Sudden break in network cause large data loss

Anybody can help me to know how to detect sudden loss of GSM network?
as We keep on fetching from flash and uploading data TCP server after every 1 second. and we remove suddenly antenna we found that data is showing on screen uploading to server but it doesn’t received by the server after 15 to 20 seconds we get +WIND: 8 indication which we have programed to stop fetching data from FLASH, we find very large amount of data lost. Please anybody can provide solution for it or any event capture?.. We tried to capture all Events in WIP but no use in these types of condition. We also find some +CIEV Events generated. Where do we get Deffination list for the same?