From: ccna instructor (ccna20877@yahoo.com)
Date: Mon Oct 14 2002 - 23:08:02 GMT-3
AS2 AS3
\ /
AS1
AS2 and AS3 are transit to internet. I want to route 40% traffic to AS2 and
60% traffic to AS3. I have been thinking of how to do it but i am not able
to find a answer , Help wanted.. thanks in advance.
sadiq
Brian McGahan <brian@cyscoexpert.com> wrote:Yes, this is normal behavior. The reason is because you only
advertise your best routes in BGP.
R1
|
R2---R3
R1 is advertising the prefix via EBGP to R2 and R3. If R3
changes the default local preference, this is sent to R2. R2 now
chooses the route through R3, due to local preference. Since the route
on R2 through R1 is not a best route, it will not advertise it to R3.
This doesn't have anything to do with the attribute you're using, this
is the default behavior of BGP.
HTH
Brian McGahan, CCIE #8593
Director of Design and Implementation
brian@cyscoexpert.com
CyscoExpert Corporation
Internetwork Consulting & Training
http://www.cyscoexpert.com
Voice: 847.674.3392
Fax: 847.674.2625
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Svuillaume8@aol.com
> Sent: Wednesday, October 02, 2002 12:23 PM
> To: ccielab@groupstudy.com
> Subject: BGP local pref help
>
> Hi,
>
> If i've two routers with an IBGP session.
> Each router has an Ebgp session to the same AS which announce a
network
> 10.0.0.0.
>
> -----
> |AS 1 |
> _____
> | |
> ________|________|_____
> |AS 2..............AS2 |
> |______________________|
>
> When i let the default parameter my two router have two
> bgp route in thier bgp table.
> In the right router, one to the left router and an other to AS1,
however
> the best route is EBGP
>
> *>10.0.0.0 to AS1
> * 10.0.0.0 to AS2 (left router)
>
> the bgp table is symetric in the left router.
>
> Problem is when i change default local pref in the right
> router, then my right router hasn't two route but only
> one, to AS1, but i have two routes in the left router
> one to AS1 and an other to AS2 (ibgp)????
>
> Is it normal or not?????
>
> Is the same symptom with MED????
---------------------------------
Do you Yahoo!?
Faith Hill - Exclusive Performances, Videos, & more
faith.yahoo.com
This archive was generated by hypermail 2.1.4 : Tue Nov 05 2002 - 08:35:47 GMT-3