There are many technical challenges in designing the architecture of globally-distributed, federated digital libraries. This paper focuses on the problem of global resource discovery and describes a service architecture and server topology for improving the performance and reliability of that process. The technique described is based on three concepts. Connectivity regions are groups of sites with relatively good network connectivity. Collection services provide the necessary metainformation so that a group of digital library servers can interoperate as a collection. Collection views represent the configuration of the collection that conforms to connectivity regions. The work that is described here is based on experience with the NCSTRL international digital library of computer science research and is implemented as part of the Dienst architecture upon which NCSTRL is based.