CCNP Enterprise 300-420 Updated Exam

The correct model set is the one that configures the IOS XE interface GigabitEthernet2/1/0 with IPv4 address 10.10.10.10 and prefix length 27 using valid XML according to the selected YANG schema. The directly connected host address 10.10.10.1/27 confirms the subnet relationship; both addresses belong to 10.10.10.0/27, so the interface configuration must use that prefix length rather than a host mask or an unrelated network. YANG-based configuration is strict: the namespace, container hierarchy, interface type, interface name, and address fields must match the device model. If an option places GigabitEthernet under the wrong container, represents the mask incorrectly, or uses a schema from a different model family, the device will reject the payload or configure the wrong object. Option D correctly represents the IOS XE XML structure and the required addressing. In real operations, the engineer should follow this with a get-config readback against the running datastore to prove that the structured configuration committed as intended. Reference topics: IOS XE interface YANG, XML payload structure, NETCONF configuration, IPv4 subnet validation.

The valid get-config reply must show OSPF process ID 400 with network 192.168.128.128/25 enabled for Area 0. A /25 prefix has a block size of 128 addresses, so 192.168.128.128/25 is a valid network boundary and covers addresses from 192.168.128.128 through 192.168.128.255. Any reply that shows the wrong OSPF process, an incorrect network boundary, the wrong prefix length or wildcard equivalent, or a nonzero area does not verify the requested model set. In Cisco IOS XE model-driven configuration, the readback has to match the schema path and values used by the model, not simply produce an approximate CLI interpretation. Option B is the reply that confirms the intended OSPF object. This verification method is important because YANG automation can fail silently in operational workflows when the payload is syntactically valid but targets the wrong container or key. A get-config verification step confirms the running datastore contains the exact OSPF process and area membership required by the design. Reference topics: YANG OSPF configuration, NETCONF get-config, prefix validation, IOS XE native models.

Advertising more-specific prefixes toward the preferred service provider is the correct way to influence inbound traffic to enter through a chosen CE interface. BGP inbound path control is indirect: the enterprise cannot set local preference inside remote autonomous systems, and MED is honored only under specific provider policies. The most deterministic option available to the customer is to advertise a longer-prefix route to the preferred provider because Internet and BGP route selection generally prefer the longest matching prefix before BGP path attributes are considered. If the aggregate is advertised to both providers but a more-specific route is advertised to the provider connected to gig0/0, return traffic for that more- specific destination is attracted through that interface. Lowering MED toward the less preferred provider is the opposite of the desired effect. AS-path prepending toward the preferred provider would make that path less attractive. Local preference affects outbound path selection inside the local AS, not inbound traffic from external networks. Reference topics: BGP inbound traffic engineering, longest-prefix match, route aggregation, AS-path prepending, MED, local preference.

The correct design is to advertise a default route from the aggregation layer toward the access layer and summarize the VLAN subnets at the aggregation layer toward the core. Cisco hierarchical campus design places summarization at aggregation or distribution boundaries because that is where access-layer routes are collected before entering the core. Summarizing the VLAN ranges into 10.0.0.0/16 hides individual access VLAN instability from the core, reducing routing table entries, protocol churn, and memory consumption on core devices. Sending a default route from aggregation to access also keeps access switches simple and prevents them from carrying unnecessary campus routing detail. This design contains failures and convergence events inside the appropriate block. Summarizing at the access layer is less practical when multiple VLANs aggregate at distribution. Advertising a default toward the core is backwards, because the core must know the summarized access block. Reference topics: hierarchical campus routing, aggregation-layer summarization, default routing to access, route-table reduction, convergence containment.