We're migrating two traditional datacenter networks to greenfield VXLAN/EVPN fabrics. The migration will take 6 to 12 months so we're trying design the network so that both the brownfield and greenfield networks are interconnected and coexisting for this period of time while we work through the migration. The brownfield (traditional network) datacenter A has BGP ASN 65000 same as Datacenter B, they both use ASN 65000. The new EVPN/VLAN fabrics have BGP ASN 65010 in Datacenter A and BGP ASN 65020 in Datacenter B. We're at the beginning stages of the design. Is having the same ASN in the brownfield environment for both DC A and B be an issue ? if so, what issues? and what are some ways to solve them? Please see the drawing below for a representation of the network.
Thank you for any feedback or input that you can provide on this.
