If I copy the backup file on to the local machine , I can restore it successfully. But that now how our jobs are designed. This restoration is one of the steps in the jobs. We have 9 other steps apart from this. We typically cannot change the step because it has dependencies.
No problem, just wanted to check the backup files themselves are ok - this would suggest they are.
From what you've described, almost certain the problem is at the network level, but I'm not a networking expert so can't help you diagnose further, sorry.
Does the NIC have any diagnostic software? Not sure perfmon can help you here.