announcing BGP prefixes from the same AS at different sites?

[Thomas Johnson]

Thank you for the feedback. I was aware of disabling aspath loop detection,
but have not yet explored it; based on my reading, it seemed like a hacky
workaround. Are there any drawbacks to this approach, aside from the
obvious possibility of creating loops?

With regard to an IBGP mesh, it seems that if a BGP session in my mesh
fails, routing of prefixes between the affected routers fails. Is this the
expected behavior? Is this where I should be using an IGP to route around
the failed IBGP?


Thanks!

On Mon, Sep 1, 2014 at 11:54 AM, Raphael Mazelier <raph at futomaki.net> wrote:

>
>
> Le 30/08/2014 01:36, Tom Daly a écrit :
>
>> Hi,
>> It sounds like you might want to try disabling aspath loop detection for
>> eBGP. Checkout the bird option called "allow local as [number]" as
>> documented at http://bird.network.cz/?get_doc&f=bird-6.html#ss6.2. This
>> will allow you to import prefixes with your own ASN in the aspath.
>>
>> However, one possible pitfall is that your upstream ISP's router might
>> try to be smart - and not send prefixes with your aspath in them too.
>> Older Foundry boxes do this and there is a per BGP peer knob you have to
>> turn.
>>
>> Overall, this should let you run everything over eBGP and run two simple
>> island networks.
>>
>> Cheers,
>> Tom
>>
>>
>>
> Unfortunately proper ISPs make their job good and does not advertise your
> own route. I have a Pop in the same configuration of yours.
> Two solution : IBGP in a GRE tunnel, it's uggly, but It works.
> Or static route :)
>
> --
> Raphael Mazelier
> AS39605
>
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