Re: How does AS-override work?

Both are different for sure : remove-private-as and as-override

remove-private-as : as stated by NN

my view is diff on as-override .I beleive that even if receiving
neighbor and advertising neighbor AS are diff ,its doesnt affect the
as-override .As-override would still do the same job.
1) Strip-Off receiving neighbor AS (Previous AS in AS-Path list need to match)
2) Add own As number in AS-Path list in the place of last AS.
3) While Sending to another neighbor ,ADD OWN AS.

normally you would see R2 AS number two times in R3 BGP Table.

Rsharma

On 5/29/09, NN Kumar <nagendra.cisco_at_gmail.com> wrote:
> Hi,
>
> "remove-private-as" command will check for private AS in your AS-PATH and
> remove all.
>
> "as-override" will check if the first AS number in AS-PATH is same as the
> neigbor's AS number to which you are advertising and if it matches, it will
> replace the AS number with its own As number.
>
> 1.1.1.1-------R1---------------R2-------------------R3
> AS100 AS200 AS100
>
> In the above case, you have AS100 partitioned by AS200 (may be ISP) with
> as-override. R2 while advertising 1.1.1.1 prefix to R3 will check if the
> first AS number in AS-PATH is 100. In this case, yes and it will be replaced
> by 200.
>
> HTH,
> Nagendra
>
>
> On 5/28/09, Joe Astorino <jastorino_at_ipexpert.com> wrote:
>>
>> Basically what it does is replace the AS in prefixes coming in with your
>> own
>> AS. I believe that is what you want to do here, although you could
>> accomplish the same thing with "remove-private-as"
>>
>>
>> Regards,
>>
>> Joe Astorino
>> CCIE #24347 (R&S)
>> Sr. Support Engineer - IPexpert, Inc.
>> URL: http://www.IPexpert.com
>>
>> -----Original Message-----
>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>> Jitendra Anbu
>> Sent: Friday, May 29, 2009 12:47 AM
>> To: ccielab_at_groupstudy.com
>> Subject: How does AS-override work?
>>
>> Hi GS,
>>
>> Can some explain how AS-override works? If I am trying to strip off a
>> private AS from an AP-Path will this command do the trick?
>>
>> ---------------------------------------------------------
>> Regards,
>>
>> Jit
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>>
>>
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG - www.avg.com
>> Version: 8.5.339 / Virus Database: 270.12.43/2139 - Release Date: 05/28/09
>> 08:10:00
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Fri May 29 2009 - 11:19:37 ART