You can't do uRPF if you're not taking full routes.

You also have a more limited set of information for analytics if you don't have full routes.



-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com

Midwest-IX
http://www.midwest-ix.com


From: "Ca By" <cb.list6@gmail.com>
To: "Dan White" <dwhite@olp.net>
Cc: 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 <dwhite@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: dwhite@mybtc.com
http://www.btcbroadband.com