Transcript Patterns in Universal Plug & Play

SIEMENS
Patterns in Universal Plug & Play
Markus Alexander Wischy
OOPSLA 2000, Jini Pattern Language Workshop
SIEMENS
Pick and verify
 Motivation:
 Avoiding a central resource manager for allocating resources
 Solution
 Randomly choose a resource
 Verify that this resource is not in use (multicast/broadcast)
 Use the resource or choose another resource
 Known uses
 Used in Auto-IP (for IP adresses)
OOPSLA 2000, Jini Pattern Language Workshop
SIEMENS
Lease and Locator
 Leases can provide a soft state
 Add robustness to changing environments
 Additional update messages provide more actuality to
the soft state
 Adding Queries and complementary Announcement
messages provide means to balance actuality and
network traffic
 Lease messages can contain other information (e.g.
location), avoiding futher messages or central
components
OOPSLA 2000, Jini Pattern Language Workshop
SIEMENS
Other concepts
 XML Descriptions
 Standardized DTD can provide Introspection functionality
 Multicast/Broadcast
 Avoiding a central component in the network
 Fails to scale to large networks
OOPSLA 2000, Jini Pattern Language Workshop
SIEMENS
Discussion points
 The pick and verify schema of Auto-IP can be described
as a pattern
 XML descriptions provide Introspection functionality
 Soft states are an important concept of leases
 Lease renew messages can contain additional
information (e.g. location)
 Location information can be distributed by a distributed
algorithm, avoiding a central component in the network
OOPSLA 2000, Jini Pattern Language Workshop