Using multiple equal-cost links and an IGP maximizes utilization between the core and distribution layers in a Layer 3 campus design. When links are routed point-to-point links and have equal routing cost, the IGP can install equal-cost multipath routes in the forwarding table. Traffic can then be distributed across multiple uplinks, improving bandwidth utilization and resiliency without depending on spanning tree. HSRP provides first-hop gateway redundancy for end hosts, but it does not by itself load-share all core-to-distribution links.
Rapid PVST+ improves Layer 2 convergence but still blocks redundant Layer 2 paths in a looped topology, so it does not maximize link use. Multiple unequal-cost links are not the normal design for maximum use unless a routing protocol and platform specifically support unequal-cost load sharing, and even then it adds complexity. Cisco enterprise campus design generally prefers routed links between distribution and core for predictable convergence and ECMP. Therefore, the correct pair is multiple equal-cost links and an IGP.
Reference topics: routed campus design, ECMP, IGP path selection, core-distribution resiliency, Layer 3 campus.

In Cisco Catalyst SD-WAN, OMP (Overlay Management Protocol) by default enables a full mesh topology between all WAN Edge routers if no policy is defined, allowing direct communication among all sites.

The IaaS (Infrastructure as a Service) model provides customers with virtualized computing resources over the internet, allowing them direct autonomy and control over the underlying hardware (such as servers, storage, and networking).

Explanation:
Cisco SD-WAN components map to distinct control, management, orchestration, and forwarding roles.
vManage is the centralized management plane used for configuration templates, monitoring, software management, and operational visibility. vSmart is the centralized control-plane component that distributes OMP routes, TLOC information, security parameters, and centralized policy to WAN Edge devices. vBond is the orchestration component used during onboarding; it authenticates devices, helps them discover controllers, and assists with NAT traversal. The WAN Edge router, whether physical or virtual, forms the data plane at the branch, campus, or data center and forwards user traffic through secure overlay tunnels. Correctly identifying these roles is essential because SD-WAN scale and resiliency depend on separating management, control, orchestration, and forwarding responsibilities. A design that confuses vManage with vSmart or vBond will misplace policy, onboarding, and forwarding functions. Reference topics: Cisco SD-WAN architecture, vManage, vSmart, vBond, WAN Edge, OMP, overlay control plane.