2 How to Modify the dm.config File to Change Camera and System Assignments System Components cameras give 128MB per second which is more than the 1000Base/T link can handle). The Correct Procedure The first thing to do is to make sure that the NIC is configured correctly. Hopefully this is an Intel Pro/1000 NIC card. If so, go to the network adapter properties and click on the Configure button next to the network card description: Next, click on the Advanced tab and you should see a list of parameters that can be tuned by the user. Look for Jumbo Frames (sometimes called Jumbo Packets ) and Receive Descriptors (sometimes called Receive Buffers ).
On some drivers these may be buried inside Performance Options . Jumbo Frames: Make sure this is set to the maximum available – typically 8192 bytes but only 5k on some NICs. Receive Descriptors: Set this to the maximum – typically 2048. Save the changes. You have just enabled the NIC to handle larger packets. This means that, instead of sending image data from the camera in chunks of 1500 bytes they can now come in chunks of 8192. That means about six times fewer packets for each image. Increasing the number of receive descriptors enables the NIC to handle more packets at any one time.
If the processor is busy when an image arrives, the NIC may not be able to send on the data immediately, but data is still coming in from the camera. These receive descriptor buffer the system against this. (It is almost essential when using a CMG50 camera). Visionscape GigE Camera Guide 2-51