[f-nsp] BGP question on same AS for two locations

["Rolf Hanßen"]

Hello Qinxue,

actually you can do that (we have such a setup running for nearly 10 yeras
now).
You need to take care of 2 things:
- the upstream sessions must have allowas-in configured
- your upstream provider that connects your locations needs to send you
routes with your AS in path. In our case he stopped doing that after
moving from Cisco to Juniper one day (told us it is a different default
behaviour) which resulted in an outage.

regards
Rolf

> Hi all,
>
> I have a question: Can we use the same AS number for two different
> locations but not IGP routable? The goal is for DR purpose so that the
> two sites can communicate.
>
> The situation can happen when the internal connections between two sites
> lose at the same time.
>
> Site A: prefix 10.1.1.0/24 advertised to providers with AS number 11111
> Site B: prefix 10.1.2.0/24 advertised to peroviders with AS number 11111
>
> No internal connections between A & B (so no IGP between A&B), we want
> communication between 10.1.1.0/24 and 10.1.2.0/24.
>
>
> Thanks
>
> -Qinxue