how to set dscp field using altq?

[h bagade]

Hi all,

I want to use combination of pf and the embedded altq to set the dscp field
on a group of packets. I didn't find any relevant configuration on pf.conf
manual, but I find out some tips which mention that altq has the ability to
do the diffserv. I need to know if there is such a possibility in altq
embedded in pf and how to do so?

Any hints or comments are really appreciated