Picking an IP multicast address

I'm building a network of fairly stupid devices. Most if not all communication with them will be via MAC-addressable frames. They aren't big or smart enough to have an IP stack, complex, heavy-weight discovery protocols, etc. BUT, I also need 'Windows-based tools to be able to reach these devices and _that_ is facilitated by writing to a multicast _IP_ address and letting the stack just do the normal thing of mapping that IP into a multicast MAC address.

The problem I have is picking the multicast IP address. I know some are reseerved (all hosts, all routers, etc.) and I know there are protocols for having one assigned dynamically on a network at run time. But, as I said, these devices are too stupid to negotiate for that assignment. Is there one or more multicast IP addresses that are intended to be used like network 10 (10.192.x.x, 10.168.x.x, etc.) for local, private communication?

Thanks for any pointers.


Reply to
Chris Nelson
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20 years ago diskless machines could boot with RARP and TFTP/UDP in maybe an 8K ROM, with the disk boot code in there, too.

I really find it hard to believe that even the smallest machine today couldn't do it. (Though I would hope BOOTP or DHCP instead of RARP.)

UDP is much easier than TCP. TFTP was designed to be easy to implement in a small ROM.

The only system that I legitimately believe should be able to work without IP is the system to power up machines based on a special ethernet frame. Only the NIC is available to process it, as the machine is off!

-- glen

Reply to
glen herrmannsfeldt

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