Shaping on a large scale

C. Jon Larsen jlarsen at
Fri Jan 30 15:40:23 UTC 2009

> 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

> -----Original Message-----
> From: Bruce Grobler [mailto:bruce at]
> Sent: Friday, January 30, 2009 12:34 AM
> To: nanog at
> Subject: Shaping on a large scale
> Hi,
> Does anyone know of  any Shaping appliances to shape customers based on
> IP, allow for a quota per IP and qos mechanisms like LLQ?,  This is
> should be something that can sit in between two border router's and
> support a small ISP (20000 customers), also an opensource solution would
> be great!

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