[LARTC] Simple case here!

[Andy Furniss]

Amit Vyas wrote:
> 
> Hi All,
> 
> I want to setup a machine to connect to internet at a limited rate of 64 
> kbps.
> That machine is connected to a switch. so my LAN and Internet both comes 
> from the same eth0.
> How can I limit only the internet access from this machine to 64kbps and 
> still using 100mbps for LAN
> 
> I am trying to implement this Please guide me If i am wrong.
> I mark all the packets going out to LAN.
> Then I can setup a root qdisc to classify packets based on that mark. If 
> match  then I can setup a class to accept those setup a fifo for those 
> packets. but if the packets are not for the LAN then i can pass them to 
> other class which is tbf shaping at rate 64kbps.
> 
> Am i right on these lines.
> This is the setup
> 
> +------------+   eth0        +-----------+   internet
> | machine   |---------------|   Switch  |-------------
> +------------+                  +-----------+
> 
> trying to get some thing like this
> 
>                         root qdisc  (CBQ or something)
>                            /     \
>                          /         \
>                        /             \
>                      /                 \
>                class              class
> Internal LAN Pcakets        Any other unclassified Packets
>                  |                      |
>                  |                      |
>               FIFO             TBF (rate 64kbps)
> 
> Please Help me out with marking the packets and to classify them.
> Just started off with Traffic Shaping.  gigles...... : )
> 
> It is alos possible to alternatively to mark internet traffic as it 
> would be less in comparison to LAN and thus processor friendly.
> 
> Amit Vyas

I would use netfilter + HTB something like -

$TC qdisc add dev eth0 root handle 1:0 htb default 0
$TC class add dev eth0 parent 1:0 classid 1:1 htb rate 64kbit

$TC filter add dev eth0 parent 1:0 protocol ip handle 1 fw flowid 1:1

$IPTABLES -t mangle -A POSTROUTING -o eth0 --dst ! 192.168.0.0/24 -j 
MARK --set-mark 1

Depending on what the PC does it may be nicer to priorotise empty acks / 
udp headed for the internet over bulk traffic.

Andy.