300-420 Exam Dumps : Designing Cisco Enterprise Networks (ENSLD) v1.1

An MPLS WAN from two separate ISPs is the strongest fit when the enterprise requires an active/backup WAN design with guaranteed SLAs for applications on either connection. MPLS VPN services are typically delivered with provider-backed service-level commitments for latency, jitter, packet loss, and availability, which is why they are selected for predictable enterprise application transport. Using two separate MPLS providers improves resiliency against a provider failure while preserving SLA-backed behavior on the backup path. A hybrid MPLS and Internet VPN model can be cost effective, but the Internet path generally does not provide the same deterministic SLA unless enhanced by a specific managed service contract. Internet from two providers improves reachability diversity but does not inherently guarantee application SLA. A single ISP hybrid design creates a provider dependency and weakens availability. Therefore, dual-provider MPLS is the conservative design for guaranteed active/backup WAN service. Reference topics: MPLS WAN design, service-level agreements, active/backup WAN, provider diversity, application performance assurance.

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.

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.