Communications Infrastructure

In order to move ahead with plans for restructuring the northern California earthquake monitoring system, the USGS Menlo Park and BSL have been working to improve their communications infrastructure.

At present, the BSL and the USGS Menlo Park are connected by two dedicated T1 circuits. One circuit is a component of the CISN ring, while the second circuit was installed last year (Figure 4.3) to support the anticipated level of dedicated traffic between Berkeley and Menlo Park above and beyond that associated with the CISN.

The installation of the second dedicated T1 between Berkeley and Menlo Park freed up a frame-relay connection deployed by the BSL as part of the CalREN project in mid-1990s. In the past year, the BSL has been reconfiguring the frame-relay circuit to serve as a second data acquisition link. The plan is to distribute the BDSN data acquisition between the two frame-relay T1 circuits, eliminating what had been a single point of failure. A second component of the plan is to establish an additional Permanent Virtual Circuit (PVC) at each BDSN site so that each station has connections to both T1s.

During the past year, the BSL worked with SBC to distribute the acquisition of seismic data between the two T1s and to establish a second PVC at each frame-relay site. This effort has improved the robustness of data acquisition at the BSL by providing redundancy in the incoming circuit.

In the long term, the BSL and USGS Menlo Park hope to have a high-bandwidth microwave or satellite connection in addition to the current land lines. Unfortunately, we have not been able to obtain funding for this additional communication link at this time.

Figure 4.3: Schematic diagram illustrating the connectivity between the real-time processing systems at the USGS Menlo Park and UC Berkeley, forming the northern California Management Center, and with other elements of the CISN.
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