When I started to backup my data with duplicity I quickly noticed a need to limit bandwidth in order to save band for my normal traffic. I wrote my own /etc/init.d/bwshape with two examples (see references).
To turn the bandwith limitation on I write
# /etc/init.d/bwlimit startTo turn the limitation of I write
# /etc/init.d/bwlimit stop
To make this automatic (limit on during the daytime) I added following lines to
# Traffic shaping off for the night 30 0 * * * root /etc/init.d/bwshape start # Traffic shaping on for the day 0 6 * * * root /etc/init.d/bwshape stop