For about 1 year we have been using Backup Exec and sending the backup files to a server connected via multimode fiber at 100 speed. The backup server is running Windows Server 2003 with a JBOD attached. Our nightly backups are exceeding 130 gb. Hoping to speed the transmission of the backup to the destination we decided to upgrade the fiber to gigabit speed. We have a Cisco SR2024 switch at each end with Transition Networks mini-gbic modules for the fiber interface. We are able to connect to the destination server without any problem. The problem is that the backup is consistently failing at the 30 billion byte mark (+/- a few thousand bytes) when connect under the gigabit setup. I can change the connection back to our original setup using D-Link switches at each end at the 100 base speed and the backup works perfectly. Help, I am at a loss as to what could be causing this.