Preparation of network data for analysis. An original frame representing a frame transmitted in a communications link can be received wherein the original frame comprises a payload. At least a portion of the payload can be removed from the original frame. Statistics can be inserted into the original frame to generate a modified frame. Original frames can be removed and not transmitted to an analysis system. A modified frame can represent several original frames that are removed. Additional frames can be generated. A frame can be generated that represents several original frames that have been removed. A generated frame or modified frame can indicate errors and/or preprocessing by a logic device.