以下為一個模擬網路狀態的script，可以模擬封包延遲與丟棄封包，並限制上下傳頻寬
#!/bin/bash
#
# tc uses the following units when passed as a parameter.
# kbps: Kilobytes per second
# mbps: Megabytes per second
# kbit: Kilobits per second
# mbit: Megabits per second
# bps: Bytes per second
# Amounts of data can be specified in:
# kb or k: Kilobytes
# mb or m: Megabytes
# mbit: Megabits
# kbit: Kilobits
# To get the byte figure from bits, divide the number by 8 bit
#
INIF="eth0"
EXTIF="eth1"
DELAYTIME="250ms"
LOSSRATE="0%"
UPRATE="512kbit"
DOWNRATE="5500kbit"
export INIF EXTIF DELAYTIME LOSSRATE UPRATE DOWNRATE
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/sbin:/usr/local/bin; export PATH
echo -e "\nCurrent qdisc define rules"
tc qdisc show
echo -e "\nRemove old define rules"
tc qdisc del dev $EXTIF root
tc qdisc del dev $INIF root
echo -e "\nDefine new define rules"
tc qdisc add dev $EXTIF root handle 1: htb default 11
tc class add dev $EXTIF parent 1: classid 1:1 htb rate 1000Mbps
tc class add dev $EXTIF parent 1:1 classid 1:11 htb rate $UPRATE ceil $UPRATE
tc qdisc add dev $EXTIF parent 1:11 handle 10: netem delay $DELAYTIME loss $LOSSRATE
tc qdisc add dev $INIF root handle 1: htb default 11
tc class add dev $INIF parent 1: classid 1:1 htb rate 1000Mbps
tc class add dev $INIF parent 1:1 classid 1:11 htb rate $DOWNRATE ceil $DOWNRATE
tc qdisc add dev $INIF parent 1:11 handle 10: netem delay $DELAYTIME loss $LOSSRATE
echo -e "\nCurrent qdisc define rules"
tc qdisc show
echo -e "\n"
若是要在 iOS 設備上模擬，iOS已經提供開發者此項模擬功能。可以直接透過GUI進行設定，設定過程如下：
 |
| 選擇 [設定] |
 |
| 選擇 Netowrk Link Conditioner |
 |
| 選擇某個Profile |
 |
| Profile 內容 |
參考資料：
頻寬限制
封包延遲與丟棄封包
