[c-nsp] Filtering BGP routes with route-map vs. not getting them in the first place

[Pete S.]

I'd say go with a mix of the two.   Request nay, demand aggregated
with a prefix-list, but also block all but the customers block, just
in case the customer started announcing something else.

Set a pre-determined minimum mask with them, if they even require it.
This gives you the safety of knowing you'll never get any unwanted
nets announced from them, and what they announce will be aggregated.
It also gives them the flexibility of load balancing across separate
blocks for inbound.

In most cases when I was receiving a full table from an ISP, they
still had filters which denied us announcing anything other then our
ip blocks, and had a pre-determined prefix minimum mask we
requested(for load balancing).

--Pete

On 7/6/07, Kristian Kielhofner <kris at krisk.org> wrote:
> Hello everyone,
>
>   I'm back with another stupid "BGP on a 3750" question.  I need
> "customer only routes" to the few providers that I have.  From what I
> can tell, I'd end up with far less than the 8,000 max routes this
> platform can handle.  I have two options when configuring this:
>
> a)  When bringing up the BGP session, I can request aggregated
> customer-only routes (what I want).
>
> or...
>
> b)  I can request a full table and filter them myself with route-map
> statements (I think).
>
>   With "a" I will have a much simpler configuration (not that it
> matters much).  Will the 3750 have problems even receiving these
> routes, even if I am filtering them?  I can imagine all sorts of
> potential nastiness with that configuration.
>
>   If not, I'd much rather go with option "b".  I would have more
> control over my routing and it would be easier to upgrade to a more
> capable router in the future (less co-ordination with ISPs, just
> remove route-map statements).  I like this idea more.  Can the 3750 do
> it?  What would happen?
>
> Thanks!
>
> --
> Kristian Kielhofner
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