Re: [MIPSHOP-MIH-DT] PS doc -- 01 version

Subir Das <subir@research.telcordia.com> Mon, 30 April 2007 15:47 UTC

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Date: Mon, 30 Apr 2007 11:47:08 -0400
From: Subir Das <subir@research.telcordia.com>
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To: Telemaco Melia <telemaco.melia@netlab.nec.de>
Subject: Re: [MIPSHOP-MIH-DT] PS doc -- 01 version
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Tele,
Sorry for the delay. Hope it is not too late.
Inserted below with a few comments/suggestions.
Search by my name.

thanks,
-Subir

Telemaco Melia wrote:
> Hi folks,
>
> Sorry to insist but we need to push this forward.
> Can we get consensus soon (today?) about the introduced changes, 
> especially section 5.2?
>
> telemaco
>
> Telemaco Melia wrote:
>> Hi all,
>>
>> Please find attached a revised version of the PS document. Comments 
>> from people should be hopefully  reflected.
>> I told Stefano that a final version for submission will be ready by 
>> Friday, so please send comments with proposed text to avoid lengthly 
>> discussions.
>> Please pay particular attention to section 5.2 (see Yoshi's email). 
>> Also the title of the doc is changed according to Alper's comment (it 
>> is in line with the terminology agreed in Prague).
>>
>> cheers,
>> telemaco
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>>
>>
>>
>> MIPSHOP                                                         T. Melia
>> Internet-Draft                                                       NEC
>> Intended status: Informational                               E. Hepworth
>> Expires: October 27, 2007                    Siemens Roke Manor Research
>>                                                          S. Sreemanthula
>>                                                    Nokia Research Center
>>                                                                  Y. Ohba
>>                                                                  Toshiba
>>                                                                 G. Vivek
>>                                                                    Intel
>>                                                              J. Korhonen
>>                                                              TeliaSonera
>>                                                                R. Aguiar
>>                                                                       IT
>>                                                        Sam(Zhongqi). Xia
>>                                                                   HUAWEI
>>                                                           April 25, 2007
>>
>>
>>              Mobility Services Transport: Problem Statement
>>                       draft-ietf-mipshop-mis-ps-01
>>
>> Status of this Memo
>>
>>    By submitting this Internet-Draft, each author represents that any
>>    applicable patent or other IPR claims of which he or she is aware
>>    have been or will be disclosed, and any of which he or she becomes
>>    aware will be disclosed, in accordance with Section 6 of BCP 79.
>>
>>    Internet-Drafts are working documents of the Internet Engineering
>>    Task Force (IETF), its areas, and its working groups.  Note that
>>    other groups may also distribute working documents as Internet-
>>    Drafts.
>>
>>    Internet-Drafts are draft documents valid for a maximum of six months
>>    and may be updated, replaced, or obsoleted by other documents at any
>>    time.  It is inappropriate to use Internet-Drafts as reference
>>    material or to cite them other than as "work in progress."
>>
>>    The list of current Internet-Drafts can be accessed at
>>    http://www.ietf.org/ietf/1id-abstracts.txt.
>>
>>    The list of Internet-Draft Shadow Directories can be accessed at
>>    http://www.ietf.org/shadow.html.
>>
>>    This Internet-Draft will expire on October 27, 2007.
>>
>> Copyright Notice
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007                [Page 1]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
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>>    Copyright (C) The IETF Trust (2007).
>>
>> Abstract
>>
>>    There are on-going activities in the networking community to develop
>>    solutions that aid in IP handover mechanisms between heterogeneous
>>    wired and wireless access systems including, but not limited to, IEEE
>>    802.21.  Intelligent access selection, taking into account link layer
>>    attributes, requires the delivery of a variety of different
>>    information types to the terminal from different sources within the
>>    network and vice-versa.  The protocol requirements for this
>>    signalling have both transport and security issues that must be
>>    considered.  The signalling must not be constrained to specific link
>>    types, so there is at least a common component to the signalling
>>    problem which is within the scope of the IETF.  This draft presents a
>>    problem statement for this core problem.
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>> Melia, et al.           Expires October 27, 2007                [Page 2]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
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>> Table of Contents
>>
>>    1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
>>    2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
>>    3.  Definition of Mobility Services  . . . . . . . . . . . . . . .  5
>>    4.  Deployment Scenarios for MoS . . . . . . . . . . . . . . . . .  5
>>      4.1.  End-to-End Signalling and Transport over IP  . . . . . . .  6
>>      4.2.  End-to-End Signalling and Partial Transport over IP  . . .  6
>>      4.3.  End-to-End Signalling with a Proxy . . . . . . . . . . . .  7
>>      4.4.  End-to-End Network-to-Network Signalling . . . . . . . . .  7
>>    5.  MoS Transport Protocol Splitting . . . . . . . . . . . . . . .  8
>>      5.1.  Payload Formats and Extensibility Considerations . . . . .  9
>>      5.2.  Requirements on the Mobility Service Transport Layer . . .  9
>>    6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
>>    7.  Conclusions  . . . . . . . . . . . . . . . . . . . . . . . . . 15
>>    8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
>>    Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
>>    Intellectual Property and Copyright Statements . . . . . . . . . . 18
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>> Melia, et al.           Expires October 27, 2007                [Page 3]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>> 1.  Introduction
>>
>>    This Internet Draft provides a problem statement for the exchange of
>>    information to support handover in heterogeneous link environments.
>>    This mobility support service allows more sophisticated handover
>>    operations by making available information about network
>>    characteristics, neighboring networks and associated characteristics,
>>    indications that a handover should take place, and suggestions for
>>    suitable target networks to which to handover.  The mobility support
>>    services work complementarily with IP mobility mechanisms to enhance
>>    the overall performance and usability perception.
>>
>>    There are two key attributes to the handover support service problem
>>    for inter-technology handovers:
>>
>>    1.  The Information: the information elements being exchanged.  The
>>        messages could be of different nature, such as Information,
>>        Command or Event, potentially being defined following a common
>>        structure.
>>
>>    2.  The Underlying Transport: the transport mechanism to support
>>        exchange of the information elements mentioned above.  This
>>        transport mechanism includes information transport, discovery of
>>        peers, and the securing of this information over the network.
>>
>>    This draft has been motivated by on-going work within IEEE 802.21
>>    [1], but the following description intentionally describes the
>>    problem from a more general perspective.  This document represents
>>    the views of the authors, and does not represent the official view of
>>    IEEE 802.21.
>>
>>    The structure of this document is as follows.  Section 3 defines
>>    mobility services.  Section 4 provides a simple model for the
>>    protocol entities involved in the signalling and their possible
>>    relationships.  Section 5 describes a decomposition of the signalling
>>    problem into service specific parts and a generic transport part.
>>    Section 5.2 describes more detailed requirements for the transport
>>    component.  Section 6 provides security considerations, and Section 7
>>    summarizes the conclusions and open issues.
>>
>>
>> 2.  Terminology
>>
>>    The following abbreviations are used in the document:
>>
>>    o  MIH: media independent handover
>>
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007                [Page 4]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>    o  MN: mobile node
>>
>>    o  NN: network node, intended to represent some device in the network
>>       (the location of the node e.g. in the access network, home network
>>       is not specified, and for the moment it is assumed that they can
>>       reside anywhere).
>>
>>    o  EP: endpoint, intended to represent the terminating endpoints of
>>       the transport protocol used to support the signalling exchanges
>>       between nodes.
>>
>>
>> 3.  Definition of Mobility Services
>>
>>    As mentioned in the introduction mobility (handover) support in
>>    heterogeneous wireless environments requires functional components
>>    located either in the mobile terminal or in the (access) network to
>>     
       Subir>comment; I  would  say more than just access network above. 
                   Suggestion: Either we delete "(access)" or add 
"(access or core)"
>>    exchange information and eventually to take decisions upon this
>>    information exchange.  For instance traditional host-based handover
>>    solutions could be complemented with more sophisticated network-
>>    centric solutions reducing terminal complexity.  Also, neighborhood
>>    discovery, potentially a complex operation in heterogeneous wireless
>>    scenarios, can result in a more simple step if implemented with an
>>    unified interface towards the access network.
>>
>>    In this document the different supporting functions for media
>>    independent handover (MIH) management are generally referred as
>>    Mobility Services (MoS) having in common different requirements for
>>     
           Subir> Comment: Do we need both "common" and "different" above?
>>    the transport protocol.  These requirements and associated
>>    functionalities are the focus of this document
>>
>>
>> 4.  Deployment Scenarios for MoS
>>
>>    The deployment scenarios are outlined in the following sections.
>>    Note: while MN-to-MN signalling exchanges are theoretically possible,
>>    these are not currently being considered.
>>
>>    The following scenarios are discussed for understanding the overall
>>    problem of transporting MIH protocol.  Although these are all
>>    possible scenarios and MIH services can be delivered through link-
>>    layer specific solutions and/or through a "layer 3 or above"
>>    protocol, this problem statement focuses on the delivery of
>>    information for MIH services for the latter case only. 
>>     
         Subir>Suggestion: I would say "the delivery of information for 
mobility services"
                   instead of "delivery of information for MIH services"
>>
>>
>>
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>>
>>
>> Melia, et al.           Expires October 27, 2007                [Page 5]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>> 4.1.  End-to-End Signalling and Transport over IP
>>
>>    In this case, the end-to-end signalling used to exchange the handover
>>    information elements (the Information Exchange) runs end-to-end
>>    between MN and NN.  The underlying transport is also end-to-end
>>
>>            +------+                              +------+
>>            |  MN  |                              |  NN  |
>>            | (EP) |                              | (EP) |
>>            +------+                              +------+
>>                         Information Exchange
>>                <------------------------------------>
>>
>>                /------------------------------------\
>>               <          Transport over IP           >
>>                \------------------------------------/
>>
>>                Figure 1: End-to-end Signalling and Transport
>>
>> 4.2.  End-to-End Signalling and Partial Transport over IP
>>
>>    As before, the Information Exchange runs end-to-end between the MN
>>    and the second NN.  However, in this scenario, some other transport
>>    means than IP is used from the MN to the first NN, and the transport
>>    over IP is used only between NNs.  This is analogous to the use of
>>    EAP end-to-end between Supplicant and Authentication Server, with an
>>    upper-layer multihop protocol such as RADIUS used as a backhaul
>>    transport protocol between an Access Point and the Authentication
>>    Server.
>>
>>
>>            +------+           +------+           +------+
>>            |  MN  |           |  NN  |           |  NN  |
>>            |      |           | (EP) |           | (EP) |
>>            +------+           +------+           +------+
>>                         Information Exchange
>>                <------------------------------------>
>>
>>                 (Transport over  /------------------\
>>                <--------------->< Transport over IP  >
>>                     e.g. L2)     \------------------/
>>
>>                         Figure 2: Partial Transport
>>
>>
>>
>>
>>
>>
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>>
>> Melia, et al.           Expires October 27, 2007                [Page 6]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>> 4.3.  End-to-End Signalling with a Proxy
>>
>>    In the final case, a number of proxies are inserted along the path
>>    between the two transport endpoints.  The use of proxies is possible
>>    in both cases 1 and 2 above, but distinguished here as there are a
>>    number of options as to how the proxy may behave with regard to the
>>    transport and end-to-end signalling exchange.
>>
>>    In this case, the proxy performs some processing on the Information
>>    Exchange before forwarding the information on.  This can be viewed as
>>    concatenating signalling exchanges between a number of EPs.
>>
>>            +------+         +---------+          +------+
>>            |  MN  |         | ProxyNN |          |  NN  |
>>            | (EP) |         |   (EP)  |          | (EP) |
>>            +------+         +---------+          +------+
>>                        Information Exchange
>>               ------------------>
>>                                 ------------------->
>>                                 <-------------------
>>               <------------------
>>               /---------------\     /----------------\
>>              <    Transport    >   <    Transport     >
>>               \---------------/     \----------------/
>>
>>                   Figure 3: Information Exchange Approach
>>
>>    The Proxy NN might process all layers of the protocol suite in the
>>    same way as an ordinary EP.
>>
>>    There is a possibility for realizing other proxy scenarios.
>>
>> 4.4.  End-to-End Network-to-Network Signalling
>>
>>    In this case NN to NN signalling is envisioned.  Such model should
>>    allow different network components to gather information from each
>>    other.  This is useful for instance in conditions where network
>>    components need to take decisions and instruct mobile terminals of
>>    operation to be executed.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007                [Page 7]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>                  +------+          +------+
>>                  |  NN  |          |  NN  |
>>                  | (EP) |          | (EP) |
>>                  +------+          +------+
>>                     Information Exchange
>>                     ------------------->
>>                     <-------------------
>>
>>                     /----------------\
>>                    <    Transport     >
>>                     \----------------/
>>
>>             Figure 4: Information Exchange between different NN
>>
>>    Network nodes exchange information about connected terminals status.
>>
>>
>> 5.  MoS Transport Protocol Splitting
>>
>>    Figure 5 shows a model where the Information Exchanges are
>>    implemented by a signalling protocol specific to a particular
>>    mobility service, and these are relayed over a generic transport
>>    layer (the Mobility Service Transport Layer).
>>
>>
>>                           +----------------+          ^
>>                           |Mobility Support|          |
>>                           |   Service 2    |          |
>>        +----------------+ |                |          | Mobility Service
>>        |Mobility Support| +----------------+          |    Signaling
>>        |    Service 1   |    +----------------+       |      Layer
>>        |                |    |Mobility Support|       |
>>        +----------------+    |   Service 3    |       |
>>                              |                |       |
>>                              +----------------+       V
>>      ================================================
>>         +---------------------------------------+     ^ Mobility Service
>>         |  Mobility Service Transport Protocol  |     |    Transport
>>         +---------------------------------------+     V      Layer
>>      ================================================
>>         +---------------------------------------+
>>         |                   IP                  |
>>         +---------------------------------------+
>>
>>                     Figure 5: Handover Services over IP
>>
>>    The Mobility Service Transport Layer provides certain functionality
>>    (outlined in Section 5.2) to the higher layer mobility support
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007                [Page 8]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>    services in order to support the exchange of information between
>>    communicating mobility service functions.  The transport layer
>>    effectively provides a container capability to mobility support
>>    services, as well as any required transport and security operations
>>    required to provide communication without regard to the protocol
>>    semantics and data carried in the specific mobility services.
>>
>>    The Mobility Support Services themselves may also define certain
>>    protocol exchanges to support the exchange of service specific
>>    Information Elements.  It is likely that the responsibility for
>>    defining the contents and significance of the Information Elements is
>>    the responsibility of other standards bodies other than the IETF.
>>    Example mobility services include the Information Services, Event and
>>    Command services.
>>
>> 5.1.  Payload Formats and Extensibility Considerations
>>
>>    The format of the Mobility Service Transport Protocol is as follows:
>>
>>    +----------------+----------------------------------------+
>>    |Mobility Service|           Opaque Payload               |
>>    |Transport Header|     (Mobility Support Service)         |
>>    +----------------+----------------------------------------+
>>
>>                        Figure 6: Protocol Structure
>>
>>    The opaque payload encompasses the Mobility Support Service 
>>     
             Subir> editorial: add (MSTP)  after Mobility Support Service
>>    information that is to be transported.  The definition of the
>>    Mobility Service Transport Header is something that is best addressed
>>    within the IETF.  MSTP does not inspect the payload and any required
>>    information will be provided by the MSTP users.
>>
>> 5.2.  Requirements on the Mobility Service Transport Layer
>>
>>    The following section outlines some of the general transport
>>    requirements that should be supported by the Mobility Service
>>    Transport Protocol.  Analysis has suggested that at least the
>>    following need to be taken into account:
>>
>>    Discovery:  Discovery: MNs need the ability to either discover nodes
>>       that support certain services, or discover services provided by a
>>       certain node.  
          Subir> comment: why not  both node and service discovery? I 
understand the service discovery is
                     not our scope but the first statement is generic.
>> The service discovery can be dealt with messages as
>>       defined in [1].  This section refers to node-discovery in either
>>       scenario.  There are no assumptions about the location of these
>>       mobility services within the network, 
          Subir> editorial: may add "node" after mobility services above...
>> therefore the discovery
>>       mechanism needs to operate across administrative boundaries.
>>       Issues such as speed of discovery, protection against spoofing,
>>       when discovery needs to take place, and the length of time over
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007                [Page 9]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>       which the discovery information may remain valid all need to be
>>       considered.  Approaches include:
>>     
         Subir> Comment: In general the following approaches fall into 
solution category. Do we need
                     them in the problem statement document? May be I 
made this comment earlier. However,
                     if the group feels that it will improve the 
clarity, I am fine.
>>       *  Hard coding information into the MN, indicating either the IP
>>          address of the NN, or information about the NN that can be
>>          resolved onto an IP address.  The configuration information
>>          could be managed dynamically, but assumes that the NN is
>>          independent of the access network to which the MN is currently
>>          attached.
>>
>>       *  Pushing information to the MN, where the information is
>>          delivered to the MN as part of other configuration operations,
>>          for example, in a Router Discovery exchange.  The benefit of
>>          this approach is that no additional exchanges with the network
>>          would be required, but the limitations associated with
>>          modifying these protocols may limit applicability of the
>>          solution.
>>
>>       *  MN dynamically requesting information about a node, which may
>>          require both MN and NN support for a particular service
>>          discovery mechanism.  This may require additional support by
>>          the access network (e.g. multicast or anycast) even when it may
>>          not be supporting the service directly itself.
>>
>>       Numerous directory and configuration services already exist, and
>>       reuse of these mechanisms may be appropriate.  There is an open
>>       question about whether multiple methods of discovery would be
>>       needed, and whether NNs would also need to discover other NNs.
>>       The definition of a service also needs to be determined, including
>>       the granularity of the description (for example, should the MN
>>       look for an "IS" service, or "IS-local information", and "IS-home
>>       network information" services.
>>     
         Subir> editorial: (for example, should the MN look for an "IS" 
service, or "IS-local information", and "IS-home
      network information" services?)


>>    Information from a trusted source:  The MN uses the Mobility Service
>>       information to make decisions about what steps to take next.  It
>>       is essential that there is some way to ensure that the information
>>       received is from a trustworthy source.  This requirement should
>>       reuse trust relationships that have already been established in
>>       the network, for example, on the relationships established by the
>>       AAA infrastructure after a mutual authentication, or on the
>>       certificate infrastructure required to support SEND [9].  The
>>       security mechanism must provide mutual authentication of MN and NN
>>       and it may provide one way authentication of either of MN and NN.
>>     
             Subir> The last part of the above sentence is not clear to 
me. Are we saying either  mutual 
                         or one way authentication?
>>    Security association management:  A common security association
>>       negotiation method, independent of any specific MSTP user, must be
>>       implemented.  
             Subir>comment: I am not sure whether we can say "must  be  
implemented"?  In some cases, 
                       security association may be needed.
                       suggestion: should is better. Or else, we should 
say if  SAs are required, it should use the
                       common one...
>> The solution must also work in case on MN mobility.
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 10]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>    Low latency:  Some of the Mobility Services generate time sensitive
>>       information.  Therefore, there is a need to deliver the
>>       information over quite short timescales, and the required lifetime
>>       of a connection might be quite short lived.  For reliable
>>       delivery, short-lived connections could be set up as and when
>>       needed, although there is a connection setup latency associated
>>       with this approach.  Alternatively, a long-lived connection could
>>       be used, but this requires advanced warning of being needed and
>>       some way to maintain the state associated with the connection.  It
>>       also assumes that the relationships between devices supporting the
>>       mobility service are fairly stable.  Another alternative is
>>       connectionless operation, but this has interactions with other
>>       requirements such as reliable delivery.
>>
>>    Reliability:  Reliable delivery for some of the mobility services may
>>       be essential, but it is difficult to trade this off against the
>>       low latency requirement.  It is also quite difficult to design a
>>       robust, high performance mechanism that can operate in
>>       heterogeneous environments, especially one where the link
>>       characteristics can vary quite dramatically.  There are two main
>>       approaches that could be adopted:
>>
>>       1.  Assume the transport cannot be guaranteed to support reliable
>>           delivery.  In this case, the Mobility Support Service itself
>>           will have to provide some sort of reliability mechanism to
>>           allow communicating endpoints to acknowledge receipt of
>>           information.
>>
>>       2.  Assume the underlying transport will deal with most error
>>           situations, and provide a very basic acknowledgement mechanism
>>           that (if no acknowledgement is received) will indicate that
>>           something more serious has occurred than a packet drop (since
>>           these other types of error conditions are dealt with at the
>>           transport layer).
>>
>>    Congestion Control:  A Mobility Service may optionally wish to
>>       transfer large amounts of data, placing a requirement for
>>       congestion control in the transport.  There is an interaction
>>       between this requirement and that of the requirement for low
>>       latency since ways to deal with timely delivery of smaller
>>       asynchronous messages around the larger datagrams is required
>>       (mitigation of head of line blocking etc.).
>>
>>    Secure delivery:  The Mobility Service information must be delivered
>>       securely (integrity and confidentiality) between trusted peers,
>>       where the transport may pass though untrusted intermediate nodes
>>       and networks.  The Mobility Service information must also be
>>       protected against replay attacks and denial of service attacks.
>>     
            Subir> comment: 'must' have is too strong here. I am not 
sure how easy it will be to prevent
                       DoS?
                       Suggestion: 'Should'
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 11]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>    Multiplexing:  The transport service needs to be able to support
>>       different mobility services.  This may require multiplexing and
>>       the ability to manage multiple discovery operations and peering
>>       relationships in parallel.
>>
>>    Multihoming:  For some information services exchanged with the MN,
>>       there is a possibility that the request and response messages can
>>       be carried over two different links e.g. a handover command
>>       request is on the current link while the response could be
>>       delivered on the new link.  Depending on the IP mobility
>>       mechanism, there is some impact on the transport option for the
>>       mobility information services.  This may potentially have some
>>       associated latency and security issues, for example, if the
>>       transport is over IP there is some transparency but Mobile IP may
>>       introduce additional delay and both TCP and UDP must use the
>>       permanent address of the MN.
>>
>>    IPv4 and IPv6 support:  The MSTP must support both IPv4 and IPv6
>>       including NAT traversal for IPv4 networks and firewall pass-
>>       through for IPv4 and IPv6 networks.
>>
>>    In addition to the above, it may be necessary for the transport to
>>    support multiple applications (or modes of operation) to support the
>>    particular requirements of the Information Exchange being carried out
>>    between nodes.  This may require the ability to multiplex multiple
>>    information exchanges into a single transport exchange (see figure
>>    Figure 7) .
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 12]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>> +==================================+
>> |                                  |
>> | +------------+  +-----------+    |
>> | |    MIH     |  |   MIH     |    |
>> | |   User 1   |  |  User 2   |... |
>> | |  e.g. MIP  |  |  e.g. SIP |    |
>> | ++++++++++++++  +++++++++++++    |  _    ..............
>> |      \                /          |   \__ :    MIH     :
>> |       \              /           |  _/   :Multiplexing:
>> |     +++++++++++++++++++++        |       :............:
>> |     |   MIH Function    |        |
>> |     |    (e.g. MIS)     |        |
>> |     +++++++++++++++++++++        |
>> |               /\                 |
>> |               ||                 |          ..............
>> |               ||                 |          : Transport  :
>> |               \/                 |          :Multiplexing:
>> |     +++++++++++++++++++++        |          :............:    +---------+
>> |     |     Transport     |        |               ____/\____   |   MIH   |
>> |     | (e.g. TCP, UDP)   |        |              /          \  |.........|
>> |     +++++++++++++++++++++        |                            |Transport|
>> |               /\                 |                            |.........|
>> |               ||                 |                       _____|   IP    |
>> |               ||                 |                      /     +=========+
>> |               ||                 |                     /
>> |               \/                 |    ^+++++++++^     /       +---------+
>> |     +++++++++++++++++++++        |   /           \   /        |   MIH   |
>> |     |         IP        |--------|--<  Internet   > -----     |.........|
>> |     +++++++++++++++++++++        |   \           /   |   \    |Transport|
>> |                                  |    v+++++++++v    |    \   |.........|
>> |                                  |                   |     \__|   IP    |
>> +==================================+                   |        +=========+
>>                                                        |             :
>>                                                        |             :
>>                                                        |        +---------+
>>                                                        |        |   MIH   |
>>                                                        |        |.........|
>>                                                        |        |Transport|
>>                                                        |        |.........|
>>                                                        |________|   IP    |
>>                                                                 +=========+
>>
>>                       Figure 7: Multiplexing examples
>>
>>
>>
>>
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 13]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>> 6.  Security Considerations
>>
>>    Network supported mobility services aim at improving decision making
>>    and management of dynamically connected hosts.  The control and
>>    maintenance of mobile nodes becomes challenging where authentication
>>    and authorization credentials used to access a network are
>>    unavailable for the purpose of bootstrapping a security association
>>    for handover services.
>>
>>    Information Services may not require authorization of the client, but
>>    both event and command services must authenticate message sources,
>>    particularly if they are mobile.  
            Subir> comment: How do we conclude the above?  The 
authorization part is not clear to me. Also
                       having message authentication is a good idea but 
I am not sure if we need to say
                       'must' if they are mobile.
                        suggestion; 'Should' is better.
>> Network side service entities will
>>    typically need to provide proof of authority to serve visiting
>>    devices.  Where signalling or radio operations can result from
>>    received messages, significant disruption may result from processing
>>    bogus or modified messages.  The effect of processing bogus messages
>>    depends largely upon the content of the message payload, which is
>>    handled by the handover services application.  Regardless of the
>>    variation in effect, message delivery mechanisms need to provide
>>    protection against tampering, and spoofing.
>>
>>    Sensitive and identifying information about a mobile device may be
>>    exchanged during handover service message exchange.  Since handover
>>    decisions are to be made based upon message exchanges, it may be
>>    possible to trace an user's movement between cells, or predict future
>>    movements, by inspecting handover service messages.  In order to
>>    prevent such tracking, message confidentiality should be available.
>>    This is particularly important since many mobile devices are
>>    associated with only one user, as divulgence of such information may
>>    violate the user's privacy.  Additionally, identifying information
>>    may be exchanged during security association construction.  As this
>>    information may be used to trace users across cell boundaries,
>>    identity protection should be available if possible, when
>>    establishing SAs.
>>
>>    In addition, the user should not have to disclose its identity to the
>>    network (any more than it needed to during authentication) in order
>>    to access the Mobility Support Services.  For example, if the local
>>    network is just aware that an anonymous user with a subscription to
>>    operatorXYX.com is accessing the network, the user should not have to
>>    divulge their true identity in order to access the Mobility Support
>>    Services available locally.
>>
>>    Finally, the network nodes themselves will potentially be subject to
>>    denial of service attacks from MNs and these problems will be
>>    exacerbated if operation of the mobility service protocols imposes a
>>    heavy computational load on the NNs.  The overall design has to
>>    consider at what stage (e.g. discovery, transport layer
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 14]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>    establishment, service specific protocol exchange) denial of service
>>    prevention or mitigation should be built in.
>>
>>
>> 7.  Conclusions
>>
>>    This Internet draft outlined a broad problem statement for the
>>    signalling of information elements across a network to support media
>>    independent handover services.  
           Subir> editorial; may change above to "mobility services" 
instead of MIH services...
>> In order to enable this type of
>>    signalling service, a need for a generic transport solution with
>>    certain transport and security properties were outlined.  Whilst the
>>    motivation for considering this problem has come from work within
>>    IEEE 802.21, a desirable goal is to ensure that solutions to this
>>    problem are applicable to a wider range of mobility services.
>>
>>    It would be valuable to establish realistic performance goals for the
>>    solution to this common problem (i.e. transport and security aspects)
>>    using experience from previous IETF work in this area and knowledge
>>    about feasible deployment scenarios.  This information could then be
>>    used as an input to other standards bodies in assisting them to
>>    design mobility services with feasible performance requirements.
>>
>>    Much of the functionality required for this problem is available from
>>    existing IETF protocols or combination thereof.  This document takes
>>    no position on whether an existing protocol can be adapted for the
>>    solution or whether new protocol development is required.  In either
>>    case, we believe that the appropriate skills for development of
>>    protocols in this area lie in the IETF.
>>
>>
>> 8.  References
>>
>>    [1]  "Draft IEEE Standard for Local and Metropolitan Area Networks:
>>         Media Independent Handover Services", IEEE LAN/MAN Draft  IEEE
>>         P802.21/D05.00, April 2007.
>>
>>    [2]  Aboba, B., "Architectural Implications of Link Indications",
>>         draft-iab-link-indications-10 (work in progress), March 2007.
>>
>>    [3]  Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
>>         August 2002.
>>
>>    [4]  Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in
>>         IPv6", RFC 3775, June 2004.
>>
>>    [5]  Moskowitz, R. and P. Nikander, "Host Identity Protocol (HIP)
>>         Architecture", RFC 4423, May 2006.
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 15]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>    [6]  Eronen, P., "IKEv2 Mobility and Multihoming Protocol (MOBIKE)",
>>         RFC 4555, June 2006.
>>
>>    [7]  3GPP, "3GPP system architecture evolution (SAE): Report on
>>         technical options and conclusions", 3GPP TR 23.882 0.10.1,
>>         February 2006.
>>
>>    [8]  Koodli, R., "Fast Handovers for Mobile IPv6", RFC 4068,
>>         July 2005.
>>
>>    [9]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
>>         Neighbor Discovery (SEND)", RFC 3971, March 2005.
>>
>>
>> Authors' Addresses
>>
>>    Telemaco Melia
>>    NEC Europe Network Laboratories
>>    Kufuerstenanlage 36
>>    Heidelberg  69115
>>    Germany
>>
>>    Phone: +49 6221 90511 42
>>    Email: telemaco.melia@netlab.nec.de
>>
>>
>>    Eleanor Hepworth
>>    Siemens Roke Manor Research
>>    Roke Manor
>>    Romsey,   SO51 5RE
>>    UK
>>
>>    Email: eleanor.hepworth@roke.co.uk
>>
>>
>>    Srivinas Sreemanthula
>>    Nokia Research Center
>>    6000 Connection Dr.
>>    Irving,   TX 75028
>>    USA
>>
>>    Email: srinivas.sreemanthula@nokia.com
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 16]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>>    Yoshihiro Ohba
>>    Toshiba America Research, Inc.
>>    1 Telcordia Drive
>>    Piscateway  NJ 08854
>>    USA
>>
>>    Email: yohba@tari.toshiba.com
>>
>>
>>    Vivek Gupta
>>    Intel Corporation
>>    2111 NE 25th Avenue
>>    Hillsboro, OR  97124
>>    USA
>>
>>    Phone: +1 503 712 1754
>>    Email: vivek.g.gupta@intel.com
>>
>>
>>    Jouni Korhonen
>>    TeliaSonera Corporation.
>>    P.O.Box 970
>>    FIN-00051 Sonera
>>    FINLAND
>>
>>    Phone: +358 40 534 4455
>>    Email: jouni.korhonen@teliasonera.com
>>
>>
>>    Rui L.A. Aguiar
>>    Instituto de Telecomunicacoes Universidade de Aveiro
>>    Aveiro  3810
>>    Portugal
>>
>>    Phone: +351 234 377900
>>    Email: ruilaa@det.ua.pt
>>
>>
>>    Sam(Zhongqi) Xia
>>    Huawei Technologies Co.,Ltd
>>    HuaWei Bld., No.3 Xinxi Rd. Shang-Di Information Industry Base,Hai-Dian District Beijing
>>    100085
>>    P.R. China
>>
>>    Phone: +86-10-82836136
>>    Email: xiazhongqi@huawei.com
>>
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 17]
>> 
>> Internet-Draft         Mobility Services Transport            April 2007
>>
>>
>> Full Copyright Statement
>>
>>    Copyright (C) The IETF Trust (2007).
>>
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>> Acknowledgment
>>
>>    Funding for the RFC Editor function is provided by the IETF
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>>
>>
>>
>>
>>
>> Melia, et al.           Expires October 27, 2007               [Page 18]
>> 
>>
>>   
>> ------------------------------------------------------------------------
>>
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>>   
>
>
> -- 
> Dr. Telemaco Melia			telemaco.melia@netlab.nec.de
> Senior Research Staff Member		Tel: +49 (0) 6221 4342- 142
> NEC Europe Ltd.				Fax: +49 (0) 6221 4342- 155
> Network Laboratories			Web: http://www.netlab.nec.de
> Kurfuersten-Anlage 36			       
> 69115 Heidelberg
> GERMANY   
>
> NEC Europe Limited | Registered Office: NEC House, 1 Victoria Road, London W3 6BL | Registered in England 2832014 
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