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<p>Hello,</p>
<p> Some time ago we had a similar discussion on this list, in that
moment I shared a small study we did in LACNIC but we had it only
in Spanish. Here is the version in English (BGP: To filter or not
to filter by prefix size. That is the question ):</p>
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<p><a class="moz-txt-link-freetext" href="https://aaaa.acostasite.com/2019/07/bgp-to-filter-or-not-to-filter-by.html">https://aaaa.acostasite.com/2019/07/bgp-to-filter-or-not-to-filter-by.html</a></p>
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<p>Alejandro,</p>
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<div class="moz-cite-prefix">On 6/4/20 11:00 PM, James Breeden
wrote:<br>
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I have been doing a lot of research recently on operating
networks with partial tables and a default to the rest of the
world. Seems like an easy enough approach for regional networks
where you have maybe only 1 upstream transit and some peering. </div>
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I come to NANOG to get feedback from others who may be doing
this. We have 3 upstream transit providers and PNI and public
peers in 2 locations. It'd obviously be easy to transition to
doing partial routes for just the peers, etc, but I'm not sure
where to draw the line on the transit providers. I've thought of
straight preferencing one over another. I've thought of using
BGP filtering and community magic to basically allow Transit AS
+ 1 additional AS (Transit direct customer) as specific routes,
with summarization to default for the rest. I'm sure there are
other thoughts that I haven't had about this as well....</div>
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And before I get asked why not just run full tables, I'm looking
at regional approaches to being able to use smaller, less
powerful routers (or even layer3 switches) to run some areas of
the network where we can benefit from summarization and full
tables are really overkill. </div>
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<b>James W. Breeden</b></p>
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