[Users] Problem introducing VDSM hosts

Hi folks, We are setting up ovirt on Proliant BL460c blades (mix of G1 & G6), and found an interesting problem. Can anyone here can offer guidance on how to approach this please? Also, I would be interested to know others' experiences of using ovirt on BladeSystem gear. The problem: When trying to introduce a new VDSM host, the install fails, immediately. It's reproducible; we tried more than a dozen times, with different combinations of NICs, to eliminate hardware faults. These messages appear on the VDSM host: Dec 13 10:55:24 bl05 sshd[2627]: pam_unix(sshd:session): session opened for user root by (uid=0) Dec 13 10:55:24 bl05 sshd[2627]: Corrupted MAC on input. Dec 13 10:55:24 bl05 sshd[2627]: Disconnecting: Packet corrupt Dec 13 10:55:24 bl05 sshd[2627]: pam_unix(sshd:session): session closed for user root It seems to be a checksum problem. Google has plenty of similar reports (none ovirt-related), and very little in the way of troubleshooting tips. We have eliminated physical hardware; memory has tested OK, and alternative network ports have been tried, with the same result. I expected to be able to reproduce the issue outside ovirt, by scping large files back and forth, however, this did not cause errors. I believe it's a software matter, possibly TOE, but I don't know how to take it further. We are using FC19 for both the ovirt-engine and vdsm hosts. Any guidance on how to solve this would be much appreciated. Thanks in advance, Garry