Network Buffer Blocks

The Ethernet library includes a sublibrary, Network Buffers, that contains blocks for managing Ethernet network buffers. The blocks in this sublibrary are core blocks that you can use to create other subsystems.

The Ethernet drivers use a set of buffers, Ethernet network buffers, that it uses to store data that is sent and received over the network. The block organizes these buffers into several pools, each with different values of maximum data size. The buffers include information about the data itself. The block allocates the buffer pools during initialization and does not change the buffer pools during run time. When the block sends, receives, or processes data, it allocates a buffer. When the operation is done, it frees the buffer.

You can control the number of buffers allocated for each allowable value of data size by using the Buffer Mngmt block parameter Buffer pool sizes. Allocate enough buffers for the maximum number of data packets that you anticipate receiving, sending, or processing at one time. You can send and receive more data by allocating many more buffers. However, each allocation reserves more memory, which you cannot then use for other purposes. Running out of buffers means that data cannot be sent and received until the block frees allocated buffers.

Monitor the buffer pool statistics at run time to find the optimal values that an application requires. To monitor the buffer pool statistics, select the Display tuning information check box in the Buffer Mngmt block parameters dialog box.

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