[119256] in North American Network Operators' Group
RE: Resilience - How many BGP providers
daemon@ATHENA.MIT.EDU (Dylan Ebner)
Wed Nov 11 12:28:26 2009
From: Dylan Ebner <dylan.ebner@crlmed.com>
To: "adel@baklawasecrets.com" <adel@baklawasecrets.com>, "nanog@nanog.org"
<nanog@nanog.org>
Date: Wed, 11 Nov 2009 17:27:23 +0000
In-Reply-To: <27203.1257959652@baklawasecrets.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
You question has many caveats. Just having two providers does not necessari=
ly get you more resiliency. If you have two providers and they are terminat=
ing on the same router, then you still have a SPOF problem. You also need t=
o look at pysical paths as well. If you have two (or three) providers and t=
hey are using a common carrier, then you have a problem as well. For exampl=
e, GLBX has a small prescence in the Minneapolis metro. If I were to use th=
em as a provider, they would use Qwest as a last mile. If my other provider=
is Qwest (which it is), I may not have path divergence.
Facilities are important too. We have three upstreams; Qwest, MCI and ATT. =
The facility only has two entrances, so that means two of these are in the =
same conduit. IF you only have one entrance, all you connections are going =
to run through that conduit, and that makes you susceptable to a rouge back=
hoe.
You are on the right track to question your resilancy. Some upstreams can o=
ffer good resilancy with multiple feeds. Others cannot. I would start with =
your provider and see what you are getting. Maybe you already have path div=
ergence, sperate last miles, and multiple paths in the isp core. If you go=
with multiple providers, you want to make sure you don't risk losing somet=
hing you already have.
-----Original Message-----
From: adel@baklawasecrets.com [mailto:adel@baklawasecrets.com]=20
Sent: Wednesday, November 11, 2009 11:14 AM
To: nanog@nanog.org
Subject: Resilience - How many BGP providers
=20
Hi,=20
After recent discussions on the list, I've been thinking about the affects
of multiple BGP feeds to the overall resilience of Internet connectivity
for my organisation.=A0 So originally when I looked at the design
proposals, there was a provision in there for four connections with the
same Internet provider.=A0 Thinking about it and with the valuable input of
members on this list, it was obvious that multiple connections from the
same provider defeated the aim of providing resilience.=20
So having come to the decision to use two providers and BGP peer with
both, I'm wondering how much more resilience I would get by peering
with=A0more than two=A0providers.=A0 So will it significantly increase my
resilience by peering with three providers for example, as both of the
upstreams I choose will be multihomed to other providers.=A0 Especially as
I am only looking at peering out of the UK.=20
Hope the above makes sense.=20
Adel
=20
