|Yes, it should be possible. But I have to wonder why you want to make a second, separate subnet on the Linksys router?? |
You showed the following as your physical setup:
ISP > Alice modem router > linksys > computers
If clients will only be connected to the second (downstream) router then you might as well just put the second router in the same subnet and connect the two routers "LAN port to LAN port"
I have written a guide for adding a second router like this. For more info, simply click on my name above in this response and read my “how-to” guide titled, “Add a second Router to your LAN”
My guide details both ways to do it. (ie: separate subnet as versus same subnet)
I use tomato on my WRT54GL at home. I've had one experience with DD-WRT and wasn't impressed. When I tried to remove it from the WRT54GL, I found I couldn't. I'm sorry but, if you do that (fix it so your firmware can't be removed once installed) I wouldn't touch your firmware on a bet. I haven't played with the QoS too much so can't help you with that. From what I remember when I looked at it, it won't be too tough to figure out. I would play with it, get it figured out and configured the way you want before you put it into production.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.