[LARTC] Creating a contended section of bandwidth with HTB and IMQ

[Charles Price]

Hi All,

I'm trying to create a contended section of bandwidth using IMQ. I have the 
imq0 device up and running, with traffic passing through it.

Firstly, I need to throttle the entire device imq0 to 2mbit/s.

I would then like to add throttle rules for individual IP addresses, allowing 
them to pass up to 512kbit/s each, as long as imq0 has not reached its 
2mbit/s.

The configuration I currently have is as follows:

tc qdisc add dev imq0 root handle 1: htb default 1
tc class add dev imq0 parent 1: classid 1:1 htb rate 2mbit burst 15k

# IP 10.0.0.10
tc class add dev imq0 parent 1:1 classid 1:10 htb rate 512kbit
tc qdisc add dev imq0 parent 10 handle 10: sfq
tc filter add dev imq0 protocol ip parent 1: prio 10 u32 \
  match ip src 10.0.0.10/32 flowid 1:10

# IP 10.0.0.20
tc class add dev imq0 parent 1:1 classid 1:20 htb rate 512kbit
tc qdisc add dev imq0 parent 20 handle 20: sfq
tc filter add dev imq0 protocol ip parent 1: prio 20 u32 \
  match ip src 10.0.0.20/32 flowid 1:20


Both IP addresses (10.0.0.10 and 10.0.0.20)  aquire their 512kbit/s without 
problem. However, when I add more classes like the ones above and pass 
plently of traffic, each IP address still obtains its full 512kbit/s - 
regardless of the 2mbit/s limit in the root class.

Is there a way to achieve this?

Thanks in advance,

Charlie