CCDE: Cisco Certified Design Expert (Practical) — Question 167

In a redundant hub and spoke "wheel" design, all spokes are connected to the hub, and spokes are connected to other spokes as well. During failure on one spoke link, the traffic from that site can be sent to a neighboring site for it to be forwarded to the hub site. But during peak hours, a link is overloaded and traffic is re-routed to a neighbor, which subsequently becomes overloaded. This overload results in network traffic oscillation as the load varies at each spoke site. This design provides more redundancy but not more resiliency because the routing protocol must process many alternate paths to determine the lowest cost path. Which two design changes help to improve resilience in this case? (Choose two.)

Answer options

• A. Increase the number of redundant paths considered during the routing convergence calculation.
• B. Eliminate links between every spoke.
• C. Increase routing protocol convergence timers.
• D. Increase unequal-cost parallel paths.
• E. Use two links to each remote site instead of one.

Correct answer: B, E

Explanation

Option B, eliminating links between every spoke, reduces inter-spoke dependencies that can lead to oscillation during overload conditions. Option E, using two links to each remote site instead of one, increases the available bandwidth and provides additional paths for traffic, enhancing resilience. The other options either complicate the routing process or don't directly address the issue of traffic oscillation and resilience.