Pass the Cisco CCNP Enterprise 300-420 Questions and answers with Dumpstech

Cisco SD-WAN WAN Edge devices can be brought into the overlay through automated zero-touch provisioning or through manual bootstrap configuration. Zero-touch provisioning allows a device to discover the SD-WAN controllers and receive the information needed to authenticate and join the overlay with minimal on-site work. This is a core operational benefit of Cisco SD-WAN because branch routers can be shipped to sites and onboarded without a specialist manually building the entire control-plane configuration locally. Manual configuration remains available when ZTP is not used, when the site has special connectivity constraints, or when the administrator needs to stage the router directly. DHCP options and DNS records can help devices learn controller information in some deployment models, but they are not the complete pair of bootstrap methods named for vEdge onboarding. vManage is the management system, not a bootstrap method by itself. Therefore, the correct methods are ZTP and manual configuration. The design should also validate certificates, organization name, system IP, site ID, and transport interface reachability during onboarding.

The requirement for end-to-end path verification identifies the Integrated Services model with RSVP. IntServ uses per-flow resource reservation, and RSVP signals the path between sender and receiver so devices along that path can admit or reject the requested service based on available resources. This makes IntServ appropriate when the design requires explicit end-to-end path validation and reservation for application flows. DiffServ works differently. In a DiffServ design, traffic is marked, normally with DSCP or CoS at the edge, and each hop applies a configured per-hop behavior. DiffServ is scalable and common in enterprise WAN and campus QoS designs, but it does not perform per-flow signaling or verify that every device in the path can reserve the requested resources. Marking traffic at the access layer is an important QoS design practice, but marking alone is not path verification. Therefore, when the customer explicitly requires end-to-end path verification for business-critical traffic, Cisco QoS architecture points to IntServ with RSVP rather than a pure DiffServ marking model.

The validated answer is Option D because this item depends on the exhibit containing configuration or model fragments. In Cisco programmability questions, the correct option is determined by whether the selected YANG or API payload accurately represents the intended configuration hierarchy, data types, and device-specific path. The answer must match the complete model structure, not merely contain the right-looking address, interface name, or protocol value. Option D should therefore be retained as the verified selection because it is the only option that aligns with the expected data model structure shown in the exhibit. For these items, the professional review must avoid inventing a replacement payload when the answer choices are embedded as images. The proper explanation is that YANG-based configuration validation requires the namespace, container path, list keys, and leaf values to match the model used by the target platform. Reference topics: YANG configuration validation, RESTCONF or NETCONF payload structure, model hierarchy, Cisco IOS XE programmability, exhibit-based option verification.

EIGRP with stub routing and variance is the best fit for Cisco-only DMVPN branches with unequal Internet link speeds and limited branch resources. EIGRP works well over DMVPN because it supports hub-and-spoke designs, unequal-cost load balancing, and simple branch optimization through stub routing. Stub branches limit query propagation and reduce CPU, memory, and bandwidth consumption on small routers. Variance allows EIGRP to use feasible unequal-cost paths, which is important when one Internet connection is 10 Mbps and the other is 100 Mbps. OSPF can run over DMVPN, but virtual links are not an appropriate branch design and OSPF is less efficient in this specific Cisco-only unequal-bandwidth scenario. IS-IS is not commonly selected for small DMVPN branch overlays. iBGP with route reflectors can scale, but it does not inherently use link utilization and unequal metric behavior as cleanly as EIGRP variance for this requirement. Reference topics: EIGRP over DMVPN, stub routing, variance, unequal-cost load balancing, branch resource optimization.

The correct answer is bidirectional PIM. Cisco describes bidirectional PIM as a multicast mode designed for many-to-many applications where traffic is forwarded only along a shared tree rooted at the rendezvous point. Unlike traditional PIM Sparse Mode, BIDIR-PIM does not build source-specific shortest-path trees for each active source. That design reduces multicast state in the network because routers maintain group state rather than separate source and group state for every sender. PIM Sparse Mode initially uses a shared tree through the RP, but it can switch to source trees after receivers and routers learn the active source. Dense mode floods and prunes and is not a shared-tree-only model. Source-specific multicast explicitly uses source-specific joins and does not use an RP-based shared tree. The wording “shared tree only” is the key distinction: BIDIR-PIM is built for scalable many-to-many multicast, accepts some non-shortest-path forwarding tradeoff, and avoids per-source state growth. Therefore, the stored answer must be corrected to bidirectional. Reference topics: BIDIR-PIM, shared trees, rendezvous points, many-to-many multicast scaling, PIM-SM source-tree behavior.

An out-of-band management network should be isolated from the production data network and protected with strict access control. Cisco SAFE design principles treat the management plane as a sensitive function because it provides administrative access to infrastructure devices. Isolation ensures that production outages, routing problems, or compromised user segments do not automatically remove the operator’s ability to manage routers, switches, firewalls, and controllers. Access control ensures that only authorized administrators and management systems can reach the management interfaces and protocols. The management network should not be treated as a backup data path, because that undermines separation and can expose management devices to production traffic risks. It should also not be used as a general-purpose data backup network. “Facilitate network integration” is too vague and can conflict with the isolation requirement. Therefore, the best practices are to enforce access control and ensure network isolation. In a mature design, this normally includes dedicated management interfaces or VRFs, jump hosts, AAA, logging, and tightly controlled management protocol access.

When congestion is sustained and QoS has already been optimized, the correct design response is to add capacity rather than continue tuning packet treatment. QoS manages contention by prioritizing, queuing, shaping, or dropping traffic, but it does not create additional bandwidth. If access-to-distribution uplinks are persistently oversubscribed, business applications will still suffer because the offered load exceeds the available link capacity. Implementing higher-speed uplink interfaces increases the physical bandwidth available for aggregate traffic. Bundling additional uplinks into EtherChannels also increases usable capacity and improves resiliency while presenting a single logical link to the switching and routing design. Random early detection and selective packet discard can improve queue behavior under congestion, but the question states that QoS is already optimized and no longer effective. Reconfiguring QoS to IntServ would add complexity and is not a realistic campus fix. Therefore, the architect should increase uplink capacity through faster links and EtherChannel where the hardware and cabling support it. Reference topics: campus oversubscription, EtherChannel, uplink capacity planning, QoS limitations, congestion remediation.

In a Cisco SD-Access fabric, DHCP relay design must account for the fact that endpoints can attach to different fabric edge nodes while using consistent anycast gateway behavior. DHCP Option 82 is important because it inserts relay-agent information that allows the DHCP infrastructure to identify where the DHCP request originated. This enables the correct address scope and policy context to be selected for the endpoint even when the gateway address is anycast across multiple fabric edges. Cisco SD-Access DHCP guidance emphasizes the use of relay information so centralized DHCP services can assign the correct address based on fabric location and endpoint context. DHCP relay is not simply enabled on border nodes, and subnets should not be stretched across fabric edges by placing DHCP servers on borders. DHCP servers do not require a special proprietary SD-Access extension in the sense described by the incorrect option; they use standard relay information such as Option 82. Therefore, the key design consideration is enabling DHCP Option 82 so the circuit information maps the request to the fabric node where it originated.

The drag-and-drop mapping is based on the standard Cisco Catalyst SD-WAN component roles. vManage, now Cisco Catalyst SD-WAN Manager, provides centralized management, configuration, monitoring, templates, and operational visibility. vSmart Controller provides the centralized control plane, distributes OMP routing information, and applies control policy to determine reachability and path selection. vBond Orchestrator supports initial authentication, orchestration, and NAT traversal so WAN Edge devices can join the overlay. WAN Edge routers provide the data plane at branches, campuses, data centers, and cloud edges; they forward user traffic, establish secure tunnels, and apply localized policies. Correctly separating these roles is critical in the design because management, control, orchestration, and forwarding scale independently. Misidentifying vBond as the data-plane element or vManage as the route controller would lead to an incorrect SD-WAN architecture. Reference topics: Cisco Catalyst SD-WAN components, vManage, vSmart, vBond, WAN Edge, OMP control plane. This role separation is also what lets large deployments scale without mixing troubleshooting, provisioning, and forwarding responsibilities on one system.

Cisco SD-WAN is the correct solution when the design must use internet circuits at each site while providing failover, load sharing, and QoS. Basic IPsec tunnels can encrypt traffic, but they do not by themselves provide a complete WAN architecture for path measurement, dynamic traffic steering, centralized policy, application-aware routing, or scalable operational control. Cisco SD-WAN builds secure overlay tunnels across available transports and continuously measures path characteristics such as loss, latency, and jitter. It can then steer applications according to SLA policy, use multiple circuits for active/active forwarding, and fail traffic over when a path degrades or fails. QoS can be applied consistently through templates and policy across the WAN Edge routers. GET VPN is best suited to private MPLS-style networks and does not address internet-circuit overlay orchestration in the same way. Traditional DMVPN is a valid dynamic VPN technology, but SD-WAN is the more complete resilient internet-WAN design for these requirements. Reference topics: Cisco SD-WAN, internet transport, application-aware routing, failover, load sharing, QoS.