• chengcui
• traffic_shaping

Traffic Shaping

Linux

add/remove an emulated latency

cc@Linux:~ % sudo tc qdisc add dev enp1s0 root netem delay 40ms
cc@Linux:~ % tc qdisc show dev enp1s0
qdisc netem 8001: root refcnt 2 limit 1000 delay 40ms
cc@Linux:~ %
cc@Linux:~ % sudo tc qdisc del dev enp1s0 root
cc@Linux:~ % tc qdisc show dev enp1s0
qdisc fq_codel 0: root refcnt 2 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 32Mb ecn drop_batch 64 
cc@Linux:~ %

iptable drop every nth packet

## add a rule
% sudo iptables -A INPUT -p tcp --dport 5201 -m statistic --mode nth --every 10000 --packet 0 -j DROP

## show current rule
cc@r1:~ % sudo iptables -L -vn --line-numbers
Chain INPUT (policy ACCEPT 270K packets, 2369M bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1       27  158K DROP       tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp dpt:5201 statistic mode nth every 10000

## modify current rule
cc@r1:~ % sudo iptables -R INPUT 1 -p tcp --dport 5201 -m statistic --mode nth --every 100 --packet 0 -j DROP

cc@r1:~ % sudo iptables -L -vn --line-numbers
Chain INPUT (policy ACCEPT 17 packets, 1614 bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1        0     0 DROP       tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp dpt:5201 statistic mode nth every 100

## delete current rule
cc@r1:~ % sudo iptables -D INPUT -p tcp --dport 5201 -m statistic --mode nth --every 100 --packet 0 -j DROP