1. 21-04-0118-00-0000 IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: Title: Application Considerations in Handover Date Submitted: July, 15, 2004 Presented at IEEE 802.21 session #76 in Portland, OR Authors or Source(s): Mahalingam Mani Abstract: Application Perspectives & Implications in Handover.

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3. 21-04-0118-00-0000 Handover Primitives Discovery Media Hardware Detection Announcement/Advertisement Selection Association/Link-in Authentication & Authorization Context Transfer Dissociation Handover is Mobility-event-driven Wire-line or wireless Is a key aspect of media-independent-interworking Primary Goal of Handover is to provide a Framework to coordinate actions initiated by mobility events (triggers)

4. 21-04-0118-00-0000 A Trigger Reference Model Triggers are asynchronous events delivered as Alerts/alarms: push-model Monitored (polled): pull-model Events and Consumers Consumers register with “L2.5” service interface Events are reported into “L2.5” handler interface(s) There is a m-to-n relationship between consumers and events The L2.5 semantic is primarily a clearing-house for triggers/events Coordination network-wide CAPWAP can facilitate but not required to coordinate

5. 21-04-0118-00-0000 Services of “L2.5” Consolidation De/RegDe/Mux MSEH (Network-wide) Coordination Service MSM: Media-Specific Event Handlers (MSEH) Consolidation (of Event Registration) Registration/deregistration Mux/Demux operations of registration Coordination

6. 21-04-0118-00-0000 Cross-network Triggers What is the scope of Triggers? Applications are interested in events that may occur from anywhere within a roaming domain (ESS, e.g.) Applications may also be interested in source of event For location services Emergency location resolution Load-balancing High availability To make Handover meaningful to seamless Mobility across a homogeneous roaming domain triggers should be uniquely identifiable in a domain L2.5 should be conducive for realization in and across multiple network access points

7. 21-04-0118-00-0000 Handover Context Attributes When a network/device handover happens several aspects are handed over/changed Clients Interface/Media IP address (possibly) Session Transport Location Infrastructure (Network Access Point) Clients association/dissociation Client contexts –QoS, Security, Location,… Seamless Handover, where desired,

8. 21-04-0118-00-0000 Events & Location There are generally three variants of locating a mobile client Absolute: Client-centric position Determined by client coordinates or references to APs/cells Absolute: Triangulation through the Infrastructure Relative To the cell/AP – as assessed by infrastructure The popular methods are the latter two These approaches call for use of network-centric trigger

9. 21-04-0118-00-0000 Handout scenario: WLAN->WWAN Alluding to the scenario discussions (M. Williams) one scenario is the one network coverage overlapping the another. When the hand-in is to the overlapping (cell)network from smaller network (WLAN) A cross-cell event is required to provide a trigger to initiate handout to meet seamless handover needs This argues for triggers to be abstractable 1. In the infrastructure 2. Across multiple cells/APs

10. 21-04-0118-00-0000 Summary Handover must allow for distributed dissemination of triggers Triggers must be allowed to be uniquely identified across a homogeneous network domain Handover triggers must also allow for disjoint authorization of clients (while network-network transitive trust & signaling is implied) (dual or multi-homes) Must allow centralized and Federated Trust models Handover must also allow for disjoint profile (multi-homes) besides H-MIH, V-MIH models