Advanced Frame Analysis

Frame Analysis focuses at analyzing network traffic on a frame-by-frame basis. Napatech Network Adapters are designed for very efficient frame analysis at line rate. When performing Frame Analysis, frames are typically analyzed for:

• Errors: Ethernet CRC errors, frames that are too small or too large
• Frame Contents: The contents of frames containing Ethernet CRC errors in order to detect the source of network traffic errors
• Timing: Latency between a request and a response

Frame Analysis will normally also include the generation of various statistical information, such as frame size distribution on the network and the network load over time. The Napatech Network Adapters provide such statistical information as an RMON1 superset at virtually zero CPU load.

When data on several network ports are analyzed as one network, it is important that the different network ports use the same clock to time-stamp frames. The Napatech multi-port adapters are time-stamping frames using the same clock on all ports. The NT Family Adapters also support hardware synchronization of multiple adapters with very high precision. It is often an advantage to have the frames from the different network ports merged in arrival time order into one stream so that the application can process frames in time sequence without any effort.

The Napatech Networks Adapters support capture of frames with errors. These can be frames with CV errors, MAC CRC errors or frame length errors. The programmable adapter filters can be set up so that frames with errors are either discarded or captured. In both cases, the errored frames are counted. Without the ability to capture frames with errors it can be very difficult, if not impossible, for a network monitoring application to identify the cause of the problem, e.g. which MAC address is sending frames with a bad CRC.