Apart from an administrator could arrange the limit bandwidth per clinet, a person admin could arrange bandwidth in accordance with extension that in download him, Along With was the method that most was easy:
/ip firewall filter add chain=forward \
src-address=[ip Local ] protocol=tcp content=.exe \
action=add-dst-to-address-list address-list=cekek \
address-list-timeout=01:00:00
/ip firewall filter add chain=forward \
src-address=[ip Local ] protocol=tcp content=.iso \
action=add-dst-to-address-list address-list=cekek \
address-list-timeout=01:00:00
/ip firewall filter add chain=forward \
src-address=[ip Local ] protocol=tcp content=.mpg \
action=add-dst-to-address-list address-list=cekek \
address-list-timeout=01:00:00
/ip firewall filter add chain=forward \
src-address=[ip Local ] protocol=tcp content=.mp3 \
action=add-dst-to-address-list address-list=cekek \
address-list-timeout=01:00:00

make mangel

/ip firewall mangle add chain=forward \
protocol=tcp src-address-list=cekek \
action=mark-packet new-packet-mark=cekek-bw

Now, You can Limit

/queue simple add name=download-files \
max-limit=64000/64000 packet-marks=cekek-bw

Source : http://mikrotik.unimedcenter.org/?p=87