Hi Bhaskar,
We teach an Administration training course that includes a lesson on uploading files. The general approach is to:
FTP files to/from the application server.
Use a File collector to monitor the directory containing the files.
Use a Data loading (file) activity to read the file and format/map data values as needed. For more complex data transformations, use an Enrichment activity.
You can also use the Enrichment to reconcile and pull in a targeting dimension if the file refers to records that already exist in Adobe Campaign.
Deduplicate as necessary.
Data update activity is used to insert/update records.
For the reverse process, use a Query to pull the data of interest and use a Data extraction (file) activity to write it to a file on the server.
Again you will need to rely on FTP to transfer the file.
Linda