An administrator has a cluster that is RDMA-enabled, and has been tasked with configuring network segmentation with RDMA over Converged Ethernet. While attempting to make this configuration change, it is observed that the option is greyed out in Prism. Which condition needs to be resolved in order to proceed?

For RDMA over Converged Ethernet (RoCE) to function correctly and for its related configuration options to be available, Nutanix requires a homogeneous network environment across all nodes in the cluster. A key requirement is that all RDMA-capable NICs participating in the cluster must be configured to operate at the same speed. If there is a mix of 10Gb and 25Gb NIC speeds, this unsupported configuration will cause the network segmentation option for RDMA to be unavailable (greyed out) in Prism.

A. The cluster is already stated to be RDMA-enabled, which implies the necessary number of NICs is present. This is not the reason for the subsequent option being greyed out.
B. CVM memory is primarily related to storage performance and feature capacity, not a direct prerequisite for enabling RDMA network segmentation.
C. While mixed NIC cards (models) are not recommended, the most direct and common blocker for RDMA configuration is a mismatch in the negotiated link speed.

1. Nutanix AOS 6.5 Networking Guide, "RDMA over Converged Ethernet (RoCE)," Section: Prerequisites and Limitations. The documentation explicitly states that all nodes in the cluster must have NICs with the same link speed (e.g., all 25GbE or all 40GbE) for RDMA to be supported.

2. Nutanix KB Article 8691, "Prerequisites for enabling RDMA": This article lists hardware and software requirements, including the need for uniform NIC speeds across all nodes in the cluster for RDMA functionality.