1. 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

2. 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

3. 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

4. 802.21 and mipshop

5. 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

6. 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

7. Less Basic Protocol Features Discovery –The common protocol has to work out how to reach the MIH service endpoint at the IP level Proxy operation –Delivery of an MIH service could involve > 2 nodes Several options (see draft section 2.3) Proxy at the MIH service level (invisible to transport) Proxy assists in discovery process (redirection/directory operation)

8. 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