Trying to identify network/storage issue ?

Hello all,
i trying to identify issue i got with 2003 STD servers.
those servers working with agent that transfer files to remote storage ,
each 3~4 days one of
the servers 5 of them report fail transfer for almost 1~2 min.
*on the servers itself there is no event that indicate link loos or what
ever for those events
i wrote a script that trying each 1 sec check if path file exist on remote
storage , in case of more than 100ms delay its start fping to see if there
is network delay ,and results form fping are saying evrything its ok 0.5
~.0.8 replay.

since i run the script on those servers i have correlated agent events to
script and got about 10 sec and more for file path checking in the same
time.
now when i am doing netstat -es on the servers i get
0 Discards and 0 Errors and only place i get errors is at TCP Statistics for
IPv4
Failed Connection Attempts = 5064
my question is that indicate that the issue exist on the other counterpart
(storage) IO or bandwidth related issue?.
Thanks