Designing Cisco Enterprise Networks (ENSLD) — Question 243

A company wants to switch from static routing to a dynamic routing protocol to ease the administrative and operational overhead. The network topology is hub and spoke, and the branches use DMVPN back to the hub with two 10-Mbps internet connections. The branch routers are multivendor and have limited memory and CPU resources.

Which routing protocol and design solution meets the requirements?

Answer options

• A. eBGP with the hub routers set up as route reflectors
• B. EIGRP with branch routers as stub routers and variance enabled
• C. ISIS with the hub and spoke routers configured in two different areas
• D. OSPF with the hub in area 0 and branch routers in stub areas with ECMP

Correct answer: D

Explanation

The correct answer is D because OSPF is an efficient protocol for hub and spoke topologies, and configuring the hub in area 0 with branch routers in stub areas helps to minimize routing overhead while supporting ECMP for load balancing. Option A is incorrect as eBGP is more suited for inter-domain routing rather than within a single organization. Option B is not ideal since EIGRP requires more resources compared to OSPF, which could be an issue for the limited-capacity branch routers. Option C is not suitable as ISIS is complex and typically not used for such scenarios.