Triggering BTeV

BTeV is a collider experiment at Fermilab designed for precision studies of CP violation and mixing. Unlike most collider experiments, the BTeV detector has a forward geometry that is optimized for the measurement of B and charm decays in a high-rate environment. While the rate of B production gives BTeV an advantage of almost four orders of magnitude over e+e- B factories, the BTeV Level 1 trigger must be able to accept data at a rate of 100 Gigabytes per second, reconstruct tracks and vertices, trigger on B events with high efficiency, and reject minimum bias events by a factor of 100:1. An overview of the Level 1 trigger will be presented.Comment: 6 pages, 3 figures. Contribution to the Proceedings, APS-Division of Particles and Fields Conference, DPF99, UCLA, Los Angeles, CA, Jan. 5-9, 199

The MeshRouter Architecture

The Joint Forces Command (JFCOM) Experimentation Directorate (J9)'s recent Joint Urban Operations (JUO) experiments have demonstrated the viability of Forces Modeling and Simulation in a distributed environment. The JSAF application suite, combined with the RTI-s communications system, provides the ability to run distributed simulations with sites located across the United States, from Norfolk, Virginia to Maui, Hawaii. Interest-aware routers are essential for communications in the large, distributed environments, and the current RTI-s framework provides such routers connected in a straightforward tree topology. This approach is successful for small to medium sized simulations, but faces a number of significant limitations for very large simulations over high-latency, wide area networks. In particular, traffic is forced through a single site, drastically increasing distances messages must travel to sites not near the top of the tree. Aggregate bandwidth is limited to the bandwidth of the site hosting the top router, and failures in the upper levels of the router tree can result in widespread communications losses throughout the system. To resolve these issues, this work extends the RTI-s software router infrastructure to accommodate more sophisticated, general router topologies, including both the existing tree framework and a new generalization of the fully connected mesh topologies used in the SF Express ModSAF simulations of 100K fully interacting vehicles. The new software router objects incorporate the scalable features of the SF Express design, while optionally using low-level RTI-s objects to perform actual site-to-site communications. The (substantial) limitations of the original mesh router formalism have been eliminated, allowing fully dynamic operations. The mesh topology capabilities allow aggregate bandwidth and site-to-site latencies to match actual network performance. The heavy resource load at the root node can now be distributed across routers at the participating sites

MeshRouter Primitives: Messages, Interest, and Interpreters

The MeshRouter architecture provides a general framework for interest-limited message ex- changes among client processes. There are two general areas in which the MeshRouter im- plementation depends on specics of the associated clients: i) the lowest level inter-processor communications model and ii) the nature/content of exchanged messages and \interest". This note describes the hierarchical object design (C++ sense) used to implement the basic Message and Interest objects of the MeshRouter. Interfaces are dened in terms of abstract base classes, and specific inherited objects appropriate for the RTI-s/JSAF application are presented as concrete examples. The MeshRouter system includes a substantial memory management com- ponent for efficient use of the basic Message objects. This system is summarized and plausible near-term extensions are noted