Comment by jandrese

It's interesting to consider that the IPv4 address space is only 32 bits wide. Back in the early 2000s asking for 4GB of RAM was unthinkable, but today (well last year) that's not even a big ask. If your routing decision can fit in a single byte (which interface to use next) you could load the entire thing as a 4GB table easily. 8GB if you need two bytes for the next hop. Multicast might be a problem but since multicast doesn't work on the backbone anyway I think we can ignore it.