Re: Duel ISP BGP question

Hi Fake,

Remember that BGP speakers only send the best routes to other BGP
speakers, including LG. As the result, the LG may not show all the
routes you advertise to the 2x ISPs - only the best routes it receives
from its peers.

If the LG shows the routes you advertise via ISP with AS2 in your
example, without AS path being prepended, then it is unusual
behaviour.

If LG only shows the routes you advertise via the other ISP (e.g.
AS3), which you do not prepend, and does not show any of the routes
you advertise via AS2, then you do not have any reason to worry about.
That could be completely a normal behaviour.

Cheers,

On Wed, Oct 6, 2010 at 1:56 AM, Fake Name <fname84_at_gmail.com> wrote:
> I have two ISP's and two routers running BGP between them peering to my AS.
>
> Both routers peer with ISP routers and have an IBGP relationship between
> them.
>
> I put the following config into one router asuming my as is 1
>
> route-map aspend permit 30
> set as-path prepend 1 1 1 1 1 1 1 1
>
> router bgp 1
> neighbor x.x.x.x.remote-as 2
> neighborx.x.x.x. route-map aspend out
>
> This should append the as 1 and make it less perfered for traffic to come
> into the link via the best path algorithm when making the decision which
> route to choose from other AS's. We did this configuration and an hour
> later on the internet we where unable to see our as prepends from any of the
> looking glasses. How long in the real world will this update take to
> propergate via the looking glasses?
>
>
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