Correct Answer: A,B,C
Explanation/Reference:
Explanation:
Best Practices Summary for Hub-and-Spoke Deployment Model
This section describes the best practices for a dual DMVPN cloud topology with the hub-and- spoke deployment, supporting IP multicast (IPmc) traffic including routing protocols.
The following are general best practices:
Use IPsec in transport mode
Configure Triple DES (3DES) or AES for encryption of transported data (exports of encryption algorithms to certain countries may be prohibited by law).
Implement Dead Peer Detection (DPD) on the spokes to detect loss of communication between peers.
Deploy hardware-acceleration of IPsec to minimize router CPU overhead, to support traffic with low latency and jitter requirements, and for the highest performance for cost.
Keep IPsec packet fragmentation to a minimum on the customer network by setting MTU size or using Path MTU Discovery (PMTUD).
Use Digital Certificates/Public Key Infrastructure (PKI) for scalable tunnel authentication.
Configure a routing protocol (for example, EIGRP, BGP or OSPF) with route summarization for dynamic routing.
Set up QoS service policies as appropriate on headend and branch router interfaces to help alleviate interface congestion issues and to attempt to keep higher priority traffic from being dropped during times of congestion.
Reference: http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/DMVPDG/ DMVPN_1.html