No abstract

Data replication is a key issue in a DataGrid and can be managed in different ways and at different levels of granularity: f o r example, at the file level or object level. In the High Energy Physics community, Data Grids are being developed to support the distributed analysis of experimental data. We have produced a prototype data replication tool, the Grid Data Management Pilot (GDMP) that is in production use in one physics experiment, with middleware provided by the Globus Toolkit used f o r authentication, data movement, and other purposes. We present here a new, enhanced GDMP architecture and prototype implementation that uses Globus Data Grid tools f o r efficient file replication. We also explain how this architecture can address object replication issues in an object-oriented database management system. File transfer over wide-area networks requires specific performance tuning in order to gain optimal data transfer rates. We present performance results obtained with GridFTP, an enhanced version of FTP, and discuss tuning parameters.

No abstract

A correctly working Domain Name System (DNS) is essential for the Internet. Due to its significance and because of deficiencies in its current design, the DNS is vulnerable to a wide range of attacks. This paper presents the design and implementation of a secure distributed name service on the level of a DNS zone. Our service is able to provide fault tolerance and security even in the presence of a fraction of corrupted name servers, avoiding any single point of failure. It further solves the problem of storing zone secrets online without leaking them to a corrupted server, while still supporting secure dynamic updates. Our service uses state-machine replication and threshold cryptography. We present results from experiments performed using a prototype implementation on the Internet in realistic setups. The results show that our design achieves the required assurances while servicing the most frequent requests in reasonable time.