Examples of techniques for upgrading a descriptor engine for a network interface card (NIC) are disclosed. An example method may include: quiescing a transmit stream to the NIC; stopping a descriptor engine from providing new receive descriptors to the NIC; creating a copy in a memory of any receive descriptors already available to the NIC prior to the stopping the descriptor engine; setting a controller to redirect inbound traffic to the memory; logging a current configuration, state, and receive pointers of the descriptor engine; updating the descriptor engine; restoring a transmit configuration and a transmit state of the descriptor engine; and enabling a transmit stream of a data router such that transmit packets are created by the descriptor engine for transmission by the NIC.