Date: Tue, 24 Aug 2010 08:43:52 -0400
From: Michael Richardson <[email protected]>
Message-ID: <[email protected]>
| There is only one reason to use non-contiguous IP masks for *ROUTING*
| tables (vs for IPsec SPDs, where a there might be multiple IP subnets in
| the 5-tuple):
| IPv4 scarcity
It actually doesn't help for that at all. Ambiguous masks might,
perhaps, but they just don't work, and never did. But non-contig
masks (the simple ones) can always be turned into contig ones by just
moving the bits in the addresses around (and hence renumbering hosts).
Since there is a contig mask for every non-contig (simple) scheme that
you can devise, using non-contig itself cannot possibly have any effect
upon address usage. It just saves renumbering effort (occasionally).
And some people consider it sexy...
kre
