scp stalled

Hello:
Since a few days, scp downloading 500MB file from a supercomputer at the
Italian center CINECA results quite often in


francesco@tya64:~/PLX$ scp -p
[email protected]:/gpfs/scratch/userexternal/fpietra0/P3f_accelMD_H2O_PLX/*29.dcd
/home/francesco/PLX
npt_accel-29.dcd                                3%   13MB   0.0KB/s -
stalled -


No problem with small files.

Check at CINECA resulted in no malfunction. The provider (TELECOM ITALY)
says their adsl if percetly functioning. Actually, the speed, ca 600kb/s,
is as expected (don't smile, Italy is at that speed; if you pay more, you
can just hope to download at 1000kb/s, while out is always impracticably
slow).

My question is: can scp, as available from my installation on a wheezy
amd64 box, be responsible?

thanks for advice

francesco pietra