Information Technology Reference
In-Depth Information
Example 3. Obligation policy. On discovering a new bluetooth headset add it to the
sound/output/bluetooth domain.
on
HeadsetDetect (X) -> X.type=bluetooth ?
/sound/output/bluetooth.
add
(X)
Example 4. Obligation policy. After 20 failures to enter a PIN, disable the Mobile Phone pol-
icy and enable the Stolen mobile phone policy
event
Stolen:
count
(PIN_failure, 20)
on
Stolen () -> /policy/mobile/normal.
disable
(),
/policy/mobile/stolen.
enable
()
4 Inter-cell Interactions and Self-organisation
Although self-managed cells provide the management capability for supporting con-
figuration and adaptation within a device, there is a need to support management
across multiple cells. The cell architecture supports two forms of inter-cell organisa-
tion:
•
Federated
to support peer-to-peer interactions between cells in order to
collaborate and share resources, for example police, ambulance and fire workers
collaborating and sharing resources at car-accident. Management relationships
between federated cells are often transient, but can be longer-lived.
Nested,
where several cell nest within an enclosing cell and nested cells are not
visible to cells external to the enclosing cell i.e. any management interaction is
via the enclosing cell. Cells can move and out of enclosing cells, for example,
the cell of a patient returning home, may nest in the home cell, and be governed
by the policies of the home cell.
•
We model cell-cell interactions through relationships. Each cell defines its own re-
lationships with respect to other cells. When a new cell is discovered it is subject to a
similar procedure as devices. However for cells, additional actions and protocols are
supported including exchange of policies, event registrations, and domain member-
ship details. These protocols allow cells to share management information and re-
sources and self-organise through federation and nesting.
5 Current Status and Future Work
We are currently developing Java-based implementations of the cell architecture to
run on Series 60 Nokia phones, HP iPaq PDAs and laptops over bluetooth, wi-fi, and
GPRS. We are also experimenting with body sensor nodes with Zigbee wireless
capability that communicate by low-power radio with the iPaq. A simulator to test
larger cells and more easily simulate repetitive events or devices coming into and out
of range is being developed.
There are many issues still to be resolved, such as making sure the protocols opti-
mise the use of battery power; how to make sure a device is 'owned' by the appropri-
ate cell and not taken over; how to present management information and policies to
