Setting max latency on classful qdiscs

["Leigh Sharpe" <lsharpe@xxxxxxxxxxxxxxxxxxxxxx>]

Hi All,

 I'm using HTB to shape traffic, a little like this:

 

tc qdisc add dev eth2 root handle 1:0 htb
tc qdisc add dev eth3 root handle 1:0 htb

tc filter add dev eth2 parent 1: protocol 0x8100 prio 5 u32 match u16 3000 0x0fff at 0 flowid 1:1 action ipt -j MARK --or-mark 0x01000000

tc filter add dev eth3 parent 1: protocol 0x8100 prio 5 u32 match u16 3000 0x0fff at 0 flowid 1:1 action ipt -j MARK --or-mark 0x01000000

 

tc class add dev eth2 parent 1:0 classid 1:1 htb rate 2000Kbit ceil 2000Kbit   
tc class add dev eth3 parent 1:0 classid 1:1 htb rate 2000Kbit ceil 2000Kbit   

tc qdisc add dev eth2 parent 1:1 handle 2: htb
tc qdisc add dev eth3 parent 1:1 handle 2: htb

 

tc class add dev eth2 parent 2:0 classid 2:1 htb rate 2000Kbit
tc class add dev eth3 parent 2:0 classid 2:1 htb rate 2000Kbit

tc filter add dev eth2 parent 2:0 protocol 0x8100 prio 2 u32 match u16 3000 0x0fff at 0 flowid 2:1 action ipt -j MARK --or-mark 0x00100000

tc filter add dev eth3 parent 2:0 protocol 0x8100 prio 2 u32 match u16 3000 0x0fff at 0 flowid 2:1 action ipt -j MARK --or-mark 0x00100000

 

This essentially provides a 2mbit/s rate limit on each of eth2 and eth3.

However, when I attempt to put more than 2mbps through it, It gets quite latent (I end up with >1second latency at times). Is there any way of specifying the maximum latency on a HTB class or qdisc? Or CBQ, for that matter? I need to use a classful qdisc, so tbf is out of the question. Ideally, I want to be able to specify that packets get dropped if they are in the queue for any longer than a specified period of time.

Any ideas?

 

Regards,
             Leigh

 

Leigh Sharpe
Network Systems Engineer
Pacific Wireless
Ph +61 3 9584 8966
Mob 0408 009 502

Helpdesk 1300 300 616
email lsharpe@xxxxxxxxxxxxxxxxxxxxxx
web www.pacificwireless.com.au

 

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