FEDERATOR
EIDA Federator

The EIDA federator provides a single, unified access point to the waveform archives and the station and quality control information from the entire EIDA data holdings, i.e. from all the datacenters in EIDA. Access is through standard FDSN and EIDA web services.

Limitations of the present beta version are:
- only non-restricted waveform data may be downloaded.
- fdsn-station using the federator will only distribute metadata from datacenters that export stationXML1.0 (presently all datacenters, except RESIF)

The Federator is released in January 2020 as a beta version. Users are encouraged to try it out and provide feedback to https://github.com/EIDA/userfeedback/ using the Template specifically created for the Federator.

The following services are exposed:

When should I use the federator, rather than the individual EIDA nodes?

Use the federator, if you want to

  • explore the entire EIDA inventory (station) or access QC information (wfcatalog).
  • explore and download (unrestricted) data from virtual networks
  • download unrestricted data that you know is distributed over multiple EIDA nodes, (e.g. "all stations with HH* channels available in the greater alpine area")
  • download unrestricted data and you are not sure which node it is archived at.

Use an individual node, if you want to

  • download restricted data (targeting each node separately)
  • download unrestricted data which you know is at a single EIDA node (e.g. all waveforms of network GE are hosted at GFZ, thus with a request for all waveforms recorded in the GE network during an event last Monday, go to GFZ's dataselect service)

Advantages of using the federator:

  • a one-stop-shop for all EIDA holdings: it returns all data using a single request, independently of which datacenter is curating it, and whether it is distributed over multiple datacenters
  • direct support for virtual networks (though it does not deliver restricted data): e.g http://eida-federator.ethz.ch/fdsnws/station/1/query?network=_ALPARRAY&level=station&format=text
  • ideal for handling large data requests: it bypasses request size limitations of the individual data centers, and includes traffic shaping and load balancing across nodes.

Disadvantages of using the Federator

  • may be slower than direct access: a request that covers multiple EIDA nodes is limited by the completion of the slowest contributing node's subtask. Complex queries covering many data centers may take some time to process. Especially large station data requests may be significantly slower via federator than submitting individual queries to individual data centers (e.g. requesting the response information of all HHE and HHZ stations operated in Europe at some random date of last year may take up to 3-8 minutes, depending on available caches and the background work load of the national nodes: http://eida-federator.ethz.ch/fdsnws/station/query?network=*&station=*&channel=HHE,HHZ&start=2019-03-09&end=2019-03-10&level=response&format=xml)
  • does not support restricted datasets: the federator does not support authentication by tokens, for these requests, the nodes must be queried directly.
  • in certain cases, http response codes may be misleading: The error codes defined for FDSN web services are poor in describing the result of a distributed task. The federator follows a best effort paradigm, it rather tries to partially fulfil a request than telling you that a request partially failed. (e.g. if somebody is asking for waveforms of the Lake Geneva region, partly hosted by INGV, RESIF and SED, but the SED fdsnws-dataselect node is down in that very moment, the federator will return the INGV and RESIF contributions with status code 200, silently dropping the issue with SED)
  • no support for different versions of stationXML: For fdsnws/station the federator currently does not support stationXML 1.1 (text and stationXML 1.0 only), nor data centers supporting stationXML in the 1.1 format only.
  • data is actualy passing from nodes through the federator to the user:, even if the user sits next to the node. This is not optimal, we should think about it knowing the environmental impact of data through the network.

Bug reports

If you experience any issues with requests to eida-federator.ethz.ch, you are encouraged to file a bug report at [[https://github.com/EIDA/userfeedback/]] using the template named "Federator".

Point of Contact: Philipp Kästli

Service Address and Identifier
FDSNWS-Dataselect http://eida-federator.ethz.ch/fdsnws/dataselect/1/
FDSNWS-Station http://eida-federator.ethz.ch/fdsnws/station/1/
EIDAWS-WFCatalog http://eida-federator.ethz.ch/eidaws/wfcatalog/1/