[c-nsp] HIDE AS BGP

David Freedman david.freedman at uk.clara.net
Mon Aug 10 09:24:20 EDT 2009


Well, not sure how your solution would work, the dual-as configuration
will not achieve this unless it is between ISP2 and ISP1 which is
unlikely to be the case.

ISP2 will not accept the customer's in updates directly from ISP1
without disabling "bgp enforce-first-as" which it is unlikely to want to do.



jack daniels wrote:
> Hi ,
> 
> Just to be more specific on the solution requirement -
> 
> Customer---ISP1---ISP2---Internet
> 
> 
> Internet should not see ISP1 AS number . I 'm looking for L3 solution.
> 
> Thanks and Regards
> J.daniels
> 
> 
> On 8/10/09, jack daniels <jckdaniels12 at gmail.com> wrote:
> 
> 
>> Hi,
>>
>> Customer---ISP1---ISP2---Internet
>>
>> using "local-as no-prepend replace-as" (Cisco commands)
>> configured for ISP1 BGP peering sessions with "Customer" and "ISP2"
>> would do the trick of hiding ISP1's AS#. ISP1 will pretend to look
>> like "Customer" to ISP2, and look like "ISP2" to "Customer".
>> Furthermore, you may use tunneling in ISP1 (e.g. deploy MPLS) and make
>> it look almost completely transparent to "Customer".
>>
>> The following conditions apply:
>>   If the AS_PATH includes both private and public AS numbers, BGP doesn't
>> remove the private AS numbers. This situation is considered a configuration
>> error.<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>>
>> Please advise how to go for this.
>> Regards
>> J.Daniels
>>
>>
>> On 8/10/09, David Freedman <david.freedman at uk.clara.net> wrote:
>>> If the ISP is in the middle , who is the upstream and what does the
>>> L2VPN do? can you provide a simple diagram?
>>>
>>> Dave.
>>>
>>> jack daniels wrote:
>>>> Hi All,
>>>>
>>>> We had a requirement in which customer wants that the ISP- AS should not
>>> be
>>>> visible when route are advertised to internet via a upstream(L2 VPN
>>>> solution).
>>>> Can we use BGP command no-prepend with Replace AS attribute to hide ISP
>>> AS
>>>> in internet. ------------
>>>>
>>>> Can we peer with customer using local AS which will be private AS.We
>>> will
>>>> use no prepend command along with Replace AS which will replace ISP AS
>>> with
>>>> the private AS which is used for Peering.While going out to any
>>>> international Peer we will remove private AS . On internet only customer
>>> AS
>>>> and Peer AS will be visible.
>>>>
>>>> Please advise is this solution will work . Also advise if any better
>>>> solution for this scenario.
>>>>
>>>>
>>>> Thanks and Regards
>>>> J.Daniels
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>>>>
>>>
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