You can use the
-l option of
scp to limit the rate of bandwidth.
-l limit Limits the used bandwidth, specified in Kbit/s.
For example, to limit the network bandwidth used. For example, to limit the bandwidth that
scp uses to at most 1000 Kbit/s, you may use command
scp -l 1000 file user@remote:/path/to/dest/
For more options, check manual of