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

Randy Bush randy at psg.com
Thu Aug 14 06:13:53 UTC 2014


>>> 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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