Subject: Re: [tsvwg] [Tsvwg] lookup time (was Re: WGLC for Port Randomization starts now (April 1st))

From: Mark Allman <[email-masked]>
Date: Mon, 15 Jun 2009 08:37:17 -0400

> If you retry random port, chances are that you may retry the same port
> more than once, instead of trying a different port that might be
> available. The larger the number of ports in uses, the more likely
> this would be. (see the pseudo-code).

Sure.  Of course.  But, we can put this in concrete terms it would
seem.  I.e., if we use something like alg. 3 then for a given connection
ID we will not test for some port X again before exhausting all the
non-X ports.  In something like alg. 2 you can in fact check X more than
once with a probability defined by the port usage at the given time and
also not test for all possible ports.

allman

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From: Fernando Gont <[email-masked]>
Date: Tue, 16 Jun 2009 09:49:04 -0300

> also not test for all possible ports.

Agreed. And in the worst case, because of checking X more than once, you
may end up not checking other port numbers that might have worked.

-- 
Fernando Gont
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