how to increase the speed of sftp

hi ,
i have to tranfer some 12 - 13 gb of files from one server to anothier presently i m using the SFTP but it is taking to much time to trafer the files is there any way to use increase the efficiency of SFTP.
i cant use the FTP

Can you not enable compression with sftp -C ?

How fast is the connection? What throughput do you get? How long does it take? How fast are the discs involved? Which OS? Any systems in the network path that could slow down transfer?

the system is on WAN
the server are AIX
and i want highest throuput

We want to know if there are VPN tunnels or any other constriction points between the host you send from and the host that reveives.

Otherwise - compress the file first, then send it, decompress on the other side.

gzip -9 bigfile
sftp myname@remotenode << EOF
put bigfile.gz
exit
ssh myname@remotenode "gunzip bigfile.gz"