1. A network traffic analysis system, comprising: a plurality of traffic behavior aggregation nodes that implement a plurality of different aggregation levels for traffic source behavior data for a network traffic analysis system, the plurality of traffic behavior aggregation nodes implemented via one or more computers comprising one or more hardware processors and configured to: receive respective indications of endpoint-specific network traffic directed to different ones of a plurality of network endpoints from a plurality of traffic sources; based, at least in part, on the respective indications of the endpoint-specific network traffic from the plurality of traffic sources, generate aggregate traffic source behavior data that is maintained across the plurality of different aggregation levels, wherein a different respective granularity of the aggregate traffic source behavior data is maintained at the plurality of different aggregation levels, wherein the plurality of traffic behavior aggregation nodes maintain different respective portions of the aggregate traffic source behavior data according to the different respective granularity of the plurality of different aggregation levels; a control plane for the network traffic analysis system, configured to: identify traffic behavior for a particular traffic source of the plurality of traffic sources based, at least in part, on the aggregate traffic source behavior data at one or more of the plurality of different aggregation levels, wherein to identify the traffic behavior for the particular traffic source of the plurality of traffic sources, the control plane is configured to: in response to a received request for traffic behavior data: identify one or more aggregation levels that provide a respective granularity of the aggregate traffic source behavior data that includes the requested traffic behavior data; identify at least one of the one or more traffic behavior aggregation nodes of the identified one or more aggregation levels to query for the traffic behavior data; and send a query to the identified at least one traffic behavior aggregation node to obtain the traffic behavior data; and provide an indication of the identified traffic behavior of the particular traffic source such that a traffic control action is performed with regard to the particular traffic source for one or more network endpoints of the plurality of endpoints, wherein the particular traffic source did not direct endpoint-specific network traffic to at least one of the one or more network endpoints.