At 09:11 PM 2/7/98 -0800, Sean M. Doran wrote:
Tli was just pointing out n messages ago that no matter how well you do in terms of aggregating data traffic into bigger chunks, you still will see an enormous number of small packets around (ACKs). You have to be prepared to switch those at line rate; engineering for some statistical mix of big and small packets is asking for a disaster when someone suddenly goes simplex.
some of the histograms i've seen show close to 50% of the packets being 40 bytes long. the 'desired' tcp behavior is to have no more than 2 data packets for every ack (since congestion control uses ack-reception to pace the transmission of data and try to quickly detect losses).
There is, however, the spectre of there being so many SYNs flying around that they alone might cause congestion collapse. I dunno if I should be frightened of that or not
you should be. not because of the packet-load it causes (as tony pointed out, you have to be able to move 40-byte packets at 'fiber speed') but because it's a symptom of lots of short-lived tcp connections. these connections never get out of slowstart. when there is only a small number of them, it's not important. when there is a large number of them, you have large, non-congestion-controlled, data flows. it's called being nibbled to death by mice.