vNIC MAC addresses can be assigned manually or by configuring a MAC address pool. It is possible to either use the burned-in MAC addresses or abstract MAC addresses from an identity pool with system-defined prefixes. Stateless computing is the salient feature of the Cisco UCS platform; it is therefore recommended to abstract vNIC MAC addresses for server profiles and hence server vNIC MAC addresses from MAC address identity pools instead of using burned-in NIC MAC addresses.

The main benefit of abstracting the MAC addresses from an identity pool is that in the event of physical server failure, the server profile can be easily associated with the replacement server and the new server will acquire all the identities associated with the old server including the vNIC MAC addresses. From the operating system perspective, there is no change at all.

It is recommended to create vNIC templates with required configurations and create individual vNICs from vNIC templates as per the requirement. Also, define MAC address pools and assign MAC addresses to individual vNICs using MAC address pools.

The following screenshot shows a vNIC template with the MAC address pool server configuration for providing vNIC MAC addresses to server profiles created using a vNIC template: