1. Patterns in Universal Plug & Play
Markus Alexander Wischy
OOPSLA 2000, Jini Pattern Language Workshop

2. OOPSLA 2000, Jini Pattern Language Workshop
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

3. OOPSLA 2000, Jini Pattern Language Workshop
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

4. OOPSLA 2000, Jini Pattern Language Workshop
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

5. OOPSLA 2000, Jini Pattern Language Workshop
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