workload myths: prevalence of IP fragmentation

myth:
tcp traffic is never fragmented
data:
while tcp traffic is fragmented much less frequently than other protocols due to path MTU discovery, we saw 0.009% by packets (0.019% by bytes) of fragmented tcp traffic.
and a majority of fragmented tunneled traffic is tcp!


myth:
nfs causes all (or almost all) fragmented traffic
data:
microsoft's media player was single largest cause (52%) of measured fragmented traffic.  Tunneled traffic, also a major cause, accounts for 16% of all fragment series.  nfs caused 0.1% of all monitored wide-area fragmented traffic.
tunneled traffic (ipencap, ipip, gre, udp l2tp), icmp, and realmedia all cause more fragmented traffic than nfs (0.1%).