[j-nsp] Default route origination for Ibgp

[OBrien, Will]

I advertise a default route via an igp. (Ospf) when traffic gets to the border routers, the best path is chosen thanks to ibgp between the two border routers. I also maintain redundant links between the two border routers so that an outage won't matter.

Will O'Brien

On Sep 30, 2013, at 5:52 PM, "George Hong" <georgehong21 at gmail.com> wrote:

> Hi Juniper Guru's.
> 
> I Have a question regarding the best way to generate a default route in BGP.
> 
> The topology is as below. Rtr1 and rtr2 both have a full EBGP feed
> from different providers (incl Default route)
> rtr1 and rtr2 have an IBGP session and exchange full tables.
> There's also IBGP sessions between:
> rtr1- fw1
> rtr1- fw2
> rtr2- fw1
> rtr2- fw2
> 
> On these sessions we only announce a default route from the routers to
> Firewalls.
> 
> 
> --------        -------
> | rtr1 |       | rtr2 |
> --------       --------
> 
> 
> --------        -------
> | fw1 |       | fw2 |
> --------       --------
> 
> The challenge I have is a good way of originating a default route.
> For example rtr1 - fw1 is most preferred path (done using local
> prefs). But I'm preferring the ISP on rtr2 (localpref).
> as a result rtr1 is not sending the default route to fw1, since its
> best route was learned through IBGP from rtr2 (unless I'd set it up as
> route-reflector).
> 
> Also I don't want the ASpath original ASpath to show up in the
> default. It should just be the "I" Locally originated, not the AS of
> my provider in there.
> 
> I *do* need the default on both routers as well (I have a few remote
> sites using same AS, so rely on default to get there, not interested
> in allow-as-in etc now).
> So I can't put in a static pointing to my iso, cause I want to make
> sure it fails over correctly if that connections becomes unavailable.
> I'm guessing that also eliminates the " no-install discard " option as
> it will over ride the default route I learned from my ISP and/or other
> border router.
> 
> So, wondering what's the best way to do this? any recommendations?
> tips? This is for both IPv4 and IPv6
> 
> Thanks,
> George
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