2V0-41.24 Question 120
Single answerAn organization has deployed an NSX-T Data Center environment and configured a Tier-0 Gateway in an Active/Active configuration. The administrators observe asymmetric routing issues when traffic flows between external networks and workloads distributed across multiple ESXi hosts. What could be the root cause of this issue, and how can it be resolved?
- A
The Tier-0 Gateway is not configured for Equal-Cost Multi-Pathing (ECMP).
- B
Stateful services such as NAT are configured on the Active/Active Tier-0 Gateway.
- C
There is a misconfiguration in the dynamic routing protocol (e.g., BGP or OSPF) between the Tier-0 Gateway and the physical routers.
- D
The Tier-0 Gateway should be reconfigured in Active/Standby mode to handle asymmetric routing.
Show answer and explanation
Correct answer: B
Explanation
Active/Active configurations for Tier-0 Gateways are designed for high availability and load distribution. However, they are not suitable for stateful services like NAT, which require traffic to be processed consistently by the same instance. When stateful services are enabled in an Active/Active configuration, asymmetric routing occurs because different instances may handle the incoming and outgoing traffic, leading to state inconsistency. To resolve this, stateful services should be avoided in Active/Active setups or the Tier-0 Gateway should be reconfigured to Active/Standby mode.
- A. Incorrect.
This is incorrect. While ECMP is used for load balancing in Active/Active configurations, its absence does not directly cause asymmetric routing issues. The problem lies elsewhere.
- B. Correct.
This is correct. Stateful services such as NAT require consistent state tracking, which cannot be achieved in an Active/Active Tier-0 Gateway configuration. This causes asymmetric routing issues when traffic is processed by different Tier-0 instances.
- C. Incorrect.
This is incorrect. While a routing protocol misconfiguration could cause network issues, it is unrelated to the asymmetric routing problem caused by stateful services in an Active/Active setup.
- D. Incorrect.
This is incorrect. Switching to an Active/Standby mode is a workaround rather than a solution. The root cause is the use of stateful services in an inappropriate configuration, which should be addressed first.