300-420 Question 224
Single answerA global enterprise network is designed with two data centers in different geographic locations, each hosting critical applications. The design includes redundant WAN links and Cisco routers configured with HSRP (Hot Standby Router Protocol) for failover. During a failover test, the primary HSRP router in one data center fails, but users report intermittent connectivity issues to the applications. What could be the most likely cause of this issue?
- A
The HSRP standby router did not take over as the active router due to misconfigured priority settings.
- B
The WAN links were not configured with sufficient bandwidth to handle failover traffic.
- C
The HSRP timers were set to their default values, causing a delayed failover.
- D
The routing protocols were not properly converging after the failover occurred.
Show answer and explanation
Correct answer: C
Explanation
HSRP failover depends on proper configuration of timers to ensure a seamless transition between the active and standby routers. Default HSRP timers can result in delayed failovers, leading to temporary connectivity issues during the transition phase. Adjusting the timers (e.g., lowering the hello and hold intervals) can help minimize downtime and provide a more seamless failover experience.
- A. Incorrect.
Incorrect: Misconfigured priority settings in HSRP would prevent the standby router from taking over as the active router, but this scenario describes intermittent connectivity issues, not a complete failure to failover.
- B. Incorrect.
Incorrect: Insufficient WAN bandwidth could cause performance issues during normal operation or failover but does not directly relate to intermittent connectivity during an HSRP failover.
- C. Correct.
Correct: Default HSRP timers (hello interval of 3 seconds and hold time of 10 seconds) can cause a delay in the failover process, leading to intermittent connectivity issues during the transition.
- D. Incorrect.
Incorrect: While routing protocol convergence is important, it would typically cause a more widespread and prolonged connectivity issue rather than intermittent access to applications.