Balancing WAN Resiliency and Cost with Dynamic Routing

The scenario requires balancing two specific constraints: increasing resiliency and minimizing costs. To determine the correct configuration, we must evaluate how each option addresses these goals within the context of WAN connectivity.

Option C (dynamic routing protocol) is the superior choice because it provides logical resiliency at a minimal cost. By implementing protocols like BGP or OSPF on the WAN link, the network gains the ability to automatically detect peer failures and converge to alternative paths without manual intervention. This enhances availability through intelligent path selection. Crucially, this is a software-based feature that does not require expensive hardware upgrades, directly satisfying the 'minimize costs' requirement.

In contrast, Options B (dual supervisors) and D (dual power supplies) focus on hardware redundancy. While they improve device-level uptime, they are significantly more expensive than enabling a routing protocol. Furthermore, hardware redundancy alone does not protect against WAN link failures or routing loops; if the physical circuit goes down, dual components inside the router cannot restore connectivity. Option A (SNMPv3) is a monitoring tool for security and visibility, not a mechanism for automatic failover or resiliency.

Community comments reflect this trade-off. One comment correctly identifies that dynamic routing allows automatic adaptation to path changes and avoids proprietary hardware costs. Another suggests dual power supplies as a low-cost hardware solution, but this ignores the broader scope of WAN resiliency which primarily depends on path diversity and routing logic rather than just internal component duplication.