Re: bgp route advertisment , particularly aggregate/summary to

From: Marko Milivojevic <markom_at_ipexpert.com>
Date: Mon, 12 Mar 2012 00:38:23 -0700

Joe,

As far the CCIE lab is concerned, if the restrictions say "no static routes", it includes static Null0 routes. Those ambiguous semantical differences are better avoided.

--
Marko Milivojevic - CCIE #18427
:: This message was sent from a mobile device. I apologize for errors and brevity. ::
On Mar 11, 2012, at 19:49, Joe Sanchez <marco207p_at_gmail.com> wrote:
> Aaron,
> 
> 172.16.1.0/24
> 172.16.2.0/24
> 172.16.3.0/24
> 
> if these networks are not part of the IGP routes in the router from which
> you wish to advertise an aggregate route you will have to create a null
> route for the 172.0.0.0/8 network.  You will not have to create a null
> route as long as a longer prefix matches the aggregate exist in the Routing
> Information Base (RIB).
> 
> A null route is not considered a static route.
> 
> 
> 
> http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_bgp/command/bgp-a1.html#GUID-D8ACCE05-4ACE-42D5-8EC6-9607FF7FA9FD
> http://www.cciecandidate.com/?p=97
> 
> 
> Joe S.
> 
> 
> On Sat, Mar 10, 2012 at 12:58 PM, Aaron <aaron1_at_gvtc.com> wrote:
> 
>> In a recent scenario I was using for my studies I was presented with the
>> following..Please tell me how to do the following or link to where it is on
>> doc cd.
>> 
>> 
>> 
>> If R1 has in its igp table.
>> 
>> 
>> 
>> 172.16.1.0/24
>> 
>> 172.16.2.0/24
>> 
>> 172.16.3.0/24
>> 
>> 
>> 
>> And you need to send an aggregate of that as 172.0.0.0/8 to a IBGP
>> neighbor
>> how would you accomplish that?  I don't think a static route is
>> permissible.
>> I don't think you can create additional interfaces on r1 either.
>> 
>> 
>> 
>> If you can just verbalize to me a few ideas of how that is accomplished
>> without some elaborate config then that's fine.like what are the moving
>> parts?
>> 
>> 
>> 
>> Is it possible to generate an aggregate based solely on the contents of the
>> IGP table?  I think I read that a subordinate part of a larger aggregate
>> needs to be present in the igp table in order for the aggregate to be sent,
>> but do I use "aggregate-address" ?....suppresmap?  unsurprssmap?  .neighbor
>> statement to that certain neighbor?
>> 
>> 
>> 
>> Aaron
>> 
>> 
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>> 
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> 
> 
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Received on Mon Mar 12 2012 - 00:38:23 ART

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