aSysBus is hard- and software to build a network of arduino nodes using a CAN-bus or other interfaces. It was build as a replacement for iSysBus(DE), which used native AVR code and a java based configuration framework instead of Arduino. It is mostly used for home automation and other control communication.
For CAN communication Seeed-Studio/CAN_BUS_Shield is required. Be aware the library frequently breaks backwards compatibility. As time of writing master should work, if problems occur look for a commit close to a commit of this library and file a bug here.
Take a look around the wiki to learn more about the protocol, the included examples should help to get you started. If you speak german there are several videos over at YouTube.