Problem Statement Media Independent Handover

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					       Problem Statement: Media
    Independent Handover Signalling
                              Ele Hepworth(*), Greg Daley,
                  Srinivas Sreemanthula, Stefano Faccin, Vivek Gupta

                                     March 2006
                                   IETF#65, Dallas

(*) Robert Hancock as a stand-in
• 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
•   This discussion is about protocol support for the MIH services
             802.21 and mipshop

                             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

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

    IEEE 802.21 Protocol
                                                                                       IETF mipshop charter items
                  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