300-420 Exam Dumps : Designing Cisco Enterprise Networks

Affinity is the Cisco SD-WAN feature used to minimize TLOC and control connections and reduce strain on vSmart controllers. Cisco documentation explains that establishing affinity between controllers and edge devices allows the operator to control overlay scaling by limiting which controllers an edge device can establish control connections with. In large deployments, unrestricted connections between every WAN Edge and every controller can create unnecessary state and operational load. Affinity lets the design distribute edge connections across controllers and data centers while still preserving redundancy through primary and backup controller relationships. Color identifies the transport type or behavior associated with a TLOC, but it does not reduce controller connection scale by itself. Control-direction and control-connections are not the feature names that provide the scaling function described in the question. A well-designed SD-WAN control plane uses affinity, controller groups, and redundancy planning to keep the overlay scalable and predictable. Reference topics: Cisco SD-WAN affinity, vSmart controller scale, TLOC connections, control-plane redundancy, overlay scaling.

Dual DMVPN with EIGRP routing is the correct solution because the requirements call for secure public-internet connectivity, redundant paths, automatic path selection, multicast support, and minimal remote-site configuration. DMVPN builds dynamic multipoint GRE tunnels protected by IPsec, allowing spoke sites to communicate securely through the public internet while supporting routing protocols and multicast over GRE. A dual DMVPN design provides redundancy through separate hubs, transports, or tunnel clouds, so a spoke can continue operating if one path fails. EIGRP can calculate alternate paths and react to metric changes, supporting automatic path selection based on failure and quality when engineered correctly. MPLS with BGP does not meet the public-internet and encryption requirements by itself. A full mesh of IPsec tunnels with OSPF or IS-IS would increase configuration complexity at every remote site and does not scale as well. DMVPN is specifically built to simplify deployment of secure, scalable, multipoint branch VPNs. Reference topics: DMVPN, IPsec, mGRE, EIGRP over DMVPN, WAN redundancy, multicast over GRE.

Graceful restart and nonstop forwarding designs depend on preserving forwarding continuity during a control-plane processor switchover. Cisco Stateful Switchover provides the mechanism for a standby route processor or supervisor to maintain synchronized state so it can assume control when the active processor fails. When SSO is combined with NSF or graceful restart capabilities in routing protocols, neighboring devices can continue forwarding traffic while the restarting device preserves or rebuilds control-plane adjacencies. Cisco Express Forwarding is required for fast data-plane forwarding, but CEF alone does not provide route processor state synchronization after processor failure. Virtual Switch System is a chassis or switching architecture that can provide high availability in certain campus designs, but it is not the required feature named by graceful restart recovery. Bidirectional Forwarding Detection is a failure-detection protocol used to detect path or neighbor failures quickly; it does not recover a failed processor. Therefore, the feature that must be incorporated for graceful restart recovery from processor failure is Stateful Switchover. In a resilient enterprise design, SSO, NSF, and protocol graceful restart are coordinated to reduce outage impact.