Problem Statement Media Independent Handover

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					       Problem Statement: Media
    Independent Handover Signalling
                   draft-hepworth-mipshop-mih-problem-statement-01
                              Ele Hepworth(*), Greg Daley,
                  Srinivas Sreemanthula, Stefano Faccin, Vivek Gupta

                                     March 2006
                                   IETF#65, Dallas


(*) Robert Hancock as a stand-in
                 Contents
• The IEEE 802.21/IETF mipshop picture
  – The overall problem and possible approaches
    to decomposition
• Focus of this draft
  – ‘Transport’ and other common aspects
• Basic MIH support functions
• Proxy and discovery issues
• What next
                    An 802.21 Primer
•   802.21 covers a varied bunch of stuff
     – Framework for service continuity (i.e. how to incorporate mobility protocols)
     – Handover enabling functions (“MIH services”)
     – SAP definitions for different link layers
•   The MIH services are control-plane things which provide information which
    improve the operation of handover algorithms
•   From the (draft) charter:
    "MIH services can be delivered through link-layer
    specific solutions and/or through a "layer 3 or above"
    protocol. MIPSHOP will define the delivery of
    information for MIH services for this latter case.
    Notice that this allows the network information to
    reside anywhere (not necessarily across the link-layer
    hop), and enables MIH services even in the absence of
    the corresponding link-layer support. An L2 or L3 based
    mechanism to identify a valid information server is also
    required; in particular for L3, we expect that any of
    the several current L3 discovery mechanisms will be
    used."
•   This discussion is about protocol support for the MIH services
             802.21 and mipshop
                                                                                      draft-ietf-mipshop-mih-




                             Scope of IEEE 802.21 Standard
Information elements for                                                                   info-elements
each 802.21 MIH service                                                                 how to use the common transport
                                                                                     protocol for MIH services in IP networks



 Common MIH Protocol
      Header




                                                             Assumed scope of IETF
                                                              protocol development
    Transport Layer                                                                   draft-ietf-mipshop-mih-
                                                                                              support
(used by all MIH services)                                                           what is the common transport protocol




    IEEE 802.21 Protocol
                                                                                       IETF mipshop charter items
        Architecture
                  Focus of this draft …                    (*)



 • … is a strawman problem statement for the
   mih-support item
      – Main aspect is common transport part
      – Status of common header is unclear
            • Could just be an issue of registry issues for some identifiers
              carried within ‘transport’
 • A solution meeting the goals in the problem
   statement should be generally useful
      – Initially for transport of 802.21 MIH services
      – Possibly other services in the future
(*)
   As compared to the next two drafts, which are about applicability to
the specific MIH services (ES/CS/IS) that 802.21 has defined
      Basic Protocol Functions
  – As derived from consideration of the MIH services so
    far …:
• Transport-like functions for moving IEs between
  the MIH service endpoints
  – Congestion/flow control, large message support, low-
    level reliability, multiplexing
• Core security functions for moving IEs between
  the MIH service endpoints
  – Integrity (including replay) protection, privacy (of
    identity and other data)
• Denial of service mitigation
  Less Basic Protocol Features
• Discovery                                      MN                ProxyNN                         NN


  – The common protocol has to work                   Full MIH Service          Full MIH Service



    out how to reach the MIH service                   MIH Transport             MIH Transport




    endpoint at the IP level
• Proxy operation
                                                 MN              Redirector                        NN
                                                               MIH Discovery Messages



  – Delivery of an MIH service could                               Full MIH Service


    involve > 2 nodes                                               MIH Transport


     • Several options (see draft section 2.3)
     • Proxy at the MIH service level            MN                Directory                       NN
                                                  MIH Discovery Messages
       (invisible to transport)
     • Proxy assists in discovery process                          Full MIH Service


       (redirection/directory operation)                            MIH Transport
        Summary / What Next
• Need a definition of the problem that mih-
  support will solve
  – This draft is a (partly complete) suggestion from
    people with 802.21 knowledge
  – Consensus has to come from mipshop WG
• Main open issues
  – Scope: should mih-support take a view on MIH
    header or restrict only to the pure IETF common-layer
  – Requirements on discovery / proxy operation
  – Then align PS with the result
• Next step would be to start exploring design
  space for solutions