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Re: So Philip Smith / Geoff Huston's CIDR report becomes worth a good hard look today


From: Randy Bush <randy () psg com>
Date: Thu, 14 Aug 2014 15:13:53 +0900

you mean your vendor won't give you the knobs to do it smartly ([j]tac
tickets open for five years)?  wonder why.

Might be useful if you mentioned what you considered a "smart" way to
trim the fib. But then you couldn't bitch and moan about people not
understanding you, which is the real reason you post to NANOG.

i did not get the original of this post, but the ad hominem speaks for
it pathetic self.

Optimization #1 -- elimination of more specifics where there's a less
specific that has the same next hop (obviously only in cases where the
less specific is the one that would be used if the more specific were
left out).

Example: if 10.10.4.0/22 has the same next hop as 10.10.7.0/24, the
latter can be left out of TCAM (assuming there's not a 10.10.6.0/23
with a different next hop).

Optimization #2 -- concatenation of adjacent routes when they have the
same next hop

Example: If 10.10.12.0/15 and 10.10.14.0/15 have the same next hop,
leave them both out of TCAM and install 10.10.14.0/14

Optimization #3 -- elimination of routes that have more specifics for
their entire range.

Example: Don't program 10.10.4.0/22 in TCAM is 10.10.4.0/23,
10.10.6.0/24 an 10.10.7.0/24 all exist

those are some of the cases.  i guess i should dig up the old [j]tac
tickets.

randy


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