History [was Re: strangest systems I've sent email from]

Paul Koning paulkoning at comcast.net
Wed Apr 27 12:04:28 CDT 2016

> On Apr 27, 2016, at 1:00 PM, Sean Conner <spc at 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.


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