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<font face="Tahoma">What would really be of interest to me would be
for those that run RFD to measure its impact to their network
(positive or otherwise) so we have something scientific to base
on.<br>
<br>
The theory (and practice of old) tells us that RFD is either very
good, or very bad. There are probably more folk that have turned
it off than run it, or vice versa. Ultimately, if we can get the
state of RFD's performance in 2018 on an axis, our words will
likely carry more weight.<br>
<br>
Mark.<br>
</font><br>
<div class="moz-cite-prefix">On 18/Dec/18 23:24, Naslund, Steve
wrote:<br>
</div>
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<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Remember
always that the local pref is just that, YOUR local
preference. Sending that flapping route upstream does not
give your peer the option to ignore it. In any case, the
downside is that you have to process that route and then
choose whether or not to use it. It’s like saying “now that
you have processed this unstable route and burned your CPU
cycles, I am now giving you to option not to install it into
your table”. Remember also that we are only talking about
default behavior here. You always have the option to
override it by changing timer, penalties, or shutting down
RFD all together. We are only talking about day-to-day
operation here.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Also,
keep in mind that when we are talking about alterative
stable paths we are only talking about what your network
sees, not the entire Internet. If you as a service provider
are experiencing major issues, you may see a route to me as
stable or unstable but making global routing decisions based
on that is not sound. What might be best for your customer
or your business might not be best for the Internet
community as a whole. It is a matter of scale, how many
services providers can allow how many unstable routes before
the entire network becomes regionally or globally unstable.
It’s important to remember that flapping routes leave a
certain amount of data in flight with no destination which
is detrimental to overall performance. As we move into a V6
world we are again worried about the size of the global
routing tables and pushing routing performance. Instability
of routes is dangerous to system running near the limits.
Propagating a known unstable route would be a major shift in
routing policy. Today, you either say you can reach
something or you don’t say anything. Using the suggested
alternative adds the option of “I might be able to reach
this but not reliably” which then brings about metrics of
“how reliably?” and that is a huge shift in how global
routing works. We have been struggling with a backbone
routing protocol that does not really do a good job of
understanding bandwidth and multiple paths so I would
suggest that adding “maybe” routes is not a good idea.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">At
least using RFD you can explain to your customer why they
are not reachable rather than explaining how you made a
manual decision to dump them for the “good of the
Internet”. There is also a business penalty to the service
provider that exposes instability to network. People don’t
want to peer or send traffic through unstable network
regions.
<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Steve<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span>Hi
Steve,<o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span>Lowering
the LP would achieve the outcome you desire, provided there
are (stable) alternative paths.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span>What
you advocate results in absolute outages in what may already
be precarious situations (natural disasters?) - what Saku
Ytti suggests like a less painful alternative with desirable
properties.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span>Kind
regards,<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">></span>Job<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
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