Shaping on a large scale

Chris Caputo ccaputo at
Fri Jan 30 19:54:00 UTC 2009

On Fri, 30 Jan 2009, C. Jon Larsen wrote:
> > Open source you can do a custom setup with IPTables and iproute2, but it
> > will take some work to get the same kind of features and management
> > interface.  LARTC is a good reference for this kind of topic:
> >  Also I'm not sure if someone has built this into any
> > of the firewall specific linux distros yet, so you may want to explore
> > those a little.
> The scripts below will set max bandwidth on an interface to 60mbit, and setup
> a queue to shape a.b.c.d to 3Mbit. Seems to work ok for me. Its used on a
> physical server to limit bandwidth to a virtual server(s) on the physical
> server. Should work just as well on a dual-armed router/firewall shaping
> devices behind it.  You would just create more classes (1:11, 1:12, etc) for
> more clients/ips to shape and you might want to knock the ceiling on the
> default (1:30) class down to guarantee the bandwidth to the 1:10,
> 1:11...classes.
> tc qdisc add dev eth0 root handle 1: htb default 30
> tc class add dev eth0 parent 1: classid 1:1 htb rate 60mbit burst 150k
> tc class add dev eth0 parent 1:1 classid 1:10 htb rate 3mbit burst 15k
> tc class add dev eth0 parent 1:1 classid 1:30 htb rate 1kbit ceil 60mbit burst
> 150k
> tc qdisc add dev eth0 parent 1:10 handle 10: sfq perturb 10
> tc qdisc add dev eth0 parent 1:30 handle 30: sfq perturb 10
> ## limit a.b.c.d to 3mbit/sec:
> U32="tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32"
> $U32 match ip src  a.b.c.d/32 flowid 1:10
> $U32 match ip dst  a.b.c.d/32 flowid 1:10
> tc -s -d qdisc show dev eth0

tcng - Traffic Control Next Generation ( 
provides a configuration language that abstracts the gnarliness above.


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