SunRay server suffers from udpInOverflows on file server connection

We are using openAFS as network filesystem for home directories and data files on our SunRay servers. As the number of users sessions (20-40) and the activity (5-10% CPU usage) rise on these SunRay servers we observe alarming values from the command "netstat -s".

IPv4    ipForwarding        =     2     ipDefaultTTL        =   255

        ipInReceives        =123501543  ipInHdrErrors       =     0

        ipInAddrErrors      =     0     ipInCksumErrs       =     0

        ipForwDatagrams     =     0     ipForwProhibits     =    19

        ipInUnknownProtos   =  3361     ipInDiscards        =     6

        ipInDelivers        =123975114  ipOutRequests       =114328336

...   

        tcpInErrs           =     0     udpNoPorts          =  3248

        udpInCksumErrs      =     0     udpInOverflows      =  1848

...

As the protocol used between the openAFS file servers and the openAFS clients on the SunRay servers is UDP based, we used rxdebug for further insight. We are seeing resends and waiting calls.

Using dtrace to analyze what kind of packets are dropped one clearly (and only) sees packets sent from openAFS fileservers x.x.[100.59,100.67,30.41] to the SunRay server client on