br@wucs.UUCP (Bill Ross) (12/07/85)
I'm looking for some general ethernet statistics. Here at Washington
University Engineering we run an Ethernet with 8+ unix and vms vax-750's.
I'm trying to find rough figures for several numbers:
Average ethernet packet length
Average time between packets
Anything else along these lines
If you have any idea what good values for these numbers might be please
let me know - Also let me know if I've overlooked an easy way of finding
them out for myself. Thanks for any help you can give!
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Bill Ross Washington University ECL, St. Louis 314-889-4794
UUCP: br@wucs.UUCP or ..!{ihnp4,seismo}!wucs!br
ARPANET: wucs!br@seismo.ARPA
CSNET: wucs!br@seismo.ARPA%csnet-relayjqj@cornell.UUCP (J Q Johnson) (12/08/85)
In article <1294@wucs.UUCP> br@wucs.UUCP (Bill Ross) writes: >I'm trying to find rough figures for several numbers: > Average ethernet packet length > Average time between packets > Anything else along these lines The distributions of these numbers very non-normal and installation dependent, so a simple average statistic is useless for almost all practical purposes. For example, packet length is sharply bi- or tri- modal, with one mode at protocol headers+1 data byte, and another mode at the typical bulk data size (headers+ 1K for bsd systems, headers+576 if you use IP and an MTU corresponding to the ARPA value, etc.). Average time between packets does not capture burstiness, which is the interesting performance limiter. One traditional statistic of some interest is the percent of packets transmitted with 1 or more collisions. On 2 ethernets I manage, this average over the last 4 days is .4% on one net, .2% on the other. More typical weekday values are order 1 to 4%. (net 1 has 4 vaxes, 10 suns, 45 Xerox DLs, 5 Symbolics LMs; net 2 has about 16 BSD systems and 10 DLs.)