Give me a break. What a bunch of terrible negative advice.
Why do you all have to be that way. I see it here a lot, and some of the people in this thread are MASTERS at pointing out how something is "too complex" and then provide no help. Acting like Smarty pants know it alls
If you can't say anything USEFUL or supportive, then don't post. Your advice is useless.
If you want to point out something is complex, at least link to some information that will support or illustrate your argument. Not one answer showed or shared any understanding of routers or router complexity. It's like I said I wanted to make cookies from scratch and you all start telling me how hard it is to manage a wheat farm.
So, in response to the original question.
A great place to start is dd-wrt, (
http://www.dd-wrt.com/wiki/index.php/What_is_DD-WRT? )an open source router that runs on a variety of different hardware. The source code is available.
By studying that firmware you can also begin to learn what is required from a system hardware standpoint.
1. Do you really understand router top level functions. Could you make a list of top level features a typical router might support
2. DO you have a reason for doing this? Are there router features that you think are needed in the marketplace, but are not provided.
3. Do you really want to build router hardware (that is, design and implement your own fully integrated microprocessor and communications peripherals system)
4. "Designing from scratch" can mean many things. Why would you design your own ethernet stack when there are stacks available? Or your own TCP stack?
Do you know what an ethernet stack or TCP stack are?
5. Since you work at testing routers, do you understand all of the low level functional blocks and interfaces incorporated within the hardware and firmware?
Hopefully that will give you some idea of the complexity of the task you have chosen for yourself.
What does a "router testing
ENGINEER" do, anyway? WHat, exactly, do you
ENGINEER. It seem strange that you can
design tests for a router, but would ask that very general, almost bottomless question on a forum.