaling messages travel over the Internet.  For
>           instance, EAP-based authentication can be used for network
>           access security, while IPsec can be used for end-to-end
>           security.  When the existing security mechanisms/protocols are
>           applied to protect the DMM entities, the security risks that
>           may be introduced by DMM MUST be considered to be eliminated.
>           Else the security protection would be degraded in the DMM
>           solution versus in existing mobility protocols.
> 
> 
> 
> Chan (Ed.), et al.      Expires February 3, 2014               [Page 13]
> 
> Internet-Draft                  DMM-Reqs                     August 2013
> 
> 
>    This requirement prevents a DMM solution from introducing
>    uncontrollable problems of potentially insecure mobility management
>    protocols which make deployment infeasible because platforms
>    conforming to the protocols are at risk for data loss and numerous
>    other dangers, including financial harm to the users.
> 
> 5.7.  Multicast
> 
>    REQ7:  Multicast considerations
> 
>           DMM SHOULD consider multicast early so that solutions can be
>           developed not only to provide IP mobility support when it is
>           needed, but also to avoid network inefficiency issues in
>           multicast traffic delivery (such as duplicate multicast
>           subscriptions towards the downstream tunnel entities).  The
>           multicast solutions should therefore avoid restricting the
>           management of all IP multicast traffic to a single host
>           through a dedicated (tunnel) interface on multicast-capable
>           access routers.
> 
>           Motivation: Existing multicast deployment have been introduced
>           after completing the design of the reference mobility
>           protocol, then optimization and extensions have been followed
>           by "patching-up" procedure, thus leading to network
>           inefficiency and non-optimal routing.  The multicast solutions
>           should therefore be required to consider efficiency nature in
>           multicast traffic delivery.
> 
>    This requirement addresses the problems PS1 and PS8 described in
>    Section 4.
> 
> 
> 6.  Security Considerations
> 
>    Please refer to the discussion under Security requirement in Section
>    5.6.
> 
> 
> 7.  IANA Considerations
> 
>    None
> 
> 
> 8.  Co-authors and Contributors
> 
>    This problem statement document is a joint effort among the numerous
>    participants.  Each individual has made significant contributions to
>    this work and have been listed as co-authors.
> 
> 
> 
> Chan (Ed.), et al.      Expires February 3, 2014               [Page 14]
> 
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> 
> 
> 9.  References
> 
> 9.1.  Normative References
> 
>    [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
>               Requirement Levels", BCP 14, RFC 2119, March 1997.
> 
> 9.2.  Informative References
> 
>    [I-D.yokota-dmm-scenario]
>               Yokota, H., Seite, P., Demaria, E., and Z. Cao, "Use case
>               scenarios  for Distributed Mobility Management",
>               draft-yokota-dmm-scenario-00 (work in progress),
>               October 2010.
> 
>    [Paper-Distributed.Centralized.Mobility]
>               Bertin, P., Bonjour, S., and J-M. Bonnin, "A Distributed
>               or Centralized Mobility",  Proceedings of Global
>               Communications Conference  (GlobeCom), December 2009.
> 
>    [Paper-Distributed.Dynamic.Mobility]
>               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.
> 
>    [Paper-Distributed.Mobility.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.
> 
>    [Paper-Distributed.Mobility.PMIP]
>               Chan, H., "Proxy Mobile IP  with Distributed Mobility
>               Anchors",  Proceedings of GlobeCom Workshop  on Seamless
>               Wireless Mobility, December 2010.
> 
>    [Paper-Distributed.Mobility.Review]
>               Chan, H., Yokota, H., Xie, J., Seite, P., and D. Liu,
>               "Distributed and Dynamic Mobility Management  in Mobile
>               Internet: Current Approaches and Issues, Journal of
>               Communications, vol. 6, no. 1, pp. 4-15, Feb 2011.",
>                Proceedings of GlobeCom Workshop  on Seamless Wireless
>               Mobility, February 2011.
> 
>    [Paper-Distributed.Mobility.SAE]
>               Fisher, M., Anderson, F., Kopsel, A., Schafer, G., and M.
> 
> 
> 
> Chan (Ed.), et al.      Expires February 3, 2014               [Page 15]
> 
> Internet-Draft                  DMM-Reqs                     August 2013
> 
> 
>               Schlager, "A Distributed IP Mobility Approach for 3G SAE",
>                Proceedings of the 19th International Symposium  on
>               Personal, Indoor and Mobile Radio Communications (PIMRC),
>               2008.
> 
>    [Paper-Locating.User]
>               Kirby, G., "Locating the User",  Communication
>               International, 1995.
> 
>    [Paper-Migrating.Home.Agents]
>               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.
> 
>    [Paper-Mobile.Data.Offloading]
>               Lee, K., Lee, J., Yi, Y., Rhee, I., and S. Chong, "Mobile
>               Data Offloading: How Much Can WiFi Deliver?",  SIGCOMM
>               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.
>               Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility
>               Management", RFC 5380, October 2008.
> 
>    [RFC5944]  Perkins, C., "IP Mobility Support for IPv4, Revised",
>               RFC 5944, November 2010.
> 
>    [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
>               Support in the Internet", RFC 6301, July 2011.
> 
>    [TS.23.401]
>               3GPP, "General Packet Radio Service (GPRS) enhancements
>               for Evolved Universal Terrestrial Radio Access Network
>               (E-UTRAN) access", 3GPP TR 23.401 10.10.0, March 2013.
> 
>    [TS.29303]
>               3GPP, "Domain Name System Procedures; Stage 3", 3GPP
>               TR 23.303 11.2.0, September 2012.
> 
> 
> 
> 
> Chan (Ed.), et al.      Expires February 3, 2014               [Page 16]
> 
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> 
> 
> Authors' Addresses
> 
>    H Anthony Chan (editor)
>    Huawei Technologies (more co-authors on P. 17)
>    5340 Legacy Dr. Building 3, Plano, TX 75024, USA
>    Email: 
> [e-mail]
> 
> 
> 
>    Dapeng Liu
>    China Mobile
>    Unit2, 28 Xuanwumenxi Ave, Xuanwu District,  Beijing 100053, China
>    Email: 
> [e-mail]
> 
> 
> 
>    Pierrick Seite
>    Orange
>    4, rue du Clos Courtel, BP 91226,  Cesson-Sevigne 35512, France
>    Email: 
> [e-mail]
> 
> 
> 
>    Hidetoshi Yokota
>    KDDI Lab
>    2-1-15 Ohara, Fujimino, Saitama, 356-8502 Japan
>    Email: 
> [e-mail]
> 
> 
> 
>    Jouni Korhonen
>    Nokia Siemens Networks
>    Email: 
> [e-mail]
> 
>    -
>    Charles E. Perkins
>    Huawei Technologies
>    Email: 
> [e-mail]
> 
>    -
>    Melia Telemaco
>    Alcatel-Lucent Bell Labs
>    Email: 
> [e-mail]
> 
>    -
>    Elena Demaria
>    Telecom Italia
>    via G. Reiss Romoli, 274, TORINO, 10148, Italy
>    Email: 
> [e-mail]
> 
>    -
>    Jong-Hyouk Lee
>    RSM Department, Telecom Bretagne
>    Cesson-Sevigne, 35512, France
>    Email: 
> [e-mail]
> 
>    -
> 
> 
> 
> Chan (Ed.), et al.      Expires February 3, 2014               [Page 17]
> 
> Internet-Draft                  DMM-Reqs                     August 2013
> 
> 
>    Kostas Pentikousis
>    Huawei Technologies
>    Carnotstr. 4 10587 Berlin, Germany
>    Email: 
> [e-mail]
> 
>    -
>    Tricci So
>    ZTE
>    Email: 
> [e-mail]
> 
>    -
>    Carlos J. Bernardos
>    Universidad Carlos III de Madrid
>    Av. Universidad, 30, Leganes, Madrid 28911, Spain
>    Email: 
> [e-mail]
> 
>    -
>    Peter McCann
>    Huawei Technologies
>    Email: 
> [e-mail]
> 
>    -
>    Seok Joo Koh
>    Kyungpook National University, Korea
>    Email: 
> [e-mail]
> 
>    -
>    Wen Luo
>    ZTE
>    No.68, Zijinhua RD,Yuhuatai District, Nanjing, Jiangsu 210012, China
>    Email: 
> [e-mail]
> 
>    -
>    Sri Gundavelli
>    
> [e-mail]
> 
>    -
>    Marco Liebsch
>    NEC Laboratories Europe
>    Email: 
> [e-mail]
> 
>    -
>    Carl Williams
>    MCSR Labs
>    Email: 
> [e-mail]
> 
>    -
>    Seil Jeon
>    Instituto de Telecomunicacoes, Aveiro
>    Email: 
> [e-mail]
> 
>    -
>    Sergio Figueiredo
>    Universidade de Aveiro
>    Email: 
> [e-mail]
> 
>    -
>    Stig Venaas
>    Email: 
> [e-mail]
> 
> 
> 
> 
> Chan (Ed.), et al.      Expires February 3, 2014               [Page 18]
> 
> Internet-Draft                  DMM-Reqs                     August 2013
> 
> 
>    -
>    Luis Miguel Contreras Murillo
>    Email: 
> [e-mail]
> 
>    -
>    Juan Carlos Zuniga
>    Email: 
> [e-mail]
> 
>    -
>    Alexandru Petrescu
>    Email: 
> [e-mail]
> 
>    -
>    Georgios Karagiannis
>    Email: 
> [e-mail]
> 
>    -
>    Julien Laganier
>    
> [e-mail]
> 
>    -
>    Wassim Michel Haddad
>    
> [e-mail]
> 
>    -
>    Dirk von Hugo
>    
> [e-mail]
> 
>    -
>    Ahmad Muhanna
>    
> [e-mail]
> 
>    -
>    Byoung-Jo Kim
>    ATT Labs
>    
> [e-mail]
> 
>    -
>    Hassan Aliahmad
>    Orange
>    
> [e-mail]
> 
>    -
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Chan (Ed.), et al.      Expires February 3, 2014               [Page 19]
> 
> 
> 
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