Shared network variables RT FIFO versus buffering

Question

Hello,
can anybody tell me why I should use network shared variables with buffering and RT FIFO (http://www.ni.com/white-paper/4679/en/)?
Only buffering: ok (reader can catch up + I can use fancy none-RT data types).
Only RT FIFO: ok (the high-prio reader/writer is time deterministic).
FIFO and buffering: why? Isn't a FIFO a buffer already?
Thanks!
Peter

Answer 1

DMA: great, I'll have a closer look.
Buffer: What do you mean by "buffer another part", and "buffering on the TCP IP side"?
Conceptually, the problem is that a writer writes, say, at rate 10 pieces of new data / second, and a reader reads 5 pieces of written data / second. If this discrepancy of rates is temporary, a buffer can be used to "remember" the written data so that the reader doesn't miss data from the writer.
Now, the problem can be tackled by a FIFO the same way, a FIFO being a special buffer with a constraint on the orders of written/read data.
So, based on the example above: what is the sense in using a FIFO and a buffer? And what does it have to do with network/TCP IT?
Thanks!
Peter