[Cake] diffserv based on firewall mark

[Jonathan Morton]

> On 12 Oct, 2016, at 08:52, ching lu <lsching17 at gmail.com> wrote:
> 
> I deprioritize bittorrent traffic by marking related connections in
> iptables (e.g. detect by port number) and route them to corresponding
> HTB class and qdisc.
> 
> How can i archive the same goal using the cake qdisc?

Modify your iptables rules to set the DSCP rather than a kernel-internal mark.  You probably want "-j DSCP —set-dscp-class CS1”, as CS1 is the “bulk low priority” code.  Cake’s default Diffserv mode will pick that up appropriately.

You also need to make sure Cake sees your packets *after* they’ve been through the firewall, which generally means attaching it to the egress port in each direction, not the ingress port.  You’ve probably already done this, if you’re happy with your HTB setup.

If you have multiple LAN interfaces (eg, both Ethernet and wifi), you should loop the inbound traffic through a common IFB device (and attach Cake to that instead of the physical interfaces) to simplify configuration.

 - Jonathan Morton