nanog mailing list archives
Re: Stupid Question maybe?
From: Fred Baker <fredbaker.ietf () gmail com>
Date: Wed, 19 Dec 2018 09:38:14 +0800
On Dec 19, 2018, at 3:50 AM, Brian Kantor <Brian () ampr org> wrote:
/24 is certainly cleaner than 255.255.255.0. I seem to remember it was Phil Karn who in the early 80's suggested that expressing subnet masks as the number of bits from the top end of the address word was efficient, since subnet masks were always a series of ones followd by zeros with no interspersing, which was incorporated (or independently invented) about a decade later as CIDR a.b.c.d/n notation in RFC1519. - Brian
Actually, not really. In the time frame, there was quite a bit of discussion about "discontiguous" subnet masks, which were masks that had at least one zero somewhere within the field of ones. There were some who thought they were pretty important. I don't recall whether it was Phil that suggested what we now call "prefixes" with a "prefix length", but it was not fait accompli. Going with prefixes as we now describe them certainly simplified a lot of things. Take a glance at https://www.google.com/search?q=discontiguous+subnet+masks for a history discussion.
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Current thread:
- Re: Stupid Question maybe?, (continued)
- Re: Stupid Question maybe? William Allen Simpson (Dec 20)
- Re: Stupid Question maybe? Saku Ytti (Dec 20)
- Re: Stupid Question maybe? Joel Halpern (Dec 20)
- Re: Stupid Question maybe? Tony Finch (Dec 24)
- Re: Stupid Question maybe? Chuck Church (Dec 26)
- Re: Stupid Question maybe? Baldur Norddahl (Dec 18)
- RE: Stupid Question maybe? Naslund, Steve (Dec 18)
- Re: Stupid Question maybe? William Herrin (Dec 18)
- RE: Stupid Question maybe? Naslund, Steve (Dec 18)
- Re: Stupid Question maybe? Florian Weimer (Dec 21)
- Re: Stupid Question maybe? Fred Baker (Dec 18)
- Re: Stupid Question maybe? William Allen Simpson (Dec 19)
- Re: Stupid Question maybe? Grant Taylor via NANOG (Dec 18)
- Re: Stupid Question maybe? Brandon Martin (Dec 18)
- Re: Stupid Question maybe? James R Cutler (Dec 18)
- Re: Stupid Question maybe? Brandon Martin (Dec 18)
- Re: Stupid Question maybe? tim () pelican org (Dec 19)