[c-nsp] Filtering BGP routes with route-map vs. not getting them in

OCOSA ListAcct listacc at ocosa.com
Fri Jul 6 18:40:02 EDT 2007 

Oh I see!  :-)      No it does not. That string tells his router to get 
routes directly connected and originated. I used it for a while when we 
first started accepting full routes from providers. But if his upstream 
does prepend then he would get the example you mentioned depending on 
how many times they prepend.. Sorry for not getting...

Otis



Michael K. Smith - Adhost wrote:
> Hello Otis:
>
> I meant to account for his provider prepending their AS, not him
> prepending his AS. :-)  So, if his upstream is NTT, he would get 2914
> 2914 11274 as well as 2914 11274.
>
> Regards,
>
> Mike
>
>   
>> -----Original Message-----
>> From: OCOSA ListAcct [mailto:listacc at ocosa.com]
>> Sent: Friday, July 06, 2007 3:28 PM
>> To: Michael K. Smith - Adhost
>> Cc: Kristian Kielhofner; cisco-nsp at puck.nether.net
>> Subject: Re: [c-nsp] Filtering BGP routes with route-map vs. not
>> getting them in
>>
>> Mike,
>>
>> I am not understanding what you are asking here? Explain please....
>>
>> Prepending would only give Kris a longer as path...making others
>>     
> prefer
>   
>> Kris shorter path over that one. I believe his goal isReceived: from ([127.0.0.1]) with MailEnable ESMTP; Fri, 06 Jul 2007 17:31:03 -0500
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> Subject: RE: [c-nsp] Filtering BGP routes with route-map vs. not getting them in
> Date: Fri, 6 Jul 2007 15:30:57 -0700
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> Thread-Topic: [c-nsp] Filtering BGP routes with route-map vs. not getting them in
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> From: "Michael K. Smith - Adhost" <mksmith at adhost.com>
> To: "OCOSA ListAcct" <listacc at ocosa.com>
> Cc: "Kristian Kielhofner" <kris at krisk.org>,
> 	<cisco-nsp at puck.nether.net>
> Return-Path: <mksmith at adhost.com>
>
> Hello Otis:
>
> I meant to account for his provider prepending their AS, not him
> prepending his AS. :-)  So, if his upstream is NTT, he would get 2914
> 2914 11274 as well as 2914 11274.
>
> Regards,
>
> Mike
>
>   
>> -----Original Message-----
>> From: OCOSA ListAcct [mailto:listacc at ocosa.com]
>> Sent: Friday, July 06, 2007 3:28 PM
>> To: Michael K. Smith - Adhost
>> Cc: Kristian Kielhofner; cisco-nsp at puck.nether.net
>> Subject: Re: [c-nsp] Filtering BGP routes with route-map vs. not
>> getting them in
>>
>> Mike,
>>
>> I am not understanding what you are asking here? Explain please....
>>
>> Prepending would only give Kris a longer as path...making others
>>     
> prefer
>   
>> Kris shorter path over that one. I believe his goal is to get full
>> routes and do what he pleases. But use all 120,000 once he gets a
>> bigger
>> router. I think it's 120,000 maybe more or less.
>>
>> Actually if Kris' upstream did communities with him he could get
>> customers routes and default that way....much cleaner I think....
>>
>> Otis
>>
>>
>>
>> Michael K. Smith - Adhost wrote:
>>     
>>> For customer only routes wouldn't this be better to account for
>>> prepending?
>>>
>>> Ip as-path access-list 5 permit ^(providerAS_)+([0-9_])+$
>>>
>>> Regards,
>>>
>>> Mike
>>>
>>>
>>>       
>>>> -----Original Message-----
>>>> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
>>>> bounces at puck.nether.net] On Behalf Of OCOSA ListAcct
>>>> Sent: Friday, July 06, 2007 12:03 PM
>>>> To: Kristian Kielhofner
>>>> Cc: cisco-nsp at puck.nether.net
>>>> Subject: Re: [c-nsp] Filtering BGP routes with route-map vs. not
>>>> getting them in
>>>>
>>>> True if really want to use option b...
>>>>
>>>> use this string to get routes directly connected to your upstream
>>>>         
> or
>   
>>>> originated.
>>>>
>>>> ip as-path access-list 5 permit ^upstream as goes here_[0-9]*$
>>>>
>>>> or
>>>>
>>>>
>>>> to deny any networks originated form your upstream...and allows
>>>> everything else which could be bad if your router does not have at
>>>> least
>>>> 512MB
>>>>
>>>> ip as-path access-list 6 deny _upstream as goes here$
>>>> ip as-path access-list 6 permit .*
>>>>
>>>>
>>>> If I remember correctly you can also limited the amount of prefixes
>>>>         
>> a
>>     
>>>> neighbor can send you...
>>>>
>>>> router bgp as number
>>>> nei x.x.x.x maximum-prefixes and the rest....
>>>>
>>>> I think the command is
>>>>
>>>>
>>>> Otis
>>>>
>>>> Kristian Kielhofner wrote:
>>>>
>>>>         
>>>>> Hello everyone,
>>>>>
>>>>>   I'm back with another stupid "BGP on a 3750" question.  I need
>>>>> "customer only routes" to the few providers that I have.  From
>>>>>           
> what
>   
>>> I
>>>
>>>       
>>>>> can tell, I'd end up with far less than the 8,000 max routes this
>>>>> platform can handle.  I have two options when configuring this:
>>>>>
>>>>> a)  When bringing up the BGP session, I can request aggregated
>>>>> customer-only routes (what I want).
>>>>>
>>>>> or...
>>>>>
>>>>> b)  I can request a full table and filter them myself with route-
>>>>>           
>> map
>>     
>>>>> statements (I think).
>>>>>
>>>>>   With "a" I will have a much simpler configuration (not that it
>>>>> matters much).  Will the 3750 have problems even receiving these
>>>>> routes, even if I am filtering them?  I can imagine all sorts of
>>>>> potential nastiness with that configuration.
>>>>>
>>>>>   If not, I'd much rather go with option "b".  I would have more
>>>>> control over my routing and it would be easier to upgrade to a
>>>>>           
> more
>   
>>>>> capable router in the future (less co-ordination with ISPs, just
>>>>> remove route-map statements).  I like this idea more.  Can the
>>>>>           
> 3750
>   
>>>> do
>>>>
>>>>         
>>>>> it?  What would happen?
>>>>>
>>>>> Thanks!
>>>>>
>>>>>
>>>>>
>>>>>           
>>>> _______________________________________________
>>>> cisco-nsp mailing list  cisco-nsp at puck.nether.net
>>>> https://puck.nether.net/mailman/listinfo/cisco-nsp
>>>> archive at http://puck.nether.net/pipermail/cisco-nsp/
>>>>
>>>>         
>
>

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