This specifies a FDSN dataselect web service. The default is the IRIS DMC. This can do a data availability via a corresponding FDSN Station web service, but because of the coarseness of the result, it is not as useful as was in the older DHI servers, so the default is off, meaning SOD pretends the available data is always the same as the requested data. The host parameter should be used to connect to another service. The baseurl and port parameters should only be used to connect to a service that does not follow the FDSN specification on how the URL should be formed. For IRIS DMC usage, see http://ds.iris.edu/ds/nodes/dmc/services/usage/ for information on resource limits. In particular for versions of SOD prior to 3.2.5 you should not have more than 3 waveform worker threads or the rate limiter at the DMC may block your requests, resulting in very slow performance. For later versions of SOD requests are batched so more worker threads can be used. However, diminishing returns sets in very quickly, and many threads may end up being slower than a few.
<dobulk>True or False</dobulk> optional
<user>Any text</user> optional
<password>Any text</password> optional