RE: Best practice for redundancy when there're more than 2x ISP

John

Sure, no ISP uses the same community scheme , but based on their
communities, I can tell if a route from an ISP is regional or intl
(from their pespective). One route can be marked as regional by one
ISP but as international by other ISP.

FYI , we have our own community scheme, and the communities advertised
from all ISPs are replaced with ours (including regional or intl) by
our border routers.

Communities are just marking! What you do with communities is what
that matters! The question again comes back to what BGP attributes to
use (ie to change) to influence the BGP selection: Local Pref, AS
Prepend, Origin, MED or what?

For simplicity sake, just consider all routes from both ISP are international!

On Saturday, September 25, 2010, Edward John
<edwardjohn2020_at_googlemail.com> wrote:
> Both ISP's will not maintain same community to represent regional/international routes. (i have never seen such like!) And its matter of your decision then, how to route your outbound traffic based on the cable path, distance, through each of your ISPs.
>
>
> On Sat, Sep 25, 2010 at 12:35 AM, Tech Guy <autechguy_at_gmail.com> wrote:
>
> John,
>
> Both ISPs are Tier1, and send us Regional as well as International
> prefixes. We obviously prefer a regional route from one ISP than the
> same route but marked with an International community from other ISP
> and vice vesa. This can be done with local preference. What do you do
> with a route that is marked the same (regional or intl) from both ISP?
>
> For simplicity sake, let consider all routes as international (which
> account for 80-90% of internet in our case). How you can load share
> outgoing traffic, yet, meet original design requirements.
>
> On Friday, September 24, 2010, Edward John
> <edwardjohn2020_at_googlemail.com> wrote:
>> Well, This is moreover depends on how your peering and how ir your ISP's tier level. In your case, I would suggest to import communities from your ISPs, choose regional base routes and give preference accordingly..
>> I assume your ISPs support communities..
>> Regards,John
>>
>>
>
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> Regards,John
>
>
>

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