We are connecting a couple dozen sites together with MPLS services from our provider. We plan to router through the provider network using BGP. We're thinking to use the same private BGP AS (e.g. 65001) at each of our sites by using the allowas-in command.
What's the down side of using the same BGP AS at all our sites? Is there a speed or scalability issue or anything?
Would there be a benefit of selecting a unique private BGP AS at each of our sites?