Say you want to transfer a large file over your network with scp, but you don’t want to hoard all of the network resources for this transfer. You can limit scp’s bandwidth usage by using the -l (lower case L) option and specifying your bandwidth limit in Kbit/s.
So, if I want to transfer a file and limit the bandwidth used to 1MB/s, I’d first compute that 1MB is equal to 1024KB, which is again equal to 8192Kb. (Here B=Byte and b=bit.) So, we end up with the command:
$ scp -l 8192 file_to_transfer user@host:/path-on-other-end