the article on Jumbo frames
that you referenced at http://sd.wareonearth.com/~phil/jumbo.html,
“while the number of packets larger than 1500 bytes
appears small, more than 50%
of the bytes were
carried by such
packets because of their larger size.”
when you look at the source of
this information (reference 1), what it actually says is:
of the bytes are carried
in packets of size 1500 bytes or larger”
This is, of
course, totally different.
As the red curve of figure 3b of http://www.caida.org/publications/papers/1998/Inet98/Inet98.html
shows, it is the 1500 byte packets that contain ~ 55% of the bytes in
analysis and in fact the total number of bytes in all packets above
1500 is a negligible
percentage of the total.
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there is a nice little "tutorial" about the Pros and Cons
of jumbo frames at http://sd.wareonearth.com/~phil/jumbo.html,
it also includes actual frame size distribution measurement on the
MCI backbone from 1998 in which you can see that there are a lot
of frames >1500B from FDDI and other sources, they mention that
more than 50% of all traffic (measured in Bytes and not in packets)
come from packets >1500B. But, larger packets also have a clear
benefit to TCP/IP performance. The difference in store-and-forward
latency between 1.5kB and 9kB is negligible at higher speeds, time
of flight is much, much higher ...
Arthur Marris wrote:
jumbo frames increase
latency in links where there is store and forward?
Both my position and that of the customers I deal with is that higher
10gbps included, is more efficient with the larger packets.
no argument from me on this
one, although the actual
efficiency gained comparing 1.5 K frames to 9 K frames is only ~ 2%,
you're on the cutting/bleeding edge of technology, every bit counts.
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