The Sensor Observation Service (SOS) extension for ArcGIS Server is implemented as a so-called Server Object Extension (SOE). It allows querying of observations, procedures/sensors, as well as features observed by sensors. The interface is compliant with the SOS 2.0 standard from OGC.
using a big database the GetFOI response can get quiet huge. allow the subsetting of the response using a filter with network IDs.