The LTER Network Information System (NIS) is the primary channel for exposing site-based data and metadata through a unified interface for use by value-added applications that include synthesis projects at both local and national scales, and is a core component of the Strategic Cyberinfrastructure Plan. The underlying framework to enable the LTER NIS is the Provenance Aware Synthesis Tracking Architecture (PASTA). The PASTA framework describes the logical flow of data and metadata from individual sites to a centralized data cache, and then into a federated data model of derived and site-based data products. The "data cache" replicates the site's data structure in a relational database by following the table description within the corresponding Ecological Metadata Language document, thereby simplifying access to individual data sets by more advanced workflows through a standard database interface. These quality-controlled, value-added data products derived from the original site data, as well as the original site data, are organized into a federated data model for access by integrative and synthetic data projects to both LTER and the broader ecological community. A functional prototype of the LTER NIS is expected by mid-2011.