Re: IPv4 Address Pool Has Been Expanded Significantly
My understanding is that one of the few (maybe the only) actual benefits from IPv6 is more compact routing tables.
That's not really much of a benefit.. At least now old routers that didn't have enough memory for a full routing table have been retired. And relatively few routers actually need a full table anyway.
Issue's really around IPv4 address depletion. There are plenty of underutilised V4 addresses, especially in the legacy 'swamp', where early adopters ended up with /8s or large blocks that they didn't really need. That was further complicated by speculation and treating IPv4 blocks as an asset, eg Microsoft buying Nortel's old space. Theoretically, that should have been returned to the RIR who could then parcel it out to other users that could justify it.
As for using 240/4.. It would mean deleting it from ISP's 'bogons' filters, which are just a list of networks that shouldn't be routed externally. That's an easy config change and shouldn't be hard-coded anywhere. Or if you're nice and use the full bogon's list, it's here-
https://www.team-cymru.org/Services/Bogons/fullbogons-ipv4.txt
and can automagically get baked into BGP filters via their tools.. But there's a fair bit of address space there. Some, like 0/8 would confuse people who don't get subnet zero, others like 10/8 would confuse more. But 240/4 shouldn't have been used in any production networks.. But that doesn't mean it hasn't been, ie companies trying to avoid clashes inside 10/8 space.
So it's a reasonable proposal, but unlikely to gain traction given IPv6 is the solution.
Biting the hand that feeds IT
