Locating tina user agents: Strategies for a broker federation and their comparison

Abstract

The future nomadic customer requires the availability of a permanent service profile, and the assignment of a permanent personal number which allows independence from the home domains of any providers. The former requirement is supposed to be realised by objects like TINA's user agent which is acting as a customer's electronic deputy in the provider domain. However, numbering issues are handled by a large, world-wide distributed federation of brokers that maps a personal number onto the current object reference of a user agent. Problems arising in this context concern interoperability between heterogeneous databases of different brokers as well as enormous search times since the flat personal numbering scheme does not give any information about where to search for the current object reference of a certain user agent. The approach presented in this paper overcomes database heterogeneity by using the OMG trading service. Furthermore, based on the trading approach different strategies are presented and evaluated for arranging and searching data entries in the broker federation.