I'm trying to understand all these options in opt.h/lwipopt.h so I can assign them intelligently instead of guessing and wondering why communication fails. So, this is what I think is correct; please correct me if I'm wrong:
In the case of all PBUFs being the same size as defined by PBUF_POOL_BUFSIZE:
-There is no point in making MEMP_NUM_TCP_SEG > PBUF_POOL_SIZE since each segment must use one PBUF at minimum, and actually can cause dropped packets since there will be no space for incoming packets despite MEMP_NUM_TCP_SEG not hitting its limit.
-(TCP_SND_BUF / PBUF_POOL_BUFSIZE) is the effective limit on the number of outgoing segments in the queue, so TCP_SND_QUEUELEN might as well be set equal to this limit, at least in the case of very small outgoing packets that fit into one PBUF.
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