North American Network Operators Group|
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Re: MTU of the Internet?
> > On Thu, 5 Feb 1998, Perry E. Metzger wrote: > > > Eric Osborne writes: > > > The problem with anything Microsoft may put forth is that it'll read > > > like "576 is good. It is the best. We do it. So should everybody. > > > If 576 is good, all else must be bad." And that's simply not the > > > case. > > > > I must admit that I'm very worried about what will happen to the > > internet if they do this. Why? > > > > This will effectively triple the number of packets that routers have > > to do processing on, that's why. > > Packets going through our border routers have an average packet size > in the region of 200 to 250 bytes. How would this triple the average > packet size? > I think that "triple" is perhaps an oversimplification. This assumes that without a 576-byte MTU, all packets would be 1500-byte MTUs. 1500/576 ~=~ 3. Remember, there's three kinds of average: mean, median, mode. While the mean packet size may be 200-250 bytes, the mode and median are probably different. I don't have any statistics on this, but I'd be willing to guess that if you plotted the packet sizes frequency you'd see something like a bimodal curve, with a small peak at around 64 (ping) and a larger one near 1500 (10Mbit Ethernet/T1 MTU). As to median packet size, I have no idea. It's probably somewhere in the middle. :) eric