RoseNMS is a Network Management System (NMS) written entirely in Python and using the Turbogears2 framework. A Network Management System is a piece of software that monitors the status of network equipment such as routers, switches and servers.
The two basic jobs of pretty much any NMS is to track the state of various “things about” in some device, which are called attributes in RoseNMS, and graph and/or alert on certain measurements about that attribute. To give a more concrete example, most NMS will monitor the state (up/down/testing) of a network interface and will graph the number of bytes or packets flowing in and out of it.
In RoseNMS terms, the interface is an Attribute of the Host. The physical interface is an AttributeType which means RoseNMS knows what Pollers to run and statistics to collect. RoseNMS will also scan a host to find various new Attributes of that host, such as when new interfaces are created.