Sentence:  The UPnP architecture provides features for connectivity layer and resource layer that are defined in general grid computing architecture. Unfortunately, collective layer mechanisms, such as co-allocation, directory service, <WSD>broking</WSD>, work load management, community account and payment, are not defined yet. 
Meaning of the word marked with <WSD> tags:  The action of a broker agent; exchange of messages or transactions involving a software agent.