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Ca, taking a self-originated default route (with or without an
additional partial view of the global routing table) from your
transit provider's edge router seems to make the assumption that
your transit provider's edge router either has a full table or a
working default route itself. In the case of transit provider
outages (planned or unplanned), the transit provider's edge router
that you peer with may be up and reachable (and generating a default
route to your routers), but may not have connectivity to the greater
internet. Put another way, if your own routers don't have a full
routing table then they don't have enough information to make
intelligent routing decisions and are offloading that responsibility
onto the transit provider. IMHO, what's the point of being
multi-homed if you can't make intelligent routing decisions and
provide routing redundancy in the case of a transit provider outage?<br>
<br>
<br>
<br>
<div class="moz-cite-prefix">Mike Hammett wrote on 5/15/2019 2:19
PM:<br>
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<blockquote type="cite"
cite="mid:400065099.3557.1557947984364.JavaMail.mhammett@ThunderFuck">
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<div style="font-family: arial,helvetica,sans-serif; font-size:
10pt; color: #000000">As an eyeball network myself, you'll
probably want to look at those things. You don't need to run a
CDN to know where your bits are going.<br>
<br>
<div><span name="x"></span><br>
<br>
-----<br>
Mike Hammett<br>
Intelligent Computing Solutions<br>
<a class="moz-txt-link-freetext" href="http://www.ics-il.com">http://www.ics-il.com</a><br>
<br>
Midwest-IX<br>
<a class="moz-txt-link-freetext" href="http://www.midwest-ix.com">http://www.midwest-ix.com</a><span name="x"></span><br>
</div>
<br>
<hr id="zwchr">
<div
style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From:
</b>"Ca By" <a class="moz-txt-link-rfc2396E" href="mailto:cb.list6@gmail.com"><cb.list6@gmail.com></a><br>
<b>To: </b>"Mike Hammett" <a class="moz-txt-link-rfc2396E" href="mailto:nanog@ics-il.net"><nanog@ics-il.net></a><br>
<b>Cc: </b>"Dan White" <a class="moz-txt-link-rfc2396E" href="mailto:dwhite@olp.net"><dwhite@olp.net></a>,
<a class="moz-txt-link-abbreviated" href="mailto:nanog@nanog.org">nanog@nanog.org</a><br>
<b>Sent: </b>Wednesday, May 15, 2019 2:14:21 PM<br>
<b>Subject: </b>Re: BGP prefix filter list<br>
<br>
<div><br>
</div>
<div><br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, May 15, 2019 at
11:52 AM Mike Hammett <<a
href="mailto:nanog@ics-il.net" target="_blank"
moz-do-not-send="true">nanog@ics-il.net</a>> wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div
style="font-family:arial,helvetica,sans-serif;font-size:10pt;color:#000000">You
can't do uRPF if you're not taking full routes.</div>
</div>
</blockquote>
<div dir="auto"><br>
</div>
<div dir="auto">I would never do uRPF , i am not a transit
shop, so no problem there. BCP38 is as sexy as i get. </div>
<div dir="auto"><br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div
style="font-family:arial,helvetica,sans-serif;font-size:10pt;color:#000000">
<div><br>
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<div>You also have a more limited set of information
for analytics if you don't have full routes.<br>
<br>
<div><span></span></div>
</div>
</div>
</div>
</blockquote>
<div dir="auto"><br>
</div>
<div dir="auto">Yep, i don’t run a sophisticate internet
CDN either. Just pumping packets from eyeballs to
clouds and back, mostly. </div>
<div dir="auto"><br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div
style="font-family:arial,helvetica,sans-serif;font-size:10pt;color:#000000">
<div>
<div><br>
<br>
-----<br>
Mike Hammett<br>
Intelligent Computing Solutions<br>
<a href="http://www.ics-il.com" target="_blank"
moz-do-not-send="true">http://www.ics-il.com</a><br>
<br>
Midwest-IX<br>
<a href="http://www.midwest-ix.com"
target="_blank" moz-do-not-send="true">http://www.midwest-ix.com</a><span></span><br>
</div>
<br>
<hr id="m_-1825445705496325099zwchr">
<div
style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt"><b>From:
</b>"Ca By" <<a
href="mailto:cb.list6@gmail.com"
target="_blank" moz-do-not-send="true">cb.list6@gmail.com</a>><br>
<b>To: </b>"Dan White" <<a
href="mailto:dwhite@olp.net" target="_blank"
moz-do-not-send="true">dwhite@olp.net</a>><br>
<b>Cc: </b><a href="mailto:nanog@nanog.org"
target="_blank" moz-do-not-send="true">nanog@nanog.org</a><br>
<b>Sent: </b>Wednesday, May 15, 2019 1:50:41 PM</div>
</div>
</div>
</div>
<div>
<div
style="font-family:arial,helvetica,sans-serif;font-size:10pt;color:#000000">
<div>
<div
style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt"><br>
<b>Subject: </b>Re: BGP prefix filter list<br>
<br>
<div><br>
</div>
<div><br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed,
May 15, 2019 at 7:27 AM Dan White <<a
href="mailto:dwhite@olp.net"
target="_blank" moz-do-not-send="true">dwhite@olp.net</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex">On
05/15/19 13:58 +0000, Phil Lavin wrote:<br>
>> We're an eyeball network. We
accept default routes from our transit<br>
>> providers so in theory there
should be no impact on reachability.<br>
>><br>
>> I'm pretty concerned about things
that I don't know due to inefficient<br>
>> routing, e.g. customers hitting a
public anycast DNS server in the wrong<br>
>> location resulting in Geolocation
issues.<br>
><br>
>Ah! Understood. The default route(s)
was the bit I missed. Makes a lot of<br>
>sense if you can't justify buying new
routers.<br>
><br>
>Have you seen issues with Anycast
routing thus far? One would assume that<br>
>routing would still be fairly
efficient unless you're picking up transit<br>
>from non-local providers over extended
L2 links.<br>
<br>
We've had no issues so far but this was a
recent change. There was no<br>
noticeable change to outbound traffic
levels. <br>
</blockquote>
<div dir="auto"><br>
</div>
<div dir="auto">+1, there is no issue with
this approach. </div>
<div dir="auto"><br>
</div>
<div dir="auto">i have been taking “provider
routes” + default for a long time, works
great. </div>
<div dir="auto"><br>
</div>
<div dir="auto">This makes sure you use each
provider’s “customer cone” and SLA to the
max while reducing your route load /
churn. </div>
<div dir="auto"><br>
</div>
<div dir="auto">IMHO, you should only take
full routes if your core business is
providing full bgp feeds to downstrean
transit customers. </div>
<div dir="auto"><br>
</div>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex"><br>
-- <br>
Dan White<br>
BTC Broadband<br>
Network Admin Lead<br>
Ph 918.366.0248 (direct) main:
(918)366-8000<br>
Fax 918.366.6610 email: <a
href="mailto:dwhite@mybtc.com"
target="_blank" moz-do-not-send="true">dwhite@mybtc.com</a><br>
<a href="http://www.btcbroadband.com"
rel="noreferrer" target="_blank"
moz-do-not-send="true">http://www.btcbroadband.com</a><br>
</blockquote>
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