I imagine our setup here is somewhat 'typical' for a large environemnt.
100Meg systems feeding 1Gig networks to a L700 tape silo.

A few times a week, I have NetBackup fail a backup with an error 4x code
(some kind of transient network error). These always seem to be on NT
machines (proportionally, there are more NT than Unix, so it might not be
directly related).

Looking at the network itself, I cannot find any switches reporting errors
between the client and the server. Netbackup On sebsequent attempts,
NetBackup is successfull in completing the backup.

Has anyone else seen this behaviour?

Jason