From: Mohamed Saeed (mohamed_saeed2@rayacorp.com)
Date: Mon Oct 30 2006 - 18:00:57 ART
Hi Brian,
Yes, the real AS 100 exists somewhere.
I have revised the situation based on your clue.
If SW1 does not use the "no-prepend" option, then it will advertise the
routes it receives from BB3 to other neighbors with the AS number 100
existing in the AS path. When such a route arrives at the real AS 100,
it will not be accepted. This will prevent the real AS 100 from having
alternative route to the BGP subnets learned originated in AS 54.
Am I right here or I am still missing something?
Kind Regards
Mohamed Saeed, CCNP - CCIP
-----Original Message-----
From: Brian McGahan [mailto:bmcgahan@internetworkexpert.com]
Sent: Monday, October 30, 2006 10:43 PM
To: Mohamed Saeed; ccielab@groupstudy.com
Subject: RE: IEWB - Ver3 - Lab 2 - Task 5.3 (Local-as)
Is the real AS 100 somewhere else in the topology? If so what happens
when it receives the routes passed through BB3 if the no-prepend option
was not configured?
Brian McGahan, CCIE #8593 (R&S/SP)
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Mohamed Saeed
> Sent: Monday, October 30, 2006 1:34 PM
> To: ccielab@groupstudy.com
> Subject: IEWB - Ver3 - Lab 2 - Task 5.3 (Local-as)
>
> Hi All,
>
>
>
> In this task, it was required to configure SW1 to appear to BB3 as if
it
> was in AS 100. The solution guide solved it as follow:
>
>
>
> On SW1:
>
>
>
> router bgp 400
>
> neighbor 204.12.1.254 local-as 100 no-prepend
>
>
>
> This way, BB3 will see the routes received from SW1 with AS path 100
> 400.
>
>
>
> The "no-prepend" option was used here to prevent SW1 from prepending
> this imaginary AS number (100) to the routes received from BB3. I do
> agree that this should be done.
>
>
>
> My question is that using the "no-prepend" option was not explicitly
> required in the task, will we lose points in a real lab exam for using
> it. What if we used the "replace-as" option also. It could be used to
> make BB3 sees the routes received from SW1 with AS path of 100.
>
>
>
> Regards
>
> Mohamed Saeed, CCNP - CCIP
>
>
This archive was generated by hypermail 2.1.4 : Wed Nov 01 2006 - 07:29:07 ART