CIDR question

Milo S. Medin (NASA ARC NSI Office) medin at
Wed Jul 28 20:49:47 UTC 1993

I strongly agree.  The issue of an "all-nets" broadcast is inconsistent with 
classless network routing.  We should be taking steps to eliminate 
knowledge of class in all router and host implementations, as flexibility
here will certainly be helpful in increasing the lifetime of the IPv4
protocol suite, and transitions from that suite.  I always thought the "all
nets" broadcast was a broken idea for many reasons, this being one of them.

OSPF was designed to be classless internally, but have defaults that are
somewhat based on class boundaries.  In general, it should be possible
emulate "class" for human factors reasons if you implement everything
in a truly classless way.  Other routing protocols are making this 
transition as well.  It's sort of back to the future, since I believe
the original NSF backbone (56 Kbps fuzzballs which did a pure mask and
match forwarding decision) had this capability!


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