Date: Tue, 04 May 1999 08:53:11 -0700 (PDT) From: John Polstra <jdp@polstra.com> To: Dmitry Khrustalev <dima@zippy.machaon.ru> Cc: freebsd-current@FreeBSD.ORG, Warner Losh <imp@harmony.village.org> Subject: Re: Any action on PR 10570 ? getting closer to 65K :-( Message-ID: <XFMail.990504085311.jdp@polstra.com> In-Reply-To: <Pine.BSF.4.05.9905041745510.39879-100000@zippy.machaon.ru>
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Dmitry Khrustalev wrote:
>> It is completely impossible to have 2^32 routes in IPv4. Period.
>
> Of course not. It is impossible to have 2^32 *host* routes in IPv4.
Independent of IPv4, IPv6, or IPvAnything, I make the following
claim. Let:
P = number of bits in a pointer
I = number of bits in the integer type used for a reference counter
U = size of addressable unit in bits (8 on most machines).
If:
U <= P <= I
then there is no way in theory or in practice to overflow the
reference count. The proof is left as an exercise for the reader.
Hint: where will you store that many pointers, and how will you
address them?
And please don't raise the red herring of code bugs in maintaining
the reference counts, because that has never been what this thread
is about.
John
---
John Polstra jdp@polstra.com
John D. Polstra & Co., Inc. Seattle, Washington USA
"Self-interest is the aphrodisiac of belief." -- James V. DeLong
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