Perhaps it's time we admitted the arpanet isn't just dead...
It's long dead. Instead of blocking 10.0.0/8, break it up into
Bs and Cs!
10.128.0/9 Bs
10.0/9 Cs (10.0.1 through 10.127.255)
Well.... That might be a good idea except 10.0.0/8 is already
consumed via RFC 1597. Won't work to split it into "B/C" nets.
Of course classfull nets are a thing of the past and what we deal
with now are CIDR prefixes and Masks.
--bill