Linux下主要是使用tc工具来进行限速。不过tc用起来真是不容易，参数非常多且很难懂，要想用好的话很耗时间。
推荐一个老外写的脚本wondershaper，简单易用，也是很好的tc参考样例。 虽然脚本早就不更新了，但是在CentOS6.2 64bit下验证仍可以用。 网址：http://lartc.org/wondershaper/ 下载：http://lartc.org/wondershaper/wondershaper-1.1a.tar.gz
解压后，编辑wshaper脚本文件，修改开头的几个限速参数： 下载，上传，网卡。速度的单位是kpbs。
DOWNLINK=1024
UPLINK=512
DEV=eth0
一个完整的配置脚本文件：
#!/bin/bash
# Wonder Shaper
# please read the README before filling out these values
#
# Set the following values to somewhat less than your actual download
# and uplink speed. In kilobits. Also set the device that is to be shaped.
DOWNLINK=1024
UPLINK=512
DEV=eth0
# low priority OUTGOING traffic - you can leave this blank if you want
# low priority source netmasks
NOPRIOHOSTSRC=80
# low priority destination netmasks
NOPRIOHOSTDST=
# low priority source ports
NOPRIOPORTSRC=
# low priority destination ports
NOPRIOPORTDST=
# Now remove the following two lines :-)
#echo Please read the documentation in 'README' first :-\)
#exit
#########################################################
if [ "$1" = "status" ]
then
tc -s qdisc ls dev $DEV
tc -s class ls dev $DEV
exit
fi
# clean existing down- and uplink qdiscs, hide errors
tc qdisc del dev $DEV root 2> /dev/null > /dev/null
tc qdisc del dev $DEV ingress 2> /dev/null > /dev/null
if [ "$1" = "stop" ]
then
exit
fi
###### uplink
# install root CBQ
tc qdisc add dev $DEV root handle 1: cbq avpkt 1000 bandwidth 10mbit
# shape everything at $UPLINK speed - this prevents huge queues in your
# DSL modem which destroy latency:
# main class
tc class add dev $DEV parent 1: classid 1:1 cbq rate ${UPLINK}kbit \
allot 1500 prio 5 bounded isolated
# high prio class 1:10:
tc class add dev $DEV parent 1:1 classid 1:10 cbq rate ${UPLINK}kbit \
allot 1600 prio 1 avpkt 1000
# bulk and default class 1:20 - gets slightly less traffic,
# and a lower priority:
tc class add dev $DEV parent 1:1 classid 1:20 cbq rate $[9*$UPLINK/10]kbit \
allot 1600 prio 2 avpkt 1000
# 'traffic we hate'
tc class add dev $DEV parent 1:1 classid 1:30 cbq rate $[8*$UPLINK/10]kbit \
allot 1600 prio 2 avpkt 1000
# all get Stochastic Fairness:
tc qdisc add dev $DEV parent 1:10 handle 10: sfq perturb 10
tc qdisc add dev $DEV parent 1:20 handle 20: sfq perturb 10
tc qdisc add dev $DEV parent 1:30 handle 30: sfq perturb 10
# start filters
# TOS Minimum Delay (ssh, NOT scp) in 1:10:
tc filter add dev $DEV parent 1:0 protocol ip prio 10 u32 \
match ip tos 0x10 0xff flowid 1:10
# ICMP (ip protocol 1) in the interactive class 1:10 so we
# can do measurements & impress our friends:
tc filter add dev $DEV parent 1:0 protocol ip prio 11 u32 \
match ip protocol 1 0xff flowid 1:10
# prioritize small packets (<64 bytes)
tc filter add dev $DEV parent 1: protocol ip prio 12 u32 \
match ip protocol 6 0xff \
match u8 0x05 0x0f at 0 \
match u16 0x0000 0xffc0 at 2 \
flowid 1:10
# some traffic however suffers a worse fate
for a in $NOPRIOPORTDST
do
tc filter add dev $DEV parent 1: protocol ip prio 14 u32 \
match ip dport $a 0xffff flowid 1:30
done
for a in $NOPRIOPORTSRC
do
tc filter add dev $DEV parent 1: protocol ip prio 15 u32 \
match ip sport $a 0xffff flowid 1:30
done
for a in $NOPRIOHOSTSRC
do
tc filter add dev $DEV parent 1: protocol ip prio 16 u32 \
match ip src $a flowid 1:30
done
for a in $NOPRIOHOSTDST
do
tc filter add dev $DEV parent 1: protocol ip prio 17 u32 \
match ip dst $a flowid 1:30
done
# rest is 'non-interactive' ie 'bulk' and ends up in 1:20
tc filter add dev $DEV parent 1: protocol ip prio 18 u32 \
match ip dst 0.0.0.0/0 flowid 1:20
########## downlink #############
# slow downloads down to somewhat less than the real speed to prevent
# queuing at our ISP. Tune to see how high you can set it.
# ISPs tend to have *huge* queues to make sure big downloads are fast
#
# attach ingress policer:
tc qdisc add dev $DEV handle ffff: ingress
# filter *everything* to it (0.0.0.0/0), drop everything that's
# coming in too fast:
tc filter add dev $DEV parent ffff: protocol ip prio 50 u32 match ip src \
0.0.0.0/0 police rate ${DOWNLINK}kbit burst 10k drop flowid :1