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?
Mike Hammett wrote on 5/15/2019 2:19 PM:
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.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
Midwest-IX
http://www.midwest-ix.com
------------------------------------------------------------------------
*From: *"Ca By" <cb.li...@gmail.com>
*To: *"Mike Hammett" <na...@ics-il.net>
*Cc: *"Dan White" <dwh...@olp.net>, nanog@nanog.org
*Sent: *Wednesday, May 15, 2019 2:14:21 PM
*Subject: *Re: BGP prefix filter list
On Wed, May 15, 2019 at 11:52 AM Mike Hammett <na...@ics-il.net
<mailto:na...@ics-il.net>> wrote:
You can't do uRPF if you're not taking full routes.
I would never do uRPF , i am not a transit shop, so no problem there.
BCP38 is as sexy as i get.
You also have a more limited set of information for analytics if
you don't have full routes.
Yep, i don’t run a sophisticate internet CDN either. Just pumping
packets from eyeballs to clouds and back, mostly.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
Midwest-IX
http://www.midwest-ix.com
------------------------------------------------------------------------
*From: *"Ca By" <cb.li...@gmail.com <mailto:cb.li...@gmail.com>>
*To: *"Dan White" <dwh...@olp.net <mailto:dwh...@olp.net>>
*Cc: *nanog@nanog.org <mailto:nanog@nanog.org>
*Sent: *Wednesday, May 15, 2019 1:50:41 PM
*Subject: *Re: BGP prefix filter list
On Wed, May 15, 2019 at 7:27 AM Dan White <dwh...@olp.net
<mailto:dwh...@olp.net>> wrote:
On 05/15/19 13:58 +0000, Phil Lavin wrote:
>> We're an eyeball network. We accept default routes from our
transit
>> providers so in theory there should be no impact on
reachability.
>>
>> I'm pretty concerned about things that I don't know due to
inefficient
>> routing, e.g. customers hitting a public anycast DNS server
in the wrong
>> location resulting in Geolocation issues.
>
>Ah! Understood. The default route(s) was the bit I missed.
Makes a lot of
>sense if you can't justify buying new routers.
>
>Have you seen issues with Anycast routing thus far? One would
assume that
>routing would still be fairly efficient unless you're picking
up transit
>from non-local providers over extended L2 links.
We've had no issues so far but this was a recent change. There
was no
noticeable change to outbound traffic levels.
+1, there is no issue with this approach.
i have been taking “provider routes” + default for a long time,
works great.
This makes sure you use each provider’s “customer cone” and SLA to
the max while reducing your route load / churn.
IMHO, you should only take full routes if your core business is
providing full bgp feeds to downstrean transit customers.
--
Dan White
BTC Broadband
Network Admin Lead
Ph 918.366.0248 (direct) main: (918)366-8000
Fax 918.366.6610 email: dwh...@mybtc.com
<mailto:dwh...@mybtc.com>
http://www.btcbroadband.com
