Re: Redundant Routes, BGP with MPLS provider

[Lee <ler762 () gmail com>]

On 8/31/12, Bill.Ingrum () t-systems com <Bill.Ingrum () t-systems com> wrote:
> I think having a GRE tunnel for the internal routing protocol is
> unnecessary.

It might be, but we have a requirement for multicast over the wan so
the GRE tunnels had to be there.

>  Can you explain the reasoning behind this?  I understand
> the technical issue whereby GRE will allow multicast for EIGRP, OSPF,
> etc, but why not just redistribute into BGP?

I see no reason to trust the provider that much.

> I work on a lot of MPLS CE routers, and in general you can accomplish
> anything you need by redistributing your internal routing protocol into
> BGP, and adjusting LP, MED and AS Prepend as needed.

Sure.. but how do you *know* you're not getting anything added/removed
by the provider?

Lee



> Thanks,
>
> Bill
>
> -----Original Message-----
> From: Lee [mailto:ler762 () gmail com]
> Sent: Friday, August 31, 2012 11:15 AM
> To: Tribble, Wesley
> Cc: nanog () nanog org
> Subject: Re: Redundant Routes, BGP with MPLS provider
>
> On 8/30/12, Tribble, Wesley <WTribble () sterneagee com> wrote:
> > Hello all,
> >
> > I am an Network Operator working in an Enterprise environment with
> > offices all over the country(mostly connected via MPLS).  We are
> > currently working towards building a Disaster Recovery Site that will
> > host some of our vendor routers and provide the capability to access
> > these vendors from both our primary and backup data center locations.
>
> > The routes(as advertised by the vendor's routers) will be the same at
> > both locations.  I would like to advertise the routes from multiple
> > locations at the same time, rather than suppress the routes and
> advertise conditionally.
>
> At work, we have our internal routing protocol running on GRE over IPSec
> tunnels & keep the BGP sessions with the MPLS provider limited to just
> the MPLS network.  And have an ACL on the MPLS network
> interface that allows only what's expected in...   some providers are
> better than others at not having anything hit the 'deny any any log'
> line
>
> Regards,
> Lee
>
>
> > What is the best method to Instruct the provider's network to prefer
> > the Primary Data Center routes over the DR site?  Keep in mind that I
> > am only peering with the provider over BGP and I have no visibility to
>
> > the underlying MPLS architecture or configuration.  Although if you
> > have specific questions  about their architecture, I can work to get
> answers.
> > Discussing in house, we have gone over a few different options:
> >
> > -Advertise specific routes from primary site and summary routes from
> > the DR site.  Most specific will always be chosen.
> > -Prepend the routes from the DR site so that they will have a longer
> > AS-path than the Primary location -Use Community Strings to influence
> > local preference.(Still working to find out if Provider will pass our
> > community strings)
> >
> > Just looking for some ideas and best practices.  Any thoughts or
> > insight would be much welcomed and appreciated.  This is my first
> > message on NANOG, so please be gentle.  I apologize in advance if I
> > have done something incorrectly.
> >
> >
> > Wes
> >
> >
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