Are you using the Oracle agent or the SAP agent for Oracle to run the backups? The reason I ask this is that the Oracle agent has the ability to resume backups from point of failure (granular to the backup piece) while SAP is not. So if you are using SAP agent and an interrupt occurs due to "network cuts" the job start over from the beginning. With the Oracle agent you can reduce the files per set setting (BFS) and while that may negatively impact performance, it will increase granularity of the backup pieces, so that if the backup gets interrupted by an error on the network, the iDA can resume the backup from point of failure and continue the job without starting over.
If you can't fix the issues on the network you may need to use the Oracle agent to protect the DB rather than the SAP for Oracle agent (if that is indeed what you are using).
Hope this helps...
Ernst F. Graeler
Senior Engineer III