[j-nsp] BGP question

[Stefan Fouant]

I think what Doug is getting at is that the loop checking that will
take place within the confederation will only compare subASes.  The
private AS that the partner is using will only be compared to your
global AS, not the SubASes which are confederation members... as long
as those two don't match you're in business...

As to the second part of Doug's comment, if you are still having
problems you can override the default behavior and allow for an AS to
repeat itself a certain number of times in a received NLRI by using
the 'as-loops n' statement where n represents the number of times the
AS is allowed to be present in the AS Path in such an NLRI.

A final suggestion is to have the partner remove the private-as on
advertisement of their NLRI.  This can be accomodated by having the
partner configure the 'remove-private' option on their neighbor
statement towards you.  One caveat to the 'remove-private' option is
that it only removes leading private AS numbers, so if there is a
private AS somewhere deeper in the AS Path list, this option won't be
of any use.

HTHs.

Stefan Fouant
Principal Network Engineer
NeuStar, Inc. - http://www.neustar.biz

On Sun, Jun 1, 2008 at 7:02 PM, Amos Rosenboim <amos at oasis-tech.net> wrote:
> Hello Doug,
>
> Thanks,
> I'm not sure I'm following you, would you mind elaborating?
>
> Regards
>
> Amos
>
> On May 30, 2008, at 2:27 AM, Doug Marschke wrote:
>
>> Depending on the implementation, these AS could be ignored confederation
>> loop checking is done on sub-as number only.
>>
>> If you still having an issue, you can override as loop detection with
>> the as-loops command.
>>
>> Doug Marschke
>> Principal Technologist
>> Strategic Networks Training
>> JNCIE-ER #3, JNCIE-M/T #41, JNCIS-FW, JNCI
>> www.ietraining.net
>> (415)902-5702
>>
>>
>> -----Original Message-----
>> From: juniper-nsp-bounces at puck.nether.net
>> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Amos Rosenboim
>> Sent: Thursday, May 29, 2008 9:56 AM
>> To: juniper-nsp
>> Subject: [j-nsp] BGP question
>>
>> Hello List,
>>
>> This is not Juniper specific, but I think it's an interesting case
>> anyway.
>> A global carrier is running an MPLS network to provide L3 and L2
>> vpns. Obviously this carrier doesn't have presence in every city and
>> every country so he forms partnerships with local carriers to extend
>> the his footprint.
>> This is done by establishing type B inter as NNI links.
>> The iBGP topology of this carrier is using confederations.
>>
>> The problem now is that one of the new partners is using a private
>> AS, which happens to match one of the BGP confederations used inside
>> the global carrier network.
>> This obviously creates a problem which I'm looking to overcome.
>>
>> Any ideas will be appreciated.
>>
>> Regards
>>
>> Amos
>>
>>
>>
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