[arin-ppml] Abandonment of 103/104

>  Steve Deering originally floated the idea.

I trawled the net looking for something and discovered that Steve did
indeed present some slides to the IETF in 1995 about something called
metropolitan addressing which is similar to City Aggregate addressing.

However, in 1995 the routing architecture of the Internet was not
yet in place, and Steve's concept was directed at the IPv4 Internet and
asked for everyone to move to metro addressing.

CA addressing is only for the IPv6 Internet and is intended to
coexist with PA and PI addressing so that network operators and
end users can choose the CA model if they want to. 

--Michael Dillon