From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Sun Apr 23 2006 - 21:42:57 GMT-3
You can use BGP conditional advertisement on R1 to accomplish
this.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Victor Cappuccio
> Sent: Sunday, April 23, 2006 6:11 PM
> To: CCIE LAB
> Subject: How to override the BGP Decision Process if possible?
>
> Hello All
>
> R1 in an AS 300 that is a dual homed system, lets say
>
> Router 1 in Remote-as 300
> Router 1 neighbor R2 in remote-as 200
> Router 1 neighbor R3 in remote-as 200
>
> Now the link between R1 and R3 is very slow, but the administrator of
AS
> 200 had set a Local Pref to 400 in R3 and 200 in R2.. Just for
example. -
> Not real world situation. - but it could happen ;)
>
> Is there any way I could override this situation??
>
> Rack1R2#show ip bgp 88.88.88.0
> BGP routing table entry for 88.88.88.0/24, version 43
> Paths: (2 available, best #1, table Default-IP-Routing-Table)
> Flag: 0x820
> Advertised to update-groups:
> 1
> 300 300 301, (Received from a RR-client)
> 164.1.23.3 from 164.1.23.3 (10.3.3.3)
> Origin IGP, metric 100, localpref 400, valid, internal, best
> 300
> 164.1.12.1 from 164.1.12.1 (10.1.1.1)
> Origin IGP, metric 200, localpref 100, valid, external
>
> Ok the BGP decision process goes like this Next Hop Reachable? ->
Weight
> -> Local Pref -> AS-PATH -> MED -> External (EBGP) is better than
> confederation external, which is better than IBGP
>
> But … lets look it this way, I’m the customer of As 200
and
> the administrators are very busy. is there any way to deal with this
> issue ? (beside shutting down my neighbor relation to R3) Also for
other
> good reasons the internal network of AS 200 (which I do not concern)
is
> using more Links to get to my AS 300
>
> Thanks
> Victor.-
>
>
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