The requirements are
- Hundreds of sites.
- Each has a router and firewall and a switch stack.
- Layer 3 MPLS WAN with BGP to provider VRF.
BGP as an IGP?
Would you distribute a public ASN across all branch sites and use iBGP to route inter-branch packets? Route reflector(s); MED based routing?
Would you assign a private ASN per branch?
... or Don't Use BGP?
DMVPN (minus encryption?) to hide/abstract away the BGP, allowing use of IGP for all inter-site routing?
Anyone think eBGP or iBGP is preferable? I find DMVPN attractive because
- My routing is separated from their routing.
- We're able to use a faster converging Interior Gateway Protocol.
- We're not using Border Gateway Protocol as an IGP.
however lean towards iBGP because it fits the use case and adds no GRE overhead. What is the best way to route traffic given this topology?