Quality of Service in TCP networks using dummynet traffic shaping

Test conditions

• ADSL line 64kbyte/s downlink, 8kbyte/s uplink
• FreeBSD 5.2.1-RELEASE with ipfw2 and dummynet
• Download: FTP transfer of 20mbyte file from local ISP
• Upload: SSH copy of file to another server (activated after the download)

Test #1

IPFW2 rules

enable one_pass
pipe 1 config bw 62Kbit/s queue 8kbits
queue 11 config pipe 1 weight 7
queue 12 config pipe 1 weight 1
add queue 11 tcp from any to any out via tun0 tcpflags ack iplen 40-52
add queue 12 out via tun0
add allow all from any to any

Graphs to illustrate the difference

Test #2

IPFW2 rules

pipe 1 config bw 62Kbit/s queue 64kbits
queue 11 config weight 7 pipe 1
queue 12 config weight 1 pipe 1
add queue 11 tcp from any to any out via tun0 tcpflags ack iplen 40-52
add queue 12 ip from any to any out via tun0
add allow ip from any to any

Graphs to illustrate the difference