This article aims at analyzing the problems of breaking off during FTP downloading large size files using TD-HSDPA.Through testing in different environment and capturing packets

the initial reason of FTP data stream broken off was found

which is the setting of MSS that coursing the broken-off of FTP data stream.Setting the value of MSS in the Gi firewall can temparorily solve the problem

but the real reason is still to be found

and some other problems are still remained to be solved