[quagga-users 11294] Re: Stupid BGP question / problem

Steve Bertrand steve at ibctech.ca
Mon Jan 4 23:42:14 GMT 2010

John Brown wrote:
> Hi Steve,
> The Cisco is off on the edge because it is the "old core" router.
> My intent is to have the following:
> Two Cat 6509's each connected to the two dell's in a full mesh manner.
> The Dell's will be the BGP speakers for the outside world and I want to
> run OSPF inside between the Dell's and the Cat 6509's

OSPF for just the loopbacks and infrastructure links, right?

imho, only infrastructure prefixes should be in the IGP, and all else
should be done via iBGP.

> Then other servers, edge routers, etc will be either single attached to
> a single Cat 6509, or dual attached to both 6509's and we will run HSRP
> on those VLAN's.

When you speak of 'edge' routers, are you referring to access-layer
gear? If you are attaching your edge routers to both core 6509's, can
you simply use iBGP as opposed to HSRP/VRRP etc?

I suppose that your servers etc attach directly to the 6509's and not
through edge gear. In that case, and you have the available port
density, then connecting to both units (using HSRP) will push the single
point of failure to the server itself.

I look at our servers much the same as our access clients, so I've got
our server racks attached to two edge routers with a similar setup as
you are considering for yours, but with the extra layer.

> The goal is that is Provider 1 or 2 fail, traffic still flows, if Dell 1
> or 2 fails, traffic still flows, if Cat-01 or 02 fails, traffic still
> flows....

In your diagram, anything connected to 'Cisco' will be dead in the water
if Dell-01 fails, even if you do have it set up to reflect routes. If
this router will stay after your upgrade, you will need to connect it to
two devices to ensure redundancy.

> I've moved all of our transit connections to Ethernet (no more POS / TDM
> / ATM) and the price/performance curve for OpenSource vis Cisco is HUGE.

I agree. Most of our edge gear is Cisco, but both of my core routers and
a couple of edges are FreeBSD/Quagga. We're a small ISP, and are mostly
under 100kpps across the core.

Also, FreeBSD (using freevrrpd) does well with gateway redundancy.

> How do I setup a reflector in bgpd ?

What Stephan said ;)

> I have to do this in steps as it's a running network

I know that feeling, however, with Quagga, it takes no time to turn up a
few boxes (booting from USB key), or VMs to simulate what you want to do
in production ;)

Good luck!


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