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

Bootstrap Router is the standards-based mechanism for dynamic Rendezvous Point discovery in PIM Sparse Mode. Cisco supports several RP discovery methods, but they are not equivalent from a standards perspective. Auto-RP is Cisco-developed and widely used in Cisco environments, but it is not the standards-based choice. Static RP configuration is simple and deterministic, but it does not provide dynamic discovery and requires every router to be configured consistently. Anycast RP is a redundancy and load-sharing design in which multiple RPs share the same RP address, usually with MSDP or another synchronization method, but it is not the RP discovery mechanism itself. BSR allows candidate RPs and candidate BSRs to advertise RP-set information through the PIM domain so routers can learn RP mappings dynamically. This makes BSR suitable for large PIM domains where manual static RP configuration becomes operationally risky. In design, the architect should also protect BSR/RP placement, scope group ranges, and validate convergence behavior during RP or BSR failure. Reference topics: PIM-SM, Bootstrap Router, RP discovery, Auto-RP comparison, multicast control-plane design.

Bidirectional PIM is the correct multicast protocol for this many-to-many financial application. The question states that most multicast sources also receive multicast traffic and that the design must not use source trees. Cisco describes BIDIR-PIM as a multicast mode built for many-to-many applications that use a shared tree rooted at the rendezvous point and avoid per-source shortest-path trees. This reduces multicast state because routers do not maintain separate source/group state for every active sender. PIM Sparse Mode can start with a shared tree, but it can switch to source trees, which violates the stated requirement. PIM-SSM is explicitly source-specific and requires receiver knowledge of the source, so it is not appropriate for a many-to-many model where source trees are disallowed. MSDP is not a multicast forwarding mode; it is used for source discovery between PIM-SM domains. The option text contains a spelling error, but the intended answer is BIDIR-PIM. The architect should verify RP placement, Designated Forwarder behavior, group ranges, and whether the application can tolerate shared-tree forwarding rather than shortest-path source trees. Reference topics: BIDIR-PIM, many-to-many multicast, shared tree, source-tree avoidance, multicast scaling.

Redistributing OSPF process 1 into process 2 on both R1 and R4 provides the required backup routing behavior between the management network and the target routers. The design requirements are failure driven: if R1 fails, NMS traffic must use R4, and if the link between R5 and R6 fails, traffic to 10.6.6.6 must still route through R4. When separate OSPF processes or domains exist, controlled redistribution at both exit points allows reachability to be maintained through either redistribution point. Advertising a single address into OSPF with high cost on R1 does not solve both failure cases. Static routes with IP SLA on R2 and R3 would be more manual and less aligned with the dynamic OSPF design. Default-information originate would provide a default path but would not accurately advertise the specific internal reachability required for the NMS destinations. The redistribution design must also include route filtering or tagging in production to prevent feedback loops. Reference topics: OSPF redistribution, redundant redistribution points, management reachability, route control, failure-path design.

Dual stack is the correct IPv4 and IPv6 deployment strategy when the customer wants a straightforward design with no information hiding and no tunnel forwarding overhead. In a dual-stack deployment, routers, switches, servers, and clients run IPv4 and IPv6 simultaneously. Applications can select IPv4 or IPv6, typically based on DNS response and protocol availability, while the network forwards each protocol natively. This avoids the translation behavior of NAT64, where address information is hidden or converted between protocols. It also avoids GRE or other tunneling mechanisms, which add encapsulation overhead and operational complexity. LISP can provide location/identity separation and mobility, but it is not the simplest migration approach for native IPv4 and IPv6 coexistence. Dual stack is often the cleanest transition model when the infrastructure supports both protocols, because it permits gradual application migration without forcing all services through translators or tunnels. Reference topics: IPv6 migration, dual-stack deployment, NAT64, tunneling overhead, native IPv4 and IPv6 forwarding.

When multicast is included in a Cisco SD-Access architecture, the architect must account for multicast transport in the overlay for endpoint traffic. Cisco SD-Access separates the underlay, which provides IP connectivity between fabric nodes, from the overlay, which carries user endpoint traffic in the endpoint identifier space. For wired and wireless clients, multicast traffic is transported as part of the overlay service rather than treating clients as underlay participants. That is why the correct design element is that multicast traffic is transported in the overlay and EID space for both wired and wireless clients. PIM SSM does not have to run in the underlay for this purpose, and multicast clients do not simply reside in the underlay. The statement about RPs being required in an SSM deployment is also wrong because source-specific multicast is specifically designed to avoid the traditional RP model. In a fabric design, multicast requirements affect border behavior, receiver placement, replication mode, wireless integration, and policy boundaries. Reference topics: Cisco SD-Access multicast, overlay forwarding, EID space, wired and wireless fabric clients.

VRRPv3 improves protocol applicability by supporting both IPv4 and IPv6 address families. VRRPv2 is associated with IPv4 virtual router redundancy, while VRRPv3 extends the protocol so the same first-hop redundancy concept can be used for IPv6 default gateways as well. In campus and branch designs, this matters because IPv6 deployments should not require a separate redundancy design from IPv4 when a standards-based FHRP is preferred. Preemption is not a unique VRRPv3 advantage because VRRP has long supported priority-based master election and preemption behavior. Authentication is also not the correct differentiator in this comparison; VRRPv3 removed the simple protocol authentication field from the base protocol and expects security to be provided by the underlying network or IPsec where required. Stateful switchover is a platform high-availability capability, not a VRRPv3 protocol feature. Therefore, the key benefit of VRRPv3 over VRRPv2 for enterprise design is IPv4 and IPv6 support under the same redundancy protocol model.

The correct routing design is OSPF with multiple areas. The company is moving away from RIP because the network has grown and now requires segmentation, summarization, fast convergence, and scalability. Cisco positions OSPF as a link-state IGP suitable for larger enterprise networks, and OSPF areas are the standard mechanism for containing topology information and scaling the link-state database. Area Border Routers can summarize routes between areas, reducing routing table size and limiting the scope of link-state flooding and SPF recalculation. This directly satisfies the requirement to segregate departments while summarizing between segments. EIGRP can converge quickly and summarize, but “stub areas” are not an EIGRP construct; EIGRP uses stub routers. OSPF virtual links are not a primary segmentation design tool; they are used to repair backbone connectivity issues. Modifying EIGRP K values changes metric calculation but does not solve segmentation or summarization. Reference topics: OSPF multi-area design, ABR summarization, SPF scope control, enterprise IGP scalability.

NETCONF supports XML, while RESTCONF supports both XML and JSON. Cisco programmability documentation describes NETCONF as an XML-based protocol that exchanges RPC requests and replies such as get, get-config, and edit-config using XML encoding. NETCONF is tightly aligned with YANG-modeled data, but the protocol message format itself is XML. RESTCONF exposes YANG-modeled data through an HTTP or HTTPS API and can represent payloads in XML or JSON. Cisco DevNet material commonly summarizes the comparison as NETCONF equals XML, while RESTCONF equals XML or JSON. That is why option D is accurate. Option A is wrong because NETCONF does not use JSON in the same way RESTCONF does. Option B is incomplete because RESTCONF is not limited to JSON. Option C reverses the protocol encodings. This distinction matters in automation design because tool selection, content type, parsing, and API workflows differ by protocol. Reference topics: NETCONF, RESTCONF, YANG, XML encoding, JSON encoding, model-driven programmability.

The drag-and-drop answer follows the practical distinction between the YANG model families. IETF models are standards-based models intended to provide a common structure for widely implemented protocol and interface functions. OpenConfig models are vendor-neutral operational and configuration models developed for cross-vendor automation, with a strong focus on consistent telemetry and network state representation. Cisco native models expose Cisco platform-specific capabilities and usually provide the deepest coverage for IOS XE, IOS XR, or NX-OS features that are not fully represented in a common model. The selected mapping therefore assigns model elements according to origin, portability, and feature depth. In a production automation design, engineers should start with open models when interoperability and long-term portability matter, but they should choose Cisco native models when a required Cisco feature is not available or is incomplete in IETF or OpenConfig. The choice is not cosmetic; it affects payload structure, namespace, validation behavior, and operational consistency across device families. Reference topics: YANG model families, IETF YANG, OpenConfig, Cisco native YANG, model-driven configuration.

The company must prevent itself from advertising routes learned from one ISP to the other ISP. If it receives full Internet tables from both providers and then re-advertises those learned prefixes, it can unintentionally become a transit autonomous system. The proper BGP design is to apply outbound route policy so only the company’s own originated prefixes are advertised to the ISPs, while routes learned from ISP1 are never advertised to ISP2 and routes learned from ISP2 are never advertised to ISP1. A route map or equivalent prefix filtering policy applied outbound to the ISP neighbors achieves that goal. Local preference influences outbound path selection inside the company AS; it does not prevent transit advertisements. MED influences how a neighboring AS may enter the company network, but it does not stop the company from advertising third-party routes. Tagging incoming routes with no-export is not as deterministic as simply filtering what is advertised to each provider and may still allow undesirable routing behavior within the directly connected provider. Therefore, the design should include outbound route filtering with a route map.