> On Apr 27, 2016, at 1:00 PM, Sean Conner <s...@conman.org> wrote:
>
> It was thus said that the Great Mouse once stated:
>>
>> And I spend over $80/month for DSL to a provider that gives me a /29
>> and a /60 from globally routed space. (That everything is now CIDR
>> blocks is another loss; I am not fond of the desupporting of
>> noncontiguous subnet masks, even though I can understand it - I'm the
>> only person I've ever heard of running that way other than for
>> testing.)
>
> One benefit of contiguous subnet masks is that it makes routing faster.
> It's still a linear search,
Not necessarily. You can do a lot better than linear search for route lookup.
That can be done with non-contiguous subnet masks too (I remember reading a
paper from 30ish years ago on that), but it takes less space -- fewer lookup
table entries -- if the subnet masks are contiguous because then each subnet is
only one numeric range rather than several.
I think the main argument against non-contiguous masks is that it's a feature
without a purpose, and a popular source of bugs.
paul
