Redundant Routes, BGP with MPLS provider

Lee ler762 at
Fri Aug 31 22:29:26 UTC 2012

On 8/31/12, Bill.Ingrum at <Bill.Ingrum at> wrote:
> I work for an MPLS provider, so I guess I tend to trust them ;)

For certain definitions of "trust" I would also.   But.. Monday? I was
told that $AGENCY had just completed an audit of our network and we
had to change the exec timeout from 15 to 10 minutes on all routers
and switches.

Apparently that extra 5 minutes is an unacceptable security risk.  But
leaving the network wide-open to all sorts of routing hijinks via
MPLS?   (I don't have route filters & acls on all of the mpls
interfaces yet)    nada

We can't trust the people in our office area to not to take advantage
of an unattended terminal but we can trust our MPLS providers to not
take advantage of their unrestricted access?   Seems backwards to me.


> Bill
> -----Original Message-----
> From: Lee [mailto:ler762 at]
> Sent: Friday, August 31, 2012 11:28 AM
> To: Ingrum, Bill
> Cc: WTribble at; nanog at
> Subject: Re: Redundant Routes, BGP with MPLS provider
> On 8/31/12, Bill.Ingrum at <Bill.Ingrum at> 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 at]
>> Sent: Friday, August 31, 2012 11:15 AM
>> To: Tribble, Wesley
>> Cc: nanog at
>> Subject: Re: Redundant Routes, BGP with MPLS provider
>> On 8/30/12, Tribble, Wesley <WTribble at> 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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