Routing issues

[dspazman at epicup.com]

I tried modifying the example.  Here is the situation.
No clients, just have my own block of IPs I want to announce (A.A.A.A/22).  I also have two /29s, one from each provider (Y.Y.Y.A/29, Y.Y.Y.B/29) that contains the external IP address for each of my router's two ethernet interfaces, as assigned by each ISP.  The two providers I'm trying to just run so one is preferred, but both can be used.  The asymetric isn't a huge deal, so if it's simpler to take it out, that's ok also.

Also, besides the bird setup, I ran the following rules:
ip rule add iif eth2 table 1
ip rule add iif eth5 table 2

(This is on Ubuntu, btw, and my two ISP interfaces are eth2 (my less prefered one) and eth5 (my high speed 10 Gig fiber one).

The problems / questions I ran into was this.

1) Does the table 1 / table 2 need to be declared in the underlying system first?  I didn't think so, like in /etc/iproute2/rt_tables?  Because the IP rules seemed to work for pinging out on the interface.

2) When I looked at the routing tables, I didn't see all the global routes, so it didn't seem like I was getting them all pushed to me with that configuration.  The routing table only showed my routes for my interfaces (have 6, actually, 2 ISP the other 4 internal for my network), and the /22 (and I think the /29s).  Is there something wrong with how the bgp protocol sections are set up with the import all / export all?  As the current way before this I was getting the full BGP tables from provider A.

3) Is the ospf part needed or helpful?  Is it a good practice to have the BGP router also run OSPF, in general?



-----Original Message-----
From: "Ondrej Zajicek" <santiago at crfreenet.org>
Sent: Tuesday, December 6, 2011 7:58am
To: dspazman at epicup.com
Cc: bird-users at trubka.network.cz
Subject: Re: Routing issues

On Mon, Dec 05, 2011 at 07:53:03PM -0500, dspazman at epicup.com wrote:
> Let's say you have two routing tables (T1, T2), one for each interface (eth0, eth1), so you can route traffic out each one separately.
> 
> https://git.nic.cz/redmine/projects/bird/wiki/BGP_example_2
> 
> I'm assuming there would have to be some changes to that BGP script to support both routing tables.  I'm not sure how to support multiple routing tables with bird.  Would someone be able to show that?  Seems like it would be a useful example in general, and be a pretty simple modification to that example for someone who knows what they are doing.
> 
> I didn't see anything on any of the examples on git.nic.cz that showed using multiple tables, as a configuration like http://lartc.org/howto/lartc.rpdb.multiple-links.html shows you'd be using for multiple outgoing connections, which you would typically have in a BGP situation.
> 

> Though maybe https://git.nic.cz/redmine/projects/bird/wiki/Policy_routing
> explains it.  I plan on keep looking into that example as well.

Yes, that is an example for using multiple routing tables. You can
prefer one uplink in one table and the other in the second table. You
can specify that internal traffic from eth0 go through the first one and
from eth1 through the second one, but:

 - The OSPF config (mentioned before) does not automatically split that
traffic, 'cost' work in a different way.

 - Even if traffic from eth0 and eth1 is sufficiently splited, that
will hel just split outgoing traffic on uplinks, splitting
incoming is harder.

-- 
Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
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