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

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

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

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

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