What is jsFlow?

jsFlow is Java library for sFlow (version 5). sFlow is an industry standard to monitor switches and routers.

So far, jsFlow does not support the complete set of headers as described by the sFlow version 5 specification.
Currently, all the headers as used by Force10 E-series switches are supported. However, the jsFlow architecture is designed to be easily extensible which means it should be easy to implement support for additional vendors and switch models.

Which use cases are covered by jsFlow?

The abstract use case for jsFlow is to work with sFlow data. jsFlow can be used as sFlow agent and as sFlow collector. However, the uses cases are not limited to these examples. Additional, other use cases are listed in the following list:

  • Transparent sFlow proxy: In case you want to modify the sFlow data that is sent by switches or routers jsFlow can be used as a transparent sFlow proxy.
  • sFlow multiplexer: Typically, routers and switches support only a limited number of sFlow collecters. In case the sflow traffic should be received by more than this number of sflow collectors a multiplexer can be used to distribute the sflow data to any number of sflow collectors.

What do you need to run jsFlow?

A Java Runtime Environment (version 5 or higher) is required to be able to use the jsFlow library.

What license does jsFlow use?

The jsFlow library is released under the GPL version 2.

Do you want to contribute?

In case you catch a bug or you implemented a missing header, please feel free to send patches to Thomas King.

Who develops and maintains the jsFlow library?

The initial version of the jsFlow library has been developed during an internal project at the DE-CIX Management GmbH.
Currently, the maintainer of the jsFlow library is Thomas King.

Where can I download jsFlow?

The latest version of jsFlow is available here. Currently, the latest version is 0.2.


  • Version 0.2 (11/12/2009): Bugfix in counter headers. Tagged mac address header added.
  • Version 0.1 (04/02/2009): Initial release