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From: Joe Touch <touch@isi.edu>
In-Reply-To: <20160110.150704.74724334.sthaug@nethelp.no>
Date: Sun, 10 Jan 2016 10:39:08 -0800
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Message-Id: <A6608E67-0673-4614-9C1F-344280455361@isi.edu>
References: <5690A82F.5020007@isi.edu>
 <03a301d14ade$57cb6e40$4001a8c0@gateway.2wire.net>
 <56925425.4070502@gmail.com> <20160110.150704.74724334.sthaug@nethelp.no>
To: sthaug@nethelp.no
Archived-At: <http://mailarchive.ietf.org/arch/msg/v6ops/o0TjmEJS3ildwXCVQQCF2bO5PFk>
Cc: v6ops@ietf.org
Subject: Re: [v6ops] Routers are hosts too!
Precedence: list



On Jan 10, 2016, at 6:07 AM, sthaug@nethelp.no wrote:

>>> But then RFC1122 does not mention classless addressing or Variable
>>> Length Subnet Masks - as I recall, they did not exist at that time.
>>> Rather, RFC1122 deals with 32 bit Host addresses and Classful Networks,
>>> ie 8 or 16 or 24 bit addresses, so while you might have more than one
>>> entry in the cache for a given destination, they will all be the same
>>> length so the concept of longest-prefix (and of course, the term prefix
>>> has no meaning at that date) match does not come into consideration.
>>=20
>> DO you mean that the longest-prefix match operation was not there since=20=

>> the earliest days of Internet?
>=20
> Reading up on the history of the Internet is recommended. See for
> instance
>=20
> https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing

Yes, but classless routing has nothing to do with longest prefix.=20

Longest prefix is relevant only if the route cache has overlapping rules. Th=
at won't happen with host redirects. It only could happen with subnet redire=
cts or manual entries (on a host / on a router, routing protocol entries wou=
ld also be included.).=20

Joe