When I was playing with wondershaper I ran into this too. After reviewing the docs I think that the wondershaper merely gives certain traffic more bandwidth, but does not prioritize it. The CBQ qdisc does not appear to prioritize. If you reduce your uplink rate to less than your slowest transfer speed, you should get the results you expect. I am not sure what it would do for latency - during my testing with VoIP, the wondershaper put packets in the right queues, but could not prevent computer traffic from hogging the bandwidth. What would be ideal is a bandwidth limiting CBQ qdisc encapsulating a PRIO qdisc. I think that can only be obtained with an HBT qdisc (I would be delighted to be corrected!). I am installing SuSE 8.1 so that I have kernel 2.4.19 which I hope will accept the HBT and tc patches (from <http://www.docum.org>'s pointer to HBT's home page) better than SuSE 7.3's 2.4.10. If anyone has sample scripts used for prioritizing VoIP traffic over a VPN (or over anything else), I would really appreciate a chance to see what was done. The only way I have been able to get good VoIP quality is by reducing the bandwidth available to everything else to unacceptably low levels. Regards, Robert ----- Original Message ----- From: "Neil Aggarwal" <neil@JAMMConsulting.com> To: "LARTC Mailing List" <lartc@mailman.ds9a.nl> Sent: Saturday, October 26, 2002 6:53 PM Subject: CBQ broken in RedHat 8.0? Hello all: Is CBQ broken in RedHat 8.0? It seems that my CBQ is not using priorities. I have this setup: Internet <-> DSL Modem <-> Linux router <-> IP Switch <-> Laptop The Linux computer is running a fresh, unmodified installation of RedHat 8.0? On the Linux computer, eth0 points to the DSL modem and eth1 points to my internal network. The Linux compter runs DHCP and masquerade. I want to make sure that ssh traffic is prioritied above all other traffic. After reading the HOWTO and the wondershaper code, I set-up the following tc rules on the Linux computer: # The downlink speed, in kilobits DOWNLINK=300 # The uplink speed, in kilobits UPLINK=100 # The device to control DEV=eth0 # Install the root CBQ at 1:0 tc qdisc add dev $DEV root handle 1: cbq avpkt 1000 bandwidth 10mbit # Add a cbq at 1:1 to limit the total bandwidth to the uplink speed tc class add dev $DEV parent 1: classid 1:1 cbq rate ${UPLINK}kbit allot 1500 prio 1 bounded isolated # Create a queue for the high priority traffic tc class add dev $DEV parent 1:1 classid 1:10 cbq rate ${UPLINK}kbit allot 1600 prio 1 avpkt 1000 bounded isolated tc qdisc add dev $DEV parent 1:10 handle 10: sfq perturb 10 # Create a queue for the low priority traffic tc class add dev $DEV parent 1:1 classid 1:20 cbq rate $[9*$UPLINK/10]kbit allot 1600 prio 2 avpkt 1000 bounded isolated tc qdisc add dev $DEV parent 1:20 handle 20: sfq perturb 10 # Filter ssh traffic into the high prioirty queue tc filter add dev $DEV parent 1:0 protocol ip prio 10 u32 match ip sport 22 0xffff flowid 1:10 tc filter add dev $DEV parent 1:0 protocol ip prio 10 u32 match ip dport 22 0xffff flowid 1:10 # Filter the rest of the traffic into the low priority queue, policing the rate and dropping any overflow packets tc filter add dev $DEV parent 1:0 protocol ip prio 13 u32 match ip dst 0.0.0.0/0 police rate $[9*$UPLINK/10]kbit burst 10k drop flowid 1:20 # Police the incoming traffic to the rate we specified tc qdisc add dev $DEV handle ffff: ingress tc filter add dev $DEV parent ffff: protocol ip prio 50 u32 match ip src 0.0.0.0/0 police rate ${DOWNLINK}kbit burst 10k drop flowid :1 What I am expecting from these rules is that the ssh traffic will take complete priority over anything else. Other traffic will only get what is left over. To test this, I set-up a large FTP upload from my laptop to a machine over the Internet and then set up and ssh transfer of a large file to another machine. After letting things settle down, I ran my traffic control script. After a while, I ran this command to see the results: tc -s qdisc ls dev eth0 Here is what I got: qdisc ingress ffff: ---------------- Sent 514549 bytes 9924 pkts (dropped 0, overlimits 0) qdisc sfq 20: quantum 1514b perturb 10sec Sent 10522893 bytes 7296 pkts (dropped 0, overlimits 0) backlog 5p qdisc sfq 10: quantum 1514b perturb 10sec Sent 7648142 bytes 5449 pkts (dropped 0, overlimits 0) qdisc cbq 1: rate 10Mbit (bounded,isolated) prio no-transmit Sent 18173599 bytes 12771 pkts (dropped 120, overlimits 18412) backlog 5p borrowed 0 overactions 0 avgidle 624 undertime 0 The low priority traffic is getting more traffic sent thru. This is not what I wanted. Any ideas why this is happening? Thanks, Neil. -- Neil Aggarwal JAMM Consulting, Inc. (972) 612-6056, http://www.JAMMConsulting.com Custom Internet Development Websites, Ecommerce, Java, databases _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
