Multiple NICs - custom protocol development

[Lowell Gilbert]

"Len Gross" <sandiegobiker at gmail.com> writes:

> First, thanks for the response; It's nice to see some community support.
>
> Here is what I am trying to do:
>
> I am building a custom MAC protocol for a wireless system that has different
> software on
> the "head end" and the "clients."  It is not peer-to-peer,  While the
> hardware is being developed
> I want to use Ethernet as a physical layer.
>
> So,I want to use one card running server code and one card running client
> code initially.   Later I will do
> the checkout with multiple client machines and a single server.
>
> If the OS "loops a packet back" (At the IP layer) before it gets to my "MAC
> layer" then I can't test any code.

If the client and server are sharing an IP stack, then the packets
*should* be looped back at the IP layer.  You want separate stacks for
testing with IP, and in my earlier message I listed some ways to do
that with a single machine.  Getting a second PC is always an option
too, and often a simple answer.

Another option could be to fake (or wrap) the socket calls, but I
doubt that's really going to be worthwhile for you.  I prefer to never
spend more time debugging the testbed than absolutely necessary.

Good luck.