Assume no Internet connection for the sake of this question, the scenario is basic - 5 offices connected by an MPLS WAN. The customer is handed a Fast Ethernet (100Mbps) circuit at each location. Each branch has 3 subnets / VLANs and wants automatic routing such that if branch x adds a new subnet, the other branches will automatically learn the subnet/route.

First Question:

Is BGP required on the customers networking devices? If so, why.

Second Question:

Assume the customer has deployed DMVPN with OSPF over that. Is BGP required on the customers networking devices? If so, why.

Thank you in advance.

  • Is the MPLS WAN L2 or L3? A lot would depend on what the provider is willing/able to do. – Ron Trunk Sep 16 '16 at 0:39
  • BGP would not be technically necessary, but again, if the MPLS provider requires it, you may be forced into it. I'm trying to imagine why you'd use DMVPN over the WAN. Encryption required? – Ron Trunk Sep 16 '16 at 0:47
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 11 '17 at 18:19

#1 BGP is required only if the provider offers no other dynamic routing protocol. In this case, your BGP peering is confined to your VRF within the providers cloud and can accept/pass private subnets to your remote sites.

#2 No.

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