On 10/26/2023 4:48 PM, Nathan Hartman wrote:
I wonder if this hasn't been solved already in some industry-accepted
manner. For example (not saying this is the solution, just thinking out
loud) there is a redundancy mechanism that makes two network interfaces
look like one, with automatic failover. What the OP wants looks like the
reverse of that: make one network interface look like two. It just feels
like a problem that might have been solved already.
As the OP mentioned in the first email, Linux already provides an
ifconfig interface to do this. I don't know how Linux implements
that,but I am pretty certain that it would not involve the MAC layer.
https://www.garron.me/en/linux/add-secondary-ip-linux.html
Perhaps this is implemented via an IOCTL command or maybe via something
like a netlink socket.
A network interface connects only to a single network so I don't think
that the objective is to make it look like two networks. At least that
doesn't make any sense to me. I don't even know what that would mean.
The objective is, I think, to support two IP addresses on that one
network. IP is not in the MAC layer. The MAC driver is part of OSI Layer
2, the "Data Link" layer. NuttX supports a very modular interface
between the network and the MAC driver. We don't want to violate that
modularity.
https://en.wikipedia.org/wiki/OSI_model
IP is part of Layer 3, the network layer (or, in another conception, the
TCP/IP layer). Within the network, the additional layers are not well
modularized.
