Context-Aware Handoff Management
The visibility of handoff-related context information is essential to operate effective handoff management operations and should include handoff type and characteristics, transient or definitive QoS degradation associated to handoff occurrence, and changes of local provisioning environment due to client handoff between WI access localities.
MUM context model can be logically divided in three parts:
MUM Context Model
Each context part includes various properties (see the table) that report all handoff, QoS, and location related information necessary to the MUM middleware to autonomously operate handoff management operations.
Context Taxonomy and Properties
MUM Service Requirement Specification
To grant service continuity MUM also needs to know service requirements.
MUM adopts standard Service Level Specifications (SLS) to express service requirements service requirements.
In particular, MUM requires the application to declare service tolerance with regards to the following parameters:
Let us stress that SLS is the only service layer information necessary to the middleware to transparently complete handoff management procedures without any other service level intervention.
In addition, MUM adopts standard XML-based formats, based on both Dublin Core (DC) and MPEG7 by Multimedia Picture Experts Group (MPEG), to represent metadata describing static characteristics of delivered multimedia streams (data encoding, frame size, ...).